Exception on onSaveInstanceState when Fragment starts another Fragment

Question

Experts,

I'm struggling with the following issue: I have an Activity that starts Fragment A. Fragment A starts Fragment B when a button is clicked. Fragment B has a ListView and a custom BaseAdapter to popuplate it.

When I place the app in the background while Fragment B is displayed, I get the exception below in Fragment A on onSaveInstanceState().

Any assistance greatly appreciated! Thanks!

// BaseActivity addFragment()
public void addFragment(@IdRes int id, Fragment fragment) {
    FragmentManager fragmentManager = getSupportFragmentManager();
    FragmentTransaction fragmentTransaction = fragmentManager.beginTransaction();
    fragmentTransaction.replace(id, fragment, fragment.toString());
    fragmentTransaction.addToBackStack(fragment.toString());
    fragmentTransaction.commit();
}

// Start Fragment A
BaseActivity activity = (BaseActivity) getActivity();
activity.addFragment(R.id.container, new FragmentAFragment());

// In FragmentAFragment: Show Fragment B
BaseActivity activity = (BaseActivity) getActivity();
activity.addFragment(R.id.container, FragmentBFragment.newInstance(getString(R.string.input_list), selectedListItem, new FragmentAFragment.ListSelectorListener() {
    @Override
    public void onSelected(final String selected) {
        // handle selection
    }
}));

FATAL EXCEPTION: main
android.support.v4.app.FragmentState.writeToParcel(Fragment.java:148)
    at android.os.Parcel.writeTypedArray(Parcel.java:1306)
    at android.support.v4.app.FragmentManagerState.writeToParcel(FragmentManager.java:564)
    at android.os.Parcel.writeParcelable(Parcel.java:1495)
    at android.os.Parcel.writeValue(Parcel.java:1401)
    at android.os.Parcel.writeArrayMapInternal(Parcel.java:723)
    at android.os.BaseBundle.writeToParcelInner(BaseBundle.java:1408)
    at android.os.Bundle.writeToParcel(Bundle.java:1133)
    at android.os.Parcel.writeBundle(Parcel.java:763)
    at android.app.ActivityManagerProxy.activityStopped(ActivityManagerNative.java:3603)
    at android.app.ActivityThread$StopInfo.run(ActivityThread.java:3744)
    at android.os.Handler.handleCallback(Handler.java:751)
    at android.os.Handler.dispatchMessage(Handler.java:95)
    at android.os.Looper.loop(Looper.java:154)
    at android.app.ActivityThread.main(ActivityThread.java:6077)
    at java.lang.reflect.Method.invoke(Native Method)
    at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:865)
    at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:755)
 Caused by: java.io.NotSerializableException: com.company.myapp.FragmentA$1
    at java.io.ObjectOutputStream.writeObject0(ObjectOutputStream.java:1224)
    at java.io.ObjectOutputStream.defaultWriteFields(ObjectOutputStream.java:1584)
    at java.io.ObjectOutputStream.writeSerialData(ObjectOutputStream.java:1549)
    at java.io.ObjectOutputStream.writeOrdinaryObject(ObjectOutputStream.java:1472)
    at java.io.ObjectOutputStream.writeObject0(ObjectOutputStream.java:1218)
    at java.io.ObjectOutputStream.writeObject(ObjectOutputStream.java:346)
    at android.os.Parcel.writeSerializable(Parcel.java:1521)
    at android.os.Parcel.writeValue(Parcel.java:1474) 
    at android.os.Parcel.writeArrayMapInternal(Parcel.java:723) 
    at android.os.BaseBundle.writeToParcelInner(BaseBundle.java:1408) 
    at android.os.Bundle.writeToParcel(Bundle.java:1133) 
    at android.os.Parcel.writeBundle(Parcel.java:763) 
    at android.support.v4.app.FragmentState.writeToParcel(Fragment.java:148) 
    at android.os.Parcel.writeTypedArray(Parcel.java:1306) 
    at android.support.v4.app.FragmentManagerState.writeToParcel(FragmentManager.java:564) 
    at android.os.Parcel.writeParcelable(Parcel.java:1495) 
    at android.os.Parcel.writeValue(Parcel.java:1401) 
    at android.os.Parcel.writeArrayMapInternal(Parcel.java:723) 
    at android.os.BaseBundle.writeToParcelInner(BaseBundle.java:1408) 
    at android.os.Bundle.writeToParcel(Bundle.java:1133) 
    at android.os.Parcel.writeBundle(Parcel.java:763) 
    at android.app.ActivityManagerProxy.activityStopped(ActivityManagerNative.java:3603) 
    at android.app.ActivityThread$StopInfo.run(ActivityThread.java:3744) 
    at android.os.Handler.handleCallback(Handler.java:751) 
    at android.os.Handler.dispatchMessage(Handler.java:95) 
    at android.os.Looper.loop(Looper.java:154) 
    at android.app.ActivityThread.main(ActivityThread.java:6077) 
    at java.lang.reflect.Method.invoke(Native Method) 
    at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:865) 
    at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:755)

Possible duplicate of [java.io.NotSerializableException](https://stackoverflow.com/questions/13895867/java-io-notserializableexception) — sushildlh, Aug 24 '17 at 13:35
If you have Overriden a `onSaveInstanceState()` in `FragmentA` then you should add that code too. Also take @sushildlh's comment, you might have incorrectly implemented `Parcelable`. — Abbas, Aug 24 '17 at 13:38
I haven't implemented Parcelable at all. I'm just passing simple data types between the Fragments. — checkmate711, Aug 24 '17 at 14:01

score 0 · Answer 1 · answered Aug 24 '17 at 14:58

I believe my issue was that the Listener inner class in Fragment A was not Parcelable or Serializable. I defined the listener as transient variable which prevented the exception.

private transient FragmentAFragment.ListSelectorListener listener = new FragmentAFragment.ListSelectorListener() {
    @Override
    public void onSelected(final String selected) {
    }
};

// then use the listener to start Fragment B
BaseActivity activity = (BaseActivity) getActivity();
activity.addFragment(R.id.container, FragmentBFragment.newInstance(getString(R.string.input_list), selectedListItem, listener));

Exception on onSaveInstanceState when Fragment starts another Fragment

1 Answers1