UIActivityIndicatorView为零？

Question

我在故事板中连接了一个activityIndicator，并以编程方式创建了一个webView。然而，当我加载VC时，程序崩溃了，报告activityIndicator为空。为什么会这样呢？我确认插座连接正确。

import UIKit
import WebKit

class ViewController: UIViewController, WKUIDelegate, WKNavigationDelegate {

    var webView: WKWebView!
    @IBOutlet weak var activityIndicator: UIActivityIndicatorView!

    override func loadView() {
        let webConfiguration = WKWebViewConfiguration()
        webView = WKWebView(frame: .zero, configuration: webConfiguration)
        webView.uiDelegate = self
        webView.navigationDelegate = self
        view = webView
    }
    override func viewDidLoad() {
        super.viewDidLoad()

        let myURL = URL(string: "https://www.google.com/")
        let myRequest = URLRequest(url: myURL!)
        webView.load(myRequest)
    }

    override func didReceiveMemoryWarning() {
        super.didReceiveMemoryWarning()
        // Dispose of any resources that can be recreated.
    }

    func webView(_ webView: WKWebView, didStartProvisionalNavigation navigation: WKNavigation!) {
        activityIndicator.startAnimating()
        print("loadingwebpage")

    }

    func webView(_ webView: WKWebView, didFinish navigation: WKNavigation!) {
        print("didfinishloadingwebpage")
        activityIndicator.stopAnimating()
    }
}

Answer 1

你有这行代码：

view = webView

这意味着您将创建的webView分配给viewController的视图。这就是为什么你的指示器会破坏并导致崩溃。

将webView添加到视图控制器的子视图中，崩溃就会消失。更改：

webView.frame = self.view.bounds
self.view.addSubview(webView)