Xcode：在实用程序/大小/视图中设置宽度和高度，而不是作为约束

Question

I'm an iOS and XCode beginner. I'm trying to set a button to have dimensions of 64 x 64. In searching how this is done, I've come across two different ways:

1. Select the button, and in the Utilities pane's Size inspector's View section, set the height and width.
2. In the bottom right corner of the storyboard pane, click the "Add New Constraints" button, check "Width" and "Height" and set them to the desired dimensions. This adds Constraints indented under the button, with height = 64 and width = 64 indented under Constraints .

Both seem to work fine, so my question is what is the difference between the two methods, if any?

Answer 1

First of all welcome to iOS development :)

The answer is: In case 2 you are using Autolayout and in case 1 you are not.

Autolayout is really important and you should definitely always use it. The constraints allow you to create "rules" that tell the app how to adjust the UI to different screen sizes. In your case the button might have the same size for all screens, but without setting the constraints the size might change nevertheless depending on the layout of the constraints of other UI Components.

I recommend reading a tutorial about Autolayout. It is easy to learn and hard to master I would say...

Answer 2

While you're building your interface check the Document Outline to the left of the Storyboard for warnings, usually this is a strong indicator of areas of concern as your application begins to grow. Rule of thumb is when in doubt add constraints.

Also worth mentioning for your 64x64 (square) example.. I personally like using a 1:1 aspect ratio constraint plus a height or width constraint so if theres ever a need to scale the view its one constraint value to modify instead of two.