二进制运算符'=='不能应用于类型'[MKAnnotation]'和'MKAnnotation'的操作数 [英] Binary operator '==' cannot be applied to operands of type '[MKAnnotation]' and 'MKAnnotation'

问题描述

我正在使用tvOS应用程序，希望在其中注释之间滑动.我将注释存储在字典中，并将字典存储在数组中以备将来使用.我只是在为加拿大，美国和墨西哥绘制三个注释.我希望能够在这些注释之间的遥控器上滑动.单击注释后，它将带您到有关该国家的信息.

I'm working on a tvOS app, where I want to be able to swipe between annotations. I store my annotations in a Dictionary, and store the Dictionary in an Array for future use. I am simply plotting three annotations for Canada, USA, and Mexico. I want to be able to swipe on the remote between these annotations. When an annotation is clicked, it will take you to information about that country.

let countriesArray = ["Canada", "Mexico", "United States of America"]  
var annotationArray = [MKPointAnnotation]()  
var locationDictionary = [String: AnyObject]()  
var locationArray = [AnyObject]()  

绘制了三个国家后，我的数组如下所示:

Once the three countries are plotted, my array looks like the following:

locationArray [{  
    annotation = "<MKPointAnnotation: 0x7fc021b01f70>";  
    country = Canada;  
    latitude = "71.47385399229037";  
    longitude = "-96.81064609999999";  
}, {  
    annotation = "<MKPointAnnotation: 0x7fc0219dcf90>";  
    country = "United States of America";  
    latitude = "37.99472997055178";  
    longitude = "-95.85629150000001";  
}, {  
    annotation = "<MKPointAnnotation: 0x7fc02260ff70>";  
    country = Mexico;  
    latitude = "23.94480686844645";  
    longitude = "-102.55803745";  
}]  

例如，当Apple遥控器向下滑动时，在以下if条件下出现以下错误.

When the Apple remote is swipped, down, for example, I'm getting the following error on the if condition below.

二进制运算符'=='不能应用于类型'[MKAnnotation]'和'MKAnnotation'的操作数

Binary operator '==' cannot be applied to operands of type '[MKAnnotation]' and 'MKAnnotation'

我怎样才能将这首注释中的注释与所选注释进行比较?

How can I compare the annotation in the arrary to the one selected?

func swipedDown(sender:UISwipeGestureRecognizer) {  
    print("Down")  

    let selectedAnnotation = mapView.selectedAnnotations  

    for x in 0 ... locationArray.count - 1 {  

        let value = locationArray[x].valueForKey("annotation") as! MKAnnotation  

        if  selectedAnnotation == value {   //error

            let currentLocation = locationArray[x].valueForKey("country")  

            print("Your on \(currentLocation)")  
        }  
    }  
}  

推荐答案

由于mapView.selectedAnnotations返回一个MKAnnotation s数组，即一个[MKAnnotation]，将其与单个MKAnnotation值与operator ==进行比较，所以不行.您需要决定如何处理数组中的多个值-具体来说，当数组中的任何注释与value匹配时，或者当第一个与value匹配时，或者所有它们都匹配时，比较是否应为true value.

Since mapView.selectedAnnotations returns an array of MKAnnotations, i.e. an [MKAnnotation], comparing it to a single MKAnnotation value with operator == does not work. You need to decide what to do with multiple values from the array - specifically, whether the comparison should be true when any of the annotations in the array matches value, or when the first one matches value, or all of them match value.

如果需要检查一个数组元素是否与值匹配，则可以使用contains，如下所示:

If you need to check that one array element matches the value, you can use contains, like this:

if  (selectedAnnotation.contains { $0.title == value.title && $0.subtitle == value.subtitle }) {
    let currentLocation = locationArray[x].valueForKey("country")  
    print("Your on \(currentLocation)")  
}

:由于MKAnnotation不符合Equatable协议，首次尝试使用非封闭式contains失败.谢谢 dan 赶上了！

The initial attempt at using non-closure contains has failed, because MKAnnotation does not conform to Equatable protocol. Thanks, dan, for catching this!

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