This section describes the Flutter notification function, mainly using the Flutter and native interaction function to call Android to send notifications.

Design sketch

Required knowledge

Flutter builds channel mechanism Channel
Android creates notification channel Notification Channel to send notifications

Implementation code

Flutter mainly implements interaction with native and transfers data

//Get the interaction channel between the plug-in and the native
static const mNotificationBar = const MethodChannel('notification_bar.flutter.io/notificationBar');

//Launch data to native and return
String result = await mNotificationBar.invokeMethod('content', map);

The Android end completes two actions: 1. Constructing native interaction channels corresponds to flutter. 2. Realize the function of sending notification

//Constructing Primary Channel
new MethodChannel(getFlutterView(), "notification_bar.flutter.io/notificationBar").setMethodCallHandler(
        new MethodCallHandler() {
            @Override
            public void onMethodCall(MethodCall call, Result result) {
                // TODO
                if (call.method.equals("content")) {
                    //Analytic parameter
                    String contentTitle = call.argument("contentTitle");
                    String contentText = call.argument("contentText");
                    // Sending notice
                    sendChatMsg(contentTitle,contentText);
                    if (true) {
                        result.success("success");
                    } else {
                        result.error("error", "failure", null);
                    }
                } else {
                    result.notImplemented();
                }
            }
        }
    );

// Create two new notification channels 8.0 features that do not allow NotificationCompat.Builder
  private void initNotificationManager(){
    if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.O) {
      String channelId = "chat";
      String channelName = "Chat messages";
      int importance = NotificationManager.IMPORTANCE_HIGH;
      createNotificationChannel(channelId, channelName, importance);
    }
  }

  @TargetApi(Build.VERSION_CODES.O)
  private void createNotificationChannel(String channelId, String channelName, int importance) {
    NotificationChannel channel = new NotificationChannel(channelId, channelName, importance);
    channel.setShowBadge(true);//Open Desktop Corner
    channel.setBypassDnd(true);    //Set bypass interference-free mode
    channel.canBypassDnd();       //Detecting whether to bypass interference-free mode
    channel.setLockscreenVisibility(Notification.VISIBILITY_SECRET);//Set up the lock screen interface to display this notification
    
    //Whether Vibration Tips are Needed
    channel.enableVibration(true);
    //Vibration mode
    channel.setVibrationPattern(new long[]{100, 200, 300, 400, 500, 400, 300, 200, 400});

    //Do you need a breathing light?
    channel.enableLights(true);
    //Breathing lamp color
    // channel.setLightColor();
    
    NotificationManager notificationManager = (NotificationManager) getSystemService( NOTIFICATION_SERVICE);
    notificationManager.createNotificationChannel(channel);
  }
  public void sendChatMsg(String contentTitle,String contentText) {
    NotificationManager manager = (NotificationManager) getSystemService(NOTIFICATION_SERVICE);
    //Check whether permissions are open
    if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.O) {
        NotificationChannel channel = manager.getNotificationChannel("chat");
        if (channel.getImportance() == NotificationManager.IMPORTANCE_NONE) {
          Intent intent = new Intent(Settings.ACTION_CHANNEL_NOTIFICATION_SETTINGS);
          intent.putExtra(Settings.EXTRA_APP_PACKAGE, getPackageName());
          intent.putExtra(Settings.EXTRA_CHANNEL_ID, channel.getId());
          startActivity(intent);
          Toast.makeText(this, "Please open the notification manually", Toast.LENGTH_SHORT).show();
        }
    }

    Notification notification = new NotificationCompat.Builder(this, "chat")
            .setContentTitle(contentTitle)
            .setContentText(contentText)
            .setWhen(System.currentTimeMillis())
            .setSmallIcon(R.mipmap.ic_launcher)
            .setLargeIcon(BitmapFactory.decodeResource(getResources(), R.mipmap.ic_launcher))
            .setAutoCancel(true)
            .setNumber(19)//Corner Display Number
            .build();
    manager.notify(1, notification);
  }

Complete code

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