NullPointerException：尝试从空对象引用上的字段'int android.app.Fragment.mContainerId'读取 [英] NullPointerException: Attempt to read from field 'int android.app.Fragment.mContainerId' on a null object reference

问题描述

仅在Android Lollipop上对片段进行交易时遇到一些有趣的问题。当我回去并删除以前添加的片段时会发生崩溃。

Having some interesting issue with transaction on fragments on Android Lollipop ONLY. Crash happens when i go back and remove previously added fragment.

这是stacktrace：

Here is stacktrace :

FATAL EXCEPTION: main
Process: com.parkme.consumer, PID: 15560
    java.lang.NullPointerException: Attempt to read from field 'int android.app.Fragment.mContainerId' on a null object reference
    at android.app.BackStackRecord$1.onPreDraw(BackStackRecord.java:1131)
    at android.view.ViewTreeObserver.dispatchOnPreDraw(ViewTreeObserver.java:944)
    at android.view.ViewRootImpl.performTraversals(ViewRootImpl.java:1970)
    at android.view.ViewRootImpl.doTraversal(ViewRootImpl.java:1061)
    at android.view.ViewRootImpl$TraversalRunnable.run(ViewRootImpl.java:5885)
    at android.view.Choreographer$CallbackRecord.run(Choreographer.java:767)
    at android.view.Choreographer.doCallbacks(Choreographer.java:580)
    at android.view.Choreographer.doFrame(Choreographer.java:550)
    at android.view.Choreographer$FrameDisplayEventReceiver.run(Choreographer.java:753)
    at android.os.Handler.handleCallback(Handler.java:739)
    at android.os.Handler.dispatchMessage(Handler.java:95)
    at android.os.Looper.loop(Looper.java:135)
    at android.app.ActivityThread.main(ActivityThread.java:5254)
    at java.lang.reflect.Method.invoke(Native Method)
    at java.lang.reflect.Method.invoke(Method.java:372)
    at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:903)
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:698)

我如何进行交易：

getFragmentManager().beginTransaction()
            .replace(R.id.list_holder, listFragment)
            .commit();

R.id.list_holder

R.id.list_holder

<FrameLayout
        android:id="@+id/list_holder"
        android:layout_width="match_parent"
        android:layout_height="match_parent">
</FrameLayout>

我如何删除它：

 getFragmentManager().beginTransaction()
            .remove(listFragment)
            .commit();

我收到了最后一个代码片段的崩溃。

And I`m receiving the crash on last code fragment.

更新

我删除后不再崩溃：

Transition slideTransition = TransitionInflater.from(ParkmeApplication.getContext()).inflateTransition(R.transition.slide_right);
setExitTransition(slideTransition);

slide_right：

slide_right :

<transitionSet xmlns:android="http://schemas.android.com/apk/res/android">
    <slide
        android:duration="@android:integer/config_shortAnimTime"
        android:slideEdge="right"/>
</transitionSet>

推荐答案

该交易不使用 getFragmentManager（）方法并使用 getSupportFragmentManager（）而是从 v4.app.Fragment 上课。
我从 android.app.Fragment 搬出后，现在没有崩溃。

The deal was in to do not use getFragmentManager() method and use getSupportFragmentManager() instead and extend from v4.app.Fragment class. After i have been moved out from android.app.Fragment it is working now without crashes.

所以，如果您使用 getFragmentManager（），那么我对所有人的建议，并且您有任何人支持您的应用程序中使用的库，然后转移到支持经理。即便它为你工作。或者你可以像我一样用一些奇怪的bug来击中崩溃。感谢所有有时间给我建议的人！

So my recommendation for all if you have such uses of getFragmentManager() and you have anyone support libraries used in your app then just move to support manager. Even it`s working for you. Or you can hit the crash with some strange bug as i did. Thanks to all who got time to give me advices !

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