In AndroidManifest.xml 加上权限:<uses-permission android:name="android.permission.WAKE_LOCK" /> public class UnLockActivity2 extends Activity { /** Called when the activity is first creat In AndroidManifest.xml 加上权限:

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

public class UnLockActivity2 extends Activity {
/** Called when the activity is first created. */
@Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.main);

getWindow().addFlags(WindowManager.LayoutParams.FLAG_KEEP_SCREEN_ON);
}
}

public class UnLockActivity extends Activity {
/** Called when the activity is first created. */

WakeLock m_wklk;

@Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.main);

PowerManager pm = (PowerManager)getSystemService(POWER_SERVICE);
m_wklk = pm.newWakeLock(PowerManager.SCREEN_DIM_WAKE_LOCK, "cn");

m_wklk.acquire(); //设置保持唤醒
}

@Override
protected void onDestroy() {
// TODO Auto-generated method stub
super.onDestroy();
m_wklk.release(); //解除保持唤醒
}

@Override
protected void onPause() {
// TODO Auto-generated method stub
super.onPause();

m_wklk.release();//解除保持唤醒

}

@Override
protected void onResume() {
// TODO Auto-generated method stub
super.onResume();


m_wklk.acquire(); //设置保持唤醒
}


}

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 Screen Keyboard PARTIAL_WAKE_LOCK SCREEN_DIM_WAKE_LOCK SCREEN_BRIGHT_WAKE_LOCK Bright FULL_WAKE_LOCK 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 a PARTIAL_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.

http://www.cnblogs.com/chengning/archive/2012/04/26/2472789.html

http://mysuperbaby.iteye.com/blog/1454178

http://wenku.baidu.com/view/a9c0fa01de80d4d8d15a4f96.html

http://blog.csdn.net/xieying15170814609/article/details/7723928

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