Scroll to bottom of webview programmatically with swift - ios

Question

I have the following webview:
#IBOutlet weak var webView_MyContent: UIWebView!
and load custom html content like so:
self.webView_MyContent.loadHTMLString(html, baseURL: nil)
I would like to scroll to the very bottom of the page programmatically when my content loads. How would this be accomplished in swift?

Answer 1

You can use scrollView property of UIWebView for that.
func webViewDidFinishLoad(_ webView: UIWebView) {
let scrollPoint = CGPoint(x: 0, y: webView.scrollView.contentSize.height - webView.frame.size.height)
webView.scrollView.setContentOffset(scrollPoint, animated: true)//Set false if you doesn't want animation
}
Note: Don't forgot to set delegate of your webView.

Answer 2

Didn't work for me with Swift 4 / WKWebView.
Instead I found the method webView.scrollToEndOfDocument()
To scroll down after loading is finished you can put it into this function:
func webView(_ webView: WKWebView, didFinish navigation: WKNavigation!) {
webView.scrollToEndOfDocument(self)
}
Don't forget to import WebKit and to make your class the delegate of your WebView:
// ...
import WebKit
// ...
class ViewController: NSViewController, WKNavigationDelegate {
// ...
Advanced: scroll down after finishing AJAX requests
Now in my case I wanted to scroll down a page that used infinite scroll (when nearly reaching the end of the page it starts loading additional content).
This can be done by injecting JavaScript and overwriting the XMLHttpRequest method:
override func viewDidLoad() {
super.viewDidLoad()
// ...
String javascript = String(contentsOfFile: Bundle.main.path(forResource: "script", ofType: "js"))
webView.configuration.userContentController.add(self, name: "injectionHandler")
webView.configuration.userContentController.addUserScript(WKUserScript.init(source: javascript, injectionTime: .atDocumentEnd, forMainFrameOnly: false))
// ...
}
And in the file script.js in your Xcode project you'll put this:
var open = XMLHttpRequest.prototype.open;
XMLHttpRequest.prototype.open = function(method, url, async, user, password) {
this.addEventListener("load", function() {
var message = {"status": this.status, "requestUrl": url, "response": this.responseText, "responseURL": this.responseURL};
webkit.messageHandlers.injectionHandler.postMessage(message);
});
open.apply(this, arguments);
};
To handle this event (and if you want also catch the AJAX response) you have to add this method:
func userContentController(_ userContentController: WKUserContentController, didReceive message: WKScriptMessage) {
if message.name == "injectionHandler", let dict = message.body as? Dictionary<String, AnyObject>, let status = dict["status"] as? Int, let response = dict["response"] as? String {
if status == 200 {
webView.scrollToEndOfDocument()
}
}
}
and make your class extend WKScriptMessageHandler:
class ViewController: NSViewController, WKNavigationDelegate, WKScriptMessageHandler {
// ...