Click on ImageView on Android screen

Question

my problem is to click on imageview and to know where, on the image (resized by imageview), i click on.

My current algorithm is:

On the onTouch method of ImageView, get the X and Y positions of the MotionEvent and do the math

int realX = (X / this.getWidth()) * bitmapWidth;
int realY = (Y / this.getHeight()) * bitmapHeight;

Where bitpmapWidth and bitmapHeight are from the original bitmap.

Can anyone help me?

do want to know the which area you clicked on image? like if image having button then your requirement is found weather you click on that button in the image ? Is this is your requirement? — Varun Jain, Mar 06 '17 at 20:22

score 0 · Accepted Answer · edited May 23 '17 at 10:30

Almost right, math should be just a little different. Also keep in mind that ImageView's getHeight() and getWidth() would be 0 during onCreate, I have used info from this answer getWidth() and getHeight() of View returns 0 to use get width and height once it's available

    iv = (ImageView) findViewById(R.id.img);

    iv.getViewTreeObserver().addOnGlobalLayoutListener(new ViewTreeObserver.OnGlobalLayoutListener() {
        @Override
        public void onGlobalLayout() {
            iv.getViewTreeObserver().removeOnGlobalLayoutListener(this);
            xScaleFactor = iv.getWidth() / originalBitmapWidth;
            yScaleFactor = iv.getHeight() / originalBitmapHeight;

            Log.v(TAG, "xScaleFactor:" + xScaleFactor + " yScaleFactor:" + yScaleFactor);
        }
    });

    iv.setOnTouchListener(new View.OnTouchListener() {
        @Override
        public boolean onTouch(View view, MotionEvent event) {
            int touchX = (int) event.getX();
            int touchY = (int) event.getY();

            int realX = touchX / xScaleFactor;
            int realY = touchY / yScaleFactor;

            Log.v(TAG, "realImageX:" + realX + " realImageY:" + realY);
            return false;
        }
    });

Click on ImageView on Android screen

1 Answers1