Xamarin无法在onSavedInstanceState后执行此操作

我打开Zxing扫描仪的相机屏幕，我也使用自定义模板。在我的自定义模板，我已经建立了SetDisplayHomeAsUpEnabled(true)但是当我点击它，我得到这个错误Java.Lang.IllegalStateException: Can not perform this action after onSaveInstanceStateXamarin无法在onSavedInstanceState后执行此操作

这里是我的单击事件：

private void Toolbar_NavigationClick(object sender, Android.Support.V7.Widget.Toolbar.NavigationClickEventArgs e) 
    { 
     var mainActivity = Activity as MainActivity; 
     mainActivity?.OnBackPressed(); 
    }

我的错误的完整堆栈跟踪：

[ERROR] FATAL UNHANDLED EXCEPTION: Java.Lang.IllegalStateException: Can not perform this action after onSaveInstanceState 
--- End of managed Java.Lang.IllegalStateException stack trace --- 
java.lang.IllegalStateException: Can not perform this action after onSaveInstanceState 
at android.support.v4.app.FragmentManagerImpl.checkStateLoss(FragmentManager.java:1842) 
at android.support.v4.app.FragmentManagerImpl.popBackStackImmediate(FragmentManager.java:775) 
at android.support.v7.widget.Toolbar_NavigationOnClickEventDispatcher.n_onClick(Native Method) 
at android.support.v7.widget.Toolbar_NavigationOnClickEventDispatcher.onClick(Toolbar_NavigationOnClickEventDispatcher.java:37) 
at android.view.View.performClick(View.java:5698) 
at android.view.View$PerformClick.run(View.java:22523) 
at android.os.Handler.handleCallback(Handler.java:739) 
at android.os.Handler.dispatchMessage(Handler.java:95) 
at android.os.Looper.loop(Looper.java:158) 
at android.app.ActivityThread.main(ActivityThread.java:7230) 
at java.lang.reflect.Method.invoke(Native Method) 
at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:1230) 
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:1120)

设备上的后退按钮工作正常，但我不知道为什么我在onBackPressed()上收到此错误。

来源

2017-09-26 Nick King

您是否在您的活动中重写此方法？

public override bool OnOptionsItemSelected(IMenuItem item) 
    { 
     switch (item.ItemId) 
     { 
      case Android.Resource.Id.Home: 
       Finish(); 
       return true; 
      default: 
       return base.OnOptionsItemSelected(item); 
     } 

    }

来源

2017-09-27 10:59:50 younes

Xamarin无法在onSavedInstanceState后执行此操作

回答

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