How to dismiss a custom dialog based on touch points?

When we write a custom dialog class or set theme style/Theme.Dialog to activity, we might be interested in dismissing the dialog if user touches outside the dialog visible area.

This can be achieved through a special class, android.graphics.Region. It has a api contains(x,y) which is used to tell you if the passed x,y falls in the region defined.

1 - we need to override the public boolean onTouchEvent (MotionEvent event) function and get the current x,y the user touched on the screen.

2 - Define the region top left x,y and bottom right x,y of the rectangle region which you are interested in listening the touch events.

Region dialogRegion = new Region (10,12,183,179 );

3 - Dismiss the dialog using finish() if the touch points falls within this region() co-ordinates.

if( dialogRegion.contains(x, y) == true)
this.finish();

Here is the complete example.

This example shows that activity is set style - Theme.Dialog.

        <activity android:name=".touch"
                  android:label="@string/app_name"
                  android:theme="@android:style/Theme.Dialog">

Size of the dialog is set using WindowManager layout params.

Depending on the height & width, i have set the region points.And in onTouchEvent() i check for the touch points, if within the region() points i simply call finish() which exits the activity.

touch.java
------------

package com.android.touch;

import android.app.Activity;
import android.graphics.Region;
import android.os.Bundle;
import android.view.MotionEvent;
import android.view.WindowManager;

public class touch extends Activity {
 Region dialogRegion;
    /** Called when the activity is first created. */
    @Override
    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.main);
        WindowManager.LayoutParams params = getWindow().getAttributes();
        
        params.height = 200;
        params.width = 200;
        

        this.getWindow().setAttributes(params);
        
        dialogRegion = new Region (10,12,183,179 );
       
    }
    public boolean onTouchEvent (MotionEvent event)
    {
     
     final int action = event.getAction();
  

   final int x = (int) event.getX();
        final int y = (int) event.getY();

      switch (action & MotionEvent.ACTION_MASK) 
      {
         case MotionEvent.ACTION_DOWN: {
          System.out.println("Action down"+x +"::"+y);
          if( dialogRegion.contains(x, y) == true)
           this.finish();
          
         }
      }
     
    return true;
    }
}