解决方法：缩短响应的时间；
具体方法：
路径：frameworks/base/services/java/com/android/server/wifi/WifiController.java
代码： class WifiController extends StateMachine {
* being enabled but not active exceeds the battery drain caused by
* re-establishing a connection to the mobile data network.
*/
- private static final long DEFAULT_IDLE_MS = 15 * 60 * 1000; /* 15 minutes */
+ private static final long DEFAULT_IDLE_MS = 1 * 60 * 1000; /* 1 minutes */
设置-wifi-高级设置，选择仅充电时保持WLAN开启/睡眠期间不保持wlan的开启状态，手机锁屏休眠几分钟后，再点亮屏幕，wifi一直显示开启状态
原文：http://blog.csdn.net/silence_cdsn/article/details/42487551