Android 屏幕常亮

本文主题：

使android程序运行过程中，屏幕背景灯保持唤醒，即不黑屏。

先上代码：

注意需要加权限

 <uses-permission android:name="android.permission.WAKE_LOCK"/>

 /**
  *
  * @author zhujianbin
  *
  */
 public class Utils {
     private static WakeLock wl;

     /**
      * 保持屏幕唤醒状态（即背景灯不熄灭）
      * @param on 是否唤醒
      */
     public static void keepScreenOn(Context context, boolean on) {
         if (on) {
             PowerManager pm = (PowerManager) context.getSystemService(Context.POWER_SERVICE);
             wl = pm.newWakeLock(PowerManager.SCREEN_BRIGHT_WAKE_LOCK | PowerManager.ON_AFTER_RELEASE, "==KeepScreenOn==");
             wl.acquire();
         }else {
             wl.release();
             wl = null;
         }
     }
 }

解释：

用到的类

PowerManager 

主要是这两个参数：PowerManager.SCREEN_BRIGHT_WAKE_LOCK | PowerManager.ON_AFTER_RELEASE

下面是 android 官方API 解释：

he following flags are defined, with varying effects on system power. These flags are mutually exclusive - you may only specify one of them.

Flag Value	CPU	Screen	Keyboard
PARTIAL_WAKE_LOCK	On*	Off	Off
SCREEN_DIM_WAKE_LOCK	On	Dim	Off
SCREEN_BRIGHT_WAKE_LOCK	On	Bright	Off
FULL_WAKE_LOCK	On	Bright	Bright

一般要使程序运行过程中背景保持常亮，使用

SCREEN_BRIGHT_WAKE_LOCK 就可以，

SCREEN_BRIGHT_WAKE_LOCK   CPU：唤醒  屏幕背光：唤醒  键盘灯：关闭

第二个参数：

In addition, you can add two more flags, which affect behavior of the screen only.These flags have no effect when combined with aPARTIAL_WAKE_LOCK.

Flag Value	Description
ACQUIRE_CAUSES_WAKEUP	Normal wake locks don't actually turn on the illumination. Instead, they cause the illumination to remain on once it turns on (e.g. from user activity). This flag will force the screen and/or keyboard to turn on immediately, when the WakeLock is acquired. A typical use would be for notifications which are important for the user to see immediately.
ON_AFTER_RELEASE	If this flag is set, the user activity timer will be reset when the WakeLock is released, causing the illumination to remain on a bit longer. This can be used to reduce flicker if you are cycling between wake lock conditions.