RGB值ontouch功能

Question

我正在尝试从图像中获取rgb值，但即使在同一像素上也总是得到不同的值。

我使用了以下代码：

imageView=(ImageView)findViewById(R.id.imageView);

final Bitmap bitmap = ((BitmapDrawable) 
imageView.getDrawable()).getBitmap();

imageView.setOnTouchListener(new View.OnTouchListener() {

    @Override
    public boolean onTouch(View v,MotionEvent event) {

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

        int redValue = Color.red(pixel);
        int greenValue = Color.green(pixel);
        int blueValue = Color.blue(pixel);

        // Toast.makeText(MainActivity.this,String.format("#%02x%02x%02x", redValue, 
        greenValue, blueValue), Toast.LENGTH_LONG).show();

        Toast.makeText(MainActivity.this, "R= " + redValue + "G= " + greenValue + 
        "B= " + blueValue, Toast.LENGTH_LONG).show();
        // Toast.makeText(MainActivity.this,""+x+"\tY "+y,Toast.LENGTH_LONG).show();

        return false;
    }
});