CODEWITHSUNDEEP
iosfunctionswiftparameters
Eamorr
Eamorr

Reputation: 10022

Swift function - pass optional object

So I'm trying to call the function "submitBoilerPlate" in Swift:

var url:String = "https://eamorr.com/ajax/getLatestContent.php"
var params = [
   "hello":"world"
]
submitBoilerPlate(url, _params:params, _button:nil)

And here is the corresponding function:

func submitBoilerPlate(_url:String, _params:[String: String!], _button:UIButton?){
    var oldTitle = _button?.titleLabel?.text

    _button?.setTitle("Please wait...", forState: UIControlState.Normal)
    _button?.enabled = false
    //etc.
    ...
}

Everything works as expected when I send a real UIButton that's declared on my xib.

However, I want to be able to send a "nil" button (this particular xib doesn't have a button).

Is this possible? Or do I have to have create a new function? I'm trying to keep code repetition to a minimum...

I get the following run-time error when the code gets to submitBoilerPlate(...):

fatal error: can't unsafeBitCast between types of different sizes

Upvotes: 1

Views: 1044

Answers (2)

Ian MacDonald
Ian MacDonald

Reputation: 14030

Pasting your code into a playground is a pretty good way to help yourself debug. I took your code into my own playground and found the following to work:

import UIKit

func submitBoilerPlate(_url:String, _params:[String: String!], _button:UIButton?){
    var oldTitle = _button?.titleLabel?.text

    _button?.setTitle("Please wait...", forState: UIControlState.Normal)
    _button?.enabled = false
}

var url:String = "https://eamorr.com/ajax/getLatestContent.php"
var params:[String: String!] = [
    "hello":"world"
]
submitBoilerPlate(url, params, nil)

Notice the explicit type of params and the removal of your _params and _button errors in the submitBoilerPlate call.

Specifying params without an explicit type was causing the compiler to not align your bits properly according to the required [String: String!] parameter type.

Having _params and _button as part of your function call is actually an error. When there's no space, there's no name to the parameters. An example of the alternative is:

func submitBoilerPlate(_url:String, someParams _params:[String: String!], andButton _button:UIButton?) {
  // .. same func body
}

submitBoilerPlate(url, someParams:params, andButton:nil)

Upvotes: 1

Zell B.
Zell B.

Reputation: 10296

Your problem is not with UIButton? but with _params:[String: String!] if you are using it somewhere below in submitBoilerPlate function . Try replacing it with _params:[String: String]

Upvotes: 1

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