The method getSupportFragmentManager() is undefined for the type MessageActivity

使用ViewPager + Fragment实现滑动标签页的时候出现了这样的错误，那是因为

down votaccepted

You import  FragmentActivity , but you don't use it.  Activity  is not from v4 nor from v7 support libraries. This should work: public class MainActivity extends FragmentActivity {

 很明白吧，没有继承FragmentActivity
， so你懂得。。。

但是我继承了

FragmentActivity 之后又出现了大量的错误

再导入
import android.support.v4.app.FragmentActivity;

ok
很简单！

 你懂得

8down voteaccepted

You import  FragmentActivity , but you don't use it.  Activity  is not from v4 nor from v7 support libraries. This should work: public class MainActivity extends FragmentActivity {