ios - 无法在SecondViewController中将JSON值传输到Label

我试图通过按主视图控制器中的按钮，将JSON值传输到另一个视图控制器中的标签。我的第一个视图控制器被称为“ ViewController”，第二个被称为“ AdvancedViewController”。下面的代码显示了如何获取JSON数据，并且工作正常，在MainViewController的标签中显示JSON值，但是当我将JSON值发送到AdvancedViewController的标签时，按下按钮，它将加载AdvancedViewController但标签值未更改？我已经在AdvancedViewController中分配了标签，但不确定为什么它不起作用。我正在尝试将其转移到高级视图控制器中的值“ avc.Label”

主要标签代码显示了如何在MainViewController中使其工作

代码如下：

我的主要ViewController：

 guard let APIUrl = URL(string: "https://api.openweathermap.org/data/2.5/weather?q=" + text +  "&appid=e7b2054dc37b1f464d912c00dd309595&units=Metric") else { return }
        //API KEY

        URLSession.shared.dataTask(with: APIUrl) { data, response, error in
            guard let data = data else { return }


            let decoder = JSONDecoder()
            //Decoder

            do {
                let weatherData = try decoder.decode(MyWeather.self, from: data)

                if (self.MainLabel != nil)
                {
                    if let gmain =  (weatherData.weather?.first?.main) { //using .first because Weather is stored in an array
                        print(gmain)
                        DispatchQueue.main.async {
                            self.MainLabel.text! = String (gmain)
                        }
                    }

                }

                let avc = AdvancedViewController(nibName: "AdvancedViewController", bundle: nil)

                if (avc.Label != nil)
                {
                    if let mTest =  (weatherData.weather?.first?.myDescription) { //using .first because Weather is stored in an array
                        DispatchQueue.main.async {
                            avc.Label.text! = String (mTest)
                                                    }
                    }
                }

最佳答案

在AdvancedViewController中，创建存储mTest值的变量

class AdvancedViewController: ViewController {

    var test: String!

    override func viewDidLoad(){
        super.viewDidLoad()

        if let test = test {
            myLabel.text = test
        }
    }

}



let vc = storyboard?.instantiateViewController(withIdentifier: "AdvancedViewController") as! AdvancedViewController
if let mTest =  (weatherData.weather?.first?.myDescription) {
    vc.test = mTest
}
DispatchQueue.main.async {
    present(vc, animated: true, completion: nil)
}