Android通知Notification

Notification是一种在你APP常规UI外用来指示某个事件发生的用户交互元素。用户可以在使用其它apps时查看notification，并在方便的时候做出回应。
这里我们来一起学习通知相关知识

建立一个Notification
学习如何创建一个notification Builder，设置需要的特征，以及发布notification。

[java]
NotificationCompat.Builder builder = new NotificationCompat.Builder(this);
//设置UI界面特征
builder.setSmallIcon(R.drawable.m4); //通知图标
builder.setContentTitle("通知标题");
builder.setContentText("1条新消息"); //通知内容
builder.setTicker("收到1条新消息"); //刚收到通知时提示
builder.setNumber(1); //消息个数
builder.setAutoCancel(true); // 点击取消通知
builder.setDefaults(Notification.DEFAULT_ALL);// requires VIBRATE permission
builder.setWhen(System.currentTimeMillis());
builder.setSound(uri); //通知声音

//设置行为特征
Intent intent = new Intent(this, BaseActivity.class);
PendingIntent pendingIntent = PendingIntent.getActivity(this, 0,intent, PendingIntent.FLAG_UPDATE_CURRENT);
builder.setContentIntent(pendingIntent); //通知点击行为

NotificationManager mNotifyManager = (NotificationManager) getSystemService(NOTIFICATION_SERVICE);
Notification notification = mBuilder.build();
int notificationId = 10; //能知ID,唯一标识当前通知
//发布通知
mNotifyManager.notify(notificationId, notification);

[/java]

注: pendingIntent字面意义：等待的，未决定的Intent。
要得到一个pendingIntent对象，使用方法类的静态方法 getActivity(Context, int, Intent, int),getBroadcast(Context, int, Intent, int),getService(Context, int, Intent, int) 分别对应着Intent的3个行为，跳转到一个activity组件、打开一个广播组件和打开一个服务组件。
可以看到，要得到这个对象，必须传入一个Intent作为参数，必须有context作为参数。

更新notifications

学习如何更新与移除notifications
想要设置一个可以被更新的Notification，需要在发布它的时候调用NotificationManager.notify(ID, notification))方法为它指定一个notification ID。更新一个已经发布的Notification，需要更新或者创建一个NotificationCompat.Builder对象，并从这个对象创建一个Notification对象，然后用与先前一样的ID去发布这个Notification。

移除Notification
你在创建notification时调用了 setAutoCancel(true)点击通知时移除
执行cancel(notificationId)或cancelAll()

当Activity启动时保留导航

学习如何为一个从notification启动的Activity执行适当的导航。

通知启动的是你application工作流中的一部分Activity。
步骤：
1 在manifest中定义你application的Activity层次，最终的manifest文件应该像这个：

[java]
<activity
    android:name=".MainActivity"
    android:label="@string/app_name" >
    <intent-filter>
        <action android:name="android.intent.action.MAIN" />
        <category android:name="android.intent.category.LAUNCHER" />
    </intent-filter>
</activity>
<activity
    android:name=".ResultActivity"
    android:parentActivityName=".MainActivity">
    <meta-data
        android:name="android.support.PARENT_ACTIVITY"
        android:value=".MainActivity"/>
</activity>[/java]

2 在基于启动Activity的Intent中创建一个返回栈，比如：

[java]
int id = 1;
…
Intent resultIntent = new Intent(this, ResultActivity.class);
TaskStackBuilder stackBuilder = TaskStackBuilder.create(this);
// Adds the back stack
stackBuilder.addParentStack(ResultActivity.class);
// Adds the Intent to the top of the stack
stackBuilder.addNextIntent(resultIntent);
// Gets a PendingIntent containing the entire back stack
PendingIntent resultPendingIntent =
        stackBuilder.getPendingIntent(0, PendingIntent.FLAG_UPDATE_CURRENT);
…
NotificationCompat.Builder builder = new NotificationCompat.Builder(this);
builder.setContentIntent(resultPendingIntent);
NotificationManager mNotificationManager =
    (NotificationManager) getSystemService(Context.NOTIFICATION_SERVICE);
mNotificationManager.notify(id, builder.build());
[/java]

在notification中展示进度

学习在notification中显示某个操作的进度，既可以用于那些你可以估算已经完成多少（确定进度，determinate）的操作，也可以用于那些你无法知道完成了多少（不确定进度，indefinite ）的操作

展示固定长度的进度指示器
调用NotificationCompat.Builder 的setProgress(max, progress, false))方法将进度条添加进notification，
调用setProgress(0, 0, false))方法移除进度条，
显示进度需不但改变progress值，同时更新通知
比如：

[java]int id = 1;
…
mNotifyManager =
        (NotificationManager) getSystemService(Context.NOTIFICATION_SERVICE);
mBuilder = new NotificationCompat.Builder(this);
mBuilder.setContentTitle("Picture Download")
    .setContentText("Download in progress")
    .setSmallIcon(R.drawable.ic_notification);
// Start a lengthy operation in a background thread
new Thread(
    new Runnable() {
        @Override
        public void run() {
            int incr;
            // Do the "lengthy" operation 20 times
            for (incr = 0; incr <= 100; incr+=5) {
                    // Sets the progress indicator to a max value, the
                    // current completion percentage, and "determinate"
                    // state
                    mBuilder.setProgress(100, incr, false);
                    // Displays the progress bar for the first time.
                    mNotifyManager.notify(id, mBuilder.build());
                        // Sleeps the thread, simulating an operation
                        // that takes time
                        try {
                            // Sleep for 5 seconds
                            Thread.sleep(5*1000);
                        } catch (InterruptedException e) {
                            Log.d(TAG, "sleep failure");
                        }
            }
            // When the loop is finished, updates the notification
            mBuilder.setContentText("Download complete")
            // Removes the progress bar
                    .setProgress(0,0,false);
            mNotifyManager.notify(id, mBuilder.build());
        }
    }
// Starts the thread by calling the run() method in its Runnable
).start();[/java]

创建一个自定义Notification

[java]
NotificationCompat.Builder mBuilder = new NotificationCompat.Builder(this);
mBuilder.setSmallIcon(R.drawable.m8);
mBuilder.setTicker("自定义通知，你有新消息");
mBuilder.setAutoCancel(true);

// ——自定义notification界面
RemoteViews view = new RemoteViews(getPackageName(),R.layout.view_notificaction_layout);
mBuilder.setContent(view);

// —-自定义notification事件处理
Intent intent = new Intent(this, RadioTabActivity.class);
PendingIntent pendingIntent = PendingIntent.getActivity(this, 01,intent, PendingIntent.FLAG_UPDATE_CURRENT);
view.setOnClickPendingIntent(R.id.player_notification, pendingIntent);

Notification notification = mBuilder.build();
int notificationId = 29;

NotificationManager mNotifyManager = (NotificationManager) getSystemService(NOTIFICATION_SERVICE);
mNotifyManager.notify(notificationId, notification);  
[/java]

转载请注明来源：Android通知Notification

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