How to draw line between two views in Swift

Question

I want to Draw lines from one object to another object. Like a Matching object game. I want Swift language with UIKit Use. Here I attach the Sample Screenshot.

Does anyone have experience with this? then please help me.

Answer 1

You have a couple of choices.

You can create a custom subclass of UIView that implements the draw(_:) function to draw custom content. That view would need to big enough to enclose all of your custom drawing. You'd fill most of the view with clear, and then draw the lines you want using Core Graphics.

The other option is to use Core Animation layers. You could add a CAShapeLayer to your view's layer, set up the shape layer with the desired line thickness and color, and add a path to the layer containing the lines you want to draw. (Note that if you use CAShapeLayers, all the lines drawn in a single shape layer will be the same color. You'll need multiple shape layers in order to draw in multiple colors.)

Both approaches will require some research. Shape layers are more efficient and take better advantage of the graphics hardware on iOS devices, but using them has a fairly steep learning curve.

You should be able to google examples of both approaches. Try search phrases like "Custom drawing in a UIView" and "drawing with CAShapeLayer". I wrote a little demo app called OvalView that demonstrates how to create a UIView subclass that manages a shape layer.

Edit:

I adapted the code from my sample app into a demo called LinesBetweenViews. The new demo has a custom UIView that draws lines between any pairs of subviews you put into it.

Here is a screenshot of the demo:

If you answer my questions I can upload the demo app to Github so you can look at it.

Edit #2

See this Github repo for a sample project that draws lines between pairs of subviews.