ios - 如何将 UILabel 连接到其他类

Question

我在 View Controller 上有一个 UI 标签，在 nsobject 上有一个字符串 (accuracy)。我想将字符串放在不断更新的 uilabel 上，因为当您打印字符串时(accuracy)它会更新。有人能帮我吗 ？谢谢

class Home: UIViewController {

    @IBOutlet weak var lbl_accuracy: UILabel! 
}

---

class PBLocation: NSObject, CLLocationManagerDelegate {

    func locationManager(_ manager: CLLocationManager, didUpdateLocations locations: [CLLocation]) {

        if CLLocationManager.locationServicesEnabled() {

            switch(CLLocationManager.authorizationStatus()) {

            case .notDetermined, .restricted, .denied:
                print("No access")

            case .authorizedAlways, .authorizedWhenInUse:

                let accuracy = String(format: "%.4f", (locations.last?.horizontalAccuracy)!)
                print("accuracy = \(accuracy)")
            }
        } else {
            print("Location services are not enabled")
        }
    }
}

Answer 1

您可以使用 delegate design pattern将定位精度发送到 Home VC。首先创建LocationUpdatable 协议(protocol) 并添加updateLocationAccuracy(_ accuracy: String) 函数。在 PBLocation 类中创建一个弱委托(delegate)对象，现在您可以通过 updateLocationAccuracy 方法将精度对象发送到 Home VC。最后确认 Home VC 中的 LocationUpdatable 协议(protocol)并实现 updateLocationAccuracy(_ accuracy: String) 函数，最重要的是设置 Home VC 的 LocationUpdatable 委托(delegate)对象的委托(delegate)。

protocol LocationUpdatable: class {
    func updateLocationAccuracy(_ accuracy: String)
}

//Confirm to the LocationUpdatable
class Home: UIViewController, LocationUpdatable {

    @IBOutlet weak var lbl_accuracy: UILabel!

    let location = PBLocation()
    var locationManager: CLLocationManager!

    override func viewDidLoad() {
        super.viewDidLoad()

        // Do any additional setup after loading the view.
        locationManager = CLLocationManager()
        locationManager.delegate = location
        locationManager.requestAlwaysAuthorization()

        location.delegate = self
    }

    func updateLocationAccuracy(_ accuracy: String) {
        lbl_accuracy.text = accuracy
    }
}

//Create a delegate object
class PBLocation: NSObject, CLLocationManagerDelegate {

    weak var delegate: LocationUpdatable?

    func locationManager(_ manager: CLLocationManager, didUpdateLocations locations: [CLLocation]) {

        if CLLocationManager.locationServicesEnabled() {

            switch(CLLocationManager.authorizationStatus()) {

            case .notDetermined, .restricted, .denied:
                print("No access")

            case .authorizedAlways, .authorizedWhenInUse:

                let accuracy = String(format: "%.4f", (locations.last?.horizontalAccuracy)!)
                print("accuracy = \(accuracy)")
                if let delegate = delegate {
                    delegate.updateLocationAccuracy(accuracy)
                }
            }
        } else {
            print("Location services are not enabled")
        }
    }
}