android - How to send and receive local broadcast

MainActivity.java

package com.cfsuman.androidtutorials;

import android.content.BroadcastReceiver;
import android.content.Context;
import android.content.Intent;
import android.content.IntentFilter;
import android.os.Bundle;
import android.app.Activity;
import android.widget.Button;
import android.widget.TextView;
import android.widget.Toast;
import androidx.localbroadcastmanager.content.LocalBroadcastManager;
import java.util.Random;


public class MainActivity extends Activity {
    private Context mContext;

    // Initialize a new BroadcastReceiver instance
    private BroadcastReceiver mRandomNumberReceiver
            = new BroadcastReceiver() {
        @Override
        public void onReceive(Context context, Intent intent) {
            // Get the received random number
            int receivedNumber = intent.getIntExtra(
                    "RandomNumber",-1);

            // Display a notification that the broadcast received
            Toast.makeText(
                    context,
                    "Received : " + receivedNumber,
                    Toast.LENGTH_SHORT
            ).show();
        }
    };

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);

        // Get the context
        mContext = getApplicationContext();

        // Register the local broadcast
        LocalBroadcastManager.getInstance(mContext).registerReceiver(
                mRandomNumberReceiver,
                new IntentFilter("BROADCAST_RANDOM_NUMBER")
        );


        // Get the widgets reference from XML layout
        Button button = findViewById(R.id.button);
        TextView textView = findViewById(R.id.textView);


        // Set a click listener for Button widget
        button.setOnClickListener(view -> {
            // Generate a random number
            int randomNumber = new Random().nextInt(500);

            // Initialize a new intent instance
            Intent intent = new Intent("BROADCAST_RANDOM_NUMBER");
            // Put the random number to intent to broadcast it
            intent.putExtra("RandomNumber",randomNumber);

            // Send the broadcast
            LocalBroadcastManager.getInstance(mContext)
                    .sendBroadcast(intent);

            // Update the TextView with random number
            textView.setText("Random number generated : "
                    + randomNumber
                    + "\nApp also broadcast it."
            );
        });
    }
}

activity_main.xml

<?xml version="1.0" encoding="utf-8"?>
<androidx.constraintlayout.widget.ConstraintLayout
    xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:app="http://schemas.android.com/apk/res-auto"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    xmlns:tools="http://schemas.android.com/tools"
    android:background="#DCDCDC"
    android:padding="24dp">

    <Button
        android:id="@+id/button"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:text="Send Local Broadcast"
        app:layout_constraintStart_toStartOf="parent"
        app:layout_constraintTop_toTopOf="parent" />

    <TextView
        android:id="@+id/textView"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:fontFamily="sans-serif"
        android:textStyle="italic"
        android:textSize="24sp"
        app:layout_constraintBottom_toBottomOf="parent"
        app:layout_constraintEnd_toEndOf="parent"
        app:layout_constraintStart_toStartOf="parent"
        app:layout_constraintTop_toBottomOf="@+id/button"
        tools:text="TextView" />

</androidx.constraintlayout.widget.ConstraintLayout>

android - How to rotate a Bitmap on Canvas center

MainActivity.java

package com.cfsuman.androidtutorials;

import android.content.res.Resources;
import android.graphics.Bitmap;
import android.graphics.BitmapFactory;
import android.graphics.Canvas;
import android.graphics.Color;
import android.graphics.Matrix;
import android.graphics.Paint;
import android.os.Bundle;
import android.app.Activity;
import android.widget.Button;
import android.widget.ImageView;


public class MainActivity extends Activity {
    private Resources mResources;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);

        // Get the Resources
        mResources = getResources();

        // Get the widgets reference from XML layout
        Button button = findViewById(R.id.button);
        ImageView imageView = findViewById(R.id.imageView);


        // Set a click listener for Button widget
        button.setOnClickListener(view -> {
            // Get the source bitmap to draw on canvas
            Bitmap srcBitmap = BitmapFactory.decodeResource(
                    mResources,
                    R.drawable.rose_small
            );

            // Initialize a new Bitmap
            Bitmap bitmap = Bitmap.createBitmap(
                    1400, // Width
                    1000, // Height
                    Bitmap.Config.ARGB_8888 // Config
            );

            // Initialize a new Canvas instance
            Canvas canvas = new Canvas(bitmap);

            // Draw a solid color on the canvas as background
            canvas.drawColor(Color.LTGRAY);

            // Initialize a new Paint instance to draw on canvas
            Paint paint = new Paint();
            paint.setAntiAlias(true);
            paint.setDither(true);
            paint.setFilterBitmap(true);

            // Initialize a new Matrix instance
            Matrix matrix = new Matrix();

            // Set rotation on matrix
            matrix.setRotate(
                    45, // degrees
                    (float) srcBitmap.getWidth() / 2, // px
                    (float)srcBitmap.getHeight() / 2 // py
            );

            // Draw the bitmap at the center position of the canvas
            // both vertically and horizontally
            matrix.postTranslate(
                    (float) canvas.getWidth() / 2
                            - (float) srcBitmap.getWidth() / 2, // dx
                    (float) canvas.getHeight() / 2
                            - (float) srcBitmap.getHeight() / 2 // dy
            );


            // Finally, draw the bitmap on canvas as a rotated bitmap
            canvas.drawBitmap(
                    srcBitmap, // Bitmap
                    matrix, // Matrix
                    paint // Paint
            );

            // Display the newly created bitmap on app interface
            imageView.setImageBitmap(bitmap);
        });
    }
}

activity_main.xml

<?xml version="1.0" encoding="utf-8"?>
<androidx.constraintlayout.widget.ConstraintLayout
    xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:app="http://schemas.android.com/apk/res-auto"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:background="#DCDCDC"
    android:padding="24dp">

    <Button
        android:id="@+id/button"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:text="Draw"
        app:layout_constraintStart_toStartOf="parent"
        app:layout_constraintTop_toTopOf="parent" />

    <ImageView
        android:id="@+id/imageView"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        app:layout_constraintBottom_toBottomOf="parent"
        app:layout_constraintEnd_toEndOf="parent"
        app:layout_constraintStart_toStartOf="parent"
        app:layout_constraintTop_toBottomOf="@+id/button" />

</androidx.constraintlayout.widget.ConstraintLayout>

android - How to rotate a Canvas

MainActivity.java

package com.cfsuman.androidtutorials;

import android.graphics.Bitmap;
import android.graphics.Canvas;
import android.graphics.Color;
import android.graphics.Paint;
import android.os.Bundle;
import android.app.Activity;
import android.widget.Button;
import android.widget.ImageView;


public class MainActivity extends Activity {
    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);

        // Get the widgets reference from XML layout
        Button button = findViewById(R.id.button);
        ImageView imageView = findViewById(R.id.imageView);


