android源码浅析--notification

在上一篇文章中，用到了Notification，准备好好的看下notification的源码。

类概述：

一个表示如何使用NotificationManager把一个持久的通知呈现给用户的类。

The Notification.Builder has been added to make it easier to construct Notifications.

添加Notification.Builder使构建Notification更容易。

静态变量：

    /**     * Bit to be bitwise-ored into the {@link #flags} field that should be     * set if you want the LED on for this notification.     * <ul>     * <li>To turn the LED off, pass 0 in the alpha channel for colorARGB     *      or 0 for both ledOnMS and ledOffMS.</li>     * <li>To turn the LED on, pass 1 for ledOnMS and 0 for ledOffMS.</li>     * <li>To flash the LED, pass the number of milliseconds that it should     *      be on and off to ledOnMS and ledOffMS.</li>     * </ul>     * <p>     * Since hardware varies, you are not guaranteed that any of the values     * you pass are honored exactly.  Use the system defaults (TODO) if possible     * because they will be set to values that work on any given hardware.     * <p>     * The alpha channel must be set for forward compatibility.     *      */    public static final int FLAG_SHOW_LIGHTS        = 0x00000001;    /**     * Bit to be bitwise-ored into the {@link #flags} field that should be     * set if this notification is in reference to something that is ongoing,     * like a phone call.  It should not be set if this notification is in     * reference to something that happened at a particular point in time,     * like a missed phone call.     */    public static final int FLAG_ONGOING_EVENT      = 0x00000002;    /**     * Bit to be bitwise-ored into the {@link #flags} field that if set,     * the audio will be repeated until the notification is     * cancelled or the notification window is opened.     */    public static final int FLAG_INSISTENT          = 0x00000004;    /**     * Bit to be bitwise-ored into the {@link #flags} field that should be     * set if you want the sound and/or vibration play each time the     * notification is sent, even if it has not been canceled before that.     */    public static final int FLAG_ONLY_ALERT_ONCE    = 0x00000008;    /**     * Bit to be bitwise-ored into the {@link #flags} field that should be     * set if the notification should be canceled when it is clicked by the     * user.  On tablets, the      */    public static final int FLAG_AUTO_CANCEL        = 0x00000010;    /**     * Bit to be bitwise-ored into the {@link #flags} field that should be     * set if the notification should not be canceled when the user clicks     * the Clear all button.     */    public static final int FLAG_NO_CLEAR           = 0x00000020;    /**     * Bit to be bitwise-ored into the {@link #flags} field that should be     * set if this notification represents a currently running service.  This     * will normally be set for you by {@link Service#startForeground}.     */    public static final int FLAG_FOREGROUND_SERVICE = 0x00000040;    /**     * Bit to be bitwise-ored into the {@link #flags} field that should be set if this notification     * represents a high-priority event that may be shown to the user even if notifications are     * otherwise unavailable (that is, when the status bar is hidden). This flag is ideally used     * in conjunction with {@link #fullScreenIntent}.     */    public static final int FLAG_HIGH_PRIORITY = 0x00000080;

FLAG_SHOW_LIGHTS:如果想为Notification添加LED灯提示，需要在Flag属性中添加FLAG_SHOW_LIGHT标志位。LED关闭状态下，0表示颜色或者LED灯开关LED开启状态下，1代表LED开，0代表LED关。LED闪烁状态下，ledOnMS表示灯亮时间，ledOffMS表示灯灭时间。因为硬件不一，所以不能保证在各种硬件上都能够奏效，应尽可能使用系统给定的默认值(TODO)，它能够适配各种硬件。alpha通道必须设置为向前兼容性

FLAG_ONGOING_EVENT：如果需要notification常驻状态栏，引用正在进行的活动，如一个打进的电话，需要在Flag属性中添加FLAG_ONGOING_EVENT标志位。但是其不能引用一个过去已经发生的活动，如一个未接电话。（设置其Flag，notification将被放入“正在进行”组）

