「ViewControler」と「AnimalChooserViewControler」の2つのビューコントローラーを使用する非常に単純な迅速なアプリケーションを構築しています。First には、単純なラベルと 1 つの項目を含むツールバーがあり、ユーザーを 2 番目の画面に移動します。2 つ目は、カスタム ピッカーです。アプリの全体的な目的は、出力 UILabel を使用して、ユーザーが 2 番目のビュー コントローラーから最初のビュー コントローラーに選択したものを表示することです。私はxCode 6.4（ios8）を使用していることに言及する必要があります
私の問題は、presentedViewController を次のようにキャストしようとするときです。ViewController アプリが「致命的なエラー: オプション値 (lldb) のラップ解除中に予期せず nil が見つかりました」という例外でクラッシュします。この問題を解決する方法、提案はありますか? ViewControler の私のコードは次のとおりです。
class ViewController: UIViewController {
@IBOutlet weak var outputLabel: UILabel!
override func viewDidLoad() {
super.viewDidLoad()
// Do any additional setup after loading the view, typically from a nib.
}
override func didReceiveMemoryWarning() {
super.didReceiveMemoryWarning()
// Dispose of any resources that can be recreated.
}
func displayAnimal(choosenAnimal: String, withSound choosenSound: String, fromComponent choosenComponent: String){
self.outputLabel.text = "You changed \(choosenComponent) (\(choosenAnimal)(and the sound \(choosenSound))"
}
}
そして、これは AnimalChooserViewControler の私のコードです
class AnimalChooserViewController: UIViewController, UIPickerViewDataSource, UIPickerViewDelegate{
let kComponentCount: Int = 2
let kAnimalComponent: Int = 0
let kSoundComponent: Int = 1
var animalNames: [String] = []
var animalSounds: [String] = []
var animalImages: [UIImageView] = []
@IBAction func dismisAnimalChooser(sender: AnyObject) {
dismissViewControllerAnimated(true, completion: nil)
}
func numberOfComponentsInPickerView(pickerView: UIPickerView) -> Int {
return kComponentCount
}
func pickerView(pickerView: UIPickerView, numberOfRowsInComponent component: Int) -> Int {
if component == kAnimalComponent{
return animalNames.count
} else {
return animalSounds.count
}
}
func pickerView(pickerView: UIPickerView, viewForRow row: Int, forComponent component: Int, reusingView view: UIView!) -> UIView {
if component == kAnimalComponent {
let choosenImageView: UIImageView = animalImages[row]
let workarroundImageView: UIImageView = UIImageView(frame: choosenImageView.frame)
workarroundImageView.backgroundColor = UIColor(patternImage: choosenImageView.image!)
return workarroundImageView
} else {
let soundLabel: UILabel = UILabel(frame: CGRectMake(0, 0, 100, 32))
soundLabel.text = animalSounds[row]
return soundLabel
}
}
func pickerView(pickerView: UIPickerView, rowHeightForComponent component: Int) -> CGFloat {
return 55.0
}
func pickerView(pickerView: UIPickerView, widthForComponent component: Int) -> CGFloat {
if component == kAnimalComponent{
return 75.0
} else {
return 150.0
}
}
func pickerView(pickerView: UIPickerView, didSelectRow row: Int, inComponent component: Int) {
let initialView : ViewController = presentedViewController as! ViewController
if component == kAnimalComponent{
let choosenSound: Int = pickerView.selectedRowInComponent(self.kSoundComponent)
initialView.displayAnimal(animalNames[row], withSound: animalSounds[choosenSound], fromComponent: "the Animal")
} else {
let choosenAnimal: Int = pickerView.selectedRowInComponent(kAnimalComponent)
initialView.displayAnimal(animalNames[choosenAnimal], withSound: animalSounds[row], fromComponent: "the Sound")
}
}
override func viewDidLoad() {
super.viewDidLoad()
animalNames = ["Mouse","Goose","Cat","Dog","Snake","Bear","Pig"]
animalSounds = ["Oink","Rawr","Sss","Meow","Honk","Squeak"]
animalImages = [UIImageView(image: UIImage(named: "mouse.png")),
UIImageView(image: UIImage(named: "goose.png")),
UIImageView(image: UIImage(named: "cat.png")),
UIImageView(image: UIImage(named: "dog.png")),
UIImageView(image: UIImage(named: "snake.png")),
UIImageView(image: UIImage(named: "bear.png")),
UIImageView(image: UIImage(named: "pig.png"))]
preferredContentSize = CGSizeMake(340,380)
}
override func viewDidAppear(animated: Bool) {
super.viewDidAppear(animated)
let initialView: ViewController = presentedViewController as! ViewController
initialView.displayAnimal(animalNames[0], withSound: animalSounds[0], fromComponent: "nothing yet...")
}
override func didReceiveMemoryWarning() {
super.didReceiveMemoryWarning()
// Dispose of any resources that can be recreated.
}
/*
// MARK: - Navigation
// In a storyboard-based application, you will often want to do a little preparation before navigation
override func prepareForSegue(segue: UIStoryboardSegue, sender: AnyObject?) {
// Get the new view controller using segue.destinationViewController.
// Pass the selected object to the new view controller.
}
*/
}