        // Set a click listener for Button widget
        button.setOnClickListener(view -> {
            // Initialize a new Bitmap
            Bitmap bitmap = Bitmap.createBitmap(
                    1200, // Width
                    600, // Height
                    Bitmap.Config.ARGB_8888 // Config
            );

            // Initialize a new Canvas instance
            Canvas canvas = new Canvas(bitmap);

            // Draw a solid color on the canvas as background
            canvas.drawColor(Color.LTGRAY);

            // Initialize a new Paint instance to draw on canvas
            Paint paint = new Paint();
            paint.setStyle(Paint.Style.FILL);
            paint.setColor(Color.parseColor("#676767"));
            paint.setAntiAlias(true);

            // Set an offset value in pixels to draw rectangle on canvas
            int offset = 200;

            // Save the canvas state
            canvas.saveLayer(
                    0, // left
                    0, // top
                    canvas.getWidth(),
                    canvas.getHeight(),
                    null // paint
            );

            // Rotate the canvas
            canvas.rotate(
                    25, // degrees
                    (float) canvas.getWidth() / 2, // px, center x
                    (float) canvas.getHeight() / 2 // py, center y
            );

            // Draw the rounded corners rectangle object on the canvas
            // The rectangle will be drawn as a 25 degrees rotated rectangle
            canvas.drawRect(
                    offset, // left
                    offset, // top
                    canvas.getWidth() - offset, // right
                    canvas.getHeight() - offset, // bottom
                    paint // Paint
            );

            // Finally, restore the canvas state
            canvas.restore();

            // Display the newly created bitmap on app interface
            imageView.setImageBitmap(bitmap);
        });
    }
}

activity_main.xml

<?xml version="1.0" encoding="utf-8"?>
<androidx.constraintlayout.widget.ConstraintLayout
    xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:app="http://schemas.android.com/apk/res-auto"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:background="#DCDCDC"
    android:padding="24dp">

    <Button
        android:id="@+id/button"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:text="Draw"
        app:layout_constraintStart_toStartOf="parent"
        app:layout_constraintTop_toTopOf="parent" />

    <ImageView
        android:id="@+id/imageView"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        app:layout_constraintBottom_toBottomOf="parent"
        app:layout_constraintEnd_toEndOf="parent"
        app:layout_constraintStart_toStartOf="parent"
        app:layout_constraintTop_toBottomOf="@+id/button" />

</androidx.constraintlayout.widget.ConstraintLayout>

android - How to draw Rounded Rectangle on Canvas

MainActivity.java

package com.cfsuman.androidtutorials;

import android.graphics.Bitmap;
import android.graphics.Canvas;
import android.graphics.Color;
import android.graphics.Paint;
import android.graphics.RectF;
import android.os.Bundle;
import android.app.Activity;
import android.widget.Button;
import android.widget.ImageView;


public class MainActivity extends Activity {
    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);

        // Get the widgets reference from XML layout
        Button button = findViewById(R.id.button);
        ImageView imageView = findViewById(R.id.imageView);


        // Set a click listener for Button widget
        button.setOnClickListener(view -> {
            // Initialize a new Bitmap
            Bitmap bitmap = Bitmap.createBitmap(
                    1200, // Width
                    600, // Height
                    Bitmap.Config.ARGB_8888 // Config
            );

            // Initialize a new Canvas instance
            Canvas canvas = new Canvas(bitmap);

            // Draw a solid color on the canvas as background
            canvas.drawColor(Color.LTGRAY);

            // Initialize a new Paint instance to
            // draw the rounded rectangle
            Paint paint = new Paint();
            paint.setStyle(Paint.Style.FILL);
            paint.setColor(Color.parseColor("#676767"));
            paint.setAntiAlias(true);

            // Set an offset value in pixels to draw
            // rounded rectangle on canvas
            int offset = 75;

            // Initialize a new RectF instance
            RectF rectF = new RectF(
                    offset, // left
                    offset, // top
                    canvas.getWidth() - offset, // right
                    canvas.getHeight() - offset // bottom
            );

            // Define the corners radius of rounded rectangle
            int cornersRadius = 50;

            // Finally, draw the rounded corners
            // rectangle object on the canvas
            canvas.drawRoundRect(
                    rectF, // rect
                    cornersRadius, // rx
                    cornersRadius, // ry
                    paint // Paint
            );

            // Display the newly created bitmap on app interface
            imageView.setImageBitmap(bitmap);
        });
    }
}

activity_main.xml

<?xml version="1.0" encoding="utf-8"?>
<androidx.constraintlayout.widget.ConstraintLayout
    xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:app="http://schemas.android.com/apk/res-auto"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:background="#DCDCDC"
    android:padding="24dp">

    <Button
        android:id="@+id/button"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:text="Draw Rounded Rectangle"
        app:layout_constraintStart_toStartOf="parent"
        app:layout_constraintTop_toTopOf="parent" />

    <ImageView
        android:id="@+id/imageView"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        app:layout_constraintBottom_toBottomOf="parent"
        app:layout_constraintEnd_toEndOf="parent"
        app:layout_constraintStart_toStartOf="parent"
        app:layout_constraintTop_toBottomOf="@+id/button" />

</androidx.constraintlayout.widget.ConstraintLayout>

android - How to draw a Bitmap on a Canvas

MainActivity.java

package com.cfsuman.androidtutorials;

import android.content.res.Resources;
import android.graphics.Bitmap;
import android.graphics.BitmapFactory;
import android.graphics.Canvas;
import android.graphics.Color;
import android.os.Bundle;
import android.app.Activity;
import android.widget.Button;
import android.widget.ImageView;


public class MainActivity extends Activity {
    private Resources mResources;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);

        // Get the Resources
        mResources = getResources();

        // Get the widgets reference from XML layout
        Button button = findViewById(R.id.button);
        ImageView imageView = findViewById(R.id.imageView);


        // Set a click listener for Button widget
        button.setOnClickListener(view -> {
            // Bitmap to draw on the canvas
            Bitmap bitmap = BitmapFactory.decodeResource(
                    mResources,
                    R.drawable.flower
            );

            // Define an offset value between canvas and bitmap
            int offset = 100;

            // Initialize a new Bitmap to hold the source bitmap
            Bitmap dstBitmap = Bitmap.createBitmap(
                    bitmap.getWidth() + offset * 2, // Width
                    bitmap.getHeight() + offset * 2, // Height
                    Bitmap.Config.ARGB_8888 // Config
            );

            // Initialize a new Canvas instance
            Canvas canvas = new Canvas(dstBitmap);

            // Draw a solid color on the canvas as background
            canvas.drawColor(Color.LTGRAY);

