enable/disable zoom in Android WebView

Issue

There are some methods in WebSettings related to zoom:

  • WebSettings.setSupportZoom
  • WebSettings.setBuiltInZoomControls

I noticed they work differently on some devices. For example, on my Galaxy S pinch to zoom is enabled by default, but on LG P500 it is disabled (And now I don’t know how to enable ONLY pinch to zoom, but hide zooming buttons).

On P500 when I call setBuiltInZoomControls(true) I get both these variants working (multitouch and buttons).

How to enable multitouch zoom and disable zooming buttons on devices such an LG P500? (Also, I know the same problems are on HTC devices)

UPDATE: Here is almost full code for the solution

if (ev.getAction()  MotionEvent.ACTION_DOWN ||
        ev.getAction()  MotionEvent.ACTION_POINTER_DOWN ||
        ev.getAction()  MotionEvent.ACTION_POINTER_1_DOWN ||
        ev.getAction()  MotionEvent.ACTION_POINTER_2_DOWN ||
        ev.getAction()  MotionEvent.ACTION_POINTER_3_DOWN) {
    if (multiTouchZoom && !buttonsZoom) {
        if (getPointerCount(ev) > 1) {
            getSettings().setBuiltInZoomControls(true);
            getSettings().setSupportZoom(true);
        } else {
            getSettings().setBuiltInZoomControls(false);
            getSettings().setSupportZoom(false);
        }
    }
}

if (!multiTouchZoom && buttonsZoom) {
    if (getPointerCount(ev) > 1) {
        return true;
    }
}

This code is in my onTouchEvent overridden method of the WebView.

Solution

I’ve looked at the source code for WebView and I concluded that there is no elegant way to accomplish what you are asking.

What I ended up doing was subclassing WebView and overriding OnTouchEvent. In OnTouchEvent for ACTION_DOWN, I check how many pointers there are using MotionEvent.getPointerCount(). If there is more than one pointer, I call setSupportZoom(true), otherwise I call setSupportZoom(false). I then call the super.OnTouchEvent().

This will effectively disable zooming when scrolling (thus disabling the zoom controls) and enable zooming when the user is about to pinch zoom. Not a nice way of doing it, but it has worked well for me so far.

Note that getPointerCount() was introduced in 2.1 so you’ll have to do some extra stuff if you support 1.6.

Answered By – gngr44

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