How to determine a fragment in FragmentStatePagerAdapter is current page or not

Question

FragmentStatePagerAdapter(for short FSPA) has pre-load mechanism.

We assume that A,B and C Fragment in FSPA

When user select the A Fragment, the B fragment will be pre-load, something in B fragment don't want to be executed because B is not the current fragment.

How cloud i determine if a fragment is a current fragment user selected ?

The code snippet can't explain what i want to do, so i have deleted it

Update my question as below :

Assume that

there are three fragments A , B, C in viewPager
fragment A is the first visible to user.
start e-ticket transaction if fragment A is visible to user
In other page (except fragment A), we need to stop e-ticket transaction

Problem: Pre-load fragment A in viewpager will cause that user don't see a e-ticket present but e-ticket start transaction

Want to do: View of fragment A is a e-ticket, so transaction can be started in fragment A only and stop in other fragment.

p.s. start and stop e-ticket transaction are in A fragment class.

Similar question [here](http://stackoverflow.com/questions/18609261/getting-the-current-fragment-instance-in-the-viewpager). Hope it helps. — gvlachakis, Aug 31 '16 at 08:51

Darshan Miskin · Accepted Answer · 2016-08-31T09:25:54.167

0

You can add an onPageChangeListener to your viewpager and inside onPageSelected(int position) you can get the current fragment as.

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

        }

        @Override
        public void onPageSelected(int position) {
             Fragment currentFragment=new MyViewPagerAdapter().getItem(position);
        }

        @Override
        public void onPageScrollStateChanged(int state) {

        }
    });

Ps- By 'user select' do you mean Clicked or Visible on screen?

edited Aug 31 '16 at 09:25

answered Aug 31 '16 at 09:02

Darshan Miskin

844
14
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It seems that i have to pass viewPager reference to fragment... Because i have to do something in fragment only – samuel yang Aug 31 '16 at 09:26
inside from a fragment as you are doing in 'onResume()' try 'if(fragmentObject.isVisible()){//Do something} – Darshan Miskin Aug 31 '16 at 09:34
Ps- By 'user select' do you mean Clicked or Visible on screen? Yes, – samuel yang Sep 01 '16 at 02:19
did you try this... if(fragmentObject.isVisible()) { //Do something } – Darshan Miskin Sep 01 '16 at 05:06
It's not work for me...After onCreateView(), isVisible() always return true in onResume, so it's can't determine the fragment is clicked or not – samuel yang Sep 01 '16 at 06:16
what exactly are you trying to do after user clicks on the fragment? – Darshan Miskin Sep 01 '16 at 07:36
Finally, i adopt your suggestion to modify my code to finish the requirement, thanks – samuel yang Sep 02 '16 at 06:08
You can accept the answer then, that will help me. :) – Darshan Miskin Sep 02 '16 at 06:13

score 0 · Answer 2 · answered Aug 31 '16 at 09:07

0

You can use setUserVisibleHint method.

 @Override
        public void setUserVisibleHint(boolean isVisibleToUser) {
if(isVisibleToUser){
... your code
}
    }

answered Aug 31 '16 at 09:07

Cüneyt

2,565
25
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The method to be called before onCreateView, but i need to do something after view is ready, if a task is independent of views, it could be a good idea. – samuel yang Sep 01 '16 at 03:32

How to determine a fragment in FragmentStatePagerAdapter is current page or not

2 Answers2