通过使用pickerview和文本字段更新标签

Question

I have a PickerView that deposit values. This values will be calculate with a user textfield input. The result will show in a label. That works for me. By starting the app the textfield have a fix number of 1. How can I now update my label automatically by use the Pickerview? I read and try many things but it don´t works. Maybe it is a little thing, but i don´t see it.

import UIKit

class BalkenbewehrungVC: UIViewController, UIPopoverPresentationControllerDelegate, UIPickerViewDataSource, UIPickerViewDelegate, UITextFieldDelegate {

    // Deklarationen Pickerview
    var multiplicator : Double = 0.0

    let multiplicators = [0.0,6.0,8.0,10.0,12.0,14.0,16.0,20.0,25.0,26.0,28.0,30.0,32.0,36.0,40.0,50.0]

    let PI = 3.1415

    // Pickerview füllen
    var pickerDataSource = ["---","Ø 6","Ø 8","Ø 10","Ø 12","Ø 14","Ø 16","Ø 20","Ø 25","Ø 26","Ø 28","Ø 30","Ø 32","Ø 36","Ø 40","Ø 50"]


    // Picker im aktivieren
    @IBOutlet weak var Pickerview: UIPickerView!


    // Ausgabewert As = xxxx cm
    @IBOutlet var AusgabePicker: UILabel!

    // Eingabe Anzahl Stäbe
    @IBOutlet var AnzahlStab: UITextField!

      @IBAction func test(sender: UITextField) {

        if AnzahlStab.text!.isEmpty {

            AnzahlStab.text = "1"

            let result1 = (multiplicator / 10) * (multiplicator / 10) * PI / 4 * 1

            AusgabePicker.text! = String(format:"%.3f", result1)


        } else {

            let result = (multiplicator / 10) * (multiplicator / 10) * PI / 4 * (AnzahlStab.text! as NSString).doubleValue
            // let resultString = "\(result)"


            AusgabePicker.text = String(format:"%.3f", result)
        }

    }

// Picker - feste Reihen
    func numberOfComponentsInPickerView(pickerView: UIPickerView) -> Int {
        return 1
    }

    // Picker - Aufaddierung neuer Reihen
    func pickerView(pickerView: UIPickerView, numberOfRowsInComponent component: Int) -> Int {
        return pickerDataSource.count

    }

    // Picker - Datenübernahme multiplicator in Picker
    func pickerView(pickerView: UIPickerView, titleForRow row: Int, forComponent component: Int) -> String? {
        return pickerDataSource[row]


    }

    // Picker - Wertefestlegung Picker
    func pickerView(pickerView: UIPickerView, didSelectRow row: Int, inComponent component: Int) {
        multiplicator = multiplicators[row]
        _ = NSNumberFormatter.localizedStringFromNumber(NSNumber(double: multiplicator), numberStyle:.DecimalStyle)

    }

Answer 1

In the didSelectRow method for the pickerView , set the label's text to your newly calculated value.

Update : To update the label's text depending on the textField's input, inside your ViewController 's viewDidLoad method, add this line

AnzahlStab.delegate = self

and then add the textFieldDidEndEditing method, and inside it update the label's text to the new value. This method is called when you are done with editing the text field.

Answer 2

Need to call function test in picker view didSelectRow . Or Simply Replace your didSelectRow with following code.

 func pickerView(pickerView: UIPickerView, didSelectRow row: Int, inComponent component: Int) { multiplicator = multiplicators[row] _ = NSNumberFormatter.localizedStringFromNumber(NSNumber(double: multiplicator), numberStyle:.DecimalStyle) self.test(AnzahlStab) } 

Hope this Answer will help you.