设置自定义 MKAnnotationView 的中心答案

【问题标题】：Set the center of custom MKAnnotationView设置自定义 MKAnnotationView 的中心
【发布时间】：2017-07-09 06:17:22
【问题描述】：

我正在使用自定义MKAnnotationView。我使用 autolayouts 工作正常，但注释视图的位置（框架）不合适。

func mapView(_ mapView: MKMapView, didSelect view: MKAnnotationView)
{
    if view.annotation is MKUserLocation
    {
        return
    }

    let starbucksAnnotation = view.annotation as! LiquorLocation
    let views = Bundle.main.loadNibNamed("CustomCalloutView", owner: nil, options: nil)
    let calloutView = views?[0] as! CustomCalloutView
    calloutView.labelLiquorShopName.text = starbucksAnnotation.title
    calloutView.labelLiquorShopAddress.text = starbucksAnnotation.address
    calloutView.labelLiquorShopAwayDistance.text = starbucksAnnotation.locationKmAway
    calloutView.imageViewLiquorShop.image = starbucksAnnotation.liquorShopIcon


    calloutView.translatesAutoresizingMaskIntoConstraints = false
    view.addSubview(calloutView)
    mapView.setCenter((view.annotation?.coordinate)!, animated: true)
}

我做错了什么？我想在图钉顶部居中注释视图。

【问题讨论】：

标签： swift3 mapkit mkannotation mkannotationview mapkitannotation

【解决方案1】：

Autolayouts 再次拯救我的一天。我在标注视图和视图（MKAnnotationView）之间添加了布局约束。我在didSelect 方法中写在view.addSubview(calloutView) 下面的行下面。

let horizontalConstraint = NSLayoutConstraint(item: calloutView, attribute: NSLayoutAttribute.centerX, relatedBy: NSLayoutRelation.equal, toItem: view, attribute: NSLayoutAttribute.centerX, multiplier: 1, constant: 0)
        let verticalConstraint = NSLayoutConstraint(item: calloutView, attribute: NSLayoutAttribute.bottom, relatedBy: NSLayoutRelation.equal, toItem: view, attribute: NSLayoutAttribute.top, multiplier: 1, constant: 0)
        let widthConstraint = NSLayoutConstraint(item: calloutView, attribute: NSLayoutAttribute.width, relatedBy: NSLayoutRelation.equal, toItem: nil, attribute: NSLayoutAttribute.notAnAttribute, multiplier: 1, constant: calloutView.frame.size.width)
        view.addConstraints([horizontalConstraint, verticalConstraint, widthConstraint])

【讨论】：