关于 ios：如何在 Swift 中更改 UIPickerView 中的字体大小？

//MARK: Properties

@IBOutlet weak var layoutLengthPicker: UIPickerView!
@IBOutlet weak var layoutWidthPicker: UIPickerView!
@IBOutlet weak var trackPicker: UIPickerView!

let layoutLengthPickerDelegate = DimensionsPickerDelegate()
let layoutWidthPickerDelegate = DimensionsPickerDelegate()
let trackPickerDelegate = TrackPickerDelegate()

override func viewDidLoad() {
    super.viewDidLoad()

    layoutLengthPicker.delegate = layoutLengthPickerDelegate
    layoutLengthPicker.dataSource = layoutLengthPickerDelegate

    layoutWidthPicker.delegate = layoutWidthPickerDelegate
    layoutWidthPicker.dataSource = layoutWidthPickerDelegate

    trackPicker.delegate = trackPickerDelegate
    trackPicker.dataSource = trackPickerDelegate

    // Do any additional setup after loading the view, typically from a nib.
}

//MARK: Actions

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

}

class DimensionsPickerDelegate: NSObject, UIPickerViewDataSource, UIPickerViewDelegate {

let feet = ["0 Ft.","1 Ft.","2 Ft.","3 Ft.","4 Ft.","5 Ft.","6 Ft.","7 Ft.","8 Ft.","9 Ft.","10 Ft.","11 Ft.","12 Ft.","13 Ft.","14 Ft.","15 Ft.","16 Ft.","17 Ft.","18 Ft.","19 Ft.","20 Ft.","21 Ft.","22 Ft.","23 Ft.","24 Ft.","25 Ft.","26 Ft.","27 Ft.","28 Ft.","29 Ft.","30 Ft.","31 Ft.","32 Ft.","33 Ft.","34 Ft.","35 Ft.","36 Ft.","37 Ft.","38 Ft.","39 Ft.","40 Ft.","41 Ft.","42 Ft.","43 Ft.","44 Ft.","45 Ft.","46 Ft.","47 Ft.","48 Ft.","49 Ft.","50 Ft.","51 Ft.","52 Ft.","53 Ft.","54 Ft.","55 Ft.","56 Ft.","57 Ft.","58 Ft.","59 Ft.","60 Ft.","61 Ft.","62 Ft.","63 Ft.","64 Ft.","65 Ft.","66 Ft.","67 Ft.","68 Ft.","69 Ft.","70 Ft.","71 Ft.","72 Ft.","73 Ft.","74 Ft.","75 Ft.","76 Ft.","77 Ft.","78 Ft.","79 Ft.","80 Ft.","81 Ft.","82 Ft.","83 Ft.","84 Ft.","85 Ft.","86 Ft.","87 Ft.","88 Ft.","89 Ft.","90 Ft.","91 Ft.","92 Ft.","93 Ft.","94 Ft.","95 Ft.","96 Ft.","97 Ft.","98 Ft.","99 Ft.","100 Ft."]

let inches = ["0 In.","1 In.","2 In.","3 In.","4 In.","5 In.","6 In.","7 In.","8 In.","9 In.","10 In.","11 In.","12 In."]

func numberOfComponents(in pickerView: UIPickerView) -> Int {
    return 2
}

func pickerView(_ pickerView: UIPickerView, numberOfRowsInComponent component: Int) -> Int {
    if component == 0 { return feet.count } else { return inches.count}

}
func pickerView(_ pickerView: UIPickerView, titleForRow row: Int, forComponent component: Int) -> String? {
    if component == 0 {return feet[row]} else {return inches[row]}

}
}

class TrackPickerDelegate: NSObject, UIPickerViewDataSource, UIPickerViewDelegate {

let manufacturers = ["Atlas True Track","Atlas Code 100","Atlas Code 83","Bachmann Nickel Silver","Bachmann Steel Alloy","Kato","Life-Like Trains Code 100","LIfe-Like Trains Power-Loc","Peco Code 100","Peco Code 83","Peco Code 75","Shinohara Code 100","Shinohara Code 70","Walthers"]

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

func pickerView(_ pickerView: UIPickerView, numberOfRowsInComponent component: Int) -> Int {
        return manufacturers.count
    }

func pickerView(_ pickerView: UIPickerView, titleForRow row: Int, forComponent component: Int) -> String? {
        return manufacturers[row]
    }

}