DialogFragment onStart的BadTokenException

Question

我浏览了100篇关于BadTokenException的帖子，但似乎每次都会有另一个原因导致这种情况发生，在我的例子中，我有时会看到这个堆栈跟踪(并不总是发生/不知道如何重现)：

Caused by android.view.WindowManager$BadTokenException: Unable to add window – token android.os.BinderProxy@2a5a564 is not valid; is your activity running?
at android.view.ViewRootImpl.setView(ViewRootImpl.java:602)
at android.view.WindowManagerGlobal.addView(WindowManagerGlobal.java:322)
at android.view.WindowManagerImpl.addView(WindowManagerImpl.java:98)
at android.app.Dialog.show(Dialog.java:319)
at android.support.v4.app.DialogFragment.onStart(SourceFile:434)
at com.mycompany.myapp.ui.about.WhatsNewDialog.onStart(SourceFile:89)
at android.support.v4.app.Fragment.performStart(SourceFile:2372)
at android.support.v4.app.FragmentManagerImpl.moveToState(SourceFile:1467)
at android.support.v4.app.FragmentManagerImpl.moveFragmentToExpectedState(SourceFile:1759)
at android.support.v4.app.FragmentManagerImpl.moveToState(SourceFile:1827)
at android.support.v4.app.BackStackRecord.executeOps(SourceFile:797)
at android.support.v4.app.FragmentManagerImpl.executeOps(SourceFile:2596)
at android.support.v4.app.FragmentManagerImpl.executeOpsTogether(SourceFile:2383)
at android.support.v4.app.FragmentManagerImpl.removeRedundantOperationsAndExecute(SourceFile:2338)
at android.support.v4.app.FragmentManagerImpl.execPendingActions(SourceFile:2245)
at android.support.v4.app.FragmentManagerImpl.dispatchStateChange(SourceFile:3248)
at android.support.v4.app.FragmentManagerImpl.dispatchResume(SourceFile:3212)
at android.support.v4.app.FragmentController.dispatchResume(SourceFile:217)
at android.support.v4.app.FragmentActivity.onResumeFragments(SourceFile:509)
at android.support.v4.app.FragmentActivity.onPostResume(SourceFile:498)
at android.support.v7.app.AppCompatActivity.onPostResume(SourceFile:171)
at android.app.Activity.performResume(Activity.java:6415)
at android.app.ActivityThread.performResumeActivity(ActivityThread.java:3146)
at android.app.ActivityThread.handleResumeActivity(ActivityThread.java:3268)
at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2520)
at android.app.ActivityThread.access$900(ActivityThread.java:179)
at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1380)
at android.os.Handler.dispatchMessage(Handler.java:102)
at android.os.Looper.loop(Looper.java:148)
at android.app.ActivityThread.main(ActivityThread.java:5560)
at java.lang.reflect.Method.invoke(Method.java)
at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:730)
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:620)

根据我对跟踪的理解，异常直接发生在DialogFragment的onStart中，这是应用程序本身唯一显示的代码行，在那一行只调用了super.onStart()，这个方法中没有更多的东西，所以这真的很混乱，你理解了吗？在这种情况下，是否也可以使用"activity.isFinishing()“解决方案？在堆栈跟踪中，我甚至看不到调用新的WhatsNewDialog().show()的行，所以这可能真的会在以某种方式恢复对话框时发生，欢迎任何提示。

Answer 1

它实际上会给你一个错误。

您正在从非活动活动启动DialogFragment。因此，您要么在启动dialogFragment后立即完成该活动，要么使用活动的死版本或内存泄漏版本启动该活动。