android通过代码设置横竖屏

1. 在activity中 
2.  // 设置为横屏模式  
3.     setRequestedOrientation(ActivityInfo.SCREEN_ORIENTATION_LANDSCAPE);
4.   // 设置为竖屏模式  
5.     setRequestedOrientation(ActivityInfo.SCREEN_ORIENTATION_PORTRAIT);
6.   // 设置为跟随系统sensor的状态 
7.     setRequestedOrientation(ActivityInfo.SCREEN_ORIENTATION_SENSOR);