Creating array of IBOutlets of NSLayoutConstraint's from Swift in iOS

While working on my iOS app, I wanted to modify UI Constraint set from Interface Builder from Swift code.

Below video shows how we can create Array of IBOutlets using Interface Builder. Here I am creating array of NSLayoutConstraint, which I want to modify from Swift Code.



Now lets see how we can manipulate constraints from swift. First we need to define array of IBOutlet. Below code shows the same.

@IBOutlet var constraints: Array?

Now, once you connect IBoutlet from Interface Builder as shown in above video. You can use those. In below code I am modifying NSLayoutConstraint's constant value.

if( Utils.isIPad() ) {
    for constraint: NSLayoutConstraint in constraints! {
        if(Utils.isIPad()) {
            constraint.constant = 30
        }
    }
}

That's it, Thank you for reading.

Creating array of IBOutlet

Sometimes you want to enable/disable bunch of buttons together or perform other such activities on bunch of UI elements created using Interface Builder.

I recently needed to perform similar operation on bunch of button for iOS game I am working on. For this kind of operation, its easier to create array of IBOutlet which can be created using IBOutletCollection. Following is my code, which create IBOutletCollection of UIButtons and then enable/disbale them together.

@interface MyViewController : UIViewController {
    IBOutletCollection(UIButton) NSArray *buttons;
}

in MyViewController.m, we can use buttons as below.

-(void) enableUI:(BOOL) enable {    
    for( UIButton* button in buttons){
        button.enabled = enable;
    }    
}

Only thing missing now is, connecting UIButtons created using Interface Builder to IBoutletCollection. We need to do this from Interface Builder, process is similar to connecting UI Elements from Interface Builder to IBOutlet.

Following snaps describes the required process. I created three buttons on view.

You can connect IBoutletCollection to UIButton as shown in below snap.

And you can repeat above process to connect more UIButton with IBOutletCollection.

That's it.