FLAG_INSISTENT：设置此Flag，在通知取消或通知窗口打开之前，音频会一直重复。

FLAG_ONLY_ALERT_ONCE：设置此Flag，震动和声音只执行一次。
FLAG_AUTO_CANCEL：
设置此Flag，当用户点击时，通知会被清除。
FLAG_NO_CLEAR：设置此Flag，当用户点击清除所有按钮时，该通知不被清除。
FLAG_FOREGROUND_SERVICE：设置此Flag，表示该通知为正运行的服务（当你退出手机QQ时，在状态栏会看到一个QQ图标）
FLAG_HIGH_PRIORITY：一个过时的Flag，现在已使用优先级字段代替。设置该Flag表示一高优先级事件，当通知不可以使用（状态栏被隐藏时）也可通知用户，应配合fullScreenIntent使用。


常量

    /**     * The timestamp for the notification.  The icons and expanded views     * are sorted by this key.     */    public long when;    /**     * The resource id of a drawable to use as the icon in the status bar.     * This is required; notifications with an invalid icon resource will not be shown.     */    public int icon;    /**     * If the icon in the status bar is to have more than one level, you can set this.  Otherwise,     * leave it at its default value of 0.     *     * @see android.widget.ImageView#setImageLevel     * @see android.graphics.drawable#setLevel     */    public int iconLevel;    /**     * The number of events that this notification represents.  For example, in a new mail     * notification, this could be the number of unread messages.  This number is superimposed over     * the icon in the status bar.  If the number is 0 or negative, it is not shown in the status     * bar.     */    public int number;    /**     * The intent to execute when the expanded status entry is clicked.  If     * this is an activity, it must include the     * {@link android.content.Intent#FLAG_ACTIVITY_NEW_TASK} flag, which requires     * that you take care of task management as described in the     * <a href="{@docRoot}guide/topics/fundamentals/tasks-and-back-stack.html">Tasks and Back     * Stack</a> document.  In particular, make sure to read the notification section     * <a href="{@docRoot}guide/topics/ui/notifiers/notifications.html#HandlingNotifications">Handling     * Notifications</a> for the correct ways to launch an application from a     * notification.     */    public PendingIntent contentIntent;    /**     * The intent to execute when the status entry is deleted by the user     * with the "Clear All Notifications" button. This probably shouldn't     * be launching an activity since several of those will be sent at the     * same time.     */    public PendingIntent deleteIntent;    /**     * An intent to launch instead of posting the notification to the status bar.     *     * @see Notification.Builder#setFullScreenIntent     */    public PendingIntent fullScreenIntent;    /**     * Text to scroll across the screen when this item is added to     * the status bar on large and smaller devices.     *     * <p>This field is provided separately from the other ticker fields     * both for compatibility and to allow an application to choose different     * text for when the text scrolls in and when it is displayed all at once     * in conjunction with one or more icons.     *     * @see #tickerView     */    public CharSequence tickerText;    /**     * The view to show as the ticker in the status bar when the notification     * is posted.     */    public RemoteViews tickerView;    /**     * The view that will represent this notification in the expanded status bar.     */    public RemoteViews contentView;    /**     * The bitmap that may escape the bounds of the panel and bar.     */    public Bitmap largeIcon;    /**     * The sound to play.     *      * <p>     * To play the default notification sound, see {@link #defaults}.      * </p>     */    public Uri sound;


