Android SubMenu Example

MainActivity.java

package com.cfsuman.androidtutorials;

import android.graphics.Color;
import android.os.Bundle;
import android.util.TypedValue;
import android.view.Menu;
import android.view.MenuInflater;
import android.view.MenuItem;
import android.widget.TextView;
import androidx.appcompat.app.AppCompatActivity;


public class MainActivity extends AppCompatActivity {
    private TextView mTextView;

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

        // Get the widgets reference from XML layout
        mTextView = findViewById(R.id.textView);
    }


    @Override
    public boolean onCreateOptionsMenu(Menu menu){
        MenuInflater inflater = getMenuInflater();
        inflater.inflate(R.menu.toolbar_options_menu, menu);
        return true;
    }


    @Override
    public boolean onOptionsItemSelected(MenuItem item){
        int id = item.getItemId();

        if (id == R.id.red){
            // Set the text color to red
            mTextView.setTextColor(Color.RED);
            return true;
        }else if(id == R.id.green){
            // Set the text color to green
            mTextView.setTextColor(Color.GREEN);
            return true;
        }else if (id == R.id.blue){
            // Set the text color to blue
            mTextView.setTextColor(Color.BLUE);
            return true;
        }else if (id == R.id.large_text){
            // Set the text size to large
            mTextView.setTextSize(
                    TypedValue.COMPLEX_UNIT_SP, 50);
            return true;
        }else if (id == R.id.medium_text){
            // Set the text size to medium
            mTextView.setTextSize(
                    TypedValue.COMPLEX_UNIT_SP, 35);
            return true;
        }else if (id == R.id.small_text){
            // Set the text size to small
            mTextView.setTextSize(
                    TypedValue.COMPLEX_UNIT_SP, 25);
            return true;
        }else {
            return super.onOptionsItemSelected(item);
        }
    }
}

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">

    <TextView
        android:id="@+id/textView"
        android:layout_width="0dp"
        android:layout_height="wrap_content"
        android:layout_marginTop="24dp"
        android:fontFamily="sans-serif"
        android:text="I am a TextView"
        android:textSize="26sp"
        android:textStyle="italic"
        app:layout_constraintEnd_toEndOf="parent"
        app:layout_constraintStart_toStartOf="parent"
        app:layout_constraintTop_toTopOf="parent" />

</androidx.constraintlayout.widget.ConstraintLayout>

res/menu/toolbar_options_menu.xml

<?xml version="1.0" encoding="utf-8"?>
<menu
    xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:app="http://schemas.android.com/apk/res-auto">

    <item
        android:id="@+id/text_color"
        android:title="Text Color"
        app:showAsAction="always|withText"
        android:icon="@drawable/ic_action_text_format"
        android:orderInCategory="1">

        <!-- Starting sub menu which have three items-->
        <menu>
            <item
                android:id="@+id/red"
                android:title="Red"
                android:icon="@drawable/ic_action_palette" />
            <item
                android:id="@+id/green"
                android:title="Green"
                android:icon="@drawable/ic_action_palette" />
            <item
                android:id="@+id/blue"
                android:title="Blue"
                android:icon="@drawable/ic_action_palette" />
        </menu>
    </item>

    <item
        android:id="@+id/large_text"
        android:title="Large Text"
        app:showAsAction="ifRoom|withText"
        android:orderInCategory="2"
        android:icon="@drawable/ic_action_text_fields" />
    <item
        android:id="@+id/medium_text"
        android:title="Medium Text"
        app:showAsAction="ifRoom|withText"
        android:orderInCategory="3"
        android:icon="@drawable/ic_action_text_fields" />
    <item
        android:id="@+id/small_text"
        android:title="Small Text"
        app:showAsAction="ifRoom|withText"
        android:orderInCategory="4"
        android:icon="@drawable/ic_action_text_fields" />
</menu>