问题
I want to run the function in the background. But I get an error. The error I received is
"nw_connection_receive_internal_block_invoke.
Why am I getting this problem? I'm trying it on an iOS 13 device. But I can't run the application in the background. I added a background run feature in Info.plist. I want to run the interator.tickTimer function in the background. But I'm getting an error. Does not work in the background. In the background, I want to periodically retrieve data from firebase.
import BackgroundTasks
@available(iOS 13.0, *)
extension AppDelegate {
func cancelAllPandingBGTask() {
BGTaskScheduler.shared.cancelAllTaskRequests()
}
func scheduleImageFetcher() {
let request = BGProcessingTaskRequest(identifier: "....")
request.requiresNetworkConnectivity = true // Need to true if your task need to network process. Defaults to false.
request.requiresExternalPower = false
request.earliestBeginDate = Date(timeIntervalSinceNow: 40)
do {
try BGTaskScheduler.shared.submit(request)
} catch {
print("Could not schedule image featch: \(error)")
}
}
func handleAppRefreshTask(task: BGAppRefreshTask) {
task.expirationHandler = {
}
DispatchQueue.main.async {
let interator = MainTableViewController()
interator.tickTimer()
}
task.setTaskCompleted(success: true)
}
func handleImageFetcherTask(task: BGProcessingTask) {
scheduleImageFetcher() // Recall
//Todo Work
task.expirationHandler = {
}
task.setTaskCompleted(success: true)
}
}
xtension AppDelegate {
func registerLocalNotification() {
let notificationCenter = UNUserNotificationCenter.current()
let options: UNAuthorizationOptions = [.alert, .sound, .badge]
notificationCenter.requestAuthorization(options: options) {
(didAllow, error) in
if !didAllow {
// print("User has declined notifications")
}
}
}
func scheduleLocalNotification() {
let notificationCenter = UNUserNotificationCenter.current()
notificationCenter.getNotificationSettings { (settings) in
if settings.authorizationStatus == .authorized {
self.fireNotification()
}
}
}
func fireNotification() {
// Create Notification Content
let notificationContent = UNMutableNotificationContent()
// Configure Notification Content
notificationContent.title = "Bg"
notificationContent.body = "BG Notifications."
// Add Trigger
let notificationTrigger = UNTimeIntervalNotificationTrigger(timeInterval: 1.0, repeats: false)
// Create Notification Request
let notificationRequest = UNNotificationRequest(identifier: "local_notification", content: notificationContent, trigger: notificationTrigger)
// Add Request to User Notification Center
UNUserNotificationCenter.current().add(notificationRequest) { (error) in
if let error = error {
print("Unable to Add Notification Request (\(error), \(error.localizedDescription))")
}
}
}
}
@UIApplicationMain
class AppDelegate: UIResponder, UIApplicationDelegate, UITabBarControllerDelegate {
var window: UIWindow?
func application(_ application: UIApplication, didFinishLaunchingWithOptions launchOptions: [UIApplication.LaunchOptionsKey: Any]?) -> Bool {
if #available(iOS 13.0, *) {
registerBackgroundTaks()
registerLocalNotification()
} else {
// Fallback on earlier versions
}
return true
}
func applicationDidEnterBackground(_ application: UIApplication) {
if #available(iOS 13.0, *) {
cancelAllPandingBGTask()
scheduleImageFetcher()
} else {
// Fallback on earlier versions
}
}
//MARK: Regiater BackGround Tasks
@available(iOS 13.0, *)
private func registerBackgroundTaks() {
BGTaskScheduler.shared.register(forTaskWithIdentifier: "....-...", using: nil) { task in
//This task is cast with processing request (BGProcessingTask)
self.scheduleLocalNotification()
self.handleImageFetcherTask(task: task as! BGProcessingTask)
}
}
来源：https://stackoverflow.com/questions/57413646/backgroundtask-ios-13-swift