Android Fragment lifecycle over orientation changes

Question

Using the compatibility package to target 2.2 using Fragments. After recoding an activity to use fragments in an app I could not get the orientation changes/state management working so I've created a small test app with a single FragmentActivity and a single Fragment. The logs from the orientation changes are weird, with multiple calls to the fragments OnCreateView. I'm obviously missing something - like detatching the fragment and reattaching it rather than creating a new instance, but I can't see any documentation which would indicate where I'm going wrong. Can anyone shed some light on what I'm doing wrong here please. Thanks The log is as follows after orientation changes. ``` Initial creation 12-04 11:57:15.808: D/FragmentTest.FragmentTestActivity(3143): onCreate 12-04 11:57:15.945: D/FragmentTest.FragmentOne(3143): OnCreateView 12-04 11:57:16.081: D/FragmentTest.FragmentOne(3143): OnCreateView->SavedInstanceState null Orientation Change 1 12-04 11:57:39.031: D/FragmentTest.Fragm…

Accepted Answer

You're layering your Fragments one on top of the other.

When a config change occurs the old Fragment adds itself to the new Activity when it's recreated. This is a massive pain in the rear most of the time.

You can stop errors occurring by using the same Fragment rather than recreating a new one. Simply add this code:

```
if (savedInstanceState == null) {
    // only create fragment if activity is started for the first time
    mFragmentManager = getSupportFragmentManager();
    FragmentTransaction fragmentTransaction = mFragmentManager.beginTransaction();

FragmentOne fragment = new FragmentOne();

fragmentTransaction.add(R.id.fragment_container, fragment);
    fragmentTransaction.commit();
} else {        
    // do nothing - fragment is recreated automatically
}
```

Be warned though: problems will occur if you try and access Activity Views from inside the Fragment as the lifecycles will subtly change. (Getting Views from a parent Activity from a Fragment isn't easy).

Android Fragment lifecycle over orientation changes

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