Update ViewPager dynamically?

Question

I can\'t update the content in ViewPager.

What is the correct usage of methods instantiateItem() and getItem() in FragmentPagerAdapter class?

I was using onl

Answer 1

You need change instantiateItem's mFragments element getItemPosition.

    if (mFragments.size() > position) {
        Fragment f = mFragments.get(position);

        if (f != null) {
            int newPosition = getItemPosition(f);
            if (newPosition == POSITION_UNCHANGED) {
                return f;
            } else if (newPosition == POSITION_NONE) {
                mFragments.set(position, null);
            } else {
                mFragments.set(newPosition, f);
            }
        }
    }

Based AndroidX FragmentStatePagerAdapter.java, because mFragments's elements position do not change when calling notifyDataSetChanged().

Source: https://github.com/cuichanghao/infivt/blob/master/library/src/main/java/cc/cuichanghao/library/FragmentStatePagerChangeableAdapter.java

Example: https://github.com/cuichanghao/infivt/blob/master/app/src/main/java/cc/cuichanghao/infivt/MainActivityChangeablePager.kt

You can run this project to confirm how to work. https://github.com/cuichanghao/infivt