framework层的空指针会让系统重启

01-01 13:13:09.140 249 307 E AndroidRuntime: *** FATAL EXCEPTION IN SYSTEM PROCESS: WindowManagerPolicy
01-01 13:13:09.140 249 307 E AndroidRuntime: java.lang.NullPointerException
01-01 13:13:09.140 249 307 E AndroidRuntime: at com.android.internal.policy.impl.LockScreen.updateLayout(LockScreen.java:741)
01-01 13:13:09.140 249 307 E AndroidRuntime: at com.android.internal.policy.impl.LockScreen.access$400(LockScreen.java:73)
01-01 13:13:09.140 249 307 E AndroidRuntime: at com.android.internal.policy.impl.LockScreen$5.onServiceStateChanged(LockScreen.java:1058)
01-01 13:13:09.140 249 307 E AndroidRuntime: at android.telephony.PhoneStateListener$2.handleMessage(PhoneStateListener.java:324)
01-01 13:13:09.140 249 307 E AndroidRuntime: at android.os.Handler.dispatchMessage(Handler.java:99)
01-01 13:13:09.140 249 307 E AndroidRuntime: at android.os.Looper.loop(Looper.java:130)
01-01 13:13:09.140 249 307 E AndroidRuntime: at com.android.server.WindowManagerService$PolicyThread.run(WindowManagerService.java:601)