Theme preview "IllegalStateException: Fragment already added" #2265
Description
Quite a few instances of this in crash reports. To repro:
- Enable "don't keep activities" in developer options
- Go to themes in the app and open a live preview
- Hit the back button then minimize the app
- Spend a minute using a few memory-intensive apps
- Return to WP Android and tap "Live preview" again
java.lang.IllegalStateException: Fragment already added: ThemePreviewFragment{422e79e0 #3 id=0x7f0b0283 org.wordpress.android.ui.themes.ThemePreviewFragment}
at android.app.FragmentManagerImpl.addFragment(FragmentManager.java:1133)
at android.app.BackStackRecord.run(BackStackRecord.java:618)
at android.app.FragmentManagerImpl.execPendingActions(FragmentManager.java:1453)
at android.app.FragmentManagerImpl$1.run(FragmentManager.java:443)
at android.os.Handler.handleCallback(Handler.java:733)
at android.os.Handler.dispatchMessage(Handler.java:95)
at android.os.Looper.loop(Looper.java:146)
at android.app.ActivityThread.main(ActivityThread.java:5511)
at java.lang.reflect.Method.invokeNative(Method.java)