java - OnTouchListener 坐标不正确

Question

我有一个 OnTouchListener，但是当我实际测试我的程序并触摸屏幕时，显示的颜色不是应有的颜色。我使用颜色 block 进行了测试，它可以工作，但是坐标仍然关闭，如果您在一种颜色上触摸得太远，它会显示另一种颜色。我相信这是因为产生的坐标是与整个屏幕而不是 ImageView 进行比较 - 我希望从中选择它。我如何使 OnTouchListener 仅用于 ImageView 而不是整个屏幕？谢谢。

final Bitmap bitmap2 = ((BitmapDrawable) imageView.getDrawable()).getBitmap();
    imageView.setOnTouchListener(new View.OnTouchListener() {
        @Override
        public boolean onTouch(View v, MotionEvent event) {


            Matrix inverse = new Matrix();
            v.getMatrix().invert(inverse);
            float[] touchPoint = new float[] {event.getX(), event.getY()};
            inverse.mapPoints(touchPoint);
            int x = Integer.valueOf((int)touchPoint[0]);
            int y = Integer.valueOf((int)touchPoint[1]);


          //  int x = (int) event.getX();
           // int y = (int) event.getY();
            int pixel = bitmap2.getPixel(x, y);


            int red = Color.red(pixel);
            int blue = Color.blue(pixel);
            int green = Color.green(pixel);

            Bitmap bitmap = BitmapFactory.decodeFile(output.getAbsolutePath());
            Paint paint = new Paint();
            paint.setAntiAlias(true);
            paint.setColor(Color.rgb(red,green,blue));


            Bitmap workingBitmap = Bitmap.createBitmap(bitmap);
            Bitmap mutableBitmap = workingBitmap.copy(Bitmap.Config.ARGB_8888, true);


            Canvas canvas = new Canvas(mutableBitmap);
            canvas.drawRect(50, 50, 500, 250, paint);

            ImageView imageView = (ImageView)findViewById(R.id.Image_view);
            imageView.setAdjustViewBounds(true);
            imageView.setImageBitmap(mutableBitmap);


            return true;
            }

    });

}


}

Answer 1

I believe this is because the the coordinates produced are in comparison to the whole screen

是的，需要做一些简单的推导才能获取imageView上的触摸坐标:

int[] imgCoords = new int[2];
imageView.getLocationOnScreen(imgCoords);

获取触摸的X,Y并从中取出imageView坐标:

int wholeX = (int) event.getX();
int wholeY = (int) event.getY();

int imageX = wholeX - imgCoords[0];
int imageY = wholeY - imgCoords[1];