            //Finally, Draw the source bitmap on the canvas
            canvas.drawBitmap(
                    bitmap, // Bitmap
                    offset, // Left
                    offset, // Top
                    null // Paint
            );

            // Display the newly created bitmap on app interface
            imageView.setImageBitmap(dstBitmap);
        });
    }
}

activity_main.xml

<?xml version="1.0" encoding="utf-8"?>
<androidx.constraintlayout.widget.ConstraintLayout
    xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:app="http://schemas.android.com/apk/res-auto"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:background="#DCDCDC"
    android:padding="24dp">

    <Button
        android:id="@+id/button"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:text="Draw Bitmap"
        app:layout_constraintStart_toStartOf="parent"
        app:layout_constraintTop_toTopOf="parent" />

    <ImageView
        android:id="@+id/imageView"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        app:layout_constraintBottom_toBottomOf="parent"
        app:layout_constraintEnd_toEndOf="parent"
        app:layout_constraintStart_toStartOf="parent"
        app:layout_constraintTop_toBottomOf="@+id/button" />

</androidx.constraintlayout.widget.ConstraintLayout>

android - How to draw a Line on Canvas

MainActivity.java

package com.cfsuman.androidtutorials;

import android.graphics.Bitmap;
import android.graphics.Canvas;
import android.graphics.Color;
import android.graphics.Paint;
import android.os.Bundle;
import android.app.Activity;
import android.widget.Button;
import android.widget.ImageView;


public class MainActivity extends Activity {
    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);

        // Get the widgets reference from XML layout
        Button button = findViewById(R.id.button);
        ImageView imageView = findViewById(R.id.imageView);


        // Set a click listener for Button widget
        button.setOnClickListener(view -> {
            // Initialize a new Bitmap object
            Bitmap bitmap = Bitmap.createBitmap(
                    1200, // Width
                    600, // Height
                    Bitmap.Config.ARGB_8888 // Config
            );

            // Initialize a new Canvas instance
            Canvas canvas = new Canvas(bitmap);

            // Draw a solid color on the canvas as background
            canvas.drawColor(Color.LTGRAY);

            // Initialize a new Paint instance to draw the line
            Paint paint = new Paint();
            // Line color
            paint.setColor(Color.parseColor("#676767"));
            paint.setStyle(Paint.Style.STROKE);
            // Line width in pixels
            paint.setStrokeWidth(12);
            paint.setAntiAlias(true);

            // Set a pixels value to offset the line from canvas edge
            int offset = 50;

            // Draw a line on canvas at the center position
            canvas.drawLine(
                    offset, // startX
                    (float) canvas.getHeight() / 2, // startY
                    canvas.getWidth() - offset, // stopX
                    (float) canvas.getHeight() / 2, // stopY
                    paint // Paint
            );

            // Display the newly created bitmap on app interface
            imageView.setImageBitmap(bitmap);
        });
    }
}

activity_main.xml

<?xml version="1.0" encoding="utf-8"?>
<androidx.constraintlayout.widget.ConstraintLayout
    xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:app="http://schemas.android.com/apk/res-auto"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:background="#DCDCDC"
    android:padding="24dp">

    <Button
        android:id="@+id/button"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:text="Draw Line"
        app:layout_constraintStart_toStartOf="parent"
        app:layout_constraintTop_toTopOf="parent" />

    <ImageView
        android:id="@+id/imageView"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        app:layout_constraintBottom_toBottomOf="parent"
        app:layout_constraintEnd_toEndOf="parent"
        app:layout_constraintStart_toStartOf="parent"
        app:layout_constraintTop_toBottomOf="@+id/button" />

</androidx.constraintlayout.widget.ConstraintLayout>

android - How to draw a Rectangle on a Canvas

MainActivity.java

package com.cfsuman.androidtutorials;

import android.graphics.Bitmap;
import android.graphics.Canvas;
import android.graphics.Color;
import android.graphics.Paint;
import android.graphics.Rect;
import android.os.Bundle;
import android.app.Activity;
import android.widget.Button;
import android.widget.ImageView;


public class MainActivity extends Activity {
    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);

        // Get the widgets reference from XML layout
        Button button = findViewById(R.id.button);
        ImageView imageView = findViewById(R.id.imageView);


        // Set a click listener for Button widget
        button.setOnClickListener(view -> {
            // Initialize a new Bitmap object
            Bitmap bitmap = Bitmap.createBitmap(
                    1200, // Width
                    600, // Height
                    Bitmap.Config.ARGB_8888 // Config
            );

            // Initialize a new Canvas instance
            Canvas canvas = new Canvas(bitmap);

            // Draw a solid color to the canvas background
            canvas.drawColor(Color.LTGRAY);

            // Initialize a new Paint instance to draw the Rectangle
            Paint paint = new Paint();
            paint.setStyle(Paint.Style.FILL);
            paint.setColor(Color.parseColor("#676767"));
            paint.setAntiAlias(true);

            // Set a pixels value to padding around the rectangle
            int padding = 50;

            // Initialize a new Rect object
            Rect rectangle = new Rect(
                    padding, // Left
                    padding, // Top
                    canvas.getWidth() - padding, // Right
                    canvas.getHeight() - padding // Bottom
            );

            // Finally, draw the rectangle on the canvas
            canvas.drawRect(rectangle,paint);

            // Display the newly created bitmap on app interface
            imageView.setImageBitmap(bitmap);
        });
    }
}

activity_main.xml

<?xml version="1.0" encoding="utf-8"?>
<androidx.constraintlayout.widget.ConstraintLayout
    xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:app="http://schemas.android.com/apk/res-auto"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:background="#DCDCDC"
    android:padding="24dp">

    <Button
        android:id="@+id/button"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:text="Draw Rectangle"
        app:layout_constraintStart_toStartOf="parent"
        app:layout_constraintTop_toTopOf="parent" />

    <ImageView
        android:id="@+id/imageView"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        app:layout_constraintBottom_toBottomOf="parent"
        app:layout_constraintEnd_toEndOf="parent"
        app:layout_constraintStart_toStartOf="parent"
        app:layout_constraintTop_toBottomOf="@+id/button" />

</androidx.constraintlayout.widget.ConstraintLayout>

android - How to draw a circle on a Canvas

MainActivity.java

package com.cfsuman.androidtutorials;

import android.graphics.Bitmap;
import android.graphics.Canvas;
import android.graphics.Color;
import android.graphics.Paint;
import android.os.Bundle;
import android.app.Activity;
import android.view.View;
import android.widget.Button;
import android.widget.ImageView;


public class MainActivity extends Activity {
    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);

        // Get the widgets reference from XML layout
        Button button = findViewById(R.id.button);
        ImageView imageView = findViewById(R.id.imageView);


