Using multiple layouts breaks orientation change

Question

I've succeeded in handling configuration change with fragments, but I only used one XML layout for the container.

Now I need to use a layout for landscape mode, and when I turn my phone and try to change currently displayed fragments I get an error:

E/AndroidRuntime: FATAL EXCEPTION: main
java.lang.IllegalStateException: Can not perform this action after onSaveInstanceState
at android.app.FragmentManagerImpl.checkStateLoss(FragmentManager.java:1328)
at android.app.FragmentManagerImpl.enqueueAction(FragmentManager.java:1346)
at android.app.BackStackRecord.commitInternal(BackStackRecord.java:729)
at android.app.BackStackRecord.commit(BackStackRecord.java:705)

Here are my two layouts:

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:id="@+id/main_layout_container"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:orientation="vertical" />

And for the landscape one:

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:id="@+id/main_layout_container"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:orientation="horizontal" />

As you can see both are the exact same except for the orientation. I guess the problem might come from reusing old fragments which were added using another orientation ?

Thanks for your help

Edit: Code for my activity

package crysteo.pluggicontroller;

public class MainFragmentActivity extends FragmentActivity implements StateModifier,IpAddressChangedListener {

private RemoteFragment remoteFragment;
private MainFragment mainFragment;
private DeviceListFragment deviceListFragment;
private RetainedFragment retainedFragment;
private HandleConnection handleConnection;
private ConnectedFragment connectedFragment;
private CameraFragment cameraFragment;
private final PluggiHandler handler = new PluggiHandler(this);


private static class PluggiHandler extends Handler {
    private final WeakReference<MainFragmentActivity> mainFragmentActivityWeakReference;

    public PluggiHandler(MainFragmentActivity mainFragmentActivity) {
        this.mainFragmentActivityWeakReference = new WeakReference<>(mainFragmentActivity);
    }

    @Override
    public void handleMessage(Message msg) {
        MainFragmentActivity mainFragmentActivity = this.mainFragmentActivityWeakReference.get();
        BluetoothConstants.BluetoothMessageWhat msgEnum = BluetoothConstants.BluetoothMessageWhat.values()[msg.what];
        switch (msgEnum) {
            case MESSAGE_STATE_CHANGE:
                BluetoothConstants.BluetoothStates argEnum = BluetoothConstants.BluetoothStates.values()[msg.arg1];
                switch (argEnum) {
                    case STATE_CONNECTED:
                        mainFragmentActivity.connected();
                        break;
                    case STATE_CONNECTING:
                        Toast.makeText(mainFragmentActivity.getApplicationContext(), R.string.connecting_bluetooth, Toast.LENGTH_SHORT).show();
                        break;
                    case STATE_NONE:
                        break;
                    default:
                        break;
                }
                break;
            case MESSAGE_WRITE:
                /*byte[] writeBuf = (byte[]) msg.obj;
                // construct a string from the buffer
                String writeMessage = new String(writeBuf);
                mConversationArrayAdapter.add("Me:  " + writeMessage);*/
                break;
            case MESSAGE_READ:
                /*byte[] readBuf = (byte[]) msg.obj;
                // construct a string from the valid bytes in the buffer
                String readMessage = new String(readBuf, 0, msg.arg1);
                mConversationArrayAdapter.add(mConnectedDeviceName + ":  " + readMessage);*/
                break;
            case MESSAGE_DEVICE_NAME:
                Toast.makeText(mainFragmentActivity, String.format(mainFragmentActivity.getResources().getString(R.string.connected_bluetooth),
                        msg.getData().getString(Constants.DEVICE_NAME)), Toast.LENGTH_SHORT).show();
                break;
            case MESSAGE_TOAST:
                if (null != mainFragmentActivity) {
                    Toast.makeText(mainFragmentActivity, msg.getData().getString(Constants.TOAST),
                            Toast.LENGTH_SHORT).show();
                }
                break;
            default:
                break;
        }
        mainFragmentActivity.connected();
    }
}

;


@Override
public void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.main_layout);

    FragmentTransaction fragmentTransaction = getFragmentManager().beginTransaction();

    if (savedInstanceState == null) {
        retainedFragment = new RetainedFragment();
        fragmentTransaction.add(retainedFragment, RetainedFragment.class.toString());
        handleConnection = new HandleConnection(this, handler);
        retainedFragment.setHandleConnection(handleConnection);

        deviceListFragment = new DeviceListFragment();
        remoteFragment = new RemoteFragment();
        mainFragment = new MainFragment();
        connectedFragment = new ConnectedFragment();
        cameraFragment = new CameraFragment();
        fragmentTransaction.add(R.id.main_layout_container, mainFragment, MainFragment.class.toString());
    } else {
        mainFragment = (MainFragment) getFragmentManager().findFragmentByTag(MainFragment.class.toString());
        deviceListFragment = (DeviceListFragment) getFragmentManager().findFragmentByTag(DeviceListFragment.class.toString());
        remoteFragment = (RemoteFragment) getFragmentManager().findFragmentByTag(RemoteFragment.class.toString());
        retainedFragment = (RetainedFragment) getFragmentManager().findFragmentByTag(RetainedFragment.class.toString());
        connectedFragment = (ConnectedFragment) getFragmentManager().findFragmentByTag(ConnectedFragment.class.toString());
        cameraFragment = (CameraFragment) getFragmentManager().findFragmentByTag(CameraFragment.class.toString());

