public class ApokusActivity extends Activity {
	
	@Override
	protected void onCreate(Bundle savedInstanceState) {
		super.onCreate(savedInstanceState);
		setContentView(new SampleView(this));
	}

	private static class SampleView extends View {

		// CONSTRUCTOR
		public SampleView(Context context) {
			super(context);
			setFocusable(true);

		}
		@Override
		protected void onDraw(Canvas canvas) {
			Paint paint = new Paint();
			
			canvas.drawColor(Color.GREEN);
            
            Bitmap b = Bitmap.createBitmap(200, 200, Bitmap.Config.ALPHA_8);
             paint.setColor(Color.BLUE);
            
            Shader mShader = new LinearGradient(0, 0, 100, 70, new int[] {
                    Color.RED, Color.GREEN, Color.BLUE },
                    null, Shader.TileMode.MIRROR);  // CLAMP MIRROR REPEAT
            Canvas c = new Canvas(b);
            paint.setShader(mShader);
            //c.drawCircle(60, 60, 30, paint);
            c.drawRect(0, 0, 200, 200, paint);
            canvas.drawBitmap(b, 10,10, paint);
		}

	}
}

public class MainActivity extends Activity {

	@Override
	protected void onCreate(Bundle savedInstanceState) {
		super.onCreate(savedInstanceState);
		setContentView(new SampleView(this));
	}

	private static class SampleView extends View {

		// CONSTRUCTOR
		public SampleView(Context context) {
			super(context);
			setFocusable(true);

		}

		@Override
		protected void onDraw(Canvas canvas) {
			Paint paint = new Paint();

			canvas.drawColor(Color.YELLOW);

			 Bitmap b = Bitmap.createBitmap(200, 200,
			 Bitmap.Config.ARGB_8888);

			// you need to insert a image flower_blue into res/drawable folder

			paint.setFilterBitmap(true);
			Bitmap bitmapOrg = BitmapFactory.decodeResource(getResources(),
					R.drawable.flower_blue);
			canvas.drawBitmap(bitmapOrg, 10, 10, paint);
			int width, height;

		    Canvas c = new Canvas(b);
		    paint.setAlpha(255); //0x80
		    c.translate(0, 30);
		    c.drawBitmap(bitmapOrg, new Matrix(), paint);
		    paint.setColor(Color.BLUE);
        Path mPath = new Path();
		    mPath.addCircle(50, 50, 50, Path.Direction.CCW);
            //c.clipPath(mPath, Region.Op.UNION);
            //c.clipPath(mPath, Region.Op.DIFFERENCE);
            c.clipPath(mPath, Region.Op.INTERSECT);
            //c.clipPath(mPath, Region.Op.REPLACE);
            //c.clipPath(mPath, Region.Op.XOR);
           paint.setColor(Color.GREEN);
           paint.setAntiAlias(true);
           c.drawCircle(30, 20, 30, paint);

		    int h = bitmapOrg.getHeight();
			//canvas.drawBitmap(bitmapOrg, 10, 10, paint);
			canvas.drawBitmap(b, 0, 10 + h + 10, paint);

		}

	}
}

Button btn.setBackgroundResource(R.drawable.back_button_answer);

<?xml version="1.0" encoding="utf-8"?>
<shape xmlns:android="//schemas.android.com/apk/res/android" android:shape="rectangle" >
   <corners android:radius="10dip" />
   <!-- background -->
   
   <gradient
                android:startColor="#D6D7D6"
                android:centerColor="#E2E2E2"
                android:centerY="0.75"
                android:endColor="#D6D7D6"
                android:angle="270"
        />
   
   <stroke android:width="2dip" android:color="#fff"/>
</shape>