CODEWITHSUNDEEP
swiftsegue
zack_falcon
zack_falcon

Reputation: 4376

Swift: Passing data from one form to another, two times in a row: second time refuses to pass

I'm working on an app that consists of forms, the structure of which goes as follows:

The idea, basically, is a table, within a table. Each table has an identifier, the "parent". MainTable's parent is MainForm, and SubTable's parent is MainTable.

We pass this between the forms via prepareForSegue:

override func prepareForSegue(segue: UIStoryboardSegue, sender: AnyObject!) {
    if segue.identifier == "CorrosionAddERMeasurementSegue" {
        let vc : CorrosionAddERMeasurementFormViewController = segue.destinationViewController as! CorrosionAddERMeasurementFormViewController
        vc.selectedCorrosionRateID = self.selectedCorrosionRateID
    }
}

For the first part, it works fine. I can pass MainForm's ID to MainTable Form, ensuring that no matter what MainTable's actual ID is, it will always belong to MainForm.

Here's where things get dicey:

override func prepareForSegue(segue: UIStoryboardSegue, sender: AnyObject!) {
    if segue.identifier == "AddCorrosionSampleTreatmentSegue" {
        let vc : CorrosionAddSampleTreatmentFormViewController = segue.destinationViewController as! CorrosionAddSampleTreatmentFormViewController
        vc.selectedCorrosionErMeasurementID = self.selectedCorrosionErMeasurementID
    }
}

When the next xib loads, I immediately print the value of selectedCorrosionErMeasurementID which returns nil.

This is the code for switching to the next form:

func addSampleButtonPressed() {
    print("Add Button Pressed. Selected Corrosion Measurements: \(self.selectedCorrosionErMeasurementID)")
    self.performSegueWithIdentifier("CorrosionAddSampleTreatmentSegue", sender: self)
}

And that does print out the correct parent ID value. Here's the opening statements of the SubTable Form:

class CorrosionAddSampleTreatmentFormViewController: BaseViewController, SampleTreatmentFormViewDelegate, UIPickerViewDataSource,UIPickerViewDelegate,UICollectionViewDataSource, UICollectionViewDelegate {
    var corrosionAddSampleFormView : SurfaceThermalSamplingAddSamplingView!
    var selectedCorrosionErMeasurementID : String!

    override func viewDidLoad() {
        print("Selected ID from FormCorrosionER is: \(self.selectedCorrosionErMeasurementID)")
        super.viewDidLoad()
    }
}

Nothing to suggest that the value is being erased.

Is there anything I need to check? Perhaps there's a limit to how deep I can go into segues? Any suggestions?

Upvotes: 0

Views: 29

Answers (1)

GetSwifty
GetSwifty

Reputation: 7746

Assuming I understood correctly, I believe your segue identifiers are mis-matched

self.performSegueWithIdentifier("CorrosionAddSampleTreatmentSegue", sender: self)

vs 

if segue.identifier == "AddCorrosionSampleTreatmentSegue" {

If the first line is supposed to lead to the second, the identifiers need to be identical.

Upvotes: 1

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