动画MapKit注释协调斯威夫特的变化？ [英] Animate MapKit annotation coordinate change in Swift?

问题描述

在iOS中8斯威夫特使用MapKit，我怎么使人们有可能在动画自定义注解的地图位置的改变？我这样说：

  UIView.animateWithDuration（0.25）{
    无功禄= ann.coordinate
    loc.latitude = loc.latitude + 0.0005
    loc.longitude = loc.longitude + 0.001
    ann.coordinate =禄
}
 

...其中安是一个自定义的注释，MyAnnotation。注释是跳跃的，没有动画，新的坐标位置。

恼人的事情是，动画作品完美的如果我写在Objective-C 的MyAnnotation。但是，如果我把它写在斯威夫特，我没有得到任何动画更多！

仅供参考，这里是我的雨燕code为MyAnnotation：

 类MyAnnotation：NSObject的，MKAnnotation {
    VAR坐标：CLLocationCoordinate2D
    VAR标题：串！
    VAR字幕：串！    的init（坐标位置：CLLocationCoordinate2D）{
        self.coordinate =坐标
        super.init（）
    }
}
 

解决方案

您几乎都有它的权利！只要改变这条线在MyAnnotation实现：

  VAR坐标：CLLocationCoordinate2D
 

这样：

 动态无功协调：CLLocationCoordinate2D
 

这将修复它。

为什么这件事情？因为注解动画依赖于志愿（键值观察）。在斯威夫特，属性是不可观测，除非它被标记为键值动态。 （为了得到多一点的技术，这又是因为志愿观测的工作方式是交叉混合属性setter方法​​的实现 - 运行时到达到您的权利类，并改变了该属性的setter code，但在雨燕，它可以。做T，除非你明确地标记属性作为动态）

When using MapKit in iOS 8 in Swift, how do I make it possible to animate a change in the map position of a custom annotation? I am saying this:

UIView.animateWithDuration(0.25) {
    var loc = ann.coordinate
    loc.latitude = loc.latitude + 0.0005
    loc.longitude = loc.longitude + 0.001
    ann.coordinate = loc
}

...where ann is a custom annotation, MyAnnotation. The annotation is jumping, not animating, to the new coordinate position.

The annoying thing is that the animation works perfectly if I write MyAnnotation in Objective-C. But if I write it in Swift, I don't get the animation any more!

Just FYI, here is my Swift code for MyAnnotation:

class MyAnnotation : NSObject, MKAnnotation {
    var coordinate : CLLocationCoordinate2D
    var title: String!
    var subtitle: String!

    init(location coord:CLLocationCoordinate2D) {
        self.coordinate = coord
        super.init()
    }
}

解决方案

You almost have it right! Just change this line in your MyAnnotation implementation:

var coordinate : CLLocationCoordinate2D

to this:

dynamic var coordinate : CLLocationCoordinate2D

That will fix it.

Why does this matter? Because annotation animation relies on KVO (key value observing). In Swift, a property is not key value observable unless it is marked as dynamic. (To get a little more technical, that in turn is because KVO observation works by swizzling the implementation of the property setter method - the runtime reaches right into your class and changes that property's setter code. But in Swift, it can't do that unless you explicitly mark the property as dynamic.)

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