我正在创建一个Clock PickerView，并使用了以下内容：

var countSec = Array(0...10)
var countMin = Array(0...59)
var countHour = Array(0...59)

func pickerView(_ pickerView: UIPickerView,titleForRow row: Int,forComponent component: Int) -> String? {
    if component == 0{
        for count in countSec {
            return "\(count)"
        }
    }else{
        for count in countMin{
            return "\(count)"
        }
    }
    return nil
}

但是当我运行时，所有数据都是0s。