[Flutter/dart] Display an icon on the notification screen with local_notification

Overview

You can create notifications using a library called local_notification. The official sample only has a title and body, but you can also add an icon like Line. This time, I will introduce how to display the icon on the notification screen.

Method

For android

set largeIcon property of AndroidNotificationDetails()

var styleInformation=DefaultStyleInformation(true, true);

var androidChannelSpecifics = AndroidNotificationDetails(
  "channel_id",
  "channel_name",
  "channel_description",
  importance: Importance.max,
  priority: Priority.high,
  largeIcon: FilePathAndroidBitmap(icon_path),  //here！
  styleInformation: styleInformation,
);

In my case, the icon image is saved locally, so I pass the image path (icon_path) to the argument of FilePathAndroidBitmap (). If you want to use the image in drawable resource, you can use DrawableResourceAndroidBitmap () (as far as I read the docs, I haven't tried it).

for ios

Do the following: icon_path is the path of the icon image.

var iosChannelSpecifics =IOSNotificationDetails(
    attachments: [IOSNotificationAttachment(icon_path)]
);

It should be noted that the image placed in icon_path will be moved by the system after creating the notification. If you're referencing icon_path anywhere other than creating a notification, make sure to copy the file and pass in that path.

reference：https://developer.apple.com/documentation/usernotifications/unnotificationattachment

Once validated, attached files are moved into the attachment data store so that they can be accessed by all of the appropriate processes.

Finally, create a platformChannelSpecific with the androidChannelSpecific and isoChannelSpecific created above as arguments.

var platformChannelSpecifics = 
NotificationDetails(
  android: androidChannelSpecifics,
  iOS: iosChannelSpecifics
);

The notification screen is as follows. (It's ios)

The image is borrowed from freepik.

Lastly

It seems that you can't bring an icon in front of the title like Line (please let me know if you can!).