onResume() 在 Fragments 中不能正常工作？

Question

I am working on Fragments,so here I have three fragments in My view pager

So here I am using onResume() method in my first fragment, so when I swipe from one fragment to another and I came back to first fragment My onResume Method is not working

So any one give the solutions guys

Answer 1

The fragment's onResume() or onPause() will be called only when the Activities onResume() or onPause() is called. They are tightly coupled to the Activity . Check this and this .

Also it may get called few times when you are on fragment screen. In your case since your viewpager is inside Activity , fragment onResume() may not get called when you swipe to that fragment .

Answer 2

This is due to the way ViewPager keeps Fragment s in memory. If the Fragment is scrolled more than the offscreen page limit (set via .setOffscreenPageLimit() ), it should be removed from memory and reinstantiated when it's reloaded (which, IIRC, may not be guaranteed to be when it comes back onscreen).

To run fragment-specific code when a page is selected, you can try something like the following:

mPager.setOnPageChangeListener(new SimpleOnPageChangeListener() {
    @Override
    public void onPageSelected(int position) {
        final MyFragment fragment = mAdapter.getFragment(position);
        fragment.myMethod();
    }
}

Answer 3

I faced this problem myself.

Add a tabListener to your viewpager first. In the onTabSelected method, create an instance of your selected fragment and call onResume() .

            ActionBar.TabListener tabListener = new ActionBar.TabListener() {

                @Override
                public void onTabUnselected(ActionBar.Tab tab, FragmentTransaction ft) {
                }

                @Override
                public void onTabSelected(ActionBar.Tab tab, FragmentTransaction ft) {
                    viewPager.setCurrentItem(tab.getPosition());
                    mContent.setUserVisibleHint(false);
                    mContent.onPause();
                    mContent = mAdapter.getItem(tab.getPosition());
                    mContent.setUserVisibleHint(true);
                    mContent.onResume();
                }

                @Override
                public void onTabReselected(ActionBar.Tab tab, FragmentTransaction ft) {
                }
            };

Here, mContent is the currently selected fragment, and mAdapter is the viewpager's adapter.

Answer 4

In fragment (with ViewPager) use setUserVisibleHint(boolean isVisibileToUser) instead onResume():

@Override
public void setUserVisibleHint(boolean isVisibleToUser) {
super.setUserVisibleHint(isVisibleToUser);
if(isVisibleToUser) {
    refresh();
} else {

    }
}