如何解决这个问题:java.lang。NoClassDefFoundError:android.support.v4.app.FragmentActivity

I have an app using ActionBarSherlock and Facebook SDK 3.0.2. After I imported ActionBarSherlock and implemented it in my app, I got these problems. First , the android_support_v4 libs conflicted. Then I removed it and point to only one jar file. My app installed. Second, when the app run the MainActivity which includes the ABS, the app forced close and there a error : java.lang.NoClassDefFoundError: android.support.v4.app.FragmentActivityI have an app using ActionBarSherlock and Faceb