Ios 无法触发添加的UIBarButtonItem

语言：

swift3.0

操作系统：

macOS 10.12.3

xcode:

8.2.1

这是一个带有ViewController的空白故事板

代码如下：

import UIKit
import WebKit

class CommonWebViewViewController: UIViewController, WKUIDelegate, WKNavigationDelegate {

    let backButton = UIBarButtonItem(title: "BACK", style: .plain, target: self, action: #selector(goBack))
    let closeButton = UIBarButtonItem(title: "CLOSE", style: .plain, target: nil, action: #selector(close))

    let webview = WKWebView()
    var url = ""

    override func viewDidLoad() {
        super.viewDidLoad()
        view = webview

        navigationItem.setLeftBarButtonItems([backButton], animated: true)

        webview.uiDelegate = self
        webview.navigationDelegate = self
        webview.allowsBackForwardNavigationGestures = true
    }

    override func didReceiveMemoryWarning() {
        super.didReceiveMemoryWarning()
    }

    func webView(_ webView: WKWebView, didFinish navigation: WKNavigation!) {
        title = webView.title
    }

    func load(withUrl url: String) {
        self.url = url
        webview.load(URLRequest(url: URL(string: self.url)!))
    }

    func goBack() {
        if webview.canGoBack {
            webview.goBack()
            navigationItem.leftBarButtonItems?.append(closeButton)
        }
        else {
            close()
        }
    }

    func close() {
        _ = self.navigationController?.popViewController(animated: true)
    }

}

我想制作一个浏览器，当我点击后退按钮时，除非单击webview中的链接，否则不会有任何响应

---

p.S如果我在viewDidload方法中创建UIBarButtonim对象，问题就会解决。

您似乎根本没有将按钮添加到视图中，您是如何“添加”它们的？通过以下行：navigationItem.SetLeftBarButtonims（[backButton]，动画：true）抱歉，没有看到它您似乎根本没有将按钮添加到视图中，您是如何看到的通过以下行“添加”了“它们”：navigationItem.SetLeftBarButtonims（[backButton]，动画：true）抱歉，没有看到它