Android保持屏幕常亮

package com.hebaijun.wakelock; 

import android.app.Activity; 
import android.os.Bundle; 
import android.os.PowerManager; 

public class WakeLockActivity extends Activity { 
 PowerManager.WakeLock wakeLock; 
 /** Called when the activity is first created. */ 
 @Override 
 public void onCreate(Bundle savedInstanceState) { 
  super.onCreate(savedInstanceState); 
  setContentView(R.layout.main); 
  wakeLock = ((PowerManager)getSystemService(POWER_SERVICE)).newWakeLock(PowerManager.SCREEN_BRIGHT_WAKE_LOCK | PowerManager.ON_AFTER_RELEASE, 
"WakeLockActivity"); 
 } 
 @Override 
 protected void onPause() { 
  super.onPause(); 
  if (wakeLock != null) { 
   wakeLock.release(); 
  } 
 } 
 @Override 
 protected void onResume() { 
  super.onResume(); 
  wakeLock.acquire(); 
 } 
}