FragmentPagerAdapter always load the next fragment instead the current

Question

@Override
protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_main_dictionary);

    getWindow().setSoftInputMode(
            WindowManager.LayoutParams.SOFT_INPUT_STATE_ALWAYS_HIDDEN);

    toolbar = (Toolbar) findViewById(R.id.toolbar);
    setSupportActionBar(toolbar);

    viewPager = (ViewPager) findViewById(R.id.viewpager);
    setupViewPager(viewPager);

    tabLayout = (TabLayout) findViewById(R.id.tabs);
    tabLayout.setupWithViewPager(viewPager);

    tabLayout.setTabGravity(TabLayout.GRAVITY_FILL);
    setupNavMenu();
}

private void setupViewPager(ViewPager viewPager) {
    adapter = new ViewPagerAdapter(getSupportFragmentManager());
    adapter.addFragment(new A(), "A");
    adapter.addFragment(new B(), "B");
    adapter.addFragment(new C(), "C");
    adapter.addFragment(new D(), "D");
    viewPager.setAdapter(adapter);
}

class ViewPagerAdapter extends FragmentPagerAdapter {
    private final List<Fragment> mFragmentList = new ArrayList<>();
    private final List<String> mFragmentTitleList = new ArrayList<>();

    public ViewPagerAdapter(FragmentManager manager) {
        super(manager);
    }

    @Override
    public Fragment getItem(int position) {
        return mFragmentList.get(position);
    }

    @Override
    public int getCount() {
        return mFragmentList.size();
    }

    public void addFragment(Fragment fragment, String title) {
        mFragmentList.add(fragment);
        mFragmentTitleList.add(title);
    }

    @Override
    public CharSequence getPageTitle(int position) {
        return mFragmentTitleList.get(position);
    }
}

The problem is: When I starts the activity, i get the first fragment's view(A), BUT the next fragment(B) loads without the view, so when I slide to the next view(B), i get the view that i'v been loaded at the previous fragment, so now It's load fragment C...

the problem is that fragment B's content depends on the input in fragment A (data saved is sharedpreferences) so I allways get the default value at fragment B because it was loaded in fragment A.

The bug works the same way when I'm in the fragment D, so when I'll slide left to fragment C, it will show fragment C AND loads fragment B also.

replace your fragment again when you have entered data from first fragment — Vivek Mishra, Jan 05 '16 at 10:25

score 1 · Answer 1 · answered Jan 05 '16 at 10:24

1

its not a bug its the default functionality of a viewpager. for each nth page (n-1)th and (n+1)th page loads automatically with the nth page. I don't think there is any straight forward way to achieve what you want.

answered Jan 05 '16 at 10:24

Ankit Aggarwal

5,317
2
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score 0 · Answer 2 · answered Aug 14 '17 at 15:04

The best way would be to use a custom onSwipeListener instead of ViewPager and load the fragment yourself..

But for ViewPager you can use a hack:

After saving data in fragment A,

    viewPager.setAdapter(adapter);

which will reload all fragments.

Don't forget to first save the current pager position. after reset, set pager position so you don't go back to the first position every time. not good coding but it should work.

score 0 · Answer 3 · answered Aug 14 '17 at 15:24

0

on your ViewPagerAdapter. override method : getItemPosition : return POSITION_NONE

answered Aug 14 '17 at 15:24

Linh Nguyen

1,264
1
10
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FragmentPagerAdapter always load the next fragment instead the current

3 Answers3

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