UIPickerView显示空的灰色框Swift

Question

I haven't a whole lot of code, so I might as well copy it here.

class ViewController: UIViewController, UIPickerViewDelegate, UIPickerViewDataSource{

    var buildings = ["BankBuilding", "Cinema" , "CornerShop", "Greg's House"]

    @IBOutlet weak var buildText: UITextField!

    var buildPickers:UIPickerView = UIPickerView()

    override func viewDidLoad() {
        super.viewDidLoad()

        buildPickers = UIPickerView()
        buildPickers.delegate = self
        buildPickers.hidden = true;
        buildText.inputView = buildPickers
        buildText.text = buildings[0]        
    }

    func numberOfComponentsInPickerView(pickerView: UIPickerView) -> Int{
        return 1
    }

    func pickerView(pickerView: UIPickerView, numberOfRowsInComponent component: Int) -> Int{
        println("Count: \(buildings.count)")
        return buildings.count
    }

    func pickerView(pickerView: UIPickerView, titleForRow row: Int, forComponent component: Int) -> String! {
        println("creating title: \(buildings[row])")
        return buildings[row]
    }

    func pickerView(pickerView: UIPickerView, didSelectRow row: Int, inComponent component: Int)
    {
        println("Selected: \(buildings[row])")
        buildText.text = buildings[row]
        buildPickers.hidden = true;
    }

    func textFieldShouldBeginEditing(textField: UITextField) -> Bool {
        buildPickers.hidden = false
        return false
    }
}

The print statements are correct. For numberOfRows... and titleForRow it is printing the correct Strings.

But there is no prints for didSelectRow because, well, I can't select a row.

This is what I get:

You can ignore the Google Map in the background, that shouldn't interfere with the Picker View and is just set up in the StoryBoard.

The Grey window appears when I click on the textField but never shows any content. But the print statements say otherwise.

Does anyone know why this is the case?

Answer 1

Just add this line in your viewDidLoad method:

buildPickers.dataSource = self

And your code will be:

override func viewDidLoad() {
    super.viewDidLoad()

    buildPickers = UIPickerView()
    buildPickers.delegate = self
    buildPickers.dataSource = self
    buildPickers.hidden = true;
    buildText.inputView = buildPickers
    buildText.text = buildings[0]        
}

And it will show your data.

UPDATE:

It is not showing because you set it hidden in your viewDidLoad .

Just remove this line from your code:

buildPickers.hidden = true

Here is your working code:

import UIKit

class ViewController: UIViewController, UIPickerViewDelegate, UIPickerViewDataSource, UITextFieldDelegate{

    var buildings = ["BankBuilding", "Cinema" , "CornerShop", "Greg's House"]

    @IBOutlet weak var buildText: UITextField!

    var buildPickers:UIPickerView = UIPickerView()

    override func viewDidLoad() {
        super.viewDidLoad()

        buildPickers = UIPickerView()
        buildPickers.delegate = self
        buildPickers.hidden = true
        buildText.delegate = self        //set delegate for textField
        buildText.inputView = buildPickers
        buildText.text = buildings[0]
    }

    func numberOfComponentsInPickerView(pickerView: UIPickerView) -> Int{
        return 1
    }

    func pickerView(pickerView: UIPickerView, numberOfRowsInComponent component: Int) -> Int{
        println("Count: \(buildings.count)")
        return buildings.count
    }

    func pickerView(pickerView: UIPickerView, titleForRow row: Int, forComponent component: Int) -> String! {
        println("creating title: \(buildings[row])")
        return buildings[row]
    }

    func pickerView(pickerView: UIPickerView, didSelectRow row: Int, inComponent component: Int)
    {
        println("Selected: \(buildings[row])")
        buildText.text = buildings[row]
        buildPickers.hidden = true;
    }


    //this method will call when you click on textField
    func textFieldShouldBeginEditing(textField: UITextField) -> Bool {
        buildPickers.hidden = false
        return true
    }
}

Answer 2

Is the delegate set on the text field? Are you getting the callback which you use to un-hide the picker?