android viewpager change adapter

Question

I\'m developing an app with a ViewPager for lateral scrolling tables, sometimes i need to change the adapter to load a different set of tables. I\'ve tried to do the following:<

Answer 1

Add this to view pager to reload for next fragment:

viewPager.setCurrentItem()

Answer 2

Exactly like my APP doing...

For change ViewPagerAdapter, what I did is :

1. Clear all Fragments inside current adapter

2. Set current adapter to null

3. Assign new adpater for ViewPager

   /* Clear all Fragments inside current adapter */
   public class MyPagerAdapter extends FragmentPagerAdapter
   {
     private ArrayList<Fragment> fragments = new ArrayList<Fragment>();
     //...some stuff
   
     public void clearAll() //Clear all page
     {
       for(int i = 0; i < fragments.size(); i ++)
       fragMan.beginTransaction().remove(fragments.get(i)).commit();
       fragments.clear();
     }
   }
   
   /* Set current adapter to null */
   Constants.VP.removeAllViews();
   Constants.VP.setAdapter(null);
   
   /* Assign new adpater for ViewPager */
   Constants.PAGER = new MyPagerAdapter(getSupportFragmentManager());
   Constants.VP.setAdapter(Constants.PAGER);
   

Hope it helps~

Answer 3

I see that @RRTW way worked for some people but it did not do the trick for me (although it was close). Without commitNow() instead of regular commit() it would not work properly. I did something like that:

private fun changePagerAdapter(newAdapter: PagerAdapter) {

    val transaction = supportFragmentManager.beginTransaction()
        supportFragmentManager.fragments.forEach {
        transaction.remove(it)
    }

    transaction.commitNow()
    view_pager.adapter = newAdapter
}

Answer 4

You need to override public int getItemPosition (Object object) in pager adapter. For every element in the viewpager, you need to return POSITION_UNCHANGED (if it is still in the pager) or POSITION_NONE (if it was removed). Otherwise the view pager won't know something has changed. I wouldn't recommend setting a new adapter, just clearing out the data in the old one.