在iOS Swift中应用程序在后台时如何通过MQTT客户端框架发布或发送消息
在iOS Swift中应用程序在后台时如何通过MQTT客户端框架发布或发送消息
提问于 2020-09-16 22:04:11
我正在开发一个应用程序，通过MQTT客户端框架每15分钟发送一次当前用户位置。当应用程序在前台时，它可以正常工作，但当应用程序在后台时，MQTT委托函数"messageDelivered“不会被调用
我们希望在iOS swift中使用MQTT客户端框架在后台发布消息。
import UIKit
import MQTTClient
class MainViewController: UIViewController {
let MQTT_HOST = "next.nanolink.com" // or IP address e.g. "192.168.0.194"
//let MQTT_HOST = "tnclicks.free.beeceptor.com" // or IP address e.g. "192.168.0.194"
let MQTT_PORT: UInt32 = 1883
private var transport = MQTTCFSocketTransport()
fileprivate var session = MQTTSession()
fileprivate var completion: (()->())?
override func viewDidLoad() {
super.viewDidLoad()
//notification observer
NotificationCenter.default.addObserver(self, selector: #selector(onDidReceiveData(_:)), name: .didReceiveData, object: nil)
//MQTT
self.session?.delegate = self
self.transport.host = MQTT_HOST
self.transport.port = MQTT_PORT
session?.transport = transport
updateUI(for: self.session?.status ?? .created)
session?.connect() { error in
print("connection completed with status \(String(describing: error?.localizedDescription))")
if error != nil {
self.updateUI(for: self.session?.status ?? .created)
} else {
self.updateUI(for: self.session?.status ?? .error)
}
}
}
private func subscribe() {
self.session?.subscribe(toTopic: "test/message", at: .exactlyOnce) { error, result in
print("subscribe result error \(String(describing: error)) result \(result!)")
}
}
private func updateUI(for clientStatus: MQTTSessionStatus) {
DispatchQueue.main.async {
switch clientStatus {
case .connected:
print("Connected")
self.publishMessage("on", onTopic: "test/message")
case .connecting,
.created:
print ("Trying to connect...")
default:
print ("Connetion Failed...")
}
}
}
private func publishMessage(_ message: String, onTopic topic: String)
{
session?.publishData(message.data(using: .utf8, allowLossyConversion: false), onTopic: topic, retain: false, qos: .exactlyOnce)
}
@objc func onDidReceiveData(_ notification:Notification) {
print("check return")
guard session?.status == .connected else {
self.updateUI(for: self.session?.status ?? .error)
return
}
let obj = notification.object! as! NSMutableDictionary
print(notification.object!)
let notificationLatitude = obj.value(forKey: "latitude")!
let notificationLongitude = obj.value(forKey: "longitude")!
//let notificationLongitude = notification.object
// print(" Saved latitude:", latitude!)
// print(" Saved longitude:", longitude!)
print(" notification latitude:", notificationLatitude)
print(" notification longitude:", notificationLongitude)
guard session?.status == .connected else {
return
}
publishMessage("on", onTopic: "test/message")
}
}
extension MainViewController: MQTTSessionManagerDelegate, MQTTSessionDelegate {
func newMessage(_ session: MQTTSession!, data: Data!, onTopic topic: String!, qos: MQTTQosLevel, retained: Bool, mid: UInt32) {
if let msg = String(data: data, encoding: .utf8) {
print("topic \(topic!), msg \(msg)")
}
}
func messageDelivered(_ session: MQTTSession, msgID msgId: UInt16) {
print("delivered")
DispatchQueue.main.async {
self.completion?()
}
}
}
extension Notification.Name {
static let didReceiveData = Notification.Name("didReceiveData")
}Stack Overflow用户
发布于 2020-09-16 22:16:24
我们已经在后台实现了更新位置，所以使用更新位置来更新您的代码，以便在后台发送消息。
import UIKit
import CoreLocation
@UIApplicationMain
class AppDelegate: UIResponder, UIApplicationDelegate,CLLocationManagerDelegate {
var window: UIWindow?
var locationManager = CLLocationManager()
var backgroundUpdateTask: UIBackgroundTaskIdentifier!
var bgtimer = Timer()
var latitude: Double = 0.0
var longitude: Double = 0.0
var current_time = NSDate().timeIntervalSince1970
var timer = Timer()
var f = 0
func application(_ application: UIApplication, didFinishLaunchingWithOptions launchOptions: [UIApplicationLaunchOptionsKey: Any]?) -> Bool {
self.doBackgroundTask()
return true
}
func applicationWillResignActive(_ application: UIApplication) {
}
func applicationWillEnterForeground(_ application: UIApplication) {
print("Entering foreBackground")
}
func applicationDidBecomeActive(_ application: UIApplication) {
}
func applicationWillTerminate(_ application: UIApplication) {
}
func applicationDidEnterBackground(_ application: UIApplication) {
print("Entering Background")
// self.doBackgroundTask()
}
func doBackgroundTask() {
DispatchQueue.main.async {
self.beginBackgroundUpdateTask()
self.StartupdateLocation()
self.bgtimer = Timer.scheduledTimer(timeInterval:-1, target: self, selector: #selector(AppDelegate.bgtimer(_:)), userInfo: nil, repeats: true)
RunLoop.current.add(self.bgtimer, forMode: RunLoopMode.defaultRunLoopMode)
RunLoop.current.run()
self.endBackgroundUpdateTask()
}
}
func beginBackgroundUpdateTask() {
self.backgroundUpdateTask = UIApplication.shared.beginBackgroundTask(expirationHandler: {
self.endBackgroundUpdateTask()
})
}
func endBackgroundUpdateTask() {
UIApplication.shared.endBackgroundTask(self.backgroundUpdateTask)
self.backgroundUpdateTask = UIBackgroundTaskInvalid
}
func StartupdateLocation() {
locationManager.delegate = self
locationManager.desiredAccuracy = kCLLocationAccuracyBest
locationManager.distanceFilter = kCLDistanceFilterNone
locationManager.requestAlwaysAuthorization()
locationManager.allowsBackgroundLocationUpdates = true
locationManager.pausesLocationUpdatesAutomatically = false
locationManager.startUpdatingLocation()
}
func locationManager(_ manager: CLLocationManager, didFailWithError error: Error) {
print("Error while requesting new coordinates")
}
func locationManager(_ manager: CLLocationManager, didUpdateLocations locations: [CLLocation]) {
let locValue:CLLocationCoordinate2D = manager.location!.coordinate
self.latitude = locValue.latitude
self.longitude = locValue.longitude
f+=1
print("New Coordinates: \(f) ")
print(self.latitude)
print(self.longitude)
}
@objc func bgtimer(_ timer:Timer!){
sleep(2)
/* if UIApplication.shared.applicationState == .active {
timer.invalidate()
}*/
self.updateLocation()
}
func updateLocation() {
self.locationManager.startUpdatingLocation()
self.locationManager.stopUpdatingLocation()
}}页面原文内容由Stack Overflow提供。腾讯云小微IT领域专用引擎提供翻译支持
原文链接：
https://stackoverflow.com/questions/63921790
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