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iOS

Posted by Hamza Ansari
Hamza Ansari
34 Points

How do I connect a button to this function?

I'm trying to make it so that a button executes this function called "incrementBy", which is supposed to add a vote to the poll choice that the button represents and return the results of the poll to the user. How do I do that?

class Counter {
        var voteCount: Int = 0
        func incrementBy(amount: Int, numberOfTimes times: Int) { voteCount += amount * times
            println(" \(voteCount) votes")
            }
Dan Merchant
Dan Merchant
Courses Plus Student 22,188 Points
Dan Merchant
Dan Merchant
Courses Plus Student 22,188 Points

select your storyboard, select the interlocking circles icon for the assistant editor which will put the view controller code on the right.

control click/drag from the button in the storyboard to your code and let go. choose action, then transfer the code you have into that func.

This is shown in the swift fun facts tutorial for app building.

Hamza Ansari
Hamza Ansari
34 Points

I know that much, but I don't now how to incorporate this function into the IBAction once I link the button into my assistant editor. Can I just write that entire code above as is below my IBAction?

Dan Merchant
Dan Merchant
Courses Plus Student 22,188 Points
Dan Merchant
Dan Merchant
Courses Plus Student 22,188 Points

in your viewDidLoad, you should instantiate a counter for each kind of vote with something like this:

var blueVoteCounter = Counter() var redVoteCounter = Counter()

then in your viewController:

            @IBAction func blueVoteCounter() {
            blueVoteCounter.incrementBy(1, numberOfTimes: 1)
            blueCounterLabel.text = String(blueVoteCounter.voteCount)  // this should work to have a count next to in in a 
                                                                                                                         IBOutlet blueLabelCount
    }
Hamza Ansari
Hamza Ansari
34 Points

Now I'm getting this error that says, '0 -> 0' does not have a member named 'incrementBy' on the line that says countOption1.incrementBy(1, numberOfTimes: 1). What do you suppose that means? Here's my new code below: 

    class Counter {
        var voteCount: Int = 0
        func incrementBy(amount: Int, numberOfTimes times: Int) { voteCount += amount * times
            println(" \(voteCount) votes")
        }

    var countOption1 = Counter()
    var countOption2 = Counter()

}

 func didReceiveMemoryWarning() {
    didReceiveMemoryWarning()
    // Dispose of any resources that can be recreated.
}


}

@IBAction func countOption1() {
    countOption1.incrementBy(1, numberOfTimes: 1)
}
@IBOutlet weak var totalVotes1: UILabel!
                   totalVotes1.text = String(countOption1.voteCount)
}

I'm also getting an "Expected declaration" error on the totalVotes1.text = String(countOption1.voteCount) line, but not sure why.

6 Answers

Dan Merchant
PLUS
Dan Merchant
Courses Plus Student 22,188 Points
Dan Merchant
Dan Merchant
Courses Plus Student 22,188 Points

this worked in my playground, if it doesn't work in your app, that means you're messing up the different variables in scope. as in, something isn't global, or available to your current scope.

class Counter {
    var voteCount: Int

    init() {
        voteCount=0
    }
    func incrementBy(amount: Int, numberOfTimes times: Int) {
        voteCount += amount * times
        println(" \(voteCount) votes")
    }
}

var countOption1=Counter.init()

countOption1.incrementBy(1, numberOfTimes: 1)
Hamza Ansari
Hamza Ansari
34 Points

Thanks, I greatly appreciate the help. You don't happen to know how I can save all this as a PFObject do you? The problem I'm running into is saving it all as a PFObject so that the votes can be saved on my database on Parse.com, which is why I formatted my variables like so:

var voteCount = PFObject(className:"VoteCount")
voteCount["votes"] = 0
voteCount["optionName"] = "crepes"
voteCount.saveInBackground()

I just can't save the voteCount variable as a PFObject without getting an error, but does it work for you?

Dan Merchant
PLUS
Dan Merchant
Courses Plus Student 22,188 Points
Dan Merchant
Dan Merchant
Courses Plus Student 22,188 Points

try changing your class to this:

class Counter {
    var voteCount: Int

    init() {
        voteCount=0
    }

    func incrementBy(amount: Int, numberOfTimes times: Int) { voteCount += amount * times
        println(" \(voteCount) votes")
    }

you might want to play around with it in a playground to suss out the problems, that's how I figured this out. I'm not an expert on this, but this should move you in the right direction.

Dan Merchant
PLUS
Dan Merchant
Courses Plus Student 22,188 Points
Dan Merchant
Dan Merchant
Courses Plus Student 22,188 Points

Not sure how that works, I'm a little mystified by pdf's, I've seen objective c sample code that works, but there's some behind the scenes magic that makes this stuff work that is beyond me.

Dan Merchant
PLUS
Dan Merchant
Courses Plus Student 22,188 Points
Dan Merchant
Dan Merchant
Courses Plus Student 22,188 Points

I had a mistype there, you probably don't want to name the action the same as your instance of Counter. That may or may not be the problem.

Hamza Ansari
Hamza Ansari
34 Points

OK, do you mean the part that says countOption1.incrementBy(1, numberOfTimes: 1)? I should change the countOption1 on that line to something else is what you're saying?

Dan Merchant
PLUS
Dan Merchant
Courses Plus Student 22,188 Points
Dan Merchant
Dan Merchant
Courses Plus Student 22,188 Points

this is the code from a post I made above.

class Counter {
    var voteCount: Int

    init() {
        voteCount=0
    }
    func incrementBy(amount: Int, numberOfTimes times: Int) {
        voteCount += amount * times
        println(" \(voteCount) votes")
    }
}

var countOption1=Counter.init()

countOption1.incrementBy(1, numberOfTimes: 1)

paste this into a playground. play around with it until it works the way you expect it to. then add it to your app. This should give you a better understanding of how you want to code to accomplish your objectives.

Hamza Ansari
Hamza Ansari
34 Points

Thanks again. That works in the Playground, but I just don't know where to stick it in the view controller so that a button executes it. I tried placing all that within an IBAction but I get the same error again. Do I need to place it in the viewDidLoad or below the closing of the didReceiveMemoryWarning? Sorry for all these questions! You've helped me out a lot so far.

Hamza Ansari
Hamza Ansari
34 Points
Hamza Ansari
Hamza Ansari
34 Points

How did you define the 'incrementBy' member? When I try to create the IBAction the way you wrote it, I'm getting an error that says '0 -> 0' does not have a member named 'incrementBy'. 

@IBAction func countOption1() {
        countOption1.incrementBy(1, numberOfTimes: 1)
    }