Dear Stackoverflowers,
Can any experts on Swift/UIKit see what I'm doing wrong in the following screenshot?
Xcode can't seem to find the convenience initializer for a UIAlertAction based on a title, style and handler, and I don't know of any other way to initialize a UIAlertAction. In practice, the handler won't be nil.
Thank you in advance,
Jamie
You are trying to pass Int to style param which is against swift rule. Try this out:
let saveAction = UIAlertAction(title: "Save", style: UIAlertActionStyle.Default, handler: nil)
Related
I can add textField to my alert as shown below using alert.addTextField()
let alert = UIAlertController(title: "Title", message: "Subtitle", preferredStyle: UIAlertController.Style.alert)
alert.addTextField()
alert.addAction(UIAlertAction(title: "Ok", style: UIAlertAction.Style.default, handler: { _ in
print(alert.textFields?[0].text ?? "")
}))
alert.addAction(UIAlertAction(title: "Cancel", style: UIAlertAction.Style.default, handler: nil))
self.present(alert, animated: true, completion: nil)
However, if I have a custom textField, like CurrencyField as shared in https://stackoverflow.com/a/29783546/3286489, how could I add that to my alert (instead of just having a generic TextField)?
The Holy Path
The Apple-given API doesn't allow for you to use a custom subclass of UITextField. It does, however, allow you to customize the UITextField:
alert.addTextField { textField in
// customize text field
}
You'll have to try and port the functionality of your CurrencyView over, having only access to the APIs available by default on UITextField.
The Unholy Path
⚠️ Disclaimer: This is a Bad Idea. Using vendor APIs in ways they weren't intended to makes your code and application less stable.
Now that we've got that out of the way: you could also add a view directly to the default UITextField. You'd have to disable interaction/editing on the original UITextField, though, and make sure it only goes to your custom text field.
If you really wanted to go to the dark side, you could swizzle UITextField and force your CurrencyView to be initialized, but, once again, this is a Bad Idea.
Is it possible to set a NSMutableAttributedString as AlertAction's title?
My aim is to visualize a math expression with a good design in my UIAlertAction's title.
let action = UIAlertAction(title: myNSMutableAttributedString, style: UIAlertActionStyle.default) {(result : UIAlertAction) -> Void in
}
Thanks in advance for the help.
It's not possible to use an NSAttributedString for a UIAlertAction's title without accessing private APIs, as the method for setting the attributedTitle to an attributed string does not work here (see this question for details on that).
I would create a custom class or use an alert library for this.
I have an alertController with a button in it. Here's how I created the button:
var myButton : UIAlertAction!
// Later...
self.myButton = UIAlertAction(title: "myButton", style: .Default, handler: {action -> Void in
self.myButton.title = "✔︎\(myButton)"
})
After the button get's selected, I want to add a "✔︎" at the beginning of the title. (As you can see in the last line of code above.) When I try doing that, I get the following error:
Cannot assign to the result of this expression
What can I do to fix that? If myButtons title is read-only, then is there a valid workaround to it?
The error is not about the "✔︎". It's because of myButton. It means nothing to assign a UIAlertAction to String. That's how you get the error.
I was under the impression that if the normal action is a destructive action and the other is a cancel action in their UIAlertController that the destructive one should be on the left and the cancel should be on the right.
If the normal action is not destructive, then the normal action should be on the right and the cancel should be on the left.
That said, I have the following:
var confirmLeaveAlert = UIAlertController(title: "Leave", message: "Are you sure you want to leave?", preferredStyle: .Alert)
let leaveAction = UIAlertAction(title: "Leave", style: .Destructive, handler: {
(alert: UIAlertAction!) in
//Handle leave
}
)
let cancelAction = UIAlertAction(title: "Cancel", style: .Cancel, handler: nil)
confirmLeaveAlert.addAction(leaveAction)
confirmLeaveAlert.addAction(cancelAction)
self.presentViewController(confirmLeaveAlert, animated: true, completion: nil)
I was under the impression that if I add the leaveAction first, then the cancelAction that the leaveAction would be the button on the left. This was not the case. I tried adding the buttons in the opposite order as well and it also resulted in the buttons being added in the same order.
Am I wrong? Is there no way to achieve this?
My solution to this was to use the .Default style instead of .Cancel for the cancelAction.
Since iOS9 there is a preferredAction property on UIAlertController. It places action on right side. From docs:
When you specify a preferred action, the alert controller highlights the text of that action to give it emphasis. (If the alert also contains a cancel button, the preferred action receives the highlighting instead of the cancel button.)
The action object you assign to this property must have already been added to the alert controller’s list of actions. Assigning an object to this property before adding it with the addAction: method is a programmer error.
I have a like button in an action sheet:
likeAction = UIAlertAction(title: "Like this post", style: UIAlertActionStyle.Default, handler: { (action) -> Void in
println("like pressed")
})
Once pressed I'd like to update the title to "Unlike this post"
Title is readonly and there isn't a SetTitle() function on UIAlertActions.
Ideas much appreciated.
This works for me.
self.alertAction.setValue("New Title", forKeyPath: "title")
Hope this helps.
This was answered by Lyndsey Scott in a comment on the original post.
Set a bool variable to indicate whether the post is "liked" then set the alert title conditionally.