How to modify sensitivity of viewpager?

For ViewPager2 extract and increase mTouchSlop using reflection.

    private fun ViewPager2.reduceDragSensitivity() {
        val recyclerViewField = ViewPager2::class.java.getDeclaredField("mRecyclerView")
        recyclerViewField.isAccessible = true
        val recyclerView = recyclerViewField.get(this) as RecyclerView

        val touchSlopField = RecyclerView::class.java.getDeclaredField("mTouchSlop")
        touchSlopField.isAccessible = true
        val touchSlop = touchSlopField.get(recyclerView) as Int
        touchSlopField.set(recyclerView, touchSlop*8)       // "8" was obtained experimentally
    }

Call this function from your view pager

val viewPager: ViewPager2 = view.findViewById(R.id.pager)
viewPager.reduceDragSensitivity()

Java version

private void reduceDragSensitivity() {
    try {
        Field ff = ViewPager2.class.getDeclaredField("mRecyclerView") ;
        ff.setAccessible(true);
        RecyclerView recyclerView =  (RecyclerView) ff.get(viewPager);
        Field touchSlopField = RecyclerView.class.getDeclaredField("mTouchSlop") ;
        touchSlopField.setAccessible(true);
        int touchSlop = (int) touchSlopField.get(recyclerView);
        touchSlopField.set(recyclerView,touchSlop*4);
    } catch (NoSuchFieldException e) {
        e.printStackTrace();
    } catch (IllegalAccessException e) {
        e.printStackTrace();
    }
}

All credits to Alexander Shevelev and Mahmoud Shabat.

I've checked out ViewPager.java from src of compatibility library and seems there's not way to do it by xml or some setter. ViewPager has code like the following:

final float density = context.getResources().getDisplayMetrics().density;
mFlingDistance = (int) (MIN_DISTANCE_FOR_FLING * density);
mCloseEnough = (int) (CLOSE_ENOUGH * density);
mDefaultGutterSize = (int) (DEFAULT_GUTTER_SIZE * density);

As You can see, it uses it's internal constants for determination of fling distance and etc.

Good news are: You can copy ViewPager (here licence of it should be considered) to Your code and extend it e.g. to get fling distance from xml attribute.