错误日志如下，求大神解答。
java.lang.ClassCastException: android.widget.ImageButton cannot be cast to android.view.ViewGroup
at android.app.FragmentManagerImpl.moveToState(FragmentManager.java:1287)
at android.app.FragmentManagerImpl.addAddedFragments(FragmentManager.java:2431)
at android.app.FragmentManagerImpl.executeOpsTogether(FragmentManager.java:2210)
at android.app.FragmentManagerImpl.removeRedundantOperationsAndExecute(FragmentManager.java:2166)
at android.app.FragmentManagerImpl.execPendingActions(FragmentManager.java:2067)
at android.app.FragmentManagerImpl$1.run(FragmentManager.java:742)
at android.os.Handler.handleCallback(Handler.java:883)
at android.os.Handler.dispatchMessage(Handler.java:100)
at android.os.Looper.loop(Looper.java:214)
at android.app.ActivityThread.main(ActivityThread.java:7356)
at java.lang.reflect.Method.invoke(Native Method)
at com.android.internal.os.RuntimeInit$MethodAndArgsCaller.run(RuntimeInit.java:492)
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:930)
