保持屏幕常亮

在不同的生命周期调用不用的WakeLock函数可以使系统正常运行(如果不调用WakeLock.release，则屏幕会一直常亮)

首先添加权限：

 public class test extends Activity{     PowerManager powerManager = null;     WakeLock wakeLock = null;     @Override     protected void onCreate(Bundle savedInstanceState) {         super.onCreate(savedInstanceState);         this.setContentView(R.layout.main);                   this.powerManager = (PowerManager)this.getSystemService(Context.POWER_SERVICE);         this.wakeLock = this.powerManager.newWakeLock(PowerManager.FULL_WAKE_LOCK, "My Lock");     }     @Override     protected void onResume() {         super.onResume();         this.wakeLock.acquire();     }     @Override     protected void onPause() {         super.onPause();         this.wakeLock.release();     } }