On mobile devices, normally only one application can be active in the foreground at any time, but many games and applications operate in a time-based or interconnected environment where events of interest to users can occur when the application is not in the foreground. In these cases, Local and Remote push notifications can allow these games to notify their users when events occur.
When the operating system delivers a local or remote push notification and the target application is not running in the foreground, it presents the notification to the user in the form of a banner. If there is a notification alert and the user taps on it, then the game is launched and an Asynchronous Push Event is called where you can check the callback string that you specify and resolve the push based on its value. If the application is running in the foreground when the notification is delivered, the application will still receive an Asynchronous Push Event, but the user will get no message displayed unless you create it yourself.
There are a few differences to note between supported platforms:
A local push notification is local to the device that the game is installed on, and requires no back-end server. You simply set the date and time for the notification and it will be displayed to the user if the game is not currently running. This type of notification is useful to set "reminders" for the user to play your game again, or to offer a daily reward for playing, etc... and when the user taps the notification it will launch the game and pass in a data string which can then be parsed by the game to give a reward or whatever.
NOTE: This functionality is limited to the iOS and Android target modules. For Android you will need to have installed the Google Push Notification extension.
The following functions are available for local notifications:
Remote notification messages are sent by a server to a service provided by the device platform app store, and this then forwards those messages onto all the devices on which your application is installed. This is supported by GameMaker Studio 2 on the iOS and Android target modules.
There are no functions in GameMaker Studio 2 to deal with remote notifications, as they must all be generated by your server and handled by the respective app atores. However, once set up correctly, GameMaker Studio 2 games will receive these notifications, which can then be dealt with in the Asynchronous Push Event, as you would a local notification.
Please note that there is no guarantee that remote push notifications will be delivered, and that the allowed data payload is fairly small. This varies between platforms, but iOS is particularly limited - the apple service only delivers the most recent notification, which must be selected by the recipient for the payload data to be delivered to your async event, and these notifications have a maximum payload size of 256bytes. Typically a remote push notification would just indicate that new data is available from your server for example.
NOTE: Implementing the server-side is entirely up to the end user, and YoYo Games do not provide any support for that side of things, other than basic set-up information available from their Knowledge Base.
For further details on how to go about setting up a server, as well as information specific to the available platforms, please see the following articles: