Question

我对Swift比较新。我在pickerView中使用PFQuery时遇到了一个问题。

我正在尝试实现一个2组件pickerView，如下所示：

组件0：组件1

“A”：“Altivo”，“Altrez”

“B”：“Beverly”，“Bijou”

从组件0中选择“A”将在组件1中显示“Altivo”，“Altrez”

使用Component 0

中的值从Parse查询Component 1中的值

这是我的代码：

var condoNameList: [String] = [String]()
var condoPicker = UIPickerView()
var condoAlphabet: [String] = [String]()
private let prefixComponent = 0
private let condoNameComponent = 1


 override func viewDidLoad() {
    super.viewDidLoad()
    condoAlphabet = ["A", "B"]
 }

 //Start: For condoName picker
func numberOfComponentsInPickerView(pickerView: UIPickerView) -> Int {
    return 2
}

func pickerView(pickerView: UIPickerView, numberOfRowsInComponent component: Int) -> Int {
    if component == prefixComponent{
        return condoAlphabet.count
    }else {
        return self.condoNameList.count

    }
}

func pickerView(pickerView: UIPickerView, didSelectRow row: Int, inComponent component: Int) {
    if component == prefixComponent {
        condoNameList.removeAll()
        let query = PFQuery(className: "condodirectory")
        let selectedalphabet: String = condoAlphabet[row] as String!

        query.whereKey("condoName", hasPrefix: selectedalphabet)
        query.findObjectsInBackgroundWithBlock{
            (objects:[PFObject]?, error:NSError?)->Void in

            if error == nil{
                for object in objects!{
                    //print(object)
                    let condoName:String = object["condoName"] as! String
                    self.condoNameList.append(condoName)
                }
            }
            //print("condo Name List is \(self.condoNameList)") //Position 1
        }
        print("condo Name List is \(self.condoNameList)") //Position 2
        condoPicker.reloadComponent(condoNameComponent)
        condoPicker.selectRow(0, inComponent: condoNameComponent, animated: true)
    }
}

func pickerView(pickerView: UIPickerView, titleForRow row: Int, forComponent component: Int) -> String? {
    if component == prefixComponent{
        return condoAlphabet[row]
    }else {
        return self.condoNameList[row]
    }
}

问题出在位置1，打印功能能够打印出condoNameList，但在位置2处打印出一个空数组。因此，组件1的列表未显示在PickerView中。

任何人都知道为什么？

提前感谢您的帮助。

Answer 1

我设法通过使用didset {}方法从另一个线程解决问题。

python C:\Python27\Projects\hello.p

使用pickerView时，将PFobjects保存到数组中

1 个答案: