如何将二维数组传递给 viewcontroller？

Question

我正在解码结果，我想将名称和 ID 发送到 viewcontroller。我刚开始学习 JSON Codeable 那么，我如何传递这些数据，我已经将这 2 个变量声明为一个数组。

var cityNames = [String]()
var cityNameId = [Int]()
for cityName in display.cities{
                            print(cityName.id , cityName.name)

                            self.cityNames.append(cityName.name)
                            self.cityNameId.append(cityName.id)
                        }

打印时我得到了输出

1 Mumbai
2 Pune
3 Thane

预期结果I'm want to display the names of the cities to the label in dropdown list of next viewController and after selecting the city name from drop down ,. I need the ID of that selected city for the button click event

Answer 1

不要那样做。

显然 cities 表示包含 name 和 id 信息的对象数组

删除数组

~~var cityNames = [String]() var cityNameId = [Int]()~~

始终传递结构的实例或 class 例如

if let firstCity = display.cities.first {
    print(firstCity.id , firstCity.name)
    // pass firstCity to next view controller
}

或

if let city = display.cities.first(where: {[=12=].name == "New York"}) {
    print(city.id , city.name)
    // pass city to next view controller
}

或在 table 视图的 didSelectRow 中

let city = display.cities[indexPath.row]
// pass city to next view controller

Answer 2

声明下一个视图控制器的引用（根据您的要求更改viewcontroller/storyboard/identifiers的名称）：

let nextVC = NextViewController()

或者如果您使用的是故事板，您也可以从故事板实例化：

let nextVC = UIStoryboard(name: "Home", bundle: nil).instantiateViewController(withIdentifier: "NextViewController") as! NextViewController

现在将您想要的任何值作为二维数组传递给 nextVC：

let cities2DArray = [cityNameId, cityNames] as [Any]
nextVC.cities2DArray = cities2DArray

如果您使用带有标识符的 segue，则可以在 prepare(for segue: UIStoryboardSegue, sender: Any?) 中完成上述所有工作，如果没有，则只需在以编程方式进入 nextVC 之前完成这些工作。

现在，确保在 NextViewController:

中声明了这些 2DArray 变量

class NextViewController: UIViewController {

    var cities2DArray = [Any]()

更新：如果您确实想在元组内的 1 个数组中并排创建一个具有 id 及其相应名称的元组，则需要按以下方式修改 for 循环：

    var citiesTuple = [(id: Int, name: String)]()
    for cityName in display.cities{
        citiesTuple.append((id: cityName.id, name: cityName.name))
    }

Answer 3

首先为 City 创建一个结构为 Class 或 Struct

class Context {
    let cities: [City]

    init(with cities: [City]) {
       self.cities = cities
    }
}

比在目标视图控制器中将变量描述为 Context，

class TargetViewController: UIViewController{ 
 ...
 var context: Context?
}

然后，如果您手动推送 viewController，

var targetController = TargetViewController()
targetController.context = Context(with: self.cities)
navigationController?.pushViewController(with: targetController)

或者您可以使用 prepareSegue 方法从情节提要中设置它。

override func prepareForSegue(segue: UIStoryboardSegue!, sender: AnyObject!) {
    if (segue.identifier == "TargetSegueIdentifier") {
        var targetController = segue.destination as? TargetViewController
        targetController.context = Context(with: self.cities)
    }
}

如何将二维数组传递给 viewcontroller？

How do I pass 2D array to the viewcontroller?

swift

swift5