Use GestureOverlayView in Android for free hand drawing


You can draw anything by using GestureOverlayView class in android.

 

Required:-

 

1. Implement the OnGesturePerformedListener interface
2. Override onGesturePerformed method.

 

In your xml layout file, add the following code.

 

Here, we use android.gesture.GestureOverlayView to take input from user and an image view to display output.

 

<RelativeLayout xmlns:android=”http://schemas.android.com/apk/res/android”
xmlns:tools=”http://schemas.android.com/tools”
android:layout_width=”match_parent”
android:layout_height=”match_parent” >
<android.gesture.GestureOverlayView
android:id=”@+id/gestureOverlayView1″
android:layout_width=”match_parent”
android:layout_height=”match_parent” />

 

<ImageView
android:id=”@+id/imageView1″
android:layout_width=”match_parent”
android:layout_height=”match_parent”
/>

 

</RelativeLayout>
In your MainActivity.java class write the following code:-
public class MainActivity extends Activity implements OnGesturePerformedListener{

 

GestureOverlayView gestureOverlayView;
private Bitmap bitmap;
private ImageView imageView;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
//Instantiate the object of image view and gesture overlay //view.

 

imageView=(ImageView) findViewById(R.id.imageView1);

gestureOverlayView = (GestureOverlayView) findViewById(R.id.gestureOverlayView1);

 

//add listener to the gesture overlay view

 

gestureOverlayView.addOnGesturePerformedListener(this);

 

//Create object of Display class to get width and height of device to create a bitmap image of screen size.

 

Display display= getWindowManager().getDefaultDisplay();
bitmap=Bitmap.createBitmap(display.getWidth(), display.getHeight(), Bitmap.Config.ARGB_8888);

}

 

//This method will be automatically called by system when //gesture is made by user.

@Override
public void onGesturePerformed(GestureOverlayView overlay, Gesture gesture) {

 

//Create object of canvas and paint class for drawing.

Canvas canvas = new Canvas(bitmap);
Paint paint = new Paint();
paint.setColor(Color.BLUE);
// gesture.getStrokes() method will return an array list of Gesture Strokes.
ArrayList<GestureStroke> gestureStrokes = gesture.getStrokes();
for (GestureStroke ges : gestureStrokes) {
//canvas.drawLines method draws the lines on bitmap image by using given points and paint object.
canvas.drawLines( ges.points, paint);
}
//finally display the image using setImageBitmap method in image view as shown below.
imageView.setImageBitmap(bitmap);
}
}