Android 4.4 闹钟流程跟踪分析

遇到这么个bug。

1. 在有gms的板子上，使用google音乐播放器播放音乐

2.定一个闹铃

3.在闹钟快响之前插入耳机然后拔出，当闹钟想起后，没有铃声。只能看到闹钟通知栏视图。

试了几块板子，感觉这是低概率事件，但是客户没有提供log。所以先花了点时间吧闹钟的流程走一下。

我在4.4的源码中吧闹钟代码拿了出来。可以正常编译通过，功能一样，只是包名换了。

截图中的DatePicker，另外一位仁兄有源码，但是我找到的是分散的。

传送门：

  http://blog.csdn.net/u012414584/article/details/44593727

我的源代码下载地址：

    http://download.csdn.net/detail/xxm282828/8609451

闹钟这一块，主要用到了这么几个类。

AlarmActivity ： 当我们点击闹钟提示的通知栏后进入的闹钟视图画面。可以看后面截图。

AlarmKlaxon:   主要控制闹钟铃声的播放以及震动，貌似5.0后没有设置了震动

AlarmNotification: 控制闹钟通知栏的显示以及消失

AlarmService: extends Service : 主要用于发送广播启动闹钟

AlarmStateManager: AlarmService发送广播后，闹钟的各种逻辑在这里处理。比如提示闹钟，播放铃声，数据库更新操作，更新闹钟状态。

另外就是涉及到数据库的相关操作：

Alarm: 当创建一个闹钟,就会创建一个Alarm对象，用于存储闹钟相关信息。

AlarmInstance: 一个定时闹钟的实例，与Alarm对应，比Alarm存储的信息量更多。一个Alarm对应一个AlarmInstance对象

添加闹钟流程以及如何实现定时触发闹钟？

和以前一样闹钟的创建流程我们就跟着代码走一遍吧。

具体流程方法省了，贴代码没意思。

  /**     * Schedule alarm instance state changes with {@link AlarmManager}.     *     * @param context application context     * @param time to trigger state change闹钟响铃时间     * @param instance to change state to     * @param newState to change to     */    @SuppressLint("NewApi")private static void scheduleInstanceStateChange(Context context, Calendar time,            AlarmInstance instance, int newState) {        long timeInMillis = time.getTimeInMillis();        Log.v("Scheduling state change " + newState + " to instance " + instance.mId +                " at " + AlarmUtils.getFormattedTime(context, time) + " (" + timeInMillis + ")");        Intent stateChangeIntent = createStateChangeIntent(context, ALARM_MANAGER_TAG, instance,                newState);        PendingIntent pendingIntent = PendingIntent.getBroadcast(context, instance.hashCode(),                stateChangeIntent, PendingIntent.FLAG_UPDATE_CURRENT);        AlarmManager am = (AlarmManager) context.getSystemService(Context.ALARM_SERVICE);        if (Utils.isKitKatOrLater()) {            am.setExact(AlarmManager.RTC_WAKEUP, timeInMillis, pendingIntent);        } else {            am.set(AlarmManager.RTC_WAKEUP, timeInMillis, pendingIntent);        }    }

这个方法会启动定时器，在定点的时间发出广播。

跟踪一下这个方法：

 Intent stateChangeIntent = createStateChangeIntent(context, ALARM_MANAGER_TAG, instance,                newState);

    /**     * Utility method to create a proper change state intent.     *     * @param context application context     * @param tag used to make intent differ from other state change intents.     * @param instance to change state to     * @param state to change to.     * @return intent that can be used to change an alarm instance state     */    public static Intent createStateChangeIntent(Context context, String tag,            AlarmInstance instance, Integer state) {        Intent intent = AlarmInstance.createIntent(context, AlarmStateManager.class, instance.mId);        //intent携带的Action        intent.setAction(CHANGE_STATE_ACTION);        intent.addCategory(tag);        intent.putExtra(ALARM_GLOBAL_ID_EXTRA, getGlobalIntentId(context));        //instance的下一个状态        if (state != null) {            intent.putExtra(ALARM_STATE_EXTRA, state.intValue());        }        return intent;    }

闹钟的各个阶段的状态

/**         * Alarm state when to show no notification.         *         * Can transitions to:         * LOW_NOTIFICATION_STATE         */        public static final int SILENT_STATE = 0;        /**         * Alarm state to show low priority alarm notification.         *         * Can transitions to:         * HIDE_NOTIFICATION_STATE         * HIGH_NOTIFICATION_STATE         * DISMISSED_STATE         */        public static final int LOW_NOTIFICATION_STATE = 1;        /**         * Alarm state to hide low priority alarm notification.         *         * Can transitions to:         * HIGH_NOTIFICATION_STATE         */        public static final int HIDE_NOTIFICATION_STATE = 2;        /**         * Alarm state to show high priority alarm notification.         *         * Can transitions to:         * DISMISSED_STATE         * FIRED_STATE         */        public static final int HIGH_NOTIFICATION_STATE = 3;        /**         * Alarm state when alarm is in snooze.         *         * Can transitions to:         * DISMISSED_STATE         * FIRED_STATE         */        public static final int SNOOZE_STATE = 4;        /**         * Alarm state when alarm is being fired.         *         * Can transitions to:         * DISMISSED_STATE         * SNOOZED_STATE         * MISSED_STATE         */        public static final int FIRED_STATE = 5;        /**         * Alarm state when alarm has been missed.         *         * Can transitions to:         * DISMISSED_STATE         */        public static final int MISSED_STATE = 6;        /**         * Alarm state when alarm is done.         */        public static final int DISMISSED_STATE = 7;

后续有时间再补上吧。。

一般闹钟的实现机制。

开关机定时闹钟如何实现的呢？

看这套代码可以让我们学习下ContentProvider等各种基础，自定义View，定时器AlarmManager等。