ClassNotFoundException的解組時：android.support.v4.view.ViewPager $ SavedState

Question

我看到下面的錯誤在我的Android崩潰報告：

android.os.BadParcelableException: ClassNotFoundException when unmarshalling: android.support.v4.view.ViewPager$SavedState 
at android.os.Parcel.readParcelable(Parcel.java:1971) 
at android.os.Parcel.readValue(Parcel.java:1859) 
at android.os.Parcel.readSparseArrayInternal(Parcel.java:2128) 
at android.os.Parcel.readSparseArray(Parcel.java:1581) 
at android.os.Parcel.readValue(Parcel.java:1916) 
at android.os.Parcel.readMapInternal(Parcel.java:2099) 
at android.os.Bundle.unparcel(Bundle.java:223) 
at android.os.Bundle.getSparseParcelableArray(Bundle.java:1225) 
at android.support.v4.app.FragmentManagerImpl.moveToState(FragmentManager.java:806) 
at android.support.v4.app.FragmentManagerImpl.moveToState(FragmentManager.java:1083) 
at android.support.v4.app.BackStackRecord.run(BackStackRecord.java:635) 
at android.support.v4.app.FragmentManagerImpl.execPendingActions(FragmentManager.java:1431) 
at android.support.v4.app.FragmentManagerImpl.executePendingTransactions(FragmentManager.java:431) 
at android.support.v4.app.FragmentStatePagerAdapter.finishUpdate(FragmentStatePagerAdapter.java:160) 
at android.support.v4.view.ViewPager.populate(ViewPager.java:895) 
at android.support.v4.view.ViewPager.populate(ViewPager.java:772) 
at android.support.v4.view.ViewPager.completeScroll(ViewPager.java:1539) 
at android.support.v4.view.ViewPager.computeScroll(ViewPager.java:1422) 
at android.view.ViewGroup.drawChild(ViewGroup.java:3028) 
at android.view.ViewGroup.dispatchDraw(ViewGroup.java:2788) 
at android.view.ViewGroup.drawChild(ViewGroup.java:3184) 
at android.view.ViewGroup.dispatchDraw(ViewGroup.java:2788) 
at android.view.ViewGroup.drawChild(ViewGroup.java:3184) 
at android.view.ViewGroup.dispatchDraw(ViewGroup.java:2788) 
at android.view.ViewGroup.drawChild(ViewGroup.java:3184) 
at android.view.ViewGroup.dispatchDraw(ViewGroup.java:2788) 
at android.view.View.draw(View.java:11017) 
at android.widget.FrameLayout.draw(FrameLayout.java:450) 
at com.android.internal.policy.impl.PhoneWindow$DecorView.draw(PhoneWindow.java:2175) 
at android.view.ViewRootImpl.draw(ViewRootImpl.java:2234) 
at android.view.ViewRootImpl.performTraversals(ViewRootImpl.java:1810) 
at android.view.ViewRootImpl.handleMessage(ViewRootImpl.java:2695) 
at android.os.Handler.dispatchMessage(Handler.java:99) 
at android.os.Looper.loop(Looper.java:154) 
at android.app.ActivityThread.main(ActivityThread.java:4977) 
at java.lang.reflect.Method.invokeNative(Native Method) 
at java.lang.reflect.Method.invoke(Method.java:511) 
at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:784) 
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:551) 
at dalvik.system.NativeStart.main(Native Method) 

恢復活動時，這似乎是間歇性地發生。我不直接訪問任何代碼中的SavedState類。

Answer 1

我有同樣的錯誤，這就是我所做的。

我的問題來自使用ViewPager和FragmentStatePagerAdapter。在ViewPager的其中一個片段中有另一個ViewPager。有第二個查看尋呼機造成這個罕見的錯誤。即使有或沒有適配器。

解決方案是簡單地設置setSaveEnabled（false）;在第二個ViewPager上。

Answer 2

以下解決方案爲我工作：從http://code.google.com/p/android/issues/detail?id=37484#c1

Answer 3

package android.support.v4.app; 

import android.os.Bundle; 
import android.view.ViewGroup; 

public abstract class FixedFragmentStatePagerAdapter extends FragmentStatePagerAdapter { 

    public FixedFragmentStatePagerAdapter(FragmentManager fm) { 
    super(fm); 
    } 

    @Override 
    public Object instantiateItem(ViewGroup container, int position) { 
    Fragment f = (Fragment)super.instantiateItem(container, position); 
    Bundle savedFragmentState = f.mSavedFragmentState; 
    if (savedFragmentState != null) { 
     savedFragmentState.setClassLoader(f.getClass().getClassLoader()); 
    } 
    return f; 
    } 

} 

如果您不想要在V4包的源，你可以聲明在您的適配器「修復」直接

@Override 
    public Object instantiateItem(ViewGroup container, int position) { 
     final Object fragment = super.instantiateItem(container, position); 
     try { 
      final Field saveFragmentStateField = Fragment.class.getDeclaredField("mSavedFragmentState"); 
      saveFragmentStateField.setAccessible(true); 
      final Bundle savedFragmentState = (Bundle) saveFragmentStateField.get(fragment); 
      if (savedFragmentState != null) { 
       savedFragmentState.setClassLoader(Fragment.class.getClassLoader()); 
      } 
     } catch (Exception e) { 
      Log.w("CustomFragmentStatePagerAdapter", "Could not get mSavedFragmentState field", e); 
     } 
     return fragment; 
    } 

Answer 4

答案可能會很晚。我用FragmentPagerAdapter代替了FragmentStatePagerAdapter。爲我工作就像一個魅力！

Answer 5

在您的活動/片段，執行以下操作：

public void onSaveInstanceState(Bundle outState){ 
    //This MUST be done before saving any of your own or your base class's  variables 
    final Bundle mapViewSaveState = new Bundle(outState); 
    mapView.onSaveInstanceState(mapViewSaveState); 
    outState.putBundle("mapViewSaveState", mapViewSaveState); 
    //Add any other variables here. 
    super.onSaveInstanceState(outState); 
} 

public void onCreate(Bundle savedInstanceState){ 
    super.onCreate(savedInstanceState); 
    final Bundle mapViewSavedInstanceState = savedInstanceState != null ?  savedInstance.getBundle("mapViewSaveState") : null; 
mapView.onCreate(mapViewSavedInstanceState); 
//.... 
} 

源：https://code.google.com/p/gmaps-api-issues/issues/detail?id=6237

或另一種解決方案是：

map.onCreate（savedInstanceState）;

對此：

map.onCreate（null）;