WKWebView equivalent for UIWebView's scalesPageToFit - ios

Question

I am updating my iOS app to replace UIWebView with WKWebView. However I don't understand how to achieve the same behavior with WKWebView. With UIWebView I used scalesPageToFit to ensure the web pag was displayed with the same size as the screen size (so as to appear full screen without scrolling).
I found that solution on the web however it does not work :
- (void)webView:(WKWebView *)webView didCommitNavigation:(WKNavigation *)navigation {
NSString *javascript = #"var meta = document.createElement('meta');meta.setAttribute('name', 'viewport');meta.setAttribute('content', 'width=device-width, initial-scale=1.0, maximum-scale=1.0, user-scalable=no');document.getElementsByTagName('head')[0].appendChild(meta);";
[webView evaluateJavaScript:javascript completionHandler:nil];
}

Answer 1

you can also try the WKUserScript.
here's my working config:
NSString *jScript = #"var meta = document.createElement('meta'); meta.setAttribute('name', 'viewport'); meta.setAttribute('content', 'width=device-width'); document.getElementsByTagName('head')[0].appendChild(meta);";
WKUserScript *wkUScript = [[WKUserScript alloc] initWithSource:jScript injectionTime:WKUserScriptInjectionTimeAtDocumentEnd forMainFrameOnly:YES];
WKUserContentController *wkUController = [[WKUserContentController alloc] init];
[wkUController addUserScript:wkUScript];
WKWebViewConfiguration *wkWebConfig = [[WKWebViewConfiguration alloc] init];
wkWebConfig.userContentController = wkUController;
wkWebV = [[WKWebView alloc] initWithFrame:self.view.frame configuration:wkWebConfig];
you can add additional configuration to your WKWebViewConfiguration.

Answer 2

Echo of nferocious76's answer, in swift code:
Swift2.x version
let jscript = "var meta = document.createElement('meta'); meta.setAttribute('name', 'viewport'); meta.setAttribute('content', 'width=device-width'); document.getElementsByTagName('head')[0].appendChild(meta);"
let userScript = WKUserScript(source: jscript, injectionTime: WKUserScriptInjectionTime.AtDocumentEnd, forMainFrameOnly: true)
let wkUController = WKUserContentController()
wkUController.addUserScript(userScript)
let wkWebConfig = WKWebViewConfiguration()
wkWebConfig.userContentController = wkUController
let youWebView = WKWebView(frame: CGRectZero, configuration: wkWebConfig)
swift3 version
let jscript = "var meta = document.createElement('meta'); meta.setAttribute('name', 'viewport'); meta.setAttribute('content', 'width=device-width'); document.getElementsByTagName('head')[0].appendChild(meta);"
let userScript = WKUserScript(source: jscript, injectionTime: .atDocumentEnd, forMainFrameOnly: true)
let wkUController = WKUserContentController()
wkUController.addUserScript(userScript)
let wkWebConfig = WKWebViewConfiguration()
wkWebConfig.userContentController = wkUController
let yourWebView = WKWebView(frame: self.view.bounds, configuration: wkWebConfig)

Answer 3

Similar to #nferocious76's but in Swift language
var scriptContent = "var meta = document.createElement('meta');"
scriptContent += "meta.name='viewport';"
scriptContent += "meta.content='width=device-width';"
scriptContent += "document.getElementsByTagName('head')[0].appendChild(meta);"
webView.evaluateJavaScript(scriptContent, completionHandler: nil)

Answer 4

I figured out below soultion. For making the content to fit with the device size.
func webView(_ webView: WKWebView, didCommit navigation: WKNavigation!) { for making the content to fit with the device size
let jscript = "var meta = document.createElement('meta'); meta.setAttribute('name', 'viewport'); meta.setAttribute('content', 'width=device-width'); document.getElementsByTagName('head')[0].appendChild(meta);"
webView.evaluateJavaScript(jscript)
}

Answer 5

C# version, for use in Xamarin Custom Renderer:
string jScript = #"var meta = document.createElement('meta'); meta.setAttribute('name', 'viewport'); meta.setAttribute('content', 'width=device-width'); document.getElementsByTagName('head')[0].appendChild(meta);";
WKUserScript wkUScript = new WKUserScript((NSString)jScript, WKUserScriptInjectionTime.AtDocumentEnd, true);
WKUserContentController wkUController = new WKUserContentController();
wkUController.AddUserScript(wkUScript);
WKWebViewConfiguration wkWebConfig = new WKWebViewConfiguration();
wkWebConfig.UserContentController = wkUController;
WKWebView webView=new WKWebView(Frame, wkWebConfig);

Answer 6

Adding the below to my HTML script helped me.
<meta name="viewport" content="width=device-width, shrink-to-fit=YES">
It does the same as scalePageToFit in UIWebView.
refer: How to set iOS WkWebview zoom scale

Answer 7

Swift 5 solution:
let javaScript = """
var meta = document.createElement('meta');
meta.setAttribute('name', 'viewport');
meta.setAttribute('content', 'width=device-width');
document.getElementsByTagName('head')[0].appendChild(meta);
"""
webView.evaluateJavaScript(javaScript)

Answer 8

This work for me, I added two attributes in meta: initial-scale=1.0, shrink-to-fit=yes, that help fit text with html have a big image in html.
let jscript = "var meta = document.createElement('meta'); meta.setAttribute('name', 'viewport'); meta.setAttribute('content', 'width=device-width, initial-scale=1.0, shrink-to-fit=yes'); document.getElementsByTagName('head')[0].appendChild(meta);"
let userScript = WKUserScript(source: jscript, injectionTime: .atDocumentEnd, forMainFrameOnly: true)
let wkUController = WKUserContentController()
wkUController.addUserScript(userScript)
let wkWebConfig = WKWebViewConfiguration()
wkWebConfig.userContentController = wkUController
self.webView = WKWebView(frame: self.view.bounds, configuration: wkWebConfig)

Answer 9

None of this answers were working for me. I was trying to open an Amazon URL for a particular artist. Turns out that Amazon has a mobile responsive URL and a desktop URL. On desktop Safari, I changed to iPhone as user-agent (Develop > User Agent > Safari - iOS 13.1.3 - iPhone) and got the appropriate URL for mobile.

Answer 10

This works for me to fit the image size within width of device for Swift 5
Helpful with dynamic html from server
func webView(_ webView: WKWebView, didCommit navigation: WKNavigation!) {
let fontAdjust = "var style = document.createElement('style');style.innerHTML = 'body { -webkit-text-size-adjust: none; }';document.getElementsByTagName('head')[0].appendChild(style);"
let imgAdjust = "var style = document.createElement('style');style.innerHTML = 'img { display: inline;height: auto;max-width: 100%; }';document.getElementsByTagName('head')[0].appendChild(style);"
webKitView.evaluateJavaScript(imgAdjust)
webKitView.evaluateJavaScript(fontAdjust)
webKitView.evaluateJavaScript(imgAdjust)
}

Answer 11

Modern Swift code to use in an extension
extension WKWebView {
func addInitialScaleMetaTag() {
evaluateJavaScript(
"""
var meta = document.createElement("meta");
meta.name = "viewport";
meta.content = "initial-scale=1.0";
document.getElementsByTagName('head')[0].appendChild(meta);
""") { result, error in
// handle error
}
}
}

Answer 12

// 100% work for me
func webView(_ webView: WKWebView, didCommit navigation: WKNavigation!) {
//print(#function)
let scriptFontSizeAdjustment = "var style = document.createElement('style');style.innerHTML = 'body { -webkit-text-size-adjust: none; }';document.getElementsByTagName('head')[0].appendChild(style);"
let scriptImgSizeAdjustment = "var style = document.createElement('style');style.innerHTML = 'img { display: inline;height: auto;max-width: 100%; }';document.getElementsByTagName('head')[0].appendChild(style);"
webKitView.evaluateJavaScript(scriptFontSizeAdjustment)
webKitView.evaluateJavaScript(scriptImgSizeAdjustment)
}