4.9

安卓通知系统与富媒体推送
安卓通知系统为应用与用户提供了重要的交互渠道，特别是在后台服务场景中。以下是 Java 实现的关键技术点：

1. 创建通知渠道（Android 8.0+）
   java
   if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.O) {
   NotificationChannel channel = new NotificationChannel(
   "channel_id",
   "Channel Name",
   NotificationManager.IMPORTANCE_DEFAULT
   );
   channel.setDescription("Channel Description");
   NotificationManager manager = getSystemService(NotificationManager.class);
   manager.createNotificationChannel(channel);
   }
2. 构建富媒体通知
   java
   NotificationCompat.Builder builder = new NotificationCompat.Builder(this, "channel_id")
   .setSmallIcon(R.drawable.ic_notification)
   .setContentTitle("New Message")
   .setContentText("You have a new message")
   .setPriority(NotificationCompat.PRIORITY_DEFAULT)
   .setStyle(new NotificationCompat.BigPictureStyle()
   .bigPicture(BitmapFactory.decodeResource(getResources(), R.drawable.big_image)))
   .setAutoCancel(true);

NotificationManagerCompat notificationManager = NotificationManagerCompat.from(this);
notificationManager.notify(notificationId, builder.build());
3. 处理通知点击事件
java
Intent intent = new Intent(this, MainActivity.class);
intent.setFlags(Intent.FLAG_ACTIVITY_NEW_TASK | Intent.FLAG_ACTIVITY_CLEAR_TASK);
PendingIntent pendingIntent = PendingIntent.getActivity(this, 0, intent, PendingIntent.FLAG_IMMUTABLE);

builder.setContentIntent(pendingIntent);