導航：

1.加載進度條

2.導航欄增加返回、關閉按鈕

加載進度條

效果圖

代碼如下：

self.progressView.trackTintColor = UIColor.white
self.progressView.progressTintColor = UIColor.colorWithHex(value: 0x72A438, alpha: 1).withAlphaComponent(0.8)
self.progressView.frame = CGRect.init(x: 0, y: 0, width: UIScreen.main.bounds.width, height: 1)
self.progressView.transform = CGAffineTransform.init(scaleX: 1, y: 3)
self.view.addSubview(self.progressView)
self.progressView.progress = 0.05 //設置初始值，防止網頁加載過慢時沒有進度

// Swift 4 KVO
self.observeBlock = webView.observe(\.estimatedProgress, options: NSKeyValueObservingOptions.new.union(NSKeyValueObservingOptions.old)) { (webview, changed) in
    
    if let new = changed.newValue{
        self.progressView.isHidden = false
        self.progressView.progress = Float(new)
        if new >= 1.0{
            delay(second: 0.3, block: {
                self.progressView.isHidden = true
            })
        }
    }
}

// 加載失敗隱藏進度條
func webView(_ webView: WKWebView, didFail navigation: WKNavigation!, withError error: Error) {
    
    self.progressView.isHidden = true
}

延遲執行函數：

func delay(second:Double,block:@escaping (() -> Void)){
    
    DispatchQueue.main.asyncAfter(deadline: .now() + second, execute: {
        block()
    })
}

導航欄增加返回、關閉按鈕

效果圖

代碼如下：

func showLeftNavigationItem(){
    
    let goBackBtn = UIButton.init()
    let closeBtn = UIButton.init()
    
    goBackBtn.setImage(UIImage.init(named: "navi_go_back"), for: UIControlState.normal)
    goBackBtn.setTitle(" 返回", for: UIControlState.normal)
    goBackBtn.addTarget(self, action: #selector(goBack), for: UIControlEvents.touchUpInside)
    goBackBtn.sizeToFit()
    goBackBtn.contentEdgeInsets = UIEdgeInsetsMake(0, -8, 0, 8)
    
    let backItem = UIBarButtonItem.init(customView: goBackBtn)
    closeBtn.setTitle("關閉", for: UIControlState.normal)
    closeBtn.addTarget(self, action: #selector(popViewController), for: UIControlEvents.touchUpInside)
    closeBtn.sizeToFit()
    let closeItem = UIBarButtonItem.init(customView: closeBtn)
    
    let items:[UIBarButtonItem] = [backItem,closeItem]
    self.navigationItem.leftBarButtonItems = items
}

按鈕對應的Selector：

@objc func goBack(){
	self.webView.goBack()
}
@objc func popViewController(){
    
    self.navigationController?.popViewController(animated: true)
}

加載完成時，決定是否顯示這兩個按鈕：

func webView(_ webView: WKWebView, didFinish navigation: WKNavigation!) {
    
    checkGoBack()
}
func webView(_ webView: WKWebView, didFail navigation: WKNavigation!, withError error: Error) {
    
    checkGoBack()
}
/// 檢查返回（pop/goback）
func checkGoBack(){
    
    self.navigationController?.interactivePopGestureRecognizer?.isEnabled = !self.webView.canGoBack
    if self.webView.canGoBack{
        showLeftNavigationItem()
    }else{
        self.navigationItem.leftBarButtonItems = nil
    }
}

白色返回箭頭圖片：

右鍵括號處保存 2x:() 3x:()

Ficow原創，轉載請註明出處：http://www.cnblogs.com/ficow/p/7639912.html

iOS WKWebView 加載進度條、導航欄返回&關閉 (Swift 4)