UIWebView : Get Webview Content size? - ios

Question

I have loaded HTML in webview.  I want to dynamically update font size(increase or decrease) of text loaded in web view Same as in Apple News Article app. But According to my design I need to stop web view scrolling and need to update it height according to text. So I need to get content size of article, but I am not getting it proper. Can anyone help?

Answer 1

When font change at that time change Webview height to 1 than get proper offsetHeight for Webview
webView1.frame.size.height = 1
let size : String = self.webView1.stringByEvaluatingJavaScript(from: "document.documentElement.offsetHeight")!

Answer 2

add below lines of code into your webViewDidFinishLoad
webView.layoutSubviews()
webView.frame.size.height = 1
webView.frame.size = webView.sizeThatFits(.zero)
print("WebView Height : \(webView.scrollView.contentSize.height)")
webViewHgtConst.constant = webView.scrollView.contentSize.height
webView.scalesPageToFit = true
webView.scrollView.isScrollEnabled = false
webView.scrollView.maximumZoomScale = 1.0
webView.scrollView.minimumZoomScale = 1.0
and don't forget to add UIWebViewDelegate
and add YOUR_WEBVIEW.delegate = self to your viewDidLoad
Hope this will help you

Answer 3

First stop its scrolling :
webView.scrollView.isScrollEnabled = false
webView.scrollView.showsVerticalScrollIndicator = false
webView.scrollView.showsHorizontalScrollIndicator = false
webView.scrollView.bounces = false
webView.loadHTMLString(dataHtmlString, baseURL: nil)
Make outlet of webView height Constraint and give its value by calculating its height:
webviewHeightConst.constant = (dataHtmlString.htmlAttributedString()?.height(withConstrainedWidth: yourwidthcont))!
This Extension Calculates height
extension String {
func htmlAttributedString() -> NSAttributedString? {
guard let data = self.data(using: String.Encoding.utf16, allowLossyConversion: false) else { return nil }
guard let html = try? NSMutableAttributedString(
data: data,
options: [NSDocumentTypeDocumentAttribute: NSHTMLTextDocumentType],
documentAttributes: nil) else { return nil }
var found = false
html.beginEditing()
html.enumerateAttribute(NSFontAttributeName, in: NSMakeRange(0, html.length), options: NSAttributedString.EnumerationOptions(rawValue: 0)) { (value, range, stop) in
if (value != nil) {
let oldFont = value as! UIFont
let newFont = oldFont.withSize(16)
html.addAttribute(NSFontAttributeName, value: newFont, range: range)
found = true
}
}
if !found{
// No font was found - do something else?
}
html.endEditing()
return html
}
}