Android 自定义通知设置高度自动展开

要实现 Android 自定义通知设置高度自动展开，可以使用以下步骤：

1. 创建一个自定义的 Notification 布局，例如 notification_layout.xml。

2. 在 notification_layout.xml 中设置一个高度固定的根布局，例如 LinearLayout，并在其中添加需要展示的内容。

3. 创建一个继承自 NotificationCompat.Style 的自定义样式类，例如 CustomNotificationStyle。

4. 在 CustomNotificationStyle 中重写 createContentView() 方法，将 notification_layout.xml 作为 ContentView 返回。

   @Override
   public RemoteViews createContentView() {
       RemoteViews contentView = new RemoteViews(getPackageName(), R.layout.notification_layout);
       // 设置通知内容
       contentView.setTextViewText(R.id.notification_title, 'Notification Title');
       contentView.setTextViewText(R.id.notification_content, 'Notification Content');
       return contentView;
   }
   

5. 在创建通知时，使用自定义样式类 CustomNotificationStyle。

   NotificationCompat.Builder builder = new NotificationCompat.Builder(context, channelId)
           .setSmallIcon(R.drawable.notification_icon)
           .setPriority(NotificationCompat.PRIORITY_HIGH)
           .setStyle(new CustomNotificationStyle());
   

6. 在 AndroidManifest.xml 中，为应用的 NotificationChannel 设置 setImportance 为 IMPORTANCE_HIGH。

   <application ...>
       <meta-data
           android:name="com.google.firebase.messaging.default_notification_channel_id"
           android:value="@string/default_notification_channel_id"/>
   
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       <!-- 设置通知渠道重要性为高 -->
       <meta-data
           android:name="com.google.firebase.messaging.default_notification_channel_importance"
           android:value="high"/>
   </application>
   

7. 运行应用，显示通知时，通知应该会自动展开到设置的固定高度。

请注意，自定义通知样式只适用于 Android 4.1（API 级别 16）及更高版本。在较旧的 Android 版本上，通知可能无法自动展开。