ViewController has a bunch of items that will be rendered as cells later on. Item is a model class that backs collection view cells.Note that the app crashes at launch, since collection view delegate and data source are not yet implemented. It already has a collection view attached in Main.storyboard and is configured as its delegate and data source. ViewController is the entry point of the the sample application.To ensure that we are on the same page, review the following highlights from the starter project: I’ve got you covered and created a starter project go ahead and grab it from Github. The specifics of step-by-step tutorial imply certain amount of tedious preparations. The former allows to setup sizing (almost) without a single line of code, making it more compelling. Use of constraints on the collection view cell content view, or override sizeThatFits: are two strategies of implementing collection view cells self-sizing. Delegate - collectionView(layout:sizeForItemAt:). Self-sizing is a way of adjusting cells size within collection view layout, where cells are responsible for calculating their own sizes. Defining Collection View Cells Self-Sizing The present step-by-step guide addresses this issue by explaining how to implement self-sizing collection view cells in iOS from scratch. While table view cells self-sizing has been elaborated numerous times and is widely adopted in community, the exact same feature for collection views is unjustly left unnoticed, despite being around since iOS 8. Table and collection views are among the most fundamental user interface components. The strategy of making user interface all-dynamic is the standard by default. Quality expectations for iOS and macOS apps are continuously being raised, making such features as dynamic fonts and internationalization a must static app content is rarely seen as well. In this article you will learn how collection view cells can dynamically adjust their size based on their content. The text of an item is left-aligned if the text appears at the top or bottom of the item.When working with collection views, chances high that you have spent considerable amount of time sizing cells programmatically. The text of an item is right-aligned if the text appears at the top or bottom of the item. Layout items are automatically resized according to their size constraints. Layout items are not resized, but the flow of items automatically wraps at the parent group’s right edge. Item Resizing when LayoutControl is Resized Empty Space Items can be helpful in preventing item stretching. Layout items are stretched within the parent layout group. The item flow automatically wraps at the group’s right edge. The drag and drop functionality allows you to add new items to the layout group and rearrange existing items.įlow and Regular Mode Comparison Characteristic Item size constraints may restrict sizing operations. Flow Layout CustomizationĪ flow layout is fully customizable at design time and runtime using drag and drop functionality, resizing operations and additional customization commands available from the context menu. Right-click a layout group and select the Convert To -> Flow Layout action.įlow layout cannot be enabled for a layout group if it contains nested groups. This mode cannot be enabled for the root group itself.Īt design time, you can enable flow layout mode from the Customization Menu. Enabling Flow Layout Modeįlow layout mode can be enabled for groups nested within the root group ( LayoutControl.Root) using the LayoutGroup.LayoutMode property. To change the default left-to-right item layout, modify the LayoutGroup.FlowDirection setting. You can force any item to start a new row by setting its BaseLayoutItem.StartNewLine property to true. So, when the group width is changed, item positions within the flow layout are updated, as shown in the following animation. In flow layout mode, layout items are arranged back-to-back in rows, and are automatically wrapped at the group’s right edge. For groups nested within the root group, you can enable flow layout mode, in which layout items are arranged back-to-back, automatically wrapping at the group’s right edge.
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