在项目\frameworks\base\wifi\java\android\net\wifi\WifiStateMachine.java里面，有如下的代码，是设置wifi热点保持状态的：如下：

private class HotspotAutoDisableObserver extends ContentObserver {

public HotspotAutoDisableObserver(Handler handler) {

super(handler);

mContext.getContentResolver().registerContentObserver(Settings.System.getUriFor(

Settings.System.WIFI_HOTSPOT_AUTO_DISABLE), false, this);

}

@Override

public void onChange(boolean selfChange) {

super.onChange(selfChange);

mDuration = Settings.System.getInt(mContext.getContentResolver(), Settings.System.WIFI_HOTSPOT_AUTO_DISABLE,

Settings.System.WIFI_HOTSPOT_AUTO_DISABLE_FOR_FIVE_MINS);

if (mDuration != Settings.System.WIFI_HOTSPOT_AUTO_DISABLE_OFF && mPluggedType == 0) {

if (mClientNum == 0 && WifiStateMachine.this.getCurrentState() == mTetheredState) {

mAlarmManager.cancel(mIntentStopHotspot);

Xlog.d(TAG, "Set alarm for setting changed, mDuration:" + mDuration);

mAlarmManager.set(AlarmManager.RTC_WAKEUP,

System.currentTimeMillis() + mDuration * HOTSPOT_DISABLE_MS, mIntentStopHotspot);

}

} else {

mAlarmManager.cancel(mIntentStopHotspot);

}

}

}

修改默认值为始终：

mDuration = Settings.System.getInt(mContext.getContentResolver(), Settings.System.WIFI_HOTSPOT_AUTO_DISABLE,

Settings.System.WIFI_HOTSPOT_AUTO_DISABLE_OFF);

另外，System.xxxx的常量定义在源码中的路径：项目\frameworks\base\core\java\android\provider\Settings.java

原文：http://www.cnblogs.com/suxiaoqi/p/5619741.html