无法暂停活动，故障状态保存

Question

我建立一个Android应用程序，现在，如果我按Home键或给定方案后，锁定屏幕（这是真的特定的），我的应用程序崩溃，并显示错误：

10-26 13:57:50.132: E/AndroidRuntime(8663): FATAL EXCEPTION: main 
10-26 13:57:50.132: E/AndroidRuntime(8663): java.lang.RuntimeException: Unable to pause activity {.views.MainActivity}: java.lang.IllegalStateException: Failure saving state: active LoginFragment{4053d5a0} has cleared index: -1 
10-26 13:57:50.132: E/AndroidRuntime(8663):  at android.app.ActivityThread.performPauseActivity(ActivityThread.java:2365) 
10-26 13:57:50.132: E/AndroidRuntime(8663):  at android.app.ActivityThread.performPauseActivity(ActivityThread.java:2322) 
10-26 13:57:50.132: E/AndroidRuntime(8663):  at android.app.ActivityThread.handlePauseActivity(ActivityThread.java:2302) 
10-26 13:57:50.132: E/AndroidRuntime(8663):  at android.app.ActivityThread.access$1700(ActivityThread.java:117) 
10-26 13:57:50.132: E/AndroidRuntime(8663):  at android.app.ActivityThread$H.handleMessage(ActivityThread.java:949) 
10-26 13:57:50.132: E/AndroidRuntime(8663):  at android.os.Handler.dispatchMessage(Handler.java:99) 
10-26 13:57:50.132: E/AndroidRuntime(8663):  at android.os.Looper.loop(Looper.java:130) 
10-26 13:57:50.132: E/AndroidRuntime(8663):  at android.app.ActivityThread.main(ActivityThread.java:3694) 
10-26 13:57:50.132: E/AndroidRuntime(8663):  at java.lang.reflect.Method.invokeNative(Native Method) 
10-26 13:57:50.132: E/AndroidRuntime(8663):  at java.lang.reflect.Method.invoke(Method.java:507) 
10-26 13:57:50.132: E/AndroidRuntime(8663):  at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:860) 
10-26 13:57:50.132: E/AndroidRuntime(8663):  at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:618) 
10-26 13:57:50.132: E/AndroidRuntime(8663):  at dalvik.system.NativeStart.main(Native Method) 
10-26 13:57:50.132: E/AndroidRuntime(8663): Caused by: java.lang.IllegalStateException: Failure saving state: active LoginFragment{4053d5a0} has cleared index: -1 
10-26 13:57:50.132: E/AndroidRuntime(8663):  at android.support.v4.app.FragmentManagerImpl.saveAllState(FragmentManager.java:1695) 
10-26 13:57:50.132: E/AndroidRuntime(8663):  at android.support.v4.app.FragmentActivity.onSaveInstanceState(FragmentActivity.java:499) 
10-26 13:57:50.132: E/AndroidRuntime(8663):  at views.MainActivity.onSaveInstanceState(MainActivity.java:62) 
10-26 13:57:50.132: E/AndroidRuntime(8663):  at android.app.Activity.performSaveInstanceState(Activity.java:1042) 
10-26 13:57:50.132: E/AndroidRuntime(8663):  at android.app.Instrumentation.callActivityOnSaveInstanceState(Instrumentation.java:1181) 
10-26 13:57:50.132: E/AndroidRuntime(8663):  at android.app.ActivityThread.performPauseActivity(ActivityThread.java:2347) 
10-26 13:57:50.132: E/AndroidRuntime(8663):  ... 12 more 

我不知道这个错误来自什么，这个错误的一般原因是什么。

编辑：
对不起，我会发出一些更多的信息。基本上，我有一个FragmentActivity（这是我的Tabhost），每个选项卡是我可以导航到另一个片段的片段。

具体方案是如下：

• 应用打开时，选项卡0与片段0（LoginFragment）被显示。
• 用户登录后，LoginFragment被ProfileFragment取代。
• 从ProfileFragment，用户必须注销的能力，这样做，再次替换Loginfragment的Profilefragment。
• 用户从TabHost导航到不同的选项卡。
• 用户导航回原始选项卡。
• 用户然后锁定屏幕/使用主页按钮，崩溃与给定的错误的应用程序。

我只在这个特定的情况下得到错误。

错误从TabManager类起源的TabHost FragmentActivity内，这里是代码（主要从Android FragmentTabs例子，有一些小的调整）：

public static class TabManager implements TabHost.OnTabChangeListener { 
    private final FragmentActivity mActivity; 
    private final TabHost mTabHost; 
    private final int mContainerId; 
    private final HashMap<String, TabInfo> mTabs = new HashMap<String, TabInfo>(); 
    TabInfo mLastTab; 

    static final class TabInfo { 
     private final String tag; 
     private final Class<?> clss; 
     private final Bundle args; 
     private Fragment fragment; 

