public class MainActivity extends Activity {
private ImageView iv_back;
private ImageView iv_up;
private Bitmap alterBitmap;
private Canvas canvas;
private Paint paint;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
iv_back = (ImageView)findViewById(R.id.iv_back);
iv_up = (ImageView)findViewById(R.id.iv_up);
BitmapFactory.Options opts = new Options();
//opts.inSampleSize = 2;
Bitmap back = BitmapFactory.decodeResource(getResources(),
R.drawable.g16_back, opts);
//只讀圖片
Bitmap up = BitmapFactory.decodeResource(getResources(),
R.drawable.g16_up, opts);
//可以修改的空白bitmap，mutable
alterBitmap = Bitmap.createBitmap(up.getWidth(),
up.getHeight(), up.getConfig());
canvas = new Canvas(alterBitmap);
paint = new Paint();
paint.setStrokeWidth(5);
paint.setColor(Color.BLACK);
canvas.drawBitmap(up, new Matrix(), paint);
iv_back.setImageBitmap(back);
iv_up.setImageBitmap(alterBitmap);
iv_up.setOnTouchListener(new OnTouchListener() {
@Override
public boolean onTouch(View v, MotionEvent event) {
switch(event.getAction()){
case MotionEvent.ACTION_DOWN:
break;
case MotionEvent.ACTION_MOVE:
int newX = (int) event.getX();
int newY = (int) event.getY();
int xx, yy;
for(int i=-8; i<=8; i++){
for(int j=-8; j<=8; j++){
alterBitmap.setPixel(xx, yy, Color.TRANSPARENT);
}
}
iv_up.setImageBitmap(alterBitmap);
break;
}
return true;
}
});
}
}
<FrameLayout 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"
tools:context=".MainActivity" >
<ImageView
android:id="@+id/iv_back"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
/>
<ImageView
android:id="@+id/iv_up"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
/>
</FrameLayout>
