ios - 在 iOS swift 的谷歌地图中为多边形添加文本标签

Question

如何在 iOS 中的 Google map 的多边形上添加文本标签？我试图添加一个叠加层，但它只接受图像而不接受文本？我在 iOS 9 上使用 google maps for ios 和 Swift。

这是令我困扰的代码部分:

func updateUIMap(){

            var str = "Hello"
            var data = str.dataUsingEncoding(NSUTF8StringEncoding, allowLossyConversion: true)
            var drawText = NSString(data: data!, encoding: NSUTF8StringEncoding)
            let size = CGSize(width: 24.0,height: 24.0)

           var inImage = UIImage()
            var textColor: UIColor = UIColor.blackColor()
            var textFont: UIFont = UIFont(name: "Helvetica Bold", size: 12)!
            UIGraphicsBeginImageContext(size)
            let textFontAttributes = [
                NSFontAttributeName: textFont,
                NSForegroundColorAttributeName: textColor,
            ]

            inImage.drawInRect(CGRectMake(0, 0, size.width, size.height))

            var rect: CGRect = CGRectMake(24, 24, size.width, size.height)

            drawText.drawInRect(rect, withAttributes: textFontAttributes)

            var newImage: UIImage = UIGraphicsGetImageFromCurrentImageContext()


            UIGraphicsEndImageContext()

            var overlay = GMSGroundOverlay(position: myposition, icon: newImage, zoomLevel:20)
            overlay.bearing = 0
            overlay.map = self.mapView
}

Answer 1

您的UIGraphics绘图方法可能不正确，您可以尝试使用以下代码从文本制作新图像:

class ViewController: UIViewController {

    override func viewDidLoad() {
        super.viewDidLoad()

        super.viewDidLoad()

        let camera = GMSCameraPosition.cameraWithLatitude(40.712216,
            longitude: -74.22655, zoom: 10)
        let mapView = GMSMapView.mapWithFrame(CGRectZero, camera: camera)
        mapView.myLocationEnabled = true
        self.view = mapView

        addGroundOverlay(camera.target)
    }

    func newImage(text: String, size: CGSize) -> UIImage {

        let data = text.dataUsingEncoding(NSUTF8StringEncoding, allowLossyConversion: true)
        let drawText = NSString(data: data!, encoding: NSUTF8StringEncoding)

        let textFontAttributes = [
            NSFontAttributeName: UIFont(name: "Helvetica Bold", size: 20)!,
            NSForegroundColorAttributeName: UIColor.redColor(),
        ]

        UIGraphicsBeginImageContextWithOptions(size, false, 0)
        drawText?.drawInRect(CGRectMake(0, 0, size.width, size.height), withAttributes: textFontAttributes)
        let newImage = UIGraphicsGetImageFromCurrentImageContext()
        UIGraphicsEndImageContext()

        return newImage
    }

    func addGroundOverlay(position: CLLocationCoordinate2D) {

        let overlay = GMSGroundOverlay(position: position, icon: newImage("Hello StackOverflow", size: CGSizeMake(150.0, 150.0)), zoomLevel: 10)
        overlay.bearing = 0
        overlay.map = (self.view as! GMSMapView)
    }

    override func didReceiveMemoryWarning() {
        super.didReceiveMemoryWarning()
        // Dispose of any resources that can be recreated.
    }

}