Swift: How do I arrange programatically added checkboxes?

I'm creating an iOS app using Swift, one with checkboxes. Currently, I've placed them inside a view (constrained and all), in the hopes that they would stay there and not mess up the rest of my app. Here's my code so far:

// UI
let lCheckboxHeight: CGFloat = 44.0;
let lCheckboxWidth: CGFloat = 180.0;

let waterSampleTreatmentTitles = ["i - Untreated", "ii - Acidified", "iii - Airfree", "iv - Filtered, Untreated","v - Filtered, Acidified","Stable Isotopes","Others"];

let lNumberOfCheckboxes = waterSampleTreatmentTitles.count

var lFrame = CGRectMake(0, 0, self.view.frame.size.width, lCheckboxHeight);

for (var counter = 0; counter < lNumberOfCheckboxes; counter++) {
    let lCheckbox = Checkbox(frame: lFrame, title: waterSampleTreatmentTitles[counter], selected: false);
    lCheckbox.mDelegate = self;
    lCheckbox.tag = counter;
    if (waterSampleTreatmentTitles[counter] == "i - Untreated" && self.flagUntreated == true){
        lCheckbox.selected = true
    }
    else if (waterSampleTreatmentTitles[counter] == "ii - Acidified" && self.flagAcidified == true){
        lCheckbox.selected = true
    }
    else if (waterSampleTreatmentTitles[counter] == "iii - Airfree" && self.flagAirfree == true){
        lCheckbox.selected = true
    }
    else if (waterSampleTreatmentTitles[counter] == "iv - Filtered, Untreated" && self.flagFilterUntreat == true){
        lCheckbox.selected = true
    }
    else if (waterSampleTreatmentTitles[counter] == "v - Filtered, Acidified" && self.flagFilterAcid == true){
        lCheckbox.selected = true
    }
    else if (waterSampleTreatmentTitles[counter] == "Stable Isotopes" && self.flagStabIso == true){
        lCheckbox.selected = true
    }
    else if (waterSampleTreatmentTitles[counter] == "Others" && self.flagOthers == true){
        lCheckbox.selected = true
    }
    self.chemistryProductionWell.viewSampTreat.addSubview(lCheckbox);
    lFrame.origin.y += lFrame.size.height;
}

Currently, this creates a list of checkboxes, which spills past the view I made, and just generally makes a mess of the app. The view is long enough for maybe two checkboxes vertically, but not eight.

How do I make it such that the checkboxes are arranged horizontally? I've tried replacing the following code:

lFrame.origin.y += lFrame.size.height;

With this:

lFrame.origin.x += lCheckboxWidth

But that doesn't take into account that the text for the checkboxes aren't the same length, and of course ignores the width restriction as well.

How do I make it such that if the checkbox length exceeds the view, it would drop down to the next line?

Thanks.