when：通知的时间戳，通知图标会根据该时间戳在状态栏进行排序。icon：
在状态栏中显示的图标，如果是无效资源，不予显示。iconLevel：
如果状态栏中的icon有等级之分，可以设置此参数，默认情况下，一般为0.number：
通知事件发生的次数，比如一个邮件通知，这个参数表示未读邮件数。这个数字会叠加到状态栏中通知图标上，如果为0或者负，则不显示。contentIntent：
The intent to execute when the expanded status entry is clicked.当扩展状态内容被点击时触发该intent（expanded status entry不知道该如何翻译是好了）如果是要跳转到一个Activity，一定要包含FLAG_ACTIVITY_NEW_TASK这个标志位，用于调整堆栈中的Task。能够确保正确的从一个通知进入一个应用。deleteIntent：
当用户点击“clean all button"或者滑动取消通知时触发该Intent，不能启动一个activity或者server（因为会在同一时间发送）。fullScreenIntent：全屏状态下代替状态栏中intent功能tickerText：
当通知发送时像股票一样提示文本。contentView：在状态栏中代表Notification的View。largeIcon：
可以脱离状态栏的图片sound：通知声音audioStreamType：
视频播放流类型vibrate：
震动类型ledARGB：
LED灯颜色ledOnMS：
LED灯闪烁时，灯亮时间。ledOffMS：
LED灯闪烁时，灯灭时间。defaults：
LED默认值。
构造函数默认构造函数：

    /**     * Constructs a Notification object with everything set to 0.     * You might want to consider using {@link Builder} instead.     */    public Notification()    {        this.when = System.currentTimeMillis();    }


可以用Notification.Builder来替代构造一个Notification（关于Builder建造者模式 http://blog.csdn.net/aomandeshangxiao/article/details/8214646）。


 /**         * An intent to launch instead of posting the notification to the status bar.         * Only for use with extremely high-priority notifications demanding the user's         * <strong>immediate</strong> attention, such as an incoming phone call or         * alarm clock that the user has explicitly set to a particular time.         * If this facility is used for something else, please give the user an option         * to turn it off and use a normal notification, as this can be extremely         * disruptive.         *         * @param intent The pending intent to launch.         * @param highPriority Passing true will cause this notification to be sent         *          even if other notifications are suppressed.         */        public Builder setFullScreenIntent(PendingIntent intent, boolean highPriority) {            mFullScreenIntent = intent;            setFlag(FLAG_HIGH_PRIORITY, highPriority);            return this;        }


一个全屏状态下替代状态栏上的Notification的intent，仅适用于使用非常高的优先级通知，会引起用户的即时关注，如用户已显式设置为一个特定的时间，一个来电或闹钟。
设置TickerText：

 /**         * Combine all of the options that have been set and return a new {@link Notification}         * object.         */        public Notification getNotification() {            Notification n = new Notification();            n.when = mWhen;            n.icon = mSmallIcon;            n.iconLevel = mSmallIconLevel;            n.number = mNumber;            n.contentView = makeContentView();            n.contentIntent = mContentIntent;            n.deleteIntent = mDeleteIntent;            n.fullScreenIntent = mFullScreenIntent;            n.tickerText = mTickerText;            n.tickerView = makeTickerView();            n.largeIcon = mLargeIcon;            n.sound = mSound;            n.audioStreamType = mAudioStreamType;            n.vibrate = mVibrate;            n.ledARGB = mLedArgb;            n.ledOnMS = mLedOnMs;            n.ledOffMS = mLedOffMs;            n.defaults = mDefaults;            n.flags = mFlags;            if (mLedOnMs != 0 && mLedOffMs != 0) {                n.flags |= FLAG_SHOW_LIGHTS;            }            if ((mDefaults & DEFAULT_LIGHTS) != 0) {                n.flags |= FLAG_SHOW_LIGHTS;            }            return n;        }


Builder的最后，提供一个完整的产品出来。

PS：写到这，正文部分大体完成，现在时间也已经是晚上11点钟，1000多行的代码，推迟了3天才把文章写完，进度确实有点慢，最近在读凯利麦格尼格尔女士的《自控力》这本书，看到“道德许可效应”，解决了自己关于很多事情的疑问。还没有读完，感觉是一本不错的书籍，推荐一下。另外，周五有次重要的谈话，祝自己顺利。