旋转设备时 RecyclerView / MapView 崩溃

Question

我有一个 Android.Support.V4.Fragment，其中包含一个 MapView 和一个 RecyclerView。这些是 Fragment.

中的独立视图

旋转设备时应用崩溃：

Android.OS.BadParcelableException: ClassNotFoundException when unmarshalling: android.support.v7.widget.RecyclerView$SavedState

我按照文档的要求将生命周期方法传递给 MapView：

private MapView mapView;
private RecyclerView myRecyclerView;
private RecyclerView.LayoutManager myLayoutManager;

public override View OnCreateView(LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState)
{
    base.OnCreateView(inflater, container, savedInstanceState);

    myRecyclerView = myRootView.FindViewById<RecyclerView>(Resource.Id.myRecyclerView);
    myLayoutManager = new LinearLayoutManager(activity, LinearLayoutManager.Horizontal, false);
    myRecyclerView.SetLayoutManager(myLayoutManager);
    myRecyclerAdapter = ...
    myRecyclerView.SetAdapter(myRecyclerAdapter);

    mapView.OnCreate(savedInstanceState);
}


public override void OnSaveInstanceState(Bundle outState)
{
    ...
    if (mapView != null) mapView.OnSaveInstanceState(outState);
    base.OnSaveInstanceState(outState);
}

如果我从 AXML 中删除 RecyclerView 它会正确旋转，如果我包含它，应用程序会在 mapView.OnCreate(savedInstanceState) 崩溃，这是为什么？

Answer 1

对于任何搜索过并遇到同样问题的人。 This is the solution，这似乎是一个 2 年前的错误。

I was able to get around it by saving the MapView's saved state on a separate Bundle and then adding it to the outgoing saved state bundle. Then in onCreate(), I would just grab the MapView's saved state from the incoming one and pass it into its onCreate() method, thus stopping the crashes.

在我的例子中，我是这样实现的：

public override View OnCreateView(LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState) 
{
    base.OnCreateView(inflater, container, savedInstanceState);

    myRecyclerView = myRootView.FindViewById<RecyclerView>(Resource.Id.myRecyclerView);
    myLayoutManager = new LinearLayoutManager(activity, LinearLayoutManager.Horizontal, false);
    myRecyclerView.SetLayoutManager(myLayoutManager);
    myRecyclerAdapter = ...
    myRecyclerView.SetAdapter(myRecyclerAdapter);

    Bundle mapViewSavedInstanceState = savedInstanceState != null ? savedInstanceState.GetBundle("mapViewSaveState") : null;
    mapView.OnCreate(mapViewSavedInstanceState); 
}


public override void OnSaveInstanceState(Bundle outState) 
{
    if (mapView != null)
    { 
        Bundle mapViewSaveState = new Bundle(outState);
        outState.PutBundle("mapViewSaveState", mapViewSaveState);
        mapView.OnSaveInstanceState(outState);

    }
    base.OnSaveInstanceState(outState); 
}

Answer 2

Tallpaul 的回答对我不起作用。不过，他链接的解决方案运行良好。

public class FragmentMain extends Fragment {

    private Bundle savedInstanceState;

    @Override
    public void onCreate(@Nullable Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);

        ... 

        this.savedInstanceState =  savedInstanceState; 
    }

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

        //mapView bug https://code.google.com/p/gmaps-api-issues/issues/detail?id=6237#c9
        final Bundle mapViewSavedInstanceState =
            savedInstanceState != null ?  
                savedInstanceState.getBundle("mapViewSaveState") : null;

        vmGoogleMap.create( mapViewSavedInstanceState  ;


        return containerView;
    }

    @Override
    public void onSaveInstanceState(Bundle outState) {

        //mapView bug https://code.google.com/p/gmaps-api-issues/issues/detail?id=6237#c9 
        final Bundle mapViewSaveState = new Bundle(outState);
        vmGoogleMap.onSaveInstanceState(mapViewSaveState);
        outState.putBundle("mapViewSaveState", mapViewSaveState);

        super.onSaveInstanceState(outState);
    }

}

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