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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 | |
| } | |
| } |
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 @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.updateHeightfunction.reloadData()loads visible views properlyMy fork can be found from the below link
https://gist.github.com/mehmetdelikaya/05eb547cb6c497483c5e11fb61b5a7cc
Hope this helps 👋