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    <p>There is another solution that does not need modifying source code of <code>ViewPager</code> and <code>FragmentStatePagerAdapter</code>, and it works with the <code>FragmentPagerAdapter</code> base class used by the author.</p> <p>I'd like to start by answering the author's question about which ID he should use; it is ID of the container, i.e. ID of the view pager itself. However, as you probably noticed yourself, using that ID in your code causes nothing to happen. I will explain why:</p> <p>First of all, to make <code>ViewPager</code> repopulate the pages, you need to call <code>notifyDataSetChanged()</code> that resides in the base class of your adapter.</p> <p>Second, <code>ViewPager</code> uses the <code>getItemPosition()</code> abstract method to check which pages should be destroyed and which should be kept. The default implementation of this function always returns <code>POSITION_UNCHANGED</code>, which causes <code>ViewPager</code> to keep all current pages, and consequently not attaching your new page. Thus, to make fragment replacement work, <code>getItemPosition()</code> needs to be overridden in your adapter and must return <code>POSITION_NONE</code> when called with an old, to be hidden, fragment as argument.</p> <p>This also means that your adapter always needs to be aware of which fragment that should be displayed in position 0, <code>FirstPageFragment</code> or <code>NextFragment</code>. One way of doing this is supplying a listener when creating <code>FirstPageFragment</code>, which will be called when it is time to switch fragments. I think this is a good thing though, to let your fragment adapter handle all fragment switches and calls to <code>ViewPager</code> and <code>FragmentManager</code>.</p> <p>Third, <code>FragmentPagerAdapter</code> caches the used fragments by a name which is derived from the position, so if there was a fragment at position 0, it will not be replaced even though the class is new. There are two solutions, but the simplest is to use the <code>remove()</code> function of <code>FragmentTransaction</code>, which will remove its tag as well.</p> <p>That was a lot of text, here is code that should work in your case:</p> <pre><code>public class MyAdapter extends FragmentPagerAdapter { static final int NUM_ITEMS = 2; private final FragmentManager mFragmentManager; private Fragment mFragmentAtPos0; public MyAdapter(FragmentManager fm) { super(fm); mFragmentManager = fm; } @Override public Fragment getItem(int position) { if (position == 0) { if (mFragmentAtPos0 == null) { mFragmentAtPos0 = FirstPageFragment.newInstance(new FirstPageFragmentListener() { public void onSwitchToNextFragment() { mFragmentManager.beginTransaction().remove(mFragmentAtPos0).commit(); mFragmentAtPos0 = NextFragment.newInstance(); notifyDataSetChanged(); } }); } return mFragmentAtPos0; } else return SecondPageFragment.newInstance(); } @Override public int getCount() { return NUM_ITEMS; } @Override public int getItemPosition(Object object) { if (object instanceof FirstPageFragment &amp;&amp; mFragmentAtPos0 instanceof NextFragment) return POSITION_NONE; return POSITION_UNCHANGED; } } public interface FirstPageFragmentListener { void onSwitchToNextFragment(); } </code></pre> <p>Hope this helps anyone!</p>
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    1. POReplace Fragment inside a ViewPager
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    1. COworks for me too, but how to implement back button to show the first fragment?
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      1. USuser1159819
    2. COGreat explanation but could you post full source code of this, specifically FirstPageFragment and SecondPageFragment classes.
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      1. USgeorgiecasey
    3. COI works for me as well, but I haven't been able to reverse the action, it's to say, and I think what @user1159819 means, once you are in NextFragment, you might want to go back to FirstFragment, I don't see how to do it with this implementation
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