ImageView after;	ImageView before;	@Override	protected void onCreate(Bundle savedInstanceState) {		super.onCreate(savedInstanceState);		setContentView(R.layout.activity_main);		after = (ImageView) findViewById(R.id.after);		before= (ImageView) findViewById(R.id.before);		Options options = new Options();//		options.inSampleSize = 2;		Bitmap afterMap = BitmapFactory.decodeResource(getResources(), R.drawable.g7_back,options );		Bitmap beforeMap = BitmapFactory.decodeResource(getResources(), R.drawable.g7_up,options);		//能够改动的bitmap		final Bitmap alterMap = Bitmap.createBitmap(600, 600, beforeMap.getConfig());		//创建画布		final Canvas canvas = new Canvas(alterMap);		//创建画笔		final Paint paint = new Paint();		paint.setColor(Color.BLACK);		paint.setStrokeWidth(5);				canvas.drawBitmap(beforeMap, new Matrix(), paint);				after.setImageBitmap(afterMap);		before.setImageBitmap(beforeMap);				before.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();					for(int i=-8;i<8;i++){						for(int j=-8;j<8;j++)							alterMap.setPixel(i+newX, j+newY, Color.TRANSPARENT);					}					before.setImageBitmap(alterMap);					break;				case MotionEvent.ACTION_UP:					break;				default:					break;			}			return true;			}		});	}