Creating a Floating Context Menu
 in Android Studio(Java) 

A Context Menu provides additional options related to a specific view—the same concept as a right-click on the desktop.

Step 1: Create a new project in Android Studio.

Step 2:  Create the menu by creating a new file in res/ menu called context_menu.xml

<?xml version="1.0" encoding="utf-8"?>
<menu xmlns:android="http://schemas.android.com/apk/res/android">
    <item android:id="@+id/menu_cast"
        android:title="Cast"/>
    <item android:id="@+id/menu_print"
        android:title="Print"/>
</menu>

Step 3: Create a new file in the res/layout directory called 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"
    tools:context=".MainActivity">
    <TextView
        android:id="@+id/showContextualMenu"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:text="Long press for menu"
        android:textSize="20sp"
        android:textStyle="bold"
        android:clickable="true"
        app:layout_constraintBottom_toBottomOf="parent"
        app:layout_constraintLeft_toLeftOf="parent"
        app:layout_constraintRight_toRightOf="parent"
        app:layout_constraintTop_toTopOf="parent" />
</androidx.constraintlayout.widget.ConstraintLayout>

Step 4: Create a new java file called MainActivity.java

Step 4-a: Create global variable to store the ActionMode instance returned when we call startActionMode().

ActionMode mActionMode;

Step 4-b: Create an ActionMode callback to pass to startActionMode().

private final ActionMode.Callback mActionModeCallback = new ActionMode.Callback() {
    @Override
    public boolean onCreateActionMode(ActionMode mode, Menu menu) {
        mode.getMenuInflater().inflate(R.menu.context_menu, menu);
        return true;
    }
    @Override
    public boolean onPrepareActionMode(ActionMode mode, Menu menu) {
        return false;
    }
    @Override
    public boolean onActionItemClicked(ActionMode mode, MenuItem item) {
        switch (item.getItemId()) {
            case R.id. menu_cast:
                Toast.makeText(MainActivity.this, "Cast", Toast.LENGTH_SHORT).show();
                mode.finish();
                return true;
            case R.id. menu_print:
                Toast.makeText(MainActivity.this, "Print", Toast.LENGTH_SHORT).show();
                mode.finish();
                return true;
            default:
                return false;
        }
    }
    @Override
    public void onDestroyActionMode(ActionMode mode) {
        mActionMode = null;
    }
};

Step 4-c: With the ActionMode callback created, we just need to call startActionMode() to begin Contextual Mode

findViewById(R.id.showContextualMenu).setOnLongClickListener(v -> {
    if (mActionMode != null) return false;
    mActionMode = startActionMode(mActionModeCallback);
    return true;
});

Step 4-d: Final code of MainActivity.java

import android.os.Bundle;
import android.view.ActionMode;
import android.view.Menu;
import android.view.MenuItem;
import android.widget.Toast;

import androidx.appcompat.app.AppCompatActivity;

public class MainActivity extends AppCompatActivity {
    //Create global variable to store the ActionMode instance returned when we call startActionMode()
    ActionMode mActionMode;
    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        //Initialise view &
        //handle the long click at TextView
        findViewById(R.id.showContextualMenu).setOnLongClickListener(v -> {
            if (mActionMode != null) return false;
            mActionMode = startActionMode(mActionModeCallback);
            return true;
        });
    }
    //Create an ActionMode callback to pass to startActionMode()
    private final ActionMode.Callback mActionModeCallback = new ActionMode.
            Callback() {
        @Override
        public boolean onCreateActionMode(ActionMode mode, Menu menu) {
            mode.getMenuInflater().inflate(R.menu.context_menu, menu);
            return true;
        }
        @Override
        public boolean onPrepareActionMode(ActionMode mode, Menu menu) {
            return false;
        }
        @Override
        public boolean onActionItemClicked(ActionMode mode, MenuItem item) {
            switch (item.getItemId()) {
                case R.id. menu_cast:
                    Toast.makeText(MainActivity.this, "Cast", Toast.LENGTH_SHORT).show();
                    mode.finish();
                    return true;
                case R.id. menu_print:
                    Toast.makeText(MainActivity.this, "Print", Toast.LENGTH_SHORT).show();
                    mode.finish();
                    return true;
                default:
                    return false;
            }
        }
        @Override
        public void onDestroyActionMode(ActionMode mode) {
            mActionMode = null;
        }
    };
}

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