        // Set a click listener for Button widget
        button.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View view) {
                // Initialize a new Bitmap object
                Bitmap bitmap = Bitmap.createBitmap(
                        1200, // Width
                        600, // Height
                        Bitmap.Config.ARGB_8888 // Config
                );

                // Initialize a new Canvas instance
                Canvas canvas = new Canvas(bitmap);

                // Draw a solid color to the canvas background
                canvas.drawColor(Color.LTGRAY);

                // Initialize a new Paint instance to draw the Circle
                Paint paint = new Paint();
                paint.setStyle(Paint.Style.FILL);
                paint.setColor(Color.RED);
                paint.setAntiAlias(true);

                // Calculate the available radius of canvas
                int radius = Math.min(
                        canvas.getWidth(),canvas.getHeight()/2);

                // Set a pixels value to padding around the circle
                int padding = 5;

                // Finally, draw the circle on the canvas
                canvas.drawCircle(
                        (float)canvas.getWidth() / 2, // cx
                        (float)canvas.getHeight() / 2, // cy
                        radius - padding, // Radius
                        paint // Paint
                );

                // Display the newly created bitmap on app interface
                imageView.setImageBitmap(bitmap);
            }
        });
    }
}

activity_main.xml

<?xml version="1.0" encoding="utf-8"?>
<androidx.constraintlayout.widget.ConstraintLayout
    xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:app="http://schemas.android.com/apk/res-auto"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:background="#DCDCDC"
    android:padding="24dp">

    <Button
        android:id="@+id/button"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:text="Draw Circle"
        app:layout_constraintStart_toStartOf="parent"
        app:layout_constraintTop_toTopOf="parent" />

    <ImageView
        android:id="@+id/imageView"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        app:layout_constraintBottom_toBottomOf="parent"
        app:layout_constraintEnd_toEndOf="parent"
        app:layout_constraintStart_toStartOf="parent"
        app:layout_constraintTop_toBottomOf="@+id/button" />

</androidx.constraintlayout.widget.ConstraintLayout>

android - Draw border and shadow around a bitmap

activity_main.xml

<androidx.constraintlayout.widget.ConstraintLayout
    xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:app="http://schemas.android.com/apk/res-auto"
    xmlns:tools="http://schemas.android.com/tools"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:background="#FFF"
    android:padding="24dp"
    tools:context=".MainActivity">

    <Button
        android:id="@+id/button"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:text="Draw Border"
        app:layout_constraintStart_toStartOf="parent"
        app:layout_constraintTop_toTopOf="parent" />

    <ImageView
        android:id="@+id/iv"
        android:layout_width="0dp"
        android:layout_height="250dp"
        android:layout_marginTop="24dp"
        android:scaleType="fitCenter"
        app:layout_constraintEnd_toEndOf="parent"
        app:layout_constraintStart_toStartOf="parent"
        app:layout_constraintTop_toBottomOf="@+id/button" />

</androidx.constraintlayout.widget.ConstraintLayout>

MainActivity.java

package com.cfsuman.androidtutorials;

import android.content.Context;
import android.content.res.Resources;
import android.graphics.Bitmap;
import android.graphics.BitmapFactory;
import android.graphics.Canvas;
import android.graphics.Color;
import android.graphics.Paint;
import android.graphics.Rect;
import android.os.Bundle;
import android.app.Activity;
import android.widget.Button;
import android.widget.ImageView;


public class MainActivity extends Activity {
        private ImageView mImageView;
        private Context mContext;
        private Resources mResources;
        private Bitmap mBitmap;

        @Override
        protected void onCreate(Bundle savedInstanceState) {
                super.onCreate(savedInstanceState);
                setContentView(R.layout.activity_main);

                // Get the application context
                mContext = getApplicationContext();

                // Get the Resources
                mResources = getResources();

                // Get the widgets reference from XML layout
                Button btn = findViewById(R.id.button);
                mImageView = findViewById(R.id.iv);

                // Get the bitmap resource id
                final int bitmapResourceID =R.drawable.flower;

                // Set an image to ImageView
                mImageView.setImageBitmap(
                        BitmapFactory.decodeResource(
                                mResources, bitmapResourceID
                        )
                );

                btn.setOnClickListener(v -> {
                        // Get the bitmap from drawable resources
                        mBitmap = BitmapFactory.decodeResource(
                                mResources, bitmapResourceID
                        );

                        // Add a border around the bitmap
                        mBitmap = addBorderToBitmap(
                                mBitmap, 50,
                                Color.parseColor("#F0F8FF")
                        );

                        // Add a border around the bitmap as shadow
                        mBitmap = addBorderToBitmap(
                                mBitmap, 10,
                                Color.LTGRAY
                        );

                        // Set the ImageView image as drawable object
                        mImageView.setImageBitmap(mBitmap);
                });
        }


        // Custom method to add a border around bitmap
        protected Bitmap addBorderToBitmap(
                Bitmap srcBitmap, int borderWidth, int borderColor){

                // Initialize a new Bitmap to make it bordered bitmap
                Bitmap dstBitmap = Bitmap.createBitmap(
                        srcBitmap.getWidth() + borderWidth*2, // Width
                        srcBitmap.getHeight() + borderWidth*2, // Height
                        Bitmap.Config.ARGB_8888 // Config
                );

                // Initialize a new Canvas instance
                Canvas canvas = new Canvas(dstBitmap);

                // Initialize a new Paint instance to draw border
                Paint paint = new Paint();
                paint.setColor(borderColor);
                paint.setStyle(Paint.Style.STROKE);
                paint.setStrokeWidth(borderWidth);
                paint.setAntiAlias(true);

                Rect rect = new Rect(
                        borderWidth / 2,
                        borderWidth / 2,
                        canvas.getWidth() - borderWidth / 2,
                        canvas.getHeight() - borderWidth / 2
                );

                // Draw a rectangle as a border/shadow on canvas
                canvas.drawRect(rect,paint);

                // Draw source bitmap to canvas
                canvas.drawBitmap(
                        srcBitmap, borderWidth, borderWidth, null
                );

                srcBitmap.recycle();

                // Return the bordered bitmap
                return dstBitmap;
        }
}

android - How to create rounded corners ImageView

activity_main.xml

<?xml version="1.0" encoding="utf-8"?>
<androidx.constraintlayout.widget.ConstraintLayout
    xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:app="http://schemas.android.com/apk/res-auto"
    xmlns:tools="http://schemas.android.com/tools"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:padding="24dp"
    tools:context=".MainActivity"
    android:background="#F8F8FF">

    <Button
        android:id="@+id/btn"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:text="Rounded It"
        app:layout_constraintStart_toStartOf="parent"
        app:layout_constraintTop_toTopOf="parent" />

