我正在用 xcode 快速编写一个 webapp。 我有一个问题“如何添加一个进度条来显示每个页面的加载情况？”
@IBOutlet var webView: UIWebView!
override func viewDidLoad() {
super.viewDidLoad()
let url = NSURL(string: "http://stackoverflow.com")
let request = NSURLRequest(URL: url)
webView.loadRequest(request)
}
（对不起我的英语）
【问题讨论】：
标签： ios xcode swift webview uiwebview
您可以找到a very good answer in this post。您可以将进度条作为子视图添加到您的 web 视图。主要问题是进度条的准确性。建议的答案是从不断地对其进行动画处理开始，在仍在加载时将其阻止在 95%，当您的请求完成时，将其一直压缩到 100%。
这是 Swift 中的一个解决方案：
添加这些属性：
//Add this progress view via Interface Builder (IBOutlet) or programatically
let myProgressView: UIProgressView
var theBool: Bool
var myTimer: NSTimer
这些函数将填充进度视图。你可以玩参数：
func funcToCallWhenStartLoadingYourWebview() {
self.myProgressView.progress = 0.0
self.theBool = false
self.myTimer = NSTimer.scheduledTimerWithTimeInterval(0.01667, target: self, selector: "timerCallback", userInfo: nil, repeats: true)
}
func funcToCallCalledWhenUIWebViewFinishesLoading() {
self.theBool = true
}
func timerCallback() {
if self.theBool {
if self.myProgressView.progress >= 1 {
self.myProgressView.hidden = true
self.myTimer.invalidate()
} else {
self.myProgressView.progress += 0.1
}
} else {
self.myProgressView.progress += 0.05
if self.myProgressView.progress >= 0.95 {
self.myProgressView.progress = 0.95
}
}
}
【讨论】：
var theBool: Bool = false var myTimer = NSTimer()
funcToCallCalledWhenUIWebViewFinishesLoading()，是在控制器中实现UIWebViewDelegate并覆盖webViewDidFinishLoad函数。您还必须将 webview 的委托设置为控制器才能正常工作。
var theBool: Bool
var myTimer: NSTimer
var didFinishTimer: NSTimer
required init(coder aDecoder: NSCoder) {
self.theBool = false
self.myTimer = NSTimer()
self.didFinishTimer = NSTimer()
super.init(coder: aDecoder)
}
func startAnimatingProgressBar() {
self.theBool = false
myProgressView.hidden = false
myProgressView.alpha = 0
UIView.animateWithDuration(0.2, animations: { () -> Void in
self.myProgressView.alpha = 0.6
})
self.myProgressView.progress = 0.0
//Tweek this number to alter the main speed of the progress bar
var number = drand48() / 80;
// println("startAnimatingProgressBar|\(number)")
self.myTimer = NSTimer.scheduledTimerWithTimeInterval(number, target: self, selector: "timerCallback", userInfo: nil, repeats: true)
// println("myTimer|\(myTimer)")
}
func finishAnimatingProgressBar() {
self.theBool = true
}
func timerCallback() {
if self.theBool {
if self.myProgressView.progress >= 1 {
UIView.animateWithDuration(0.2, animations: { () -> Void in
self.myProgressView.alpha = 0
// }, completion: { (success:Bool) -> Void in
// self.myProgressView.hidden = true
})
self.myTimer.invalidate()
} else {
//Loaded and zoom to finish
var number = drand48() / 40
// println("finished:\(number)")
self.myProgressView.progress += Float(number)
}
} else {
//Start slow
if self.myProgressView.progress >= 0.00 && self.myProgressView.progress <= 0.10 {
var number = drand48() / 8000;
// println("Start:\(number)")
self.myProgressView.progress += Float(number)
//Middle speed up a bit
} else if self.myProgressView.progress >= 0.10 && self.myProgressView.progress <= 0.42 {
var smallerNumber = drand48() / 2000;
self.myProgressView.progress += Float(smallerNumber)
// println("Middle:\(smallerNumber)")
//slow it down again
} else if myProgressView.progress >= 0.42 && self.myProgressView.progress <= 0.80 {
var superSmallNumber = drand48() / 8000;
self.myProgressView.progress += Float(superSmallNumber)
// println("slow it down:\(superSmallNumber)")
//Stop it
} else if myProgressView.progress == 0.80 {
println("Stop:\(myProgressView.progress)")
self.myProgressView.progress = 0.80
}
}
}
var webViewLoads = 0
var webViewDidStart:Int = 0
var webViewDidFinish:Int = 0
func webViewDidStartLoad(webView: UIWebView) {
webViewDidStart++
webViewLoads++
if webViewLoads <= 1 {
startAnimatingProgressBar()
}
println("webViewDidStartNumber: = \(webViewDidStart)")
println("webViewLoadsStart: = \(webViewLoads)")
// println("webViewDidStartLoad")
UIApplication.sharedApplication().networkActivityIndicatorVisible = true
updateToolbarItems()
}
func webViewDidFinishLoad(webView: UIWebView) {
webViewLoads--
webViewDidFinish++
println("webViewDidFinishLoad \(webViewDidFinish)")
if webViewLoads == 0 {
finishAnimatingProgressBar()
// println("webViewLoads \(webViewLoads)")
return
}
getWebsiteInfo()
UIApplication.sharedApplication().networkActivityIndicatorVisible = false
updateToolbarItems()
func webView(webView: UIWebView, didFailLoadWithError error: NSError) {
theBool = true
webViewLoads = 0
UIApplication.sharedApplication().networkActivityIndicatorVisible = false
println("didFailLoadWithError")
updateToolbarItems()
}
我花了很长时间才弄清楚如何确定网站何时已完全加载并根据进度条设置动画......经过一些铁杆谷歌搜索后，这是我能想到的最好的。很多人说了很多东西，其中大部分对我没有帮助....添加和改进，如果您发现更好的东西，请告诉我。
【讨论】：
我正在使用它，看起来不错。
@IBOutlet var webView: UIWebView!
@IBOutlet var progressView: UIProgressView!
override func viewDidLoad() {
super.viewDidLoad()
let url = NSURL(string: "http://stackoverflow.com")
let request = NSURLRequest(URL: url)
webView.loadRequest(request)
webView.delegate=self
}
func webViewDidStartLoad(_ webView: UIWebView) {
self.progressView.setProgress(0.1, animated: false)
}
func webViewDidFinishLoad(_ webView: UIWebView) {
self.progressView.setProgress(1.0, animated: true)
}
func webView(_ webView: UIWebView, didFailLoadWithError error: NSError?) {
self.progressView.setProgress(1.0, animated: true)
}
【讨论】：
斯威夫特 5
@IBOutlet weak var webView: WKWebView!
@IBOutlet weak var progressView: UIProgressView!
override func viewDidLoad() {
super.viewDidLoad()
webView.addObserver(self, forKeyPath:
#keyPath(WKWebView.estimatedProgress), options: .new, context: nil)
}
override func observeValue(forKeyPath keyPath: String?, of object: Any?, change: [NSKeyValueChangeKey : Any]?, context: UnsafeMutableRawPointer?) {
if keyPath == "estimatedProgress" {
print("estimatedProgress")
progressView.progress = Float(webView.estimatedProgress)
}
}
func webView(_ webView: WKWebView, didFinish navigation: WKNavigation!) {
progressView.isHidden = true
}
【讨论】：
为什么不使用
loadRequest(_ request: URLRequest, progress: ((UInt, Int64, Int64) -> Swift.Void)?, success: ((HTTPURLResponse, String) -> String)?, failure: ((Error) -> Swift.Void)? = nil)
【讨论】：