MainActivity.kt
package com.cfsuman.kotlintutorials
import android.app.Activity
import android.content.Context
import android.graphics.*
import android.os.Bundle
import android.widget.*
import java.io.IOException
import kotlin.math.min
class MainActivity : Activity() {
override fun onCreate(savedInstanceState: Bundle?) {
super.onCreate(savedInstanceState)
setContentView(R.layout.activity_main)
// get the widgets reference from XML layout
val imageView = findViewById<ImageView>(R.id.imageView)
val imageView2 = findViewById<ImageView>(R.id.imageView2)
val textView = findViewById<TextView>(R.id.textView)
val textView2 = findViewById<TextView>(R.id.textView2)
// get the bitmap from assets folder
val bitmap = assetsToBitmap("flower103.jpg")
bitmap?.apply {
// show original bitmap in first image view
imageView.setImageBitmap(this)
textView.text = "Source Bitmap ($width * $height)"
// crop bitmap to square
toSquare()?.let {
imageView2.setImageBitmap(it)
textView2.text = "Square Bitmap (${it.width} " +
"* ${it.height})"
}
}
}
}
// extension function to get bitmap from assets
fun Context.assetsToBitmap(fileName:String):Bitmap?{
return try {
val stream = assets.open(fileName)
BitmapFactory.decodeStream(stream)
} catch (e: IOException) {
e.printStackTrace()
null
}
}
// extension function to crop bitmap to square
fun Bitmap.toSquare():Bitmap?{
// get the small side of bitmap
val side = min(width,height)
// calculate the x and y offset
val xOffset = (width - side) /2
val yOffset = (height - side)/2
// create a square bitmap
// a square is closed, two dimensional shape with 4 equal sides
return Bitmap.createBitmap(
this, // source bitmap
xOffset, // x coordinate of the first pixel in source
yOffset, // y coordinate of the first pixel in source
side, // width
side // height
)
}
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:id="@+id/rootLayout"
android:background="#DCDCDC"
android:padding="24dp">
<ImageView
android:id="@+id/imageView"
android:layout_width="0dp"
android:layout_height="250dp"
android:layout_marginTop="8dp"
app:layout_constraintEnd_toEndOf="parent"
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:layout_marginTop="8dp"
android:text="Original Bitmap"
app:layout_constraintEnd_toEndOf="parent"
app:layout_constraintStart_toStartOf="@+id/imageView"
app:layout_constraintTop_toBottomOf="@+id/imageView" />
<ImageView
android:id="@+id/imageView2"
android:layout_width="0dp"
android:layout_height="250dp"
android:layout_marginTop="24dp"
app:layout_constraintEnd_toEndOf="parent"
app:layout_constraintStart_toStartOf="parent"
app:layout_constraintTop_toBottomOf="@+id/textView" />
<TextView
android:id="@+id/textView2"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_marginTop="8dp"
android:text="Square Bitmap"
app:layout_constraintEnd_toEndOf="@+id/imageView2"
app:layout_constraintStart_toStartOf="@+id/imageView2"
app:layout_constraintTop_toBottomOf="@+id/imageView2" />
</androidx.constraintlayout.widget.ConstraintLayout>
- android kotlin - BitmapShader example
- android kotlin - Bitmap tint solid color
- android kotlin - Rounded corners bitmap
- android kotlin - Circular bitmap with border
- android kotlin - Bitmap crop circular area
- android kotlin - Bitmap add border
- android kotlin - ListView add item programmatically
- android kotlin - ListView add header programmatically
- android kotlin - ListView OnItemClickListener example
- android kotlin - MaterialCardView checked unchecked example
- android kotlin - MaterialCardView shadow color example
- android kotlin - MaterialButtonToggleGroup example
- android kotlin - Material button change color example
- android kotlin - Material button rounded corners example
- android kotlin - Add view to ConstraintLayout programmatically
