Swift 3.0 Map viewForAnnotation不输出正确标注

我无法理解viewForAnnotation方法的代码以及何时调用它。我的意图是根据引脚颜色的颜色显示特定的标注。在第一次加载mapView时，标注显示正确，但是在切换视图控制器后，根据引脚颜色不能正确显示标注按钮。我有一个预感，这可能与viewForAnnotation调用时有关（无论每次出现地图时调用它）。我无法弄清楚什么是错误的，因为我不确定代码的每个部分是干什么的。Swift 3.0 Map viewForAnnotation不输出正确标注

func mapView(_ map: MKMapView, viewFor annotation: MKAnnotation) -> MKAnnotationView? { 

if (annotation is MKUserLocation) { 

    return nil 
} 

let identifier = "pinAnnotation" 


// In particular I am not sure what the code below does 

if let pin = annotation as? ColorPointAnnotation { 


    if let view = map.dequeueReusableAnnotationView(withIdentifier: identifier) as? MKPinAnnotationView { 
     view.annotation = annotation 
     view.pinTintColor = pin.color ?? .purple 

     return view 

    } else { 

     let view = MKPinAnnotationView(annotation: annotation, reuseIdentifier: identifier) 
     view.isEnabled = true 

     view.canShowCallout = true 

     view.pinTintColor = pin.color ?? .purple 

     let btn = UIButton(type: .detailDisclosure) 
     view.rightCalloutAccessoryView = btn 


     if view.pinTintColor == .red || view.pinTintColor == .green { 
      let button = UIButton(frame: CGRect(x: 0, y: 0, width: 30, height: 30)) 
      button.setBackgroundImage(UIImage(named: "car"), for: .normal) 
      button.addTarget(self, action: #selector(MapVC.getDirections), for: .touchUpInside) 
      view.leftCalloutAccessoryView = button 
     } else { 
      let button = UIButton(frame: CGRect(x: 0, y: 0, width: 30, height: 30)) 
      button.setBackgroundImage(UIImage(named: "other"), for: .normal) 
      button.addTarget(self, action: #selector(MapVC.other), for: .touchUpInside) 
      view.leftCalloutAccessoryView = button 
     } 

     return view 
    } 
} 

if let annotationView = map.dequeueReusableAnnotationView(withIdentifier: identifier) { 
    annotationView.annotation = annotation 
    return annotationView 
} else { 
    let annotationView = MKPinAnnotationView(annotation:annotation, reuseIdentifier: identifier) 
    annotationView.isEnabled = true 
    annotationView.canShowCallout = true 

    let btn = UIButton(type: .detailDisclosure) 
    annotationView.rightCalloutAccessoryView = btn 

    if annotationView.pinTintColor == .red || annotationView.pinTintColor == .green { 

     let smallSquare = CGSize(width: 120, height: 120) 
     let button = UIButton(frame: CGRect(origin: CGPoint(x: 0,y :0), size: smallSquare)) 
     button.setBackgroundImage(UIImage(named: "car"), for: .normal) 
     button.addTarget(self, action: #selector(MapVC.getDirections), for: .touchUpInside) 
     annotationView.leftCalloutAccessoryView = button 
    } else { 
     let button = UIButton(frame: CGRect(x: 0, y: 0, width: 30, height: 30)) 
     button.setBackgroundImage(UIImage(named: "other"), for: .normal) 
     button.addTarget(self, action: #selector(MapVC.other), for: .touchUpInside) 
     annotationView.leftCalloutAccessoryView = button 
    } 

    return annotationView 
} 

}

来源

2017-07-26 Kevin

方法func mapView(_ map: MKMapView, viewFor annotation: MKAnnotation) -> MKAnnotationView?是MapViewDelegate的委托方法，这个方法，每次执行您的MapView显示批注在一个地区的时间，而如果实现了您可以显示annotationView任何子类如地图annotationView，显示自定义标注需要实现MapViewDelegate

//example code 
func mapView(_ mapView: MKMapView, didSelect view: MKAnnotationView){ 
    let customCallout = CustomCallout(frame: CGRect(x: 0, y: 0, width: self.view.frame.size.width * 0.8, height: 50)) 
    customCallout.backgroundColor = UIColor.red //your color here 
    view.addSubView(customCallout) 
    //adjust any param you need here 
}

希望这种方法这可以帮助你

来源

2017-07-26 14:47:43

为了澄清，当你说的MapView显示了重新注解gion，你的意思是如果注释被放置，或者用户看到的当前视图是否有注释。还有什么意思，“把任何UIView作为注释在地图上”？ – Kevin

@Kevin是的，如果注释添加在一个区域内的坐标，然后显示使用这种委托方法，如果实施，再次检查我的答案已更新 –

@Kevin您正在使用2种类型的注释?,我想missunderstood您的问题 –

Swift 3.0 Map viewForAnnotation不输出正确标注

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