java 安卓奥利奥(8+)

安卓奥利奥(8+)

中的通知

原文:https://www . geesforgeks . org/notifications-in-Android-Oreo-8/

安卓奥利奥带来了大量变化。这也包括用户在应用程序中发布通知的方式。在本文中，我们将讨论通知部门需要进行的更改。

发布通知时，请记住以下事项:

设计通知通道
每个通知渠道的重要性
通知标识(不同于频道标识)不应设置为零。

在继续之前，确保这一行被添加到 build.gradle(模块:应用程序)依赖项中:

implementation 'com.android.support:appcompat-v7:26.1.0'

让我们从创建通知渠道开始。下面的方法创建一个通知通道:

@RequiresApi(api = Build.VERSION_CODES.O)
void makeNotificationChannel(String id, String name, int importance)
{
    NotificationChannel channel = new NotificationChannel(id, name, importance);
    channel.setShowBadge(true); // set false to disable badges, Oreo exclusive

    NotificationManager notificationManager =
         (NotificationManager)getSystemService(NOTIFICATION_SERVICE);

    assert notificationManager != null;
    notificationManager.createNotificationChannel(channel);
}

让我们详细看看这个方法是做什么的。

该方法接受字符串 id、字符串名称、int 重要性。。
- 字符串 id: 这是您在通知通道中发出通知时使用的 id。您可以将这个确切的 id 用于同一通道中的多个通知。
- 字符串名称:这是当有人点击导航到设置->App&通知- >【你的 _ App _ name】->App 通知时可见的频道名称。
- int 重要性:这是通道的重要性等级。级别如下:
  1. 通知管理器。重要性 _ 最小–仅在通知阴影下显示，没有声音或窥视。
  2. 通知管理器。重要性 _ 低–无处不在，不发声，不偷看。
  3. 通知管理器。重要性 _ 默认值–到处显示，发出声音但不偷看。
  4. 通知管理器。重要性 _ 高–到处显示，发出声音和窥视(视觉中断)。
  5. NotificationManager.IMPORTANCE_MAX – this importance level is usually not used. Works similar to IMPORTANCE_HIGH.
    
    通常，IMPORTANCE _ DEFAULT 参数是首选参数，但这会产生令人讨厌的通知声音。要静音，在make notificationchannel()方法中，在最后一行之前添加以下一行。
    
```java channel.setSound(null, null);

```
然后，该方法使用参数创建通道。
设置显示标记(真)通过奥利奥通知点功能提供通知。
Finally, the notification channel is created by the createNotificationChannel() method of NotificationManager.

现在让我们发出通知。我们将使用通知兼容性进行向后兼容性。

```java void issueNotification() {

// make the channel. The method has been discussed before.     if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.O) {         makeNotificationChannel("CHANNEL_1", "Example channel", NotificationManager.IMPORTANCE_DEFAULT);     }     // the check ensures that the channel will only be made     // if the device is running Android 8+

NotificationCompat.Builder notification =                 new NotificationCompat.Builder(this, "CHANNEL_1");     // the second parameter is the channel id.     // it should be the same as passed to the makeNotificationChannel() method

notification         .setSmallIcon(R.mipmap.ic_launcher) // can use any other icon         .setContentTitle("Notification!")         .setContentText("This is an Oreo notification!")         .setNumber(3); // this shows a number in the notification dots

NotificationManager notificationManager =                 (NotificationManager)getSystemService(NOTIFICATION_SERVICE);

assert notificationManager != null;     notificationManager.notify(1, notification.build());     // it is better to not use 0 as notification id, so used 1. } ```

执行是这样进行的:
- First, the above method initially creates a notification channel with id = “CHANNEL_1” and the name “Example channel”. The id isn’t visible anywhere but the name can be viewed by opening the “App notifications” option of the App Info page.
- Then a NotificationCompat.Builder object is made specifying the context and id as “CHANNEL_1”. A different channel id can be mentioned provided it is made with the makeNotificationChannel() method. The rest is self-explanatory. The setNumber() method shows a number in the notification dot of the app.
- Finally, the notification id (here 1) is better to not set 0 as in cases where the notification is used for a Foreground service, it will fail to display if the id is 0. On executing the issueNotification() method, we get the following notification: