MKAnnotation Swift [英] MKAnnotation Swift

问题描述

我不确定如何用快速语言注释地图。我不知道如何创建NSObject类。以下是我尝试但无法运行的代码：

I am unsure how to annotate a map in the swift language. I don't know how to create the NSObject class. The following is code I tried but was unable to run:

import Foundation
import MapKit
class MapPin : MKAnnotation
{
    var mycoordinate: CLLocationCoordinate2D
    var mytitle: String
    var mysubtitle: String

    func initMapPin (coordinate: CLLocationCoordinate2D!, title: String!, subtitle: String!)
    {
        mycoordinate = coordinate
        mytitle = title
        mysubtitle = subtitle
    }
}

推荐答案

1. Swift中的所有初始化方法必须只是init


2. MKAnnotation要求对象继承自NSObjectProtocol。要做到这一点，你应该让你的类继承自NSObject


3. 你应该声明你的属性与MKAnnotation协议的属性相匹配


4. 你不应该声明您的参数为隐式展开的选项，除非您真的必须这样做。让编译器检查某些东西是否为nil而不是抛出运行时错误。

1. All initialization methods in Swift must simply be "init"
2. MKAnnotation requires that the object inherit from NSObjectProtocol. To do that, you should have your class inherit from NSObject
3. You should declare your properties to match those of the MKAnnotation protocol
4. You should not declare your parameters as Implicitly Unwrapped Optionals unless you really have to. Let the compiler check if something is nil instead of throwing runtime errors.

这会给你结果：

class MapPin : NSObject, MKAnnotation {
    var coordinate: CLLocationCoordinate2D
    var title: String?
    var subtitle: String?

    init(coordinate: CLLocationCoordinate2D, title: String, subtitle: String) {
        self.coordinate = coordinate
        self.title = title
        self.subtitle = subtitle
    }
}

这篇关于MKAnnotation Swift的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！