Android Kitkat 如何让系统永久不休眠

修改 frameworks/base/packages/SettingsProvider/res/values/defaults.xml中的def_screen_off_timeout 做法在Android 4.4上已经无效了。

解决方法：

[kris@ecovacs:~/daogou/frameworks/base]$ g df services/java/com/android/server/power/PowerManagerService.java
diff --git a/services/java/com/android/server/power/PowerManagerService.java b/s
index da9548f..4382df0 100644
--- a/services/java/com/android/server/power/PowerManagerService.java
+++ b/services/java/com/android/server/power/PowerManagerService.java
@@ -1429,7 +1429,10 @@ public final class PowerManagerService extends IPowerMana
         if (mUserActivityTimeoutOverrideFromWindowManager >= 0) {
             timeout = (int)Math.min(timeout, mUserActivityTimeoutOverrideFromWi
         }
-        return Math.max(timeout, MINIMUM_SCREEN_OFF_TIMEOUT);
+
+        /*Kris, 20150811, disable system sleep forever.*/
+        return mMaximumScreenOffTimeoutFromDeviceAdmin;
+        //return Math.max(timeout, MINIMUM_SCREEN_OFF_TIMEOUT);
     }