swift3

来源： https://stackoverflow.com/questions/41029912/efficient-way-of-downsample-collection-via-decimating-or-extracting-every-nth-el

来源： https://stackoverflow.com/questions/41875343/drag-and-drop-cell-between-different-collection-views

来源： https://stackoverflow.com/questions/41875343/drag-and-drop-cell-between-different-collection-views

来源： https://stackoverflow.com/questions/41875343/drag-and-drop-cell-between-different-collection-views

来源： https://stackoverflow.com/questions/41875343/drag-and-drop-cell-between-different-collection-views

来源： https://stackoverflow.com/questions/41189763/how-to-show-two-row-of-text-in-a-menu-bar-app-in-mac-os

来源： https://stackoverflow.com/questions/40263754/back-button-showing-on-root-view-controller

来源： https://stackoverflow.com/questions/40263754/back-button-showing-on-root-view-controller

来源： https://stackoverflow.com/questions/40263754/back-button-showing-on-root-view-controller

问题 I have a problem that I can't create a view that can collapse it's contents that may be dynamic height , i know it's easy to collapse it with height constant = 0 , but i can't figure out how to make it expand again as the content of that view is dynamic and sub-itmes may be added later I want that behavior 回答1: Your answer has massively overcomplicated a very simple solution. You should first create your zeroHeightConstraint as a property. let zeroHeightConstraint: NSLayoutConstraint =