Viewpager setCurrentItem() method don't work normally after activity jump in "don't keep activity" develop option

Question

I turn on the "don't keep activity" develop option.
In activity A,there is a viewpager.
Then Activity a jump to Activity B, then press back button return to A,this time viewpager's setCurrentItem() method don't work normally.Unnormally means don't trigger onPageSelected() method in ViewPager.OnPageChangeListener,and at the same time the related Tablayout don't perform right.
I've tried call the method in viewpager.post() (the solution written in other post in stackoverflow,like this post).
By the way,i use Android Annotation,and i call the setCurrentItem() in @AfterViews.

Answer 1

Try this code:
@Override
void onStart(Bundle savedInstanceBundle){
    if (savedInstanceBundle != null){
       viewPager.setCurrentItem(savedInstanceBundle.getInt(VIEWPAGER_PAGE);
    }
}
    @Override
void onSavedInstanceState(Bundle outState){
    // Put your current ViewPager Page here;
    outState.putInt(VIEWPAGER_PAGE, page));
}

Answer 2

I've find the reason. It caused by the ViewPager's onSaveInstanceState and onRestoreInstanceState. I don't know the detailed reason now, i'll post the detailed answer when i know.