swift - 绘制路径有MKMapView问题

Question

我正在尝试绘制一条路径(使用 MKMapView)。但是我有:

NSInvalidArgumentException ', reason:' *** - [NSMutableOrderedSet addObject:]: object can not be nil '.

我的这个按钮操作带有调用函数 stop 的 NSTimer

@IBAction func startRoute(sender: UIButton) {
    // Timer stop() function
    // Each 4 seconds
    timer = NSTimer.scheduledTimerWithTimeInterval(4.0, target: self, selector: #selector(ViewController.stop), userInfo: nil, repeats: true)
}

这是我的 stop() 函数，它放置一个“起点”并将当前位置添加到类型为 的名为 points 的向量中>var points: [CLLocationCoordinate2D] = [] 并使用 addOverlay 绘制路径。

func stop() {
    if (self.initialFlag == 0) {
        // Put flag to 1
        self.initialFlag = 1

        // Add a Annotation
        let sourceAnnotation = MKPointAnnotation()
        sourceAnnotation.title = "Start Point"
        sourceAnnotation.coordinate = (self.locationManager.location?.coordinate)!
        self.mapView.showAnnotations([sourceAnnotation], animated: true)                        
    }

    // Get current point location
    let currentLocation = CLLocationCoordinate2DMake((self.locationManager.location?.coordinate.latitude)!,(self.locationManager.location?.coordinate.longitude)!);

    // We add points every 4 seconds then draw the map points
    self.points.append(currentLocation)


    // Draw the path

    geodesic = MKGeodesicPolyline(coordinates: &points[0], count: points.count)

    // And I have the error in this line below.
    self.mapView.addOverlay(self.geodesic, level: .AboveRoads)

}

Answer 1

嘿，如果您没有足够的坐标来创建 MKGeodesicPolyline，它会抛出一个错误，我的解决方案就是它

if points.count > 1{
   geodesic = MKGeodesicPolyline(coordinates: &points[0], count: points.count)
   self.mapView.addOverlay(self.geodesic, level: .AboveRoads)
}