User Notifications in iOS 10!

With iOS 10, beside just text base notification, we can now add other items like images, GIF or even video clips. In this post, we will create a simple text notification, followed by image and GIF.

Setup

The minimum setup to create a local notification require four thing:

Authorization (one time)
Content
Trigger
Request

Authorization

Before creating any notification, we need to ask user for permission to receive notification. Add the following in AppDelegate:

let center = UNUserNotificationCenter.current()
center.requestAuthorization (options: [.alert, .sound]) {(accepted, error) in
    if !accepted {
        print("User denied authorisation.")
    }
}

We could also ask for more options like .badge if needed.

Notification Content

An instance of UNMutableNotificationContent is required. We should at least be setting the notification content with title, body and sound.

func createNotificationContent(title: String, text: String) -> UNNotificationContent {
    let content = UNMutableNotificationContent()
    content.title = title
    content.body = text
    content.sound = UNNotificationSound.default()

    return content
}

We could set more properties if needed. A list of properties could be found in the docs here.

Trigger

In order to trigger a notification, we could use either of the following three option UNTimeIntervalNotificationTrigger, UNCalendarNotificationTrigger or UNLocationNotificationTrigger.

UNTimeIntervalNotificationTrigger is the simplest of all. We just pass in a timeInterval for seconds later to trigger the notification.

let trigger = UNTimeIntervalNotificationTrigger(timeInterval: 5, repeats: false)

UNCalendarNotificationTrigger require a Calendar A example to post a notification for the next day could be as follow:

let date = Date(timeIntervalSinceNow: 86400)
let tomorrow = Calendar.current.dateComponents([.year,.month,.day,.hour,.minute,.second,], from: date)
let trigger = UNCalendarNotificationTrigger(dateMatching: tomorrow, repeats: false)

UNLocationNotificationTrigger trigger a notification when user enters or leave a CLRegion.

let trigger = UNLocationNotificationTrigger(triggerWithRegion: region, repeats:false)

Request

Having both the content and trigger ready, we could easily create a request now.

let request = UNNotificationRequest(identifier: "UniqueName", content: content, trigger: trigger)
UNUserNotificationCenter.current().add(request) { error in
    if let error = error {
        print(error)
    }
}

identifier is a unique string given to each request. If the same identifier is passed, the existing notification will be replaced with the latest one.

Sample Project

I have created a simple cafe ordering app. You will able to order three item, each showing a different type of local notification after a short interval.

The project can be clone from GitHub. After clicking on a order, user should leave the app to wait for notification. Local notification will not be display when the app is on foreground.

The project also uses UNNotificationAction that I will write about in the next post.