{"id":24379,"date":"2022-12-02T13:36:59","date_gmt":"2022-12-02T08:06:59","guid":{"rendered":"https:\/\/jassweb.com\/solved\/solved-why-does-my-app-lags-when-scrolling-uicollectionview-swift-closed\/"},"modified":"2022-12-02T13:36:59","modified_gmt":"2022-12-02T08:06:59","slug":"solved-why-does-my-app-lags-when-scrolling-uicollectionview-swift-closed","status":"publish","type":"post","link":"https:\/\/jassweb.com\/solved\/solved-why-does-my-app-lags-when-scrolling-uicollectionview-swift-closed\/","title":{"rendered":"[Solved] Why does my App lags when scrolling UICollectionView (Swift)? [closed]"},"content":{"rendered":"<p> [ad_1]<br \/>\n<\/p>\n<div id=\"answer-36324063\" class=\"answer js-answer accepted-answer js-accepted-answer\" data-answerid=\"36324063\" data-parentid=\"36323693\" data-score=\"1\" data-position-on-page=\"1\" data-highest-scored=\"1\" data-question-has-accepted-highest-score=\"1\" itemprop=\"acceptedAnswer\" itemscope itemtype=\"https:\/\/schema.org\/Answer\">\n<div class=\"post-layout\">\n<div class=\"votecell post-layout--left\"><\/div>\n<div class=\"answercell post-layout--right\">\n<div class=\"s-prose js-post-body\" itemprop=\"text\">\n<p>For the future, it is better to post the relevant code here rather than post an image of all the code. <\/p>\n<p>You can start off with changing the <code>cellForItemAtIndexPath<\/code> implementation. You are downloading the image in the method (as a synchronous implementation). So unless the image is downloaded by <code>contentsOfURL:<\/code> and rendered, the cell won&#8217;t display. And the image is being downloaded every time the cell renders.<\/p>\n<p>A better alternative is to download images in a separate thread, keep them for later use (and avoid downloading every time) and update the cell when the image is available. You can use an existing implementation like <a rel=\"nofollow noopener\" target=\"_blank\" href=\"https:\/\/github.com\/rs\/SDWebImage\">SDWebImage<\/a> to make things easier for you.<\/p>\n<\/p><\/div>\n<div class=\"mt24\"><\/div>\n<\/div>\n<p>            <span class=\"d-none\" itemprop=\"commentCount\">1<\/span> <\/p><\/div>\n<\/div>\n<p>[ad_2]<\/p>\n<p>solved Why does my App lags when scrolling UICollectionView (Swift)? [closed] <\/p>\n","protected":false},"excerpt":{"rendered":"<p>[ad_1] For the future, it is better to post the relevant code here rather than post an image of all the code. You can start off with changing the cellForItemAtIndexPath implementation. You are downloading the image in the method (as a synchronous implementation). So unless the image is downloaded by contentsOfURL: and rendered, the cell &#8230; <a title=\"[Solved] Why does my App lags when scrolling UICollectionView (Swift)? [closed]\" class=\"read-more\" href=\"https:\/\/jassweb.com\/solved\/solved-why-does-my-app-lags-when-scrolling-uicollectionview-swift-closed\/\" aria-label=\"More on [Solved] Why does my App lags when scrolling UICollectionView (Swift)? [closed]\">Read more<\/a><\/p>\n","protected":false},"author":1,"featured_media":0,"comment_status":"closed","ping_status":"closed","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[320],"tags":[522,544,830],"class_list":["post-24379","post","type-post","status-publish","format-standard","hentry","category-solved","tag-swift","tag-uicollectionview","tag-xcode"],"yoast_head":"<!-- This site is optimized with the Yoast SEO plugin v27.4 - https:\/\/yoast.com\/product\/yoast-seo-wordpress\/ -->\n<title>[Solved] Why does my App lags when scrolling UICollectionView (Swift)? [closed] - JassWeb<\/title>\n<meta name=\"robots\" content=\"index, follow, max-snippet:-1, max-image-preview:large, max-video-preview:-1\" \/>\n<link rel=\"canonical\" href=\"https:\/\/jassweb.com\/solved\/solved-why-does-my-app-lags-when-scrolling-uicollectionview-swift-closed\/\" \/>\n<meta property=\"og:locale\" content=\"en_US\" \/>\n<meta property=\"og:type\" content=\"article\" \/>\n<meta property=\"og:title\" content=\"[Solved] Why does my App lags when scrolling UICollectionView (Swift)? [closed] - JassWeb\" \/>\n<meta property=\"og:description\" content=\"[ad_1] For the future, it is better to post the relevant code here rather than post an image of all the code. You can start off with changing the cellForItemAtIndexPath implementation. You are downloading the image in the method (as a synchronous implementation). So unless the image is downloaded by contentsOfURL: and rendered, the cell ... 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