如何在GMSMapView中获取动画折线路径，以便在移动地图时它与地图一起移动？

问题描述

我已经通过以下代码创建了像CAShapeLayer这样的动画折线，我已经将CAShapeLayer添加为GMSMapiew的子图层，但是，如果我移动地图，图层将不会移动。在哪里添加图层，以便它与地图一起移动？

I have created animated polyline like CAShapeLayer by following code, I have added CAShapeLayer as sublayer to GMSMapiew but, if I move the map the layer won't moves. where to add the layer, so that it move along with map?

   func layer(from path: GMSPath) -> CAShapeLayer {
        let breizerPath = UIBezierPath()
        let firstCoordinate: CLLocationCoordinate2D = path.coordinate(at: 0)
        breizerPath.move(to: self.mapView.projection.point(for: firstCoordinate))
        for i in 1 ..< Int((path.count())){
            print(path.coordinate(at: UInt(i)))
            let coordinate: CLLocationCoordinate2D = path.coordinate(at: UInt(i))
            breizerPath.addLine(to: self.mapView.projection.point(for: coordinate))
        }

        let shapeLayer = CAShapeLayer()
        shapeLayer.path = breizerPath.reversing().cgPath
        shapeLayer.strokeColor = UIColor.green.cgColor
        shapeLayer.lineWidth = 4.0
        shapeLayer.fillColor = UIColor.clear.cgColor
        shapeLayer.lineJoin = kCALineJoinRound
        shapeLayer.lineCap = kCALineCapRound
        shapeLayer.cornerRadius = 5
        return shapeLayer
    }

    func animatePath(_ layer: CAShapeLayer) {
        let pathAnimation = CABasicAnimation(keyPath: "strokeEnd")
        pathAnimation.duration = 6
        //pathAnimation.delegate = self
        pathAnimation.timingFunction = CAMediaTimingFunction(name: kCAMediaTimingFunctionEaseOut)
        pathAnimation.fromValue = Int(0.0)
        pathAnimation.toValue = Int(1.0)
        pathAnimation.repeatCount = 100
        layer.add(pathAnimation, forKey: "strokeEnd")
    }

通过

    let shapelayer: CAShapeLayer = self.layer(from: path!)
    self.animatePath(shapelayer)
    self.mapView.layer.addSublayer(shapelayer)

推荐答案

我创建 GMSPath 路径坐标

目标C

界面

@interface MapWithTracking ()

@property (weak, nonatomic) IBOutlet GMSMapView *mapView;

@property (nonatomic,strong) GMSMutablePath *path2;

@property (nonatomic,strong)NSMutableArray *arrayPolylineGreen;

@property (nonatomic,strong) GMSPolyline *polylineBlue;

@property (nonatomic,strong) GMSPolyline *polylineGreen;

@end

实施

-(void)viewDidLoad {
    _arrayPolylineGreen = [[NSMutableArray alloc] init];
    _path2