    <ImageView
        android:id="@+id/iv"
        android:layout_width="match_parent"
        android:layout_height="250dp"
        android:layout_marginTop="24dp"
        app:layout_constraintEnd_toEndOf="parent"
        app:layout_constraintStart_toStartOf="parent"
        app:layout_constraintTop_toBottomOf="@+id/btn" />

</androidx.constraintlayout.widget.ConstraintLayout>

MainActivity.java

package com.cfsuman.androidtutorials;

import android.app.Activity;
import android.content.Context;
import android.content.res.Resources;
import android.graphics.Bitmap;
import android.graphics.BitmapFactory;
import android.os.Bundle;
import android.widget.Button;
import android.widget.ImageView;
import androidx.core.graphics.drawable.RoundedBitmapDrawable;
import androidx.core.graphics.drawable.RoundedBitmapDrawableFactory;


public class MainActivity extends Activity {
    private Context mContext;
    private Resources mResources;
    private Button mBTN;
    private ImageView mImageView;
    private Bitmap mBitmap;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);

        // Get the application context
        mContext = getApplicationContext();

        // Get the Resources
        mResources = getResources();

        // Get the widgets reference from XML layout
        mImageView = (ImageView) findViewById(R.id.iv);
        mBTN = (Button) findViewById(R.id.btn);

        // Get the bitmap from drawable resources
        mBitmap = BitmapFactory.decodeResource(
                mResources,
                R.drawable.flower
        );

        // Display the bitmap in ImageView
        mImageView.setImageBitmap(mBitmap);

        // Set a click listener for Button widget
        mBTN.setOnClickListener(view -> {
            // Define the ImageView corners radius
            float cornerRadius = 80.0f;

            // Initialize a new RoundedBitmapDrawable
            RoundedBitmapDrawable roundedBitmapDrawable
                    = RoundedBitmapDrawableFactory.create(
                    mResources,
                    mBitmap
            );

            // Set the RoundedBitmapDrawable corners radius
            roundedBitmapDrawable.setCornerRadius(cornerRadius);

            roundedBitmapDrawable.setAntiAlias(true);

            // Set the ImageView image as drawable object
            mImageView.setImageDrawable(roundedBitmapDrawable);
        });
    }
}

android - How to save image to file in external storage

activity_main.xml

<androidx.constraintlayout.widget.ConstraintLayout
    xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:app="http://schemas.android.com/apk/res-auto"
    xmlns:tools="http://schemas.android.com/tools"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:background="#F8F8FF"
    android:padding="16dp"
    tools:context=".MainActivity">

    <Button
        android:id="@+id/button"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:text="Save Image To External Storage"
        app:layout_constraintStart_toStartOf="parent"
        app:layout_constraintTop_toTopOf="parent" />

    <ImageView
        android:id="@+id/ivSource"
        android:layout_width="0dp"
        android:layout_height="200dp"
        android:layout_marginTop="12dp"
        android:src="@drawable/flower3"
        android:scaleType="centerCrop"
        app:layout_constraintEnd_toEndOf="parent"
        app:layout_constraintStart_toStartOf="parent"
        app:layout_constraintTop_toBottomOf="@+id/button" />

    <TextView
        android:id="@+id/tvSource"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_marginTop="8dp"
        android:text="Original Image"
        app:layout_constraintStart_toStartOf="@+id/ivSource"
        app:layout_constraintTop_toBottomOf="@+id/ivSource" />

    <ImageView
        android:id="@+id/ivSaved"
        android:layout_width="0dp"
        android:layout_height="200dp"
        android:layout_marginTop="48dp"
        android:scaleType="centerCrop"
        app:layout_constraintEnd_toEndOf="parent"
        app:layout_constraintStart_toStartOf="parent"
        app:layout_constraintTop_toBottomOf="@+id/tvSource" />

    <TextView
        android:id="@+id/tvSaved"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_marginTop="8dp"
        app:layout_constraintStart_toStartOf="@+id/ivSaved"
        app:layout_constraintTop_toBottomOf="@+id/ivSaved" />

</androidx.constraintlayout.widget.ConstraintLayout>

MainActivity.java

package com.cfsuman.androidtutorials;

import android.content.Context;
import android.graphics.Bitmap;
import android.graphics.drawable.BitmapDrawable;
import android.graphics.drawable.Drawable;
import android.net.Uri;
import android.os.Bundle;
import android.app.Activity;
import android.os.Environment;
import android.widget.Button;
import android.widget.ImageView;
import android.widget.TextView;
import androidx.core.content.ContextCompat;
import java.io.File;
import java.io.FileOutputStream;
import java.io.IOException;
import java.io.OutputStream;


public class MainActivity extends Activity {
        private ImageView mIvSaved;
        private TextView mTvSaved;
        private Context mContext;

        @Override
        protected void onCreate(Bundle savedInstanceState) {
                super.onCreate(savedInstanceState);
                setContentView(R.layout.activity_main);

                // Get the application context
                mContext = getApplicationContext();

                // Get the widgets reference from XML layout
                Button btn = findViewById(R.id.button);
                mIvSaved = findViewById(R.id.ivSaved);
                mTvSaved = findViewById(R.id.tvSaved);

                btn.setOnClickListener(v -> {
                        // Get the image from drawable
                        // resource as drawable object
                        Drawable drawable = ContextCompat.getDrawable(
                                mContext, R.drawable.flower3
                        );

                        // Get the bitmap from drawable object
                        //assert drawable != null;
                        Bitmap bitmap = ((BitmapDrawable) drawable)
                                .getBitmap();

                        // Initializing a new file
                        File file;

                        // Get the external storage directory path
                        String path = Environment.getExternalStorageDirectory()
                                .toString();

                        // Create a file to save the image
                        file = new File(path, "UniqueFileName" + ".jpg");

                        try {
                                OutputStream stream = null;
                                stream = new FileOutputStream(file);
                                bitmap.compress(
                                        Bitmap.CompressFormat.JPEG,
                                        100, stream
                                );
                                stream.flush();
                                stream.close();

                        } catch (IOException e) // Catch the exception
                        {
                                e.printStackTrace();
                        }

                        // Parse the saved image path to uri
                        Uri savedImageURI = Uri.parse(file.getAbsolutePath());

                        // Display the saved image to ImageView
                        mIvSaved.setImageURI(savedImageURI);

                        // Display saved image uri to TextView
                        mTvSaved.setText(
                                "Image saved in external storage.\n"
                                        + savedImageURI
                        );
                });
        }
}

AndroidManifest.xml [permission]

<uses-permission android:name="android.permission.WRITE_EXTERNAL_STORAGE"/>

android - How to save an image to gallery

activity_main.xml

<androidx.constraintlayout.widget.ConstraintLayout
    xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:app="http://schemas.android.com/apk/res-auto"
    xmlns:tools="http://schemas.android.com/tools"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:background="#F8F8FF"
    android:padding="16dp"
    tools:context=".MainActivity">

    <Button
        android:id="@+id/button"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:text="Save Image To Gallery"
        app:layout_constraintStart_toStartOf="parent"
        app:layout_constraintTop_toTopOf="parent" />

    <ImageView
        android:id="@+id/ivSource"
        android:layout_width="0dp"
        android:layout_height="200dp"
        android:layout_marginTop="12dp"
        android:src="@drawable/flower4"
        android:scaleType="centerCrop"
        app:layout_constraintEnd_toEndOf="parent"
        app:layout_constraintStart_toStartOf="parent"
        app:layout_constraintTop_toBottomOf="@+id/button" />

    <TextView
        android:id="@+id/tvSource"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_marginTop="8dp"
        android:text="Original Image"
        app:layout_constraintStart_toStartOf="@+id/ivSource"
        app:layout_constraintTop_toBottomOf="@+id/ivSource" />

    <ImageView
        android:id="@+id/ivSaved"
        android:layout_width="0dp"
        android:layout_height="200dp"
        android:layout_marginTop="48dp"
        android:scaleType="centerCrop"
        app:layout_constraintEnd_toEndOf="parent"
        app:layout_constraintStart_toStartOf="parent"
        app:layout_constraintTop_toBottomOf="@+id/tvSource" />

    <TextView
        android:id="@+id/tvSaved"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_marginTop="8dp"
        app:layout_constraintStart_toStartOf="@+id/ivSaved"
        app:layout_constraintTop_toBottomOf="@+id/ivSaved" />

</androidx.constraintlayout.widget.ConstraintLayout>

MainActivity.java

package com.cfsuman.androidtutorials;

import android.content.Context;
import android.graphics.Bitmap;
import android.graphics.drawable.BitmapDrawable;
import android.graphics.drawable.Drawable;
import android.net.Uri;
import android.os.Bundle;
import android.app.Activity;
import android.provider.MediaStore;
import android.widget.Button;
import android.widget.ImageView;
import android.widget.TextView;
import androidx.core.content.ContextCompat;


public class MainActivity extends Activity {
        private ImageView mIvSaved;
        private TextView mTvSaved;
        private Context mContext;

        @Override
        protected void onCreate(Bundle savedInstanceState) {
                super.onCreate(savedInstanceState);
                setContentView(R.layout.activity_main);

                // Get the application context
                mContext = getApplicationContext();

                // Get the widgets reference from XML layout
                Button btn = findViewById(R.id.button);
                mIvSaved = findViewById(R.id.ivSaved);
                mTvSaved = findViewById(R.id.tvSaved);

                btn.setOnClickListener(v -> {
                        // Get the image from drawable
                        // resource as drawable object
                        Drawable drawable = ContextCompat.getDrawable(
                                mContext,R.drawable.flower4
                        );

                        // Get the bitmap from drawable object
                        //assert drawable != null;
                        Bitmap bitmap = ((BitmapDrawable)drawable)
                                .getBitmap();

                        // Save image to gallery
                        String savedImageURL = MediaStore.Images.Media
                                .insertImage(
                                        getContentResolver(),
                                        bitmap,
                                        "flower",
                                        "Image of flower"
                        );

                        // Parse the gallery image url to uri
                        Uri savedImageURI = Uri.parse(savedImageURL);

                        // Display the saved image to ImageView
                        mIvSaved.setImageURI(savedImageURI);

                        // Display saved image url to TextView
                        mTvSaved.setText(
                                "Image saved to gallery.\n" + savedImageURL
                        );
                });
        }
}

AndroidManifest.xml [permission]

<uses-permission android:name="android.permission.WRITE_EXTERNAL_STORAGE"/>

android - How to take ScreenShot programmatically

activity_main.xml

<androidx.constraintlayout.widget.ConstraintLayout
    xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:tools="http://schemas.android.com/tools"
    xmlns:app="http://schemas.android.com/apk/res-auto"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:padding="24dp"
    android:id="@+id/rootLayout"
    tools:context=".MainActivity"
    android:background="#DCDCDC">

    <Button
        android:id="@+id/button"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:text="Take ScreenShot"
        app:layout_constraintStart_toStartOf="parent"
        app:layout_constraintTop_toTopOf="parent" />

    <ImageView
        android:id="@+id/imageView"
        android:layout_width="0dp"
        android:layout_height="0dp"
        android:layout_marginTop="16dp"
        android:scaleType="centerCrop"
        android:src="@drawable/flower7"
        app:layout_constraintBottom_toBottomOf="parent"
        app:layout_constraintEnd_toEndOf="parent"
        app:layout_constraintStart_toStartOf="parent"
        app:layout_constraintTop_toBottomOf="@+id/button" />

</androidx.constraintlayout.widget.ConstraintLayout>

MainActivity.java

package com.cfsuman.androidtutorials;

import android.graphics.Bitmap;
import android.graphics.Canvas;
import android.os.Bundle;
import android.app.Activity;
import android.provider.MediaStore;
import android.view.View;
import android.widget.Button;
import android.widget.Toast;
import androidx.constraintlayout.widget.ConstraintLayout;


public class MainActivity extends Activity {

        @Override
        protected void onCreate(Bundle savedInstanceState) {
                super.onCreate(savedInstanceState);
                setContentView(R.layout.activity_main);

                // Get the widgets reference from XML layout
                Button button = findViewById(R.id.button);
                ConstraintLayout rootLayout = findViewById(R.id.rootLayout);

                button.setOnClickListener(view -> {
                        // Take the screenshot
                        Bitmap screenShot = TakeScreenShot(rootLayout);

                        // Save the screenshot on device gallery
                        MediaStore.Images.Media.insertImage(
                                getContentResolver(),
                                screenShot,
                                "Image",
                                "Captured ScreenShot"
                        );

                        // Notify the user that screenshot taken.
                        Toast.makeText(
                                getApplicationContext(),
                                "Screen Captured.",
                                Toast.LENGTH_SHORT
                        ).show();
               });
        }


        // Custom method to take screenshot
        public Bitmap TakeScreenShot(View rootView){
                // Screenshot taken for the specified root
                // view and its child elements.
                Bitmap bitmap = Bitmap.createBitmap(
                        rootView.getWidth(),
                        rootView.getHeight(),
                        Bitmap.Config.ARGB_8888
                );
                Canvas canvas = new Canvas(bitmap);
                rootView.draw(canvas);
                return bitmap;
        }
}

AndroidManifest.xml [permission]

<uses-permission android:name="android.permission.WRITE_EXTERNAL_STORAGE"/>

android - How to change ActionBar title programmatically

MainActivity.java

package com.cfsuman.androidtutorials;

import android.os.Bundle;
import android.widget.Button;
import androidx.appcompat.app.ActionBar;
import androidx.appcompat.app.AppCompatActivity;


public class MainActivity extends AppCompatActivity {
    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);

