Android：获取双击的x / y坐标？

Question

我正在构建一个应用程序，当用户双击图像时，该应用程序会在屏幕上绘制一个圆圈。我希望圆圈出现在用户点击屏幕的精确x和y坐标处。现在，它会在屏幕的右上角绘制图像。我是否必须实现onTouchEvent，我该怎么做？

以下是On Touch Listener :(触摸是图像视图）

@Override
protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_image_display);
    Intent intent = getIntent();
    String path = getIntent().getStringExtra(ImageDisplayActivity.KEY_PATH);
    try {
        java.io.FileInputStream in = this.openFileInput(path);
        bitmap = BitmapFactory.decodeStream(in);
        bitmap = bitmap.copy(bitmap.getConfig(), true);
        touch = (ZoomInZoomOut)findViewById(R.id.IMAGEID);
        touch = arrangeImageView(touch);
        touch.setImageBitmap(bitmap);
        in.close();
        touch.setOnTouchListener(new View.OnTouchListener() {
            GestureDetector gestureDetector = new
                    GestureDetector(new MyGestureDetector(context));
            @Override
            public boolean onTouch(View v, MotionEvent event) {
                return gestureDetector.onTouchEvent(event);
            }
        });

    } catch (Exception e) {
        e.printStackTrace();
    }
}

这是应该绘制圆圈的类

class MyGestureDetector extends GestureDetector.SimpleOnGestureListener {
    public Context context;

    public MyGestureDetector(Context con)
    {
        this.context=con;
    }

    @Override
    public boolean onDoubleTap(MotionEvent event) {
         Bitmap bmOverlay = Bitmap.createBitmap(bitmap.getWidth(),
         bitmap.getHeight(),
         bitmap.getConfig());
         Canvas canvas = new Canvas(bmOverlay);
         Paint p = new Paint();
         p.setAntiAlias(true);
         p.setColor(Color.RED);
         p.setStrokeWidth(2);
         p.setStyle(Paint.Style.STROKE);
         canvas.drawBitmap(bitmap,new Matrix(),null);
         canvas.drawCircle(event.getX(),event.getY(),
                100, p);
         touch.setImageBitmap(bmOverlay);
        return false;
    }
}