UIimageView 未在视图控制器中显示图像

Question

我正在尝试在我的视图控制器中显示图表图像。我的资产中有一个名为"powerchart"的图像，但我无法让它显示在视图控制器中。我正在尝试以编程方式构建应用程序，因此不使用故事板。下面的代码。我尝试使用UIImage的几种组合。函数，但无法加载图像。任何帮助将不胜感激

import Foundation
import UIKit
class MarketViewController: UIViewController {
    override func viewDidLoad() {
        super.viewDidLoad()
        view.backgroundColor = UIColor.yellow
        navigationController?.title = "Market"

        view.addSubview(marketChart)
        setupMarketScreen()
    }
//    create chart
    let marketChart: UIImageView = {
        let chart = UIImageView()
        chart.image = UIImage.init(imageLiteralResourceName: "powerchart")
        return chart
    }()
    func setupMarketScreen() {
        marketChart.centerXAnchor.constraint(equalTo: view.centerXAnchor).isActive=true
        marketChart.centerYAnchor.constraint(equalTo: view.centerYAnchor).isActive=true
        marketChart.widthAnchor.constraint(equalToConstant: 500).isActive=true
        marketChart.heightAnchor.constraint(equalToConstant: 200).isActive=true
    }
}

Answer 1

以

这种方式声明。下面的代码对我来说很好用。

import UIKit
class ViewController: UIViewController {
    /*
    let marketChart: UIImageView = {
        let chart = UIImageView()
        chart.image = UIImage.init(imageLiteralResourceName: "backimg3.jpeg")
        return chart
    }() */
    let marketChart:UIImageView = UIImageView.init(image: UIImage (named: "backimg3.jpeg"))
    override func viewDidLoad() {
        super.viewDidLoad()
           self.view.addSubview(marketChart)
    }
}