IllegalStateException

Question

我在 Google-Play 控制台中看到 IllegalStateException，我无法重现。

这是堆栈跟踪：

java.lang.RuntimeException: 
      at android.app.ActivityThread.performLaunchActivity (ActivityThread.java:3253)
      at android.app.ActivityThread.handleLaunchActivity (ActivityThread.java:3349)
      at android.app.ActivityThread.access00 (ActivityThread.java:221)
      at android.app.ActivityThread$H.handleMessage (ActivityThread.java:1794)
      at android.os.Handler.dispatchMessage (Handler.java:102)
      at android.os.Looper.loop (Looper.java:158)
      at android.app.ActivityThread.main (ActivityThread.java:7224)
      at java.lang.reflect.Method.invoke (Native Method)
      at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run (ZygoteInit.java:1230)
      at com.android.internal.os.ZygoteInit.main (ZygoteInit.java:1120)
Caused by: java.lang.IllegalStateException: 
      at android.support.v4.app.FragmentManagerImpl.getFragment (FragmentManager.java:668)
      at android.support.v4.app.FragmentManagerImpl.moveToState (FragmentManager.java:999)
      at android.support.v4.app.FragmentManagerImpl.moveToState (FragmentManager.java:1252)
      at android.support.v4.app.FragmentManagerImpl.moveToState (FragmentManager.java:1234)
      at android.support.v4.app.FragmentManagerImpl.dispatchCreate (FragmentManager.java:2041)
      at android.support.v4.app.Fragment.performCreate (Fragment.java:1964)
      at android.support.v4.app.FragmentManagerImpl.moveToState (FragmentManager.java:1029)
      at android.support.v4.app.FragmentManagerImpl.moveToState (FragmentManager.java:1252)
      at android.support.v4.app.FragmentManagerImpl.moveToState (FragmentManager.java:1234)
      at android.support.v4.app.FragmentManagerImpl.dispatchCreate (FragmentManager.java:2041)
      at android.support.v4.app.Fragment.performCreate (Fragment.java:1964)
      at android.support.v4.app.FragmentManagerImpl.moveToState (FragmentManager.java:1029)
      at android.support.v4.app.FragmentManagerImpl.moveToState (FragmentManager.java:1252)
      at android.support.v4.app.FragmentManagerImpl.moveToState (FragmentManager.java:1234)
      at android.support.v4.app.FragmentManagerImpl.dispatchCreate (FragmentManager.java:2041)
      at android.support.v4.app.FragmentController.dispatchCreate (FragmentController.java:163)
      at android.support.v4.app.FragmentActivity.onCreate (FragmentActivity.java:331)
      at android.support.v7.app.AppCompatActivity.onCreate (AppCompatActivity.java:85)
      at com.example.eliran.forum.RootActivity.onCreate (RootActivity.java:53)
      at com.example.eliran.forum.MainActivity.onCreate (MainActivity.java:58)
      at android.app.Activity.performCreate (Activity.java:6876)
      at android.app.Instrumentation.callActivityOnCreate (Instrumentation.java:1135)
      at android.app.ActivityThread.performLaunchActivity (ActivityThread.java:3206)

我有 activity 包含片段的 NavigationView。

我怀疑当用户按下后退按钮并调用包含以下代码的函数时会发生此异常：

if (getSupportFragmentManager().getBackStackEntryCount() > 0) {
    getSupportFragmentManager().popBackStack();
}

Google-Play控制台不显示这个，但这是异常错误：

    throwException(new IllegalStateException("Fragment no longer exists for key "
            + key + ": index " + index));

Answer 1

您可能在代码的某处使用了 setTargetFragment()。只是避免使用它。相反，通过回调和侦听器在碎片之间进行通信，如下所示：在 fragmentDialog -

受保护的 OnRemovedTopicListener 回调 = null；

public interface OnRemovedTopicListener {
    public abstract void onTopicRemoved(int position);
}

public void setOnRemovedTopicListener(OnRemovedTopicListener l){
    callback = l;
}

并使用回调 - callback.onTopicRemoved（位置）；

在父片段中 -

    dialogFragment.setOnRemovedTopicListener(new ForumTopicDialogFragment.OnRemovedTopicListener() {
        @Override
        public void onTopicRemoved(int position) {
            // you code here
        }
    });

IllegalStateException - 片段不再存在

IllegalStateException - Fragment no longer exists

android

android-fragments