结合两个 onTouch 事件

Question

For my app I need to combine two onTouch events. With the first I want to get the color of a clicked pixel of an imageView and the other event should make the picture zoomable. I tried it separate and it seemed to work on its own, but when I try to combine these two things it doesn't work anymore. Why won't they work together?

My code:

public class MainActivity extends AppCompatActivity {

private ImageView imageView;
private Bitmap bitmap;
private ScaleGestureDetector mScaleGestureDetector;
private float mScaleFactor = 1.0f;

@Override
protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_main);

    final ImageView imageView = (ImageView) findViewById(R.id.imageView);
    imageView.setScaleType(ImageView.ScaleType.FIT_XY);
    imageView.setDrawingCacheEnabled(true);
    imageView.buildDrawingCache(true);

    mScaleGestureDetector = new ScaleGestureDetector(this, new ScaleListener());

    imageView.setOnTouchListener(new View.OnTouchListener() {
        @Override
        public boolean onTouch(View v, MotionEvent event) {

            mScaleGestureDetector.onTouchEvent(event);

            bitmap = imageView.getDrawingCache();
            int pixel = bitmap.getPixel((int) event.getX(), (int) event.getY());
            String text = "x = " + event.getX() + ", y = " + event.getY();
            Log.d("Position", text);
            int redValue = Color.red(pixel);
            int greenValue = Color.green(pixel);
            int blueValue = Color.blue(pixel);

            return true;
        }
    });
}



private class ScaleListener extends ScaleGestureDetector.SimpleOnScaleGestureListener {

    @Override
    public boolean onScale(ScaleGestureDetector scaleGestureDetector){
        mScaleFactor *= scaleGestureDetector.getScaleFactor();
        mScaleFactor = Math.max(1.0f,
                Math.min(mScaleFactor, 1.7f));
        imageView.setScaleX(mScaleFactor);
        imageView.setScaleY(mScaleFactor);

        return true;

    }
}

}

Answer 1

 imageView.setOnTouchListener(new View.OnTouchListener() {
    @Override
    public boolean onTouch(View v, MotionEvent event) {

        mScaleGestureDetector.onTouchEvent(event);

        bitmap = imageView.getDrawingCache();
        int pixel = bitmap.getPixel((int) event.getX(), (int) event.getY());
        String text = "x = " + event.getX() + ", y = " + event.getY();
        Log.d("Position", text);
        int redValue = Color.red(pixel);
        int greenValue = Color.green(pixel);
        int blueValue = Color.blue(pixel);

        return false;
    }
});

I guess its because you are consuming the touch here. Try returning false.