Question

在viewcontroller中，我正在加载启用了大导航标题的webview（WKWebview）。问题在于，一旦加载了Webview，它就会缩小到正常大小，从而在WebView加载之前完美地显示了较大的导航栏和标题。任何帮助将不胜感激。

预先感谢...！

Answer 1

Swift4，Swift5：

此问题的原因是当webView开始加载页面时，navigationBar的高度正在改变。因此，使用viewLayoutMarginsDidChange()我们可以更改navigationBar的高度。
viewLayoutMarginsDidChange()调用以通知视图控制器其根视图的布局边距已更改。每当NavigationBar高度更改时，都会调用此方法。

以下代码对我有用

import WebKit

class ViewController: UIViewController, WKNavigationDelegate {

    private var webView: WKWebView!
    var didChange = false //Set true when we have to update navigationBar height in viewLayoutMarginsDidChange()

    override func viewLayoutMarginsDidChange() {
        if didChange {
            print("Height : - \(self.navigationController?.navigationBar.frame.size.height)")
        // set NavigationBar Height here    
           self.navigationController!.navigationBar.frame = CGRect(x: 0, y: 0, width: UIScreen.main.bounds.width, height: 96.0)
            didChange.toggle() 
            }
        }

    override func viewDidLoad() {
        super.viewDidLoad()

    let appearance = UIBarButtonItem.appearance()
    appearance.setBackButtonTitlePositionAdjustment(UIOffset.init(horizontal: 0.0, vertical: -60), for: .default)

    self.navigationItem.title = "WebView"
    self.navigationController?.navigationBar.isTranslucent = true
    self.navigationController?.navigationBar.tintColor = UIColor.black
    self.navigationController?.navigationBar.prefersLargeTitles = true

    webView = WKWebView(frame: CGRect(x: 0, y: 0, width: self.view.frame.size.width, height: self.view.frame.size.height))
    webView.navigationDelegate = self
    view = webView


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

    }


    func webView(_ webView: WKWebView, didStartProvisionalNavigation navigation: WKNavigation!) {
        print("Did Start")
      //webView page starts loading
        didChange = true
    }

}

Answer 2

这个解决方案对我有用，但不是使用

self.navigationController!.navigationBar.frame = CGRect(x: 0, y: 0, width: UIScreen.main.bounds.width, height: 96.0)

我们可以使用：

self.navigationController?.navigationBar.sizeToFit()

加载Webview时，具有大标题的导航栏会缩小

2 个答案: