最近任务及桌面出现问题

最近任务及桌面出现问题
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不知道干了啥,现在桌面总是出问题
特别是开最近任务的时候
windowlist是不是就是最近桌面相关的类啊
错误日志:
java.lang.NullPointerException: Attempt to read from field ‘com.android.server.wm.WindowList com.android.server.wm.WindowContainer.mChildren’ on a null object reference
at android.os.Parcel.createException(Parcel.java:2077)
at android.os.Parcel.readException(Parcel.java:2039)
at android.os.Parcel.readException(Parcel.java:1987)
at android.app.IActivityTaskManager$Stub$Proxy.activityPaused(IActivityTaskManager.java:4489)
at android.app.servertransaction.PauseActivityItem.postExecute(PauseActivityItem.java:64)
at android.app.servertransaction.TransactionExecutor.executeLifecycleState(TransactionExecutor.java:177)
at android.app.servertransaction.TransactionExecutor.execute(TransactionExecutor.java:97)
at android.app.ActivityThread$H.handleMessage(ActivityThread.java:2016)
at android.os.Handler.dispatchMessage(Handler.java:107)
at android.os.Looper.loop(Looper.java:214)
at android.app.ActivityThread.main(ActivityThread.java:7356)
at java.lang.reflect.Method.invoke(Native Method)
at com.android.internal.os.RuntimeInit$MethodAndArgsCaller.run(RuntimeInit.java:491)
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:940)

追加:刚删除了默认Launcher,应用切换器彻底消失了
难道切换器是Launcher提供的功能?