android - 谷歌地图代码中的 BadParcelableException

Question

运行稍加修改的 Google map 示例会在 Google map 代码中引发 BadParcelableException。 LatLng 类是 parcelable 但找不到。谷歌地图代码似乎试图解开未被它包裹的对象。什么情况下的问题？

package com.example.mapdemo;

import com.google.android.gms.maps.GoogleMap;
import com.google.android.gms.maps.MapView;
import com.google.android.gms.maps.model.LatLng;
import com.google.android.gms.maps.model.MarkerOptions;

import android.os.Bundle;

public class RawMapViewDemoActivity extends android.support.v4.app.FragmentActivity {
    private MapView mMapView;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.raw_mapview_demo);

        mMapView = (MapView) findViewById(R.id.map);
        mMapView.onCreate(savedInstanceState);
    }

    @Override
    public void onSaveInstanceState(Bundle outState) {
        super.onSaveInstanceState(outState);
        mMapView.onSaveInstanceState(outState);

        outState.putParcelable("marker", new LatLng(0, 0));
    }

    @Override
    protected void onRestoreInstanceState(Bundle savedInstanceState) {
        super.onRestoreInstanceState(savedInstanceState);

        LatLng ll = savedInstanceState.getParcelable("marker");
    }
}

...

FATAL EXCEPTION: main
java.lang.RuntimeException: Unable to start activity 
    ComponentInfo{com.example.mapdemo/com.example.mapdemo.RawMapViewDemoActivity}: 
    android.os.BadParcelableException: ClassNotFoundException when unmarshalling: 
    com.google.android.gms.maps.model.LatLng
   at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:1647)
   at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:1663)
   at android.app.ActivityThread.handleRelaunchActivity(ActivityThread.java:2832)
   at android.app.ActivityThread.access$1600(ActivityThread.java:117)
   at android.app.ActivityThread$H.handleMessage(ActivityThread.java:935)
   at android.os.Handler.dispatchMessage(Handler.java:99)
   at android.os.Looper.loop(Looper.java:130)
   at android.app.ActivityThread.main(ActivityThread.java:3683)
   at java.lang.reflect.Method.invokeNative(Native Method)
   at java.lang.reflect.Method.invoke(Method.java:507)
   at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:839)
   at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:597)
   at dalvik.system.NativeStart.main(Native Method)

Caused by: android.os.BadParcelableException: 
ClassNotFoundException when unmarshalling: com.google.android.gms.maps.model.LatLng
   at android.os.Parcel.readParcelable(Parcel.java:1958)
   at android.os.Parcel.readValue(Parcel.java:1846)
   at android.os.Parcel.readMapInternal(Parcel.java:2083)
   at android.os.Bundle.unparcel(Bundle.java:208)
   at android.os.Bundle.getBundle(Bundle.java:1078)
   at com.google.android.gms.maps.internal.MapStateHelper
       .getParcelableFromMapStateBundle(MapStateHelper.java:41)
   at maps.y.ae.a(Unknown Source)
   at maps.y.bm.onCreate(Unknown Source)
   at com.google.android.gms.maps.internal.IMapViewDelegate$Stub
       .onTransact(IMapViewDelegate.java:66)
   at android.os.Binder.transact(Binder.java:279)
   at com.google.android.gms.maps.internal.IMapViewDelegate$a$a
       .onCreate(Unknown Source)
   at com.google.android.gms.maps.MapView$b.onCreate(Unknown Source)
   at com.google.android.gms.internal.c$3.a(Unknown Source)
   at com.google.android.gms.internal.i.b(Unknown Source)
   at com.google.android.gms.maps.MapView$a.a(Unknown Source)
   at com.google.android.gms.maps.MapView$a.a(Unknown Source)
   at com.google.android.gms.internal.c.a(Unknown Source)
   at com.google.android.gms.internal.c.onCreate(Unknown Source)
   at com.google.android.gms.maps.MapView.onCreate(Unknown Source)
   at com.example.mapdemo.RawMapViewDemoActivity
       .onCreate(RawMapViewDemoActivity.java:40)
   at android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1047)
   at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:1611)
   ... 12 more

Answer 1

只是为了在此处添加现有答案，在调用 mapView.onCreate 之前，我一直在将我的包裹从保存状态中删除，它工作正常。

但是，在我的 Fragment 添加 ViewPager 之后，我没有意识到 BadParcelableException 已经返回并且代码已投入生产。事实证明 ViewPager 也保存了它的状态，因为它是支持库的一部分，谷歌地图找不到类来解包它。

所以我选择了反转这个过程，而不是从我知道的 Bundle 中删除 Parcel，我选择为 map 创建一个新的 Bundle，只复制 map 的状态。

private final static String BUNDLE_KEY_MAP_STATE = "mapData";

@Override
public void onSaveInstanceState(Bundle outState) {
    // Save the map state to it's own bundle
    Bundle mapState = new Bundle();
    mapView.onSaveInstanceState(mapState);
    // Put the map bundle in the main outState
    outState.putBundle(BUNDLE_KEY_MAP_STATE, mapState);
    super.onSaveInstanceState(outState);
}

@Override
public View onCreateView(LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState) {
    View view = inflater.inflate(R.layout.fragment_map, container, false);
    mapView = (MapView) view.findViewById(R.id.mapView);
    mapView.getMapAsync(this);

    Bundle mapState = null;
    if (savedInstanceState != null) {
        // Load the map state bundle from the main savedInstanceState
        mapState = savedInstanceState.getBundle(BUNDLE_KEY_MAP_STATE);
    }

    mapView.onCreate(mapState);
    return view;
}