        if (mainFragment == null)
            mainFragment = new MainFragment();

        if (deviceListFragment == null)
            deviceListFragment = new DeviceListFragment();

        if (remoteFragment == null)
            remoteFragment = new RemoteFragment();

        if (connectedFragment == null)
            connectedFragment = new ConnectedFragment();

        if (cameraFragment == null)
            cameraFragment = new CameraFragment();

        handleConnection = retainedFragment.getHandleConnection();
    }

    fragmentTransaction.commit();

    mainFragment.setBluetoothListener(handleConnection);
    if (retainedFragment.getSelectedMac() != null)
        mainFragment.onMacAddressChanged(retainedFragment.getSelectedMac());
    remoteFragment.setHandleConnection(handleConnection);
    mainFragment.setStateModifier(this);
    deviceListFragment.setStateModifier(this);
    deviceListFragment.setMacAddressChangedListener(mainFragment);
    connectedFragment.setStateModifier(this);
    connectedFragment.setIpAddressChangedListener(this);
}

@Override
public void onDestroy() {
    retainedFragment.setHandleConnection(handleConnection);
    super.onDestroy();
}

@Override
public void listDevices() {
    FragmentTransaction fragmentTransaction = getFragmentManager().beginTransaction();
    fragmentTransaction.replace(R.id.main_layout_container, deviceListFragment, DeviceListFragment.class.toString());
    fragmentTransaction.addToBackStack("listDevices");
    fragmentTransaction.commit();
}

@Override
public void deviceSelected(String macAddress) {
    getFragmentManager().popBackStack();
    retainedFragment.setSelectedMac(macAddress);
    mainFragment.onMacAddressChanged(macAddress);
}

@Override
public void connected() {
    FragmentTransaction fragmentTransaction = getFragmentManager().beginTransaction();
    fragmentTransaction.replace(R.id.main_layout_container, connectedFragment, ConnectedFragment.class.toString());
    fragmentTransaction.addToBackStack("connected");
    fragmentTransaction.commit();
}

@Override
public void onBackPressed() {
    if (getFragmentManager().getBackStackEntryCount() > 0) {
        getFragmentManager().popBackStack();
    } else {
        super.onBackPressed();
    }
}

@Override
public void remoteControl() {
    FragmentTransaction fragmentTransaction = getFragmentManager().beginTransaction();
    fragmentTransaction.remove(connectedFragment);
    fragmentTransaction.add(R.id.main_layout_container, cameraFragment, CameraFragment.class.toString());
    fragmentTransaction.add(R.id.main_layout_container, remoteFragment, RemoteFragment.class.toString());
    fragmentTransaction.addToBackStack("manualMode");
    fragmentTransaction.commit();
}

@Override
public void soundsControl() {
    FragmentTransaction fragmentTransaction = getFragmentManager().beginTransaction();
    fragmentTransaction.replace(R.id.main_layout_container, cameraFragment, CameraFragment.class.toString());
    fragmentTransaction.addToBackStack("soundControl");
    fragmentTransaction.commit();
}

@Override
public void infoDisplay() {

}

@Override
public void onIpChangedListener(String ip) {
    cameraFragment.setIp(ip);
}
}

And for the fragment which should be displayed:

public class ConnectedFragment extends Fragment {

private StateModifier stateModifier;
private IpAddressChangedListener ipAddressChangedListener;

@Nullable
@Override
public View onCreateView(LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState) {
    View root = inflater.inflate(R.layout.connected_fragment_layout, container, false);

    root.findViewById(R.id.remote_control_button).setOnClickListener(new View.OnClickListener() {
        @Override
        public void onClick(View v) {
            stateModifier.remoteControl();
        }
    });

    root.findViewById(R.id.sounds_button).setOnClickListener(new View.OnClickListener() {
        @Override
        public void onClick(View v) {
            stateModifier.soundsControl();
        }
    });

    final EditText editText = (EditText)root.findViewById(R.id.ip_edit_text);

    root.findViewById(R.id.change_ip_button).setOnClickListener(new View.OnClickListener() {
        @Override
        public void onClick(View v) {
            ipAddressChangedListener.onIpChangedListener(editText.getText().toString());
        }
    });

    return root;
}

public void setStateModifier(StateModifier stateModifier) {
    this.stateModifier = stateModifier;
}

public void setIpAddressChangedListener(IpAddressChangedListener ipAddressChangedListener) {
    this.ipAddressChangedListener = ipAddressChangedListener;
}
}

Answer 1

So the problem came from my HandleConnection object. I didn't update the reference to the handler, which means that the handler called was referring to an already destroyed activity.

I found that by using commitAllowingStateLoss() in my fragment transaction. Instead of getting only a java.lang.IllegalStateException: Can not perform this action after onSaveInstanceState I got a java.lang.IllegalStateException: Activity has been destroyed error which allowed me to guess what the issue was.