Question

我正在从服务器加载一组自定义注释，并希望使用以下代码将它们添加到地图中。当应用程序位于前台时，注释仅在10秒左右时出现在地图上。但是，当我进入主屏幕（应用程序在后台）然后返回应用程序时，它们会立即出现。当应用程序位于前台时，如何能够立即显示这些注释？

我从服务器获取自定义注释数组，并尝试将它们添加到地图中，如下所示：

if UIApplication.sharedApplication().applicationState == .Active {
self.myMap.showAnnotations(self.these_new_pins, animated: true)
}

我的mapView viewForAnnotation如下所示：

func mapView(mapView: MKMapView!, viewForAnnotation annotation: MKAnnotation!) -> MKAnnotationView! {

if !(annotation is CustomPointAnnotation) {
                return nil
            }

            // ... otherwise continue executing function
            var pinView = mapView.dequeueReusableAnnotationViewWithIdentifier("pin")

            if pinView == nil {
                pinView = MKAnnotationView(annotation: annotation, reuseIdentifier: "pin")
                pinView!.canShowCallout = true
                pinView!.alpha = 0.97
                pinView!.centerOffset.y = -23

            }

            else {

                pinView!.annotation = annotation
            }


            let cpa = annotation as! CustomPointAnnotation

            // Pin color varies (user green, server blue)
                pinView!.image = UIImage(named: cpa.pin_image)

            // Add detail button to right callout
                var calloutButton = UIButton.buttonWithType(.System) as! UIButton
                var btnimage = UIImage(named: cpa.pin_btnimage)!

                    calloutButton.frame = CGRectMake(0, 0, 30, 30)
                    calloutButton.setBackgroundImage(btnimage, forState: UIControlState.Normal)

                pinView!.rightCalloutAccessoryView = calloutButton

            // Add detail button to left callout
                var optionsButton = UIButton.buttonWithType(.System) as! UIButton
                var btnimage_options = UIImage(named: cpa.pin_btnimage_options)

                    optionsButton.frame = CGRectMake(0, 0, 30, 30)
                    optionsButton.setBackgroundImage(btnimage_options, forState: UIControlState.Normal)

                pinView!.leftCalloutAccessoryView = optionsButton


            return pinView
        }

谢谢！

Answer 1

答案是从主线程调用showAnnotations（感谢Mozilla）。这是代码：

dispatch_async(dispatch_get_main_queue()) { if UIApplication.sharedApplication().applicationState == .Active { self.myMap.showAnnotations(self.these_new_pins, animated: true) } }

MapKit注释仅在前景延迟（或进入主屏幕和后退）后显示

1 个答案: