alarmmanager 定期操作未生效

参看：http://msdx.github.io/androiddoc/docs/reference/android/app/AlarmManager.html

Note: Beginning with API 19 (

KITKAT

)
alarm delivery is inexact: the OS will shift alarms in order to minimize wakeups and battery use. There are new APIs to support applications which need strict delivery guarantees; see 

setWindow(int,
long, long, PendingIntent)

 and 

setExact(int,
long, PendingIntent)

. Applications whose

targetSdkVersion

 is
earlier than API 19 will continue to see the previous behavior in which all alarms are delivered exactly when requested.

原来用的是 set(RTC_WAKEUP..) 没能把手机唤醒。

现在改用

public void setExact (int type, long triggerAtMillis, PendingIntent operation)