        // Get the widgets reference from XML layout
        Button button = findViewById(R.id.button);


        // Set the button click listener
        button.setOnClickListener(view -> {
            // Get the ActionBar
            ActionBar actionBar = getSupportActionBar();

            // Change the ActionBar title text
            assert actionBar != null;
            actionBar.setTitle("Updated ActionBar Title");
        });
    }
}

activity_main.xml

<?xml version="1.0" encoding="utf-8"?>
<androidx.constraintlayout.widget.ConstraintLayout
    xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:app="http://schemas.android.com/apk/res-auto"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:background="#DCDCDC"
    android:padding="24dp">

    <Button
        android:id="@+id/button"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:text="Change ActionBar Title Text"
        android:textAllCaps="false"
        app:layout_constraintBottom_toBottomOf="parent"
        app:layout_constraintEnd_toEndOf="parent"
        app:layout_constraintStart_toStartOf="parent"
        app:layout_constraintTop_toTopOf="parent" />

</androidx.constraintlayout.widget.ConstraintLayout>

How to show an indeterminate ProgressBar in Android

MainActivity.java

package com.cfsuman.androidtutorials;

import android.os.Bundle;
import android.app.Activity;
import android.os.Handler;
import android.view.View;
import android.widget.Button;
import android.widget.ProgressBar;
import android.widget.TextView;


public class MainActivity extends Activity {
    private int progressStatus = 0;
    private Handler handler = new Handler();

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);

        // Get the widgets reference from XML layout
        Button button = findViewById(R.id.button);
        ProgressBar progressBar = findViewById(R.id.progressBar);
        TextView textView = findViewById(R.id.textView);


        // Set a click listener for Button widget
        button.setOnClickListener(view -> {
            // Disable the button itself
            view.setEnabled(false);

            // Set the progress status zero on each button click
            progressStatus = 0;
            // Visible the progress bar and text view
            progressBar.setVisibility(View.VISIBLE);
            textView.setVisibility(View.VISIBLE);

            // Start the lengthy operation in a background thread
            new Thread(new Runnable() {
                @Override
                public void run() {
                    while (progressStatus < 100) {
                        // Update the progress status
                        progressStatus += 1;

                        // Try to sleep the thread for 20 milliseconds
                        try {
                            Thread.sleep(100);
                        } catch (InterruptedException e) {
                            e.printStackTrace();
                        }

                        // Update the progress bar
                        handler.post(new Runnable() {
                            @Override
                            public void run() {
                                progressBar.setProgress(progressStatus);
                                // Show the progress on TextView
                                textView.setText(progressStatus + "");
                                // If task execution completed
                                if (progressStatus == 100) {
                                    // Hide the progress bar from layout
                                    // after finishing task
                                    progressBar.setVisibility(View.GONE);
                                    // Set a message of completion
                                    textView.setText("Operation completed.");

                                    // Enable the button itself
                                    view.setEnabled(true);
                                }
                            }
                        });
                    }
                }
            }).start(); // Start the operation
        });
    }
}

activity_main.xml

<?xml version="1.0" encoding="utf-8"?>
<androidx.constraintlayout.widget.ConstraintLayout
    xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:app="http://schemas.android.com/apk/res-auto"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    xmlns:tools="http://schemas.android.com/tools"
    android:background="#DCDCDC"
    android:padding="24dp">

    <TextView
        android:id="@+id/textView"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_marginTop="64dp"
        android:fontFamily="sans-serif"
        android:textSize="24sp"
        app:layout_constraintEnd_toEndOf="parent"
        app:layout_constraintStart_toStartOf="parent"
        app:layout_constraintTop_toTopOf="parent"
        tools:text="TextView" />

    <ProgressBar
        android:id="@+id/progressBar"
        style="@android:style/Widget.Holo.Light.ProgressBar.Horizontal"
        android:visibility="gone"
        android:indeterminate="true"
        android:layout_width="0dp"
        android:layout_height="wrap_content"
        android:layout_below="@id/textView"
        android:layout_marginTop="16dp"
        app:layout_constraintEnd_toEndOf="parent"
        app:layout_constraintStart_toStartOf="parent"
        app:layout_constraintTop_toBottomOf="@+id/textView" />

    <Button
        android:id="@+id/button"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_marginTop="24dp"
        android:text="Start Task"
        app:layout_constraintEnd_toEndOf="parent"
        app:layout_constraintStart_toStartOf="parent"
        app:layout_constraintTop_toBottomOf="@+id/progressBar" />

</androidx.constraintlayout.widget.ConstraintLayout>

How to create a ProgressBar programmatically in Android

Create a ProgressBar In Code

ProgressBar is used to indicate the progress of an operation or long-running task, so the user can get a visual idea of how much time it will take to finish the job. We can simply add a ProgressBar widget to our XML layout file but when android developers want to put a ProgressBar in their app interface is a little bit harder. This android app development tutorial will guide you on how you can add a ProgressBar widget to your app rapidly in java code.




In the first step, we will create a ProgressBar in Java code. After that, we will set its layout parameters and define relative layout rules, and put it to relative layout on a specific location. The relative layout addView method allows us to add a dynamic view to it.




In the second step, we will show the operation progress in our newly added ProgressBar after a button click event. This is a determinate progress bar, so we can simply show the progress percentage in our widget. We also applied a color filter on our programmatically created ProgressBar widget.




The operation run on a background thread, so the app user interface is not blocked by the long-running task. We run an example task using runnable and handler in this tutorial. Button click starts the operation and the handler runs it periodically and completes it on time.

activity_main.xml

<RelativeLayout
    xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:tools="http://schemas.android.com/tools"
    android:id="@+id/rl"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:padding="10dp"
    tools:context=".MainActivity"
    android:background="#d6e6de"
    >
    <Button
        android:id="@+id/btn"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:text="Create ProgressBar"
        />
    <Button
        android:id="@+id/btn_start"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:text="Start Operation"
        android:layout_toRightOf="@id/btn"
        />
    <TextView
        android:id="@+id/tv"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_below="@id/btn_start"
        />
</RelativeLayout>

MainActivity.java

package com.cfsuman.me.androidcodesnippets;

import android.graphics.Color;
import android.graphics.PorterDuff;
import android.os.Bundle;
import android.app.Activity;
import android.view.View;
import android.widget.Button;
import android.widget.RelativeLayout;
import android.widget.TextView;
import android.widget.ProgressBar;
import android.os.Handler;
import android.widget.RelativeLayout.LayoutParams;


public class MainActivity extends Activity {
    private int progressStatus = 0;
    private Handler handler = new Handler();
    ProgressBar pb;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);

