SF android app 3.1.2 按back键返回桌面时崩溃

[li2]

SF android app 3.1.2 按back键返回桌面时崩溃，只碰到过一次。我抓了下log，只发现这一段有嫌疑，供参考：

E/AndroidRuntime(16854): FATAL EXCEPTION: main
E/AndroidRuntime(16854): Process: com.segmentfault.app, PID: 16854
E/AndroidRuntime(16854): java.lang.NullPointerException: Attempt to invoke virtual method 'android.view.Window android.app.Activity.getWindow()' on a null object reference
E/AndroidRuntime(16854):    at com.segmentfault.app.fragment.SplashFragment.a(Unknown Source)
E/AndroidRuntime(16854):    at com.segmentfault.app.fragment.SplashFragment.a(Unknown Source)
E/AndroidRuntime(16854):    at com.segmentfault.app.fragment.SplashFragment.a(Unknown Source)
E/AndroidRuntime(16854):    at com.segmentfault.app.fragment.aw.onAnimationUpdate(Unknown Source)
E/AndroidRuntime(16854):    at android.animation.ValueAnimator.animateValue(ValueAnimator.java:1374)
E/AndroidRuntime(16854):    at android.animation.ValueAnimator.setCurrentFraction(ValueAnimator.java:602)
E/AndroidRuntime(16854):    at android.animation.ValueAnimator.setCurrentPlayTime(ValueAnimator.java:550)
E/AndroidRuntime(16854):    at android.animation.ValueAnimator.start(ValueAnimator.java:1039)
E/AndroidRuntime(16854):    at android.animation.ValueAnimator.start(ValueAnimator.java:1050)
E/AndroidRuntime(16854):    at com.segmentfault.app.fragment.SplashFragment.a(Unknown Source)
E/AndroidRuntime(16854):    at com.segmentfault.app.fragment.SplashFragment.a(Unknown Source)
E/AndroidRuntime(16854):    at com.segmentfault.app.fragment.av.run(Unknown Source)
E/AndroidRuntime(16854):    at android.os.Handler.handleCallback(Handler.java:739)
E/AndroidRuntime(16854):    at android.os.Handler.dispatchMessage(Handler.java:95)
E/AndroidRuntime(16854):    at android.os.Looper.loop(Looper.java:145)
E/AndroidRuntime(16854):    at android.app.ActivityThread.main(ActivityThread.java:6872)
E/AndroidRuntime(16854):    at java.lang.reflect.Method.invoke(Native Method)
E/AndroidRuntime(16854):    at java.lang.reflect.Method.invoke(Method.java:372)
E/AndroidRuntime(16854):    at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:1404)
E/AndroidRuntime(16854):    at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:1199)