Where to put "ViewPager.setCurrentItem()" Method

Question

I have Nested Fragments [1 main Fragment called "MainFrag" and many child Fragments] the App can show MainFrag or can show other fragments.

what I want to do is to setCurrentItem of MainFrag's ViewPager every time the user selects to show that MainFrag so I tried to put it at it's onCreateView but this only works for the first time the User Shows MainFrag as if user Selects another fragment and then re-selects MainFrag the seCurrentItem is not working

I also tried to put it inside MainFrag's onResume, It worked as required but it also causes a problem that if the user moved the App to background and then reOpen it viewPager will Scroll and i don't want this

So where Exactly Can I put setCurrentItem ?

mViewPager.setCurrentItem(mCurrentWeekFragmentItemNumber);

Edit: I am using Navigation Menu to Move between 3 main fragments where MainFrag is one of them.

Answer 1

After your mViewPager.setAdapter(adapter); method you can put

mViewPager.setCurrentItem(mCurrentWeekFragmentItemNumber);

Answer 2

将适配器设置为viewpager后添加setCurrentItem方法

mViewPager.setAdapter(adapter);
mViewPager.setCurrentItem(mCurrentWeekFragmentItemNumber);

Answer 3

试试这个：

viewPager.addOnPageChangeListener(new ViewPager.OnPageChangeListener() {
            @Override
            public void onPageScrolled(int position, float positionOffset, int positionOffsetPixels) {

            }

            @Override
            public void onPageSelected(int position) {
                viewPager.setCurrentItem(position);
            }

            @Override
            public void onPageScrollStateChanged(int state) {

            }
        });

    }