发现一个崩溃问题，空指针异常。

[ho2xing]

04-21 16:44:09.566 8417-8417/ E/AndroidRuntime: FATAL EXCEPTION: main

java.lang.NullPointerException
at com.cjj.MaterialRefreshLayout.setProgressValue(MaterialRefreshLayout.java:393)
at com.cjj.MaterialRefreshLayout.finishRefreshing(MaterialRefreshLayout.java:484)
at com.cjj.MaterialRefreshLayout$2.run(MaterialRefreshLayout.java:492)
at android.os.Handler.handleCallback(Handler.java:733)
at android.os.Handler.dispatchMessage(Handler.java:95)
at android.os.Looper.loop(Looper.java:136)
at android.app.ActivityThread.main(ActivityThread.java:5072)
at java.lang.reflect.Method.invokeNative(Native Method)
at java.lang.reflect.Method.invoke(Method.java:515)
at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:793)
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:609)
at dalvik.system.NativeStart.main(Native Method)