visual indication of over scroll in android

Question

I am trying to add some visual indication, that there are no more pages in the desired fling direction in the ViewPager. However I am struggling to find a place, where to put relevant code.

I have tried extending ViewPager class with following code, but the Toast is not displaying (ev.getOrientation() returns always 0). I have also tried the same with history points, but ev.getHistorySize() returns also 0.

What am I missing?

Class example:

public class CustomViewPager extends ViewPager {

    public CustomViewPager(Context context) {
        super(context);
    }

    public CustomViewPager(Context context, AttributeSet attrs) {
        super(context, attrs);
    }

    /**
     * @see android.support.v4.view.ViewPager#onTouchEvent(android.view.MotionEvent)
     */
    @Override
    public boolean onTouchEvent(MotionEvent ev) {
        boolean result = super.onTouchEvent(ev);

        switch (ev.getAction() & MotionEventCompat.ACTION_MASK) {
            case MotionEvent.ACTION_MOVE:
                if (ev.getOrientation() > 0) {
                    Toast.makeText(getContext(), "left", 0).show();
                }
        }

        return result;
    }
}

Answer 1

You can overload the setUserVisibleHint(boolean) function in your fragments. Pseudo code:

    void setUserVisibleHint(boolean isVisibleToUser) {
        // If this fragment is becoming visible
        if (isVisibleToUser == true) {
             // Check if it is the last fragment in the viewpager
             if (indexOfThis == getActivity().indexOfLast) {
                // Display right limit reached
                Toast(..., "No more Frags to right",...)
                }
             // Check if it is the first fragment in the viewpager
             else if (indexOfThis == getActivity().indexOfFirst) {
                // Display Left Limit reached
                Toast(..., "No more Frags to left",...)
             }
        }
    }

I have not used this function for this purpose, but have used it for other reasons and it does fire appropriately. Hope this helps...

Answer 2

I've implemented a bounce back effect based on Renard's ViewPager3D: https://stackoverflow.com/a/17425468/973379