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EmbedsViewController Example Code
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| // | |
| // EmbedsViewController.swift | |
| // | |
| // Created by Evan Sobkowicz. | |
| // Copyright © 2019 Twitter. All rights reserved. | |
| // | |
| import UIKit | |
| import WebKit | |
| import SafariServices | |
| let DefaultCellHeight: CGFloat = 1000 | |
| let TweetPadding: CGFloat = 20 | |
| let HtmlTemplate = "<html><head><meta name='viewport' content='width=device-width, initial-scale=1.0, maximum-scale=1.0, minimum-scale=1.0, user-scalable=no'></head><body><div id='wrapper'></div></body></html>" | |
| let TweetIds = ["1190287688685047808", "1190058389134610433", "1189695999633186816", "1189200245827211264", "1188969975454879747", "1187520413661892608", "1187158033077620736", "1184489710409961473", "1184260182924283906", "1182314890419146752", "1180500441764962304", "1178317279366434818", "1177241651552632833", "1176286416181108736", "1172661285877628931", "1171576431677267969"] | |
| let HeightCallback = "heightCallback" | |
| let ClickCallback = "clickCallback" | |
| class EmbedsViewController: UITableViewController { | |
| let Tweets = TweetsManager.shared | |
| let WidgetsJs = WidgetsJsManager.shared | |
| override func viewDidLoad() { | |
| super.viewDidLoad() | |
| title = "Embeds" | |
| // Set up tableview | |
| tableView.allowsSelection = false | |
| tableView.estimatedRowHeight = DefaultCellHeight | |
| tableView.separatorStyle = .none | |
| tableView.register(UITableViewCell.self, forCellReuseIdentifier: "WebCell") | |
| self.initializeView(TweetIds) | |
| } | |
| func initializeView(_ tweetIds: [String]) { | |
| Tweets.initializeWithTweetIds(tweetIds) | |
| // Load widgets.js globally | |
| WidgetsJs.load() | |
| // Preload WebViews before they are rendered | |
| preloadWebviews() | |
| tableView.reloadData() | |
| } | |
| // WebView Management | |
| func preloadWebviews() { | |
| Tweets.all().forEach { tweet in | |
| tweet.setWebView(createWebView(idx: tweet.idx)) | |
| } | |
| } | |
| func createWebView(idx: Int) -> WKWebView { | |
| let webView = WKWebView() | |
| // Set delegates | |
| webView.navigationDelegate = self | |
| webView.uiDelegate = self | |
| // Register callbacks | |
| webView.configuration.userContentController.add(self, name: ClickCallback) | |
| webView.configuration.userContentController.add(self, name: HeightCallback) | |
| // Set index as tag | |
| webView.tag = idx | |
| // Set initial frame | |
| webView.frame = CGRect(x: 0, y: 0, width: view.bounds.width, height: CGFloat(DefaultCellHeight)) | |
| // Prevent scrolling | |
| webView.scrollView.isScrollEnabled = false | |
| // Load HTML template and set your domain | |
| webView.loadHTMLString(HtmlTemplate, baseURL: URL(string: "https://your-apps-website.com")!) | |
| return webView | |
| } | |
| // UITableViewController | |
| override func tableView(_ tableView: UITableView, numberOfRowsInSection section: Int) -> Int { | |
| return Tweets.count() | |
| } | |
| override func tableView(_ tableView: UITableView, cellForRowAt indexPath: IndexPath) -> UITableViewCell { | |
| let cell = tableView.dequeueReusableCell(withIdentifier: "WebCell", for: indexPath) | |
| if let tweet = Tweets.getByIdx(indexPath.row), let webView = tweet.webView { | |
| cell.contentView.addSubview(webView) | |
| } | |
| return cell | |
| } | |
| override func tableView(_ tableView: UITableView, didEndDisplaying cell: UITableViewCell, forRowAt indexPath: IndexPath) { | |
| cell.contentView.subviews.forEach { (view) in | |
| view.removeFromSuperview() | |
| } | |
| } | |
| override func tableView(_ tableView: UITableView, heightForRowAt indexPath: IndexPath) -> CGFloat { | |
| if let tweet = Tweets.getByIdx(indexPath.row) { | |
| return tweet.height | |
| } | |
| return DefaultCellHeight | |
| } | |
| // Helpers | |
| func updateHeight(idx: Int, height: String) { | |
| if let tweet = Tweets.getByIdx(idx) { | |
| if (tweet.height == DefaultCellHeight) { | |
| // Store the height to display the UITableViewCell at the correct height | |
| tweet.setHeight(stringToCGFloat(height) + TweetPadding) | |
| // Prevent UITableViewCells from jumping around and changing | |
| // the scroll position as they resize | |
| tableView.reloadRowWithoutAnimation(IndexPath(row: idx, section: 0)) | |
| } | |
| } | |
| } | |
| func openTweet(_ id: String) { | |
| if let url = URL(string: "https://twitter.com/i/status/\(id)") { | |
| openInSafarViewController(url) | |
| } | |
| } | |
| func openInSafarViewController(_ url: URL) { | |
| let vc = SFSafariViewController(url: url) | |
| self.showDetailViewController(vc, sender: self) | |
| } | |
| func stringToCGFloat (_ s: String) -> CGFloat { | |
| if let intHeight = Int(s) { | |
| return CGFloat(integerLiteral: intHeight) | |
| } | |
| return DefaultCellHeight | |
| } | |
| } | |
| extension EmbedsViewController: WKNavigationDelegate { | |
| func webView(_ webView: WKWebView, decidePolicyFor navigationAction: WKNavigationAction, decisionHandler: @escaping (WKNavigationActionPolicy) -> Void) { | |
| if let url = navigationAction.request.url, navigationAction.navigationType == .linkActivated { | |
| openInSafarViewController(url) | |
| decisionHandler(.cancel) | |
| } else { | |
| decisionHandler(.allow) | |
| } | |
| } | |
| func webView(_ webView: WKWebView, didFinish navigation: WKNavigation!) { | |
| loadTweetInWebView(webView) | |
| } | |
| // Tweet Loader | |
| func loadTweetInWebView(_ webView: WKWebView) { | |
| if let widgetsJsScript = WidgetsJs.getScriptContent(), let tweet = Tweets.getByIdx(webView.tag) { | |
| webView.evaluateJavaScript(widgetsJsScript) | |
| webView.evaluateJavaScript("twttr.widgets.load();") | |
| // Documentation: | |
| // https://developer.twitter.com/en/docs/twitter-for-websites/embedded-tweets/guides/embedded-tweet-javascript-factory-function | |
| webView.evaluateJavaScript(""" | |
| twttr.widgets.createTweet( | |
| '\(tweet.id)', | |
| document.getElementById('wrapper'), | |
| { align: 'center' } | |
| ).then(el => { | |
| window.webkit.messageHandlers.heightCallback.postMessage(el.offsetHeight.toString()) | |
| }); | |
| """) | |
| } | |
| } | |
| } | |
| extension EmbedsViewController: WKUIDelegate { | |
| func webView(_ webView: WKWebView, createWebViewWith configuration: WKWebViewConfiguration, for navigationAction: WKNavigationAction, windowFeatures: WKWindowFeatures) -> WKWebView? { | |
| // Allow links with target="_blank" to open in SafariViewController | |
| // (includes clicks on the background of Embedded Tweets | |
| if let url = navigationAction.request.url, navigationAction.targetFrame == nil { | |
| openInSafarViewController(url) | |
| } | |
| return nil | |
| } | |
| } | |
| extension EmbedsViewController: WKScriptMessageHandler { | |
| func userContentController(_ userContentController: WKUserContentController, didReceive message: WKScriptMessage) { | |
| switch message.name { | |
| case HeightCallback: | |
| updateHeight(idx: message.webView!.tag, height: message.body as! String) | |
| default: | |
| print("Unhandled callback") | |
| } | |
| } | |
| } | |
| extension UITableView { | |
| func reloadRowWithoutAnimation(_ indexPath: IndexPath) { | |
| let lastScrollOffset = contentOffset | |
| UIView.performWithoutAnimation { | |
| reloadRows(at: [indexPath], with: .none) | |
| } | |
| setContentOffset(lastScrollOffset, animated: false) | |
| } | |
| } | |
| class TweetsManager { | |
| static let shared = TweetsManager() | |
| var tweets: [Tweet] = [] | |
| func initializeWithTweetIds(_ tweetIds: [String]) { | |
| tweets = buildIndexedTweets(tweetIds) | |
| } | |
| func count() -> Int { | |
| return tweets.count | |
| } | |
| func all() -> [Tweet] { | |
| return tweets | |
| } | |
| func getByIdx(_ idx: Int) -> Tweet? { | |
| return tweets.first { $0.idx == idx } | |
| } | |
| private func buildIndexedTweets(_ tweetIds: [String]) -> [Tweet] { | |
| return tweetIds.enumerated().map { (idx, id) in | |
| return Tweet(id: id, idx: idx) | |
| } | |
| } | |
| } | |
| class Tweet { | |
| // The Tweet ID | |
| var id: String | |
| // An index value we'll use to map Tweets to the WKWebView tag property and the UITableView row | |
| var idx: Int | |
| // The height of the WKWebView | |
| var height: CGFloat | |
| // The WKWebView we'll use to display the Tweet | |
| var webView: WKWebView? | |
| init(id: String, idx: Int) { | |
| self.id = id | |
| self.idx = idx | |
| self.height = DefaultCellHeight | |
| } | |
| func setHeight(_ value: CGFloat) { | |
| height = value | |
| } | |
| func setWebView(_ value: WKWebView) { | |
| webView = value | |
| } | |
| } | |
| class WidgetsJsManager { | |
| static let shared = WidgetsJsManager() | |
| // The contents of https://platform.twitter.com/widgets.js | |
| var content: String? | |
| func load() { | |
| do { | |
| content = try String(contentsOf: URL(string: "https://platform.twitter.com/widgets.js")!) | |
| } catch { | |
| print("Could not load widgets.js script") | |
| } | |
| } | |
| func getScriptContent() -> String? { | |
| return content | |
| } | |
| } |
Hey @evansobkowicz,
Thanks for your demonstration and work, it is really helpful. However I had some scrolling issues and blank spaces like @ollita7 mentioned before. I have fixed them by modifying the code. I would like to share my fixes as there may be people face the same issues.
-
Firstly
tableView.dataSource = selfandtableView.delegate = selfshould be declared when setting up tableview. Otherwise tableview will not display tweets. -
I remove subviews of content view just after cell definition inside
func tableView(_ tableView: UITableView, cellForRowAt indexPath: IndexPath)not indidEndDisplaying. This makes me sure that I get clean cell withdequeueReusableCellmethod when the cell gets visible.
override func tableView(_ tableView: UITableView, cellForRowAt indexPath: IndexPath) -> UITableViewCell {
let cell = tableView.dequeueReusableCell(withIdentifier: "WebCell", for: indexPath)
cell.contentView.subviews.forEach { (view) in
view.removeFromSuperview()
}
if let tweet = Tweets.getByIdx(indexPath.row), let webView = tweet.webView {
cell.contentView.addSubview(webView)
}
return cell
}
- Lastly I have changed the reload method inside
updateHeightfunction.reloadData()loads visible views properly
//tableView.reloadRowWithoutAnimation(IndexPath(row: idx, section: 0))
tableView.reloadData()
My fork can be found from the below link
https://gist.github.com/mehmetdelikaya/05eb547cb6c497483c5e11fb61b5a7cc
Hope this helps 👋
I am not sure but trying all the solutions, I am always getting some blanks
@RajanMaheshwari Did you try my solution as well?
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Hey are you still having this problem? the solution will be , add a default web view to cell and constraint it to the the cell view. then assign the loaded web view to this default web view, this has fixed the blank issue for me