Android - Scroll Parent Layout with ViewPager

In Android, we often need to use ViewPager to achieve page sliding effects. However, sometimes we may want to scroll the parent layout while scrolling the ViewPager. This article will show you how to achieve this effect in Android.

First, we need to define a parent layout that contains the ViewPager in the XML layout file. For example:

```xml


    

Then, in the Java code, we need to set a custom ViewPager.OnTouchListener for the ViewPager to intercept its scroll events. We can do this by implementing the following:

ViewPager viewPager = findViewById(R.id.view_pager);
viewPager.setOnTouchListener(new View.OnTouchListener() {
    @Override
    public boolean onTouch(View v, MotionEvent event) {
        switch (event.getAction()) {
            case MotionEvent.ACTION_DOWN:
                // When the finger is pressed, request the parent layout not to intercept touch events
                v.getParent().requestDisallowInterceptTouchEvent(true);
                break;
            case MotionEvent.ACTION_UP:
            case MotionEvent.ACTION_CANCEL:
                // When the finger is lifted or the scroll is canceled, request the parent layout to intercept touch events
                v.getParent().requestDisallowInterceptTouchEvent(false);
                break;
        }
        return false;
    }
});

By setting the OnTouchListener for the ViewPager, we can request the parent layout not to intercept touch events when the finger is pressed, and request the parent layout to intercept touch events when the finger is lifted or the scroll is canceled.

Now, when we scroll on the ViewPager, the parent layout will scroll as well, and the ViewPager will also switch pages. This way, we have achieved the effect of scrolling the parent layout while scrolling the ViewPager.

I hope this article has helped you understand how to scroll the parent layout with a ViewPager. If you have any questions, please feel free to ask.