     TabInfo(String _tag, Class<?> _class, Bundle _args) { 
      tag = _tag; 
      clss = _class; 
      args = _args; 
     } 
    } 

    static class DummyTabFactory implements TabHost.TabContentFactory { 
     private final Context mContext; 

     public DummyTabFactory(Context context) { 
      mContext = context; 
     } 

     public View createTabContent(String tag) { 
      View v = new View(mContext); 
      v.setMinimumWidth(0); 
      v.setMinimumHeight(0); 
      return v; 
     } 
    } 

    public TabManager(FragmentActivity activity, TabHost tabHost, int containerId) { 
     mActivity = activity; 
     mTabHost = tabHost; 
     mContainerId = containerId; 
     mTabHost.setOnTabChangedListener(this); 
    } 

    public void addTab(TabHost.TabSpec tabSpec, Class<?> clss, Bundle args) { 
     tabSpec.setContent(new DummyTabFactory(mActivity)); 
     String tag = tabSpec.getTag(); 

     TabInfo info = new TabInfo(tag, clss, args); 

     // Check to see if we already have a fragment for this tab, probably 
     // from a previously saved state. If so, deactivate it, because our 
     // initial state is that a tab isn't shown. 
     info.fragment = mActivity.getSupportFragmentManager().findFragmentByTag(tag); 
       if (info.fragment != null && !info.fragment.isDetached()) { 
        FragmentTransaction ft = mActivity.getSupportFragmentManager().beginTransaction(); 
        ft.detach(info.fragment); 
        ft.commit(); 
       } 

       mTabs.put(tag, info); 
       mTabHost.addTab(tabSpec); 
    } 

    public void onTabChanged(String tabId) { 

     TabInfo newTab = mTabs.get(tabId); 
     if (mLastTab != newTab) { 
      FragmentTransaction ft = mActivity.getSupportFragmentManager().beginTransaction(); 
      if (mLastTab != null) { 
       if (mLastTab.fragment != null) { 
        ft.detach(mLastTab.fragment); 
       } 
      } 
      if (newTab != null) { 
       if (newTab.fragment == null) { 
        newTab.fragment = Fragment.instantiate(mActivity, 
          newTab.clss.getName(), newTab.args); 
        ft.add(mContainerId, newTab.fragment, newTab.tag); 

       } else { 
        ft.attach(newTab.fragment); 
       } 
      } 
      int backEntryCount = mActivity.getSupportFragmentManager().getBackStackEntryCount(); 
      if (backEntryCount > 1) { 
       mActivity.getSupportFragmentManager().popBackStack(null, 0); 
      } 

      //If there's a current BackTrace, remove it and instantiate the original fragment of the selected tab. 
      FragmentManager fm = mActivity.getSupportFragmentManager(); 
      if (fm.getBackStackEntryCount() >= 1) { 
       fm.popBackStack(); 
       newTab.fragment.getFragmentManager().beginTransaction().add(mLastTab.fragment.getId(), newTab.fragment = Fragment.instantiate(mActivity, 
         newTab.clss.getName(), newTab.args)); 
      } 
      if (mActivity.getSupportFragmentManager().findFragmentByTag("userprofile") != null) { 
       Fragment fragment = mActivity.getSupportFragmentManager().findFragmentByTag("userprofile"); 
       ft.detach(fragment); 

      } 
      if (newTab.fragment.getClass().getName().contains("Login") && Preferences.getUser(mActivity).getApikey() != null) { 
       ft.replace(mLastTab.fragment.getId(), new ProfileFragment(), "userprofile"); 
       ft.detach(newTab.fragment); 
      } 

      if (mActivity.getSupportFragmentManager().findFragmentByTag("Profile") != null) { 
       if (mActivity.getSupportFragmentManager().findFragmentByTag("Profile").isDetached() == true) { 
        System.out.println(true); 
        Fragment fragment = mActivity.getSupportFragmentManager().findFragmentByTag("Profile"); 
        mActivity.getSupportFragmentManager().beginTransaction().replace(fragment.getId(), new LoginFragment(), "Profile").commit(); 
       } 
      } 
      mLastTab = newTab; 
      ft.commit(); 
      mActivity.getSupportFragmentManager().executePendingTransactions(); 

     } 
    } 
} 

Answer 1

对不起，这个答案是晚了，但我发现为什么我有这个错误。出于某种原因，我有多个导致崩溃的LoginFragment实例。我删除了一些代码，这样片段只会被实例化一次，之后我再也没有崩溃。