How to expand the view while zooming an image into ViewPager2 - zooming

Question

I was trying, with ViewPager2, to get default gallery-like experience of common Android SmartPhone, where you can zoom an image with pan and pinch controls along with the ability to navigate to another photo by swipe gestures.
I faced a problem in which when the zoomed image is swiped expecting it to get panned, instead of that, the ViewPager2 switched to another page.
ViewPager2 responds to the swipe event and causes page change and it doesn’t let zoomable view to respond to that event.
How do I solve the problem? Thanks.

Answer 1

The only solution I found is to use the old ViewPager with which it is possible to intercept events and if the photo is enlarged, it is possible to disable the page change and allow the management of the zoom.
First I defined a field, in a static class, to keep track of the state the photo is in:
public class Utilities {
....
static boolean isZoomed;
private Utilities () { }
static public void setIsZoomed (boolean z) {
isZoomed = z;
}
static public boolean getIsZoomed () {
return isZoomed;
}
....
}
Then in the custom class for managing the zoom I detect the status of the photo:
public class TouchImageView extends ImageView {
...
Utilities.setIsZoomed(normalizedScale != 1);
...
}
Finally, in the ViewPager custom class I disable or allow pagination based on the state of the photo:
public class CustomViewPager extends ViewPager {
public CustomViewPager (Context context) {
super(context);
}
public CustomViewPager (Context context, AttributeSet attrs) {
super(context, attrs);
}
#Override
public boolean onInterceptTouchEvent (MotionEvent ev) {
try {
if (Utilities.getIsZoomed())
return false;
else
return super.onInterceptTouchEvent(ev);
} catch (IllegalArgumentException e) {
return false;
}
}
}