How to disable a constraint programmatically?

问题

How to disable a constraint programmatically?

I have two constraints, that the priority of one depends for the other. As far as I know the constraints priority can’t change programmatically when they are installed (it throw me an error), So the idea is, when X occurs the constraint A is disable and the constraint B is enable, and when Y occur A is enable and B disable

IBOutlet weak var constraint_A
IBOutlet weak var constraint_B

... 

func configureViews() {
   if x {
        constraint_A.disable = true
        constraint_B.disable = false
   }  else {
        constraint_A.disable = false
        constraint_B.disable = true
   }
}
...

回答1:

The constraints have a boolean property called active so if you want to disable a constraint you can easily call it:

constraint_A.active = false

来源：https://stackoverflow.com/questions/39044218/how-to-disable-a-constraint-programmatically