项目在google play上被报了一个错误，日志如下：
java.lang.RuntimeException: Unable to create application com.mdtv.phware.MyAPP: java.lang.NullPointerException
at android.app.ActivityThread.handleBindApplication(ActivityThread.java:3288)
at android.app.ActivityThread.access$2200(ActivityThread.java:117)
at android.app.ActivityThread$H.handleMessage(ActivityThread.java:980)
at android.os.Handler.dispatchMessage(Handler.java:99)
at android.os.Looper.loop(Looper.java:130)
at android.app.ActivityThread.main(ActivityThread.java:3735)
at java.lang.reflect.Method.invokeNative(Native Method)
at java.lang.reflect.Method.invoke(Method.java:507)
at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:904)
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:662)
at dalvik.system.NativeStart.main(Native Method)
Caused by: java.lang.NullPointerException
at com.mdtv.phware.MTEngine.initConstant(MTEngine.java:792)
at com.mdtv.phware.MTEngine.initialize(MTEngine.java:759)
at com.mdtv.phware.MyAPP.onCreate(MyAPP.java:23)
at android.app.Instrumentation.callApplicationOnCreate(Instrumentation.java:969)
at android.app.ActivityThread.handleBindApplication(ActivityThread.java:3285)
... 10 more
追了下代码，空指针对应的代码是：
从代码来看，应该是getFilesDir返回了null。为什么这个会返回null，求解释。
另外，这个项目是运行在android2.3以下(包括2.3)的设备上的。
