fragment-recreator

A utility to handle fragment view-recreation when used in an Activity that handles configuration changes.

Why?

Unlike android's view system, jetpack compose is able to handle configuration changes gracefully. This opens up new possibilities like simplifying app architecture and doing fun things like animations on rotation. Unfortunately you can't really take advantage of that in an hybrid app that still uses views. This library lets you set the option for view recreation per-fragment, allowing you slowly migrate one fragment at a time.

Usage

First make sure your activity is handling configuration changes.

<activity
    android:name=".MainActivity"
    android:configChanges="orientation|screenSize|screenLayout|keyboardHidden"
    android:exported="true"
    android:windowSoftInputMode="adjustResize">
    <intent-filter>
        <category android:name="android.intent.category.LAUNCHER" />
        <action android:name="android.intent.action.MAIN" />
    </intent-filter>
</activity>

Then, for any fragments you want to recreate their views, set recreateOnConfigurationChange to true.

class MyLegacyFragment : Fragment() {
    override fun onCreate(savedInstanceState: Bundle?) {
        super.onCreate(savedInstanceState)
        recreateOnConfigurationChange = true
    }
}

You could also automatically set this for all fragments on an activity by registering fragment lifecycle callbacks. Note: doing this explicitly per-fragment is preferred as it calls out all the places where you are opting into the behavior, but this may be necessary if for example you have 3rd-party fragments you need to control.

supportFragmentManager.registerFragmentLifecycleCallbacks(object :
    FragmentLifecycleCallbacks() {
    override fun onFragmentAttached(fm: FragmentManager, f: Fragment, context: Context) {
        f.recreateOnConfigurationChange = true
    }
}, true)

ViewPager2

ViewPager2 controls attaching a fragment's view to it's container itself instead of letting the fragment handle this. Therefore you need to let the adapter know that they views may have changed. You can either use the provided subclass

import me.tatarka.fragmentrecreator.viewpager2.FragmentStateAdapter

class MyAdapter(..) : FragmentStateAdapter(..)

or do it manually yourself by notifying in onConfigurationChanged().

override fun onConfigurationChanged(newConfig: Configuration) {
    super.onConfigurationChanged(newConfig)
    adapter.notifyDataSetChanged()
}