android_alarm.docx

1.设置定时时间文件：packages/apps/alarmclock/src/com/android/alarmclock/Alarms.javaprivate static void enableAlert(Context context, final Alarm alarm, final long atTimeInMillis) AlarmManager am = (AlarmManager) context.getSystemService(Context.ALARM_SERVICE); . am.set(AlarmManager.RTC_WAKEUP, atTimeInMillis, sender); . 由闹钟管理器设置定时时间。2.闹钟管理器文件：frameworks/base/core/java/android/app/AlarmManager.javapublic static final int RTC_WAKEUP = 0; public static final int RTC = 1; public static final int ELAPSED_REALTIME_WAKEUP = 2;public static final int ELAPSED_REALTIME = 3; AlarmManager(IAlarmManager service) mService = service; public void set(int type, long triggerAtTime, PendingIntent operation) try mService.set(type, triggerAtTime, operation); catch (RemoteException ex) 将type, triggerAtTime, operation等参数转向闹钟管理器服务。3.闹钟管理器服务文件：frameworks/base/services/java/com/android/server/AlarmManagerService.java3.1定时设置public AlarmManagerService(Context context) mDescriptor = init(); .public void set(int type, long triggerAtTime, PendingIntent operation) setRepeating(type, triggerAtTime, 0, operation); public void setRepeating(int type, long triggerAtTime, long interval, PendingIntent operation) if (operation = null) Log.w(TAG, set/setRepeating ignored because there is no intent); return; synchronized (mLock) Alarm alarm = new Alarm(); alarm.type = type; alarm.when = triggerAtTime; alarm.repeatInterval = interval; alarm.operation = operation; / Remove this alarm if already scheduled. removeLocked(operation); if (localLOGV) Log.v(TAG, set: + alarm); int index = addAlarmLocked(alarm); if (index = 0) setLocked(alarm); private void setLocked(Alarm alarm) if (mDescriptor != -1) set(mDescriptor, alarm.type, (alarm.when * 1000 * 1000); else Message msg = Message.obtain(); msg.what = ALARM_EVENT; mHandler.removeMessages(ALARM_EVENT); mHandler.sendMessageAtTime(msg, alarm.when); Init,set 为底层操作函数，set(mDescriptor, alarm.type, (alarm.when * 1000 * 1000); 由底层来完成定时设置。3.2等待计时结束private class AlarmThread extends Thread public void run() . while (true) int result = waitForAlarm(mDescriptor); . if (result & RTC_WAKEUP_MASK) != 0) triggerAlarmsLocked(mRtcWakeupAlarms, triggerList, nowRTC); if (result & RTC_MASK) != 0) triggerAlarmsLocked(mRtcAlarms, triggerList, nowRTC); if (result & ELAPSED_REALTIME_WAKEUP_MASK) != 0) triggerAlarmsLocked(mElapsedRealtimeWakeupAlarms, triggerList, nowELAPSED); if (result & ELAPSED_REALTIME_MASK) != 0) triggerAlarmsLocked(mElapsedRealtimeAlarms, triggerList, nowELAPSED); . 在服务里采用线程来处理计时结束返回的信息，根据等待计时结束返回的信息触发不同的操作。4.硬件调用文件：frameworks/base/services/jni/com_android_server_AlarmManagerService.cpp4.1 定时设置static jint android_server_AlarmManagerService_init(JNIEnv* env, jobject obj)#if HAVE_ANDROID_OS return open(/dev/alarm, O_RDWR);#else return -1;#endifstatic void android_server_AlarmManagerService_close(JNIEnv* env, jobject obj, jint fd)#if HAVE_ANDROID_OS close(fd);#endifstatic void android_server_AlarmManagerService_set(JNIEnv* env, jobject obj, jint fd, jint type, jlong nanoseconds)#if HAVE_ANDROID_OS struct timespec ts; ts.tv_sec = NANOSECONDS_TO_SECONDS(nanoseconds); ts.tv_nsec = nanoseconds - SECONDS_TO_NANOSECONDS(ts.tv_sec); int result = ioctl(fd, ANDROID_ALARM_SET(type), &ts); if (result 0) LOGE(Unable to set alarm to %lld: %sn, nanoseconds, strerror(errno); #endif以上函数的绑定如下： init, ()I, (void*)android_server_AlarmManagerService_init, close, (I)V, (void*)android_server_AlarmManagerService_close, set, (IIJ)V, (void*)android_server_AlarmManagerService_set,由上可知，通过ioctl接口，设置定时时间。4.2 等待计时结束static jint android_server_AlarmManagerService_waitForAlarm(JNIEnv* env, jobject obj, jint fd)#if HAVE_ANDROID_OS int result = 0; do result = ioctl(fd, ANDROID_ALARM_WAIT); while (result 0 & errno = EINTR); if (result