        // Get the widgets reference from XML layout
        final RelativeLayout rl = (RelativeLayout) findViewById(R.id.rl);
        final Button btn = (Button) findViewById(R.id.btn);
        final Button btn_start = (Button) findViewById(R.id.btn_start);
        final TextView tv = (TextView) findViewById(R.id.tv);

        btn.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View view) {
                //ProgressBar(Context context, AttributeSet attrs, int defStyleAttr)
                // Initialize a new Progressbar instance
                // Create a new progress bar programmatically
                pb = new ProgressBar(getApplicationContext(), null, android.R.attr.progressBarStyleHorizontal);

                // Create new layout parameters for progress bar
                LayoutParams lp = new LayoutParams(
                        550, // Width in pixels
                        LayoutParams.WRAP_CONTENT // Height of progress bar
                );

                // Apply the layout parameters for progress bar
                pb.setLayoutParams(lp);

                // Get the progress bar layout parameters
                LayoutParams params = (LayoutParams) pb.getLayoutParams();

                // Set a layout position rule for progress bar
                params.addRule(RelativeLayout.BELOW, tv.getId());

                // Apply the layout rule for progress bar
                pb.setLayoutParams(params);

                // Set the progress bar color
                pb.getProgressDrawable().setColorFilter(Color.BLUE, PorterDuff.Mode.SRC_IN);

                // Finally,  add the progress bar to layout
                rl.addView(pb);
            }
        });

        btn_start.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View view) {
                // Set the progress status zero on each button click
                progressStatus = 0;
                // Start the lengthy operation in a background thread
                new Thread(new Runnable() {
                    @Override
                    public void run() {
                        while(progressStatus < 100){
                            // Update the progress status
                            progressStatus +=1;

                            // Try to sleep the thread for 20 milliseconds
                            try{
                                Thread.sleep(20);
                            }catch(InterruptedException e){
                                e.printStackTrace();
                            }

                            // Update the progress bar
                            handler.post(new Runnable() {
                                @Override
                                public void run() {
                                    pb.setProgress(progressStatus);
                                    // Show the progress on TextView
                                    tv.setText(progressStatus+"");
                                }
                            });
                        }
                    }
                }).start(); // Start the operation
           }
        });
    }
}

How to change ProgressBar color programmatically in Android

MainActivity.java

package com.cfsuman.androidtutorials;

import android.graphics.Color;
import android.graphics.PorterDuff;
import android.os.Bundle;
import android.app.Activity;
import android.os.Handler;
import android.widget.Button;
import android.widget.ProgressBar;
import android.widget.TextView;


public class MainActivity extends Activity {
    private int progressStatus = 0;
    private Handler handler = new Handler();

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);

        // Get the widgets reference from XML layout
        Button button = findViewById(R.id.button);
        ProgressBar pbDefault = findViewById(R.id.pbDefault);
        ProgressBar pbColored = findViewById(R.id.pbColored);
        TextView tvProgress = findViewById(R.id.tvProgress);


        // Change the default color of progress bar programmatically
        pbColored.getProgressDrawable()
                .setColorFilter(Color.RED, PorterDuff.Mode.SRC_IN);


        // Set a click listener for Button widget
        button.setOnClickListener(view -> {
            // Disable the button itself
            view.setEnabled(false);

            // Set the progress status zero on each button click
            progressStatus = 0;

            // Start the lengthy operation in a background thread
            new Thread(new Runnable() {
                @Override
                public void run() {
                    while(progressStatus < 100){
                        // Update the progress status
                        progressStatus +=1;

                        // Try to sleep the thread for 20 milliseconds
                        try{
                            Thread.sleep(100);
                        }catch(InterruptedException e){
                            e.printStackTrace();
                        }

                        // Update the progress bar
                        handler.post(new Runnable() {
                            @Override
                            public void run() {
                                pbDefault.setProgress(progressStatus);
                                pbColored.setProgress(progressStatus);
                                // Show the progress on TextView
                                tvProgress.setText(progressStatus+"");
                            }
                        });
                    }
                }
            }).start(); // Start the operation
        });
    }
}

activity_main.xml

<?xml version="1.0" encoding="utf-8"?>
<androidx.constraintlayout.widget.ConstraintLayout
    xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:app="http://schemas.android.com/apk/res-auto"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    xmlns:tools="http://schemas.android.com/tools"
    android:background="#DCDCDC"
    android:padding="24dp">

    <TextView
        android:id="@+id/tvProgress"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_marginStart="32dp"
        android:layout_marginTop="48dp"
        android:fontFamily="sans-serif"
        android:textSize="24sp"
        android:textStyle="bold"
        app:layout_constraintStart_toStartOf="parent"
        app:layout_constraintTop_toTopOf="parent"
        tools:text="TextView" />

    <ProgressBar
        android:id="@+id/pbDefault"
        style="@android:style/Widget.Holo.Light.ProgressBar.Horizontal"
        android:layout_width="0dp"
        android:layout_height="wrap_content"
        android:layout_below="@id/tvProgress"
        android:layout_marginTop="16dp"
        android:layout_marginEnd="8dp"
        app:layout_constraintEnd_toStartOf="@+id/tvDefault"
        app:layout_constraintStart_toStartOf="parent"
        app:layout_constraintTop_toBottomOf="@+id/tvProgress" />

    <TextView
        android:id="@+id/tvDefault"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:fontFamily="sans-serif"
        android:textSize="16sp"
        android:textStyle="italic"
        app:layout_constraintBottom_toBottomOf="@+id/pbDefault"
        app:layout_constraintEnd_toEndOf="parent"
        android:text="Default Color" />

    <ProgressBar
        android:id="@+id/pbColored"
        style="@android:style/Widget.Holo.Light.ProgressBar.Horizontal"
        android:layout_width="0dp"
        android:layout_height="wrap_content"
        android:layout_below="@id/tvProgress"
        android:layout_marginTop="16dp"
        android:layout_marginEnd="8dp"
        app:layout_constraintEnd_toStartOf="@+id/tvColored"
        app:layout_constraintStart_toStartOf="parent"
        app:layout_constraintTop_toBottomOf="@+id/pbDefault" />

    <TextView
        android:id="@+id/tvColored"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:fontFamily="sans-serif"
        android:textSize="16sp"
        android:textStyle="italic"
        app:layout_constraintBottom_toBottomOf="@+id/pbColored"
        app:layout_constraintEnd_toEndOf="parent"
        android:text="Custom Color" />

    <Button
        android:id="@+id/button"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_marginTop="24dp"
        android:text="Start"
        app:layout_constraintEnd_toEndOf="parent"
        app:layout_constraintStart_toStartOf="parent"
        app:layout_constraintTop_toBottomOf="@+id/pbColored" />

</androidx.constraintlayout.widget.ConstraintLayout>