Pickerview不显示

Question

我的选取器视图由于某种原因无法显示，即使在重新加载所有组件之后也是如此。我点击开始，它只是不加载拾取器视图，因为我希望它加载，然后您可以选择一个选项，并进入下一个问题？

import UIKit

class QuestionsViewController: UIViewController, UIPickerViewDelegate {

@IBOutlet weak var Next: UIButton!
@IBOutlet weak var pickerview: UIPickerView!
@IBOutlet weak var itemLabel: UILabel!
@IBOutlet weak var label1: UILabel!
@IBOutlet weak var Question: UILabel!


@IBAction func Next(_ sender: Any) {
    cQuestion.currentQuestion = cQuestion.currentQuestion + 1
    pickerview.reloadAllComponents()


}

override func didReceiveMemoryWarning() {
    super.didReceiveMemoryWarning()
    // Dispose of any resources that can be recreated.
}
//var LabelText: String = ""
//var arrayOfQuestions: [String] = ["&","&&","||","None of above"]
//var correctAns:String = ""
//var currentQuestion = 0

let cQuestion = Questions()


//init(arrayOfQuestions:String, correctAns:String, LabelText:String) {
    //self.arrayOfQuestions = [arrayOfQuestions]
   // self.correctAns = correctAns
   // self.LabelText = LabelText
//}




override func viewDidLoad() {
    super.viewDidLoad()

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

    itemLabel.text = cQuestion.arrayOfQuestions[0]
}

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

    return 1

}

func pickerView(_ pickerView: UIPickerView, numberOfRowsInComponent component: Int) -> Int{

    if(cQuestion.currentQuestion == 0) {
        Question.text = "Q1. Which is a logical OR operator"
        return cQuestion.arrayOfQuestions.count
    }   else if (cQuestion.currentQuestion == 1) {
        Question.text = "Q2. Compiler generates_file"
        return cQuestion.arrayOfQuestions.count
    }
    hide()
    Question.text = "You have finished"
    Next.isHidden = true
    return cQuestion.arrayOfQuestions.count

}


func pickerView(_ pickerView: UIPickerView, titleForRow row: Int, forComponent component: Int) -> String?{

    if(cQuestion.currentQuestion == 0) {
        return cQuestion.arrayOfQuestions[row]
    } else if (cQuestion.currentQuestion == 1) {
        return cQuestion.arrayOfQuestions[row]
    }
    return cQuestion.arrayOfQuestions[row]

}


func pickerView(_ pickerView: UIPickerView, didSelectRow row: Int, inComponent component: Int){

    if (cQuestion.currentQuestion == 0) {
        let itemSelected = cQuestion.arrayOfQuestions[row]
        itemLabel.text = itemSelected
    } else if (cQuestion.currentQuestion == 1) {
        let itemSelected = cQuestion.arrayOfQuestions[row]
        itemLabel.text = itemSelected
    }
}

func hide() {
    pickerview.isHidden = true
    itemLabel.isHidden = true
} 
}

Answer 1

我的猜测是:看起来只要调用numberOfRowsInComponent (它在准备添加到视图时就会这样做)，您也会调用hide()，这反过来似乎会将您的pickerView设置为isHidden = true。在您的代码中，我看不到isHidden随后被设置为false的地方。

如果不是这样，还要检查pickerview.dataSource的值是什么，以确保它不是nil。