Question

我有两个图像视图，一个是图库图像，一个是第二个图像上的透明图像绘制画布，我想用手指清洁透明图像

我试图这样做链接：https://play.google.com/store/apps/details?id=com.steam.doodle&hl=en

我试过下面的代码

公共类MainActivity扩展Activity实现OnTouchListener {

ImageView image,transimage;
 Paint paint;
 Bitmap bitmap,resultbitmap;
 Canvas canvas;
 Button clear;
@Override
protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_main);
    image=(ImageView)findViewById(R.id.imageView1);
    transimage=(ImageView)findViewById(R.id.imageView2);

    //Bitmap mBitmap = BitmapFactory.decodeResource(getResources(), R.drawable.saibaba);
       Bitmap mBitmap2 = BitmapFactory.decodeResource(getResources(), R.drawable.snw);
       Bitmap bmOverlay = Bitmap.createBitmap(mBitmap2.getWidth(), mBitmap2.getHeight(), mBitmap2.getConfig());
       Canvas canvas = new Canvas();
       canvas.setBitmap(bmOverlay);
       paint=new Paint();
         paint.setAlpha(200);
      // canvas.drawBitmap(mBitmap, 0, 0, null);
       canvas.drawBitmap(mBitmap2, 0, 0, paint);
       transimage.setImageBitmap(bmOverlay);

} }

如何用手指清洁画布

Answer 1

你只需要在方法onDraw上设置Color = Transparent。这是经过测试的代码，并且正在运行。

 @Override
            protected void onDraw(Canvas canvas) {

                if(isEraseMode){
                    paint.setColor(Color.TRANSPARENT);
                    canvas.drawPath(eraserPath, erasePaint);
                     //canvas.save();
                }else{
                    canvas.drawPath(path, paint);
                     canvas.restore();
                }
                 canvas.drawPath(path, paint);

                    super.dispatchDraw(canvas);

            }

希望这会对你有所帮助.. :)

如何用手指清洁画布区域

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