I added a bar button item programmatically to a view controller:
override func viewDidLoad() {
super.viewDidLoad()
self.navigationItem.leftBarButtonItem = UIBarButtonItem(title: "Menu", style: .Plain, target: nil, action: nil)
}
Now I want to assign that bar button item to an IBOutlet programmatically. How would I do that using Swift?
The IB of IBOutlet stands for Interface Builder and it represents a connection from the interface builder to the source code. Assigning an IBOutlet programmatically couldn't make less sense.
An IBOutlet is simply an instance variable of a class which is tied to part of the interface or can be set via the interface builder. If we want a reference to our button (in the same way we'd have a reference to it if we made it in the interface builder), we simply add a property to our class, and then assign our newly created button to that:
class MyViewController: UIViewController {
var someBarButton: UIBarButtonItem?
override func viewDidLoad() {
super.viewDidLoad()
self.someBarButton = UIBarButtonItem(title: "Menu", style: .Plain, target: nil, action: nil)
self.navigationItem.leftBarButtonItem = self.someBarButton
}
}
And now, someBarButton is our "IBOutlet".
Some notes...
There's a pretty decent chance we might not actually want to do things this way.
This creates an extra strong reference to the button (self.navigationItem already holds a strong reference to its leftBarButtonItem).
You'll notice, if you make an IBOutlet from interface builder, it is set up as a weak property. So perhaps we want a weak property?
But we can actually do ourselves one better. Try this on for size:
var leftNavBarButton: UIBarButtonItem? {
get {
return self.navigationItem.leftBarButtonItem
}
set (newValue) {
self.navigationItem.leftBarButtonItem = newValue
}
}
Now, self.leftNavBarButton is essentially just a convenient way of accessing self.navigationItem.leftBarButtonItem.
Collected from the Internet
Please contact [email protected] to delete if infringement.
Comments