How does one go about making a delegate, i.e. NSUserNotificationCenterDelegate
in swift?
Here's a little help on delegates between two view controllers:
Step 1: Make a protocol in the UIViewController that you will be removing/will be sending the data.
protocol FooTwoViewControllerDelegate:class {
func myVCDidFinish(_ controller: FooTwoViewController, text: String)
}
Step2: Declare the delegate in the sending class (i.e. UIViewcontroller)
class FooTwoViewController: UIViewController {
weak var delegate: FooTwoViewControllerDelegate?
[snip...]
}
Step3: Use the delegate in a class method to send the data to the receiving method, which is any method that adopts the protocol.
@IBAction func saveColor(_ sender: UIBarButtonItem) {
delegate?.myVCDidFinish(self, text: colorLabel.text) //assuming the delegate is assigned otherwise error
}
Step 4: Adopt the protocol in the receiving class
class ViewController: UIViewController, FooTwoViewControllerDelegate {
Step 5: Implement the delegate method
func myVCDidFinish(_ controller: FooTwoViewController, text: String) {
colorLabel.text = "The Color is " + text
controller.navigationController.popViewController(animated: true)
}
Step 6: Set the delegate in the prepareForSegue:
override func prepare(for segue: UIStoryboardSegue, sender: Any?) {
if segue.identifier == "mySegue" {
let vc = segue.destination as! FooTwoViewController
vc.colorString = colorLabel.text
vc.delegate = self
}
}
And that should work. This is of course just code fragments, but should give you the idea. For a long explanation of this code you can go over to my blog entry here:
If you are interested in what's going on under the hood with a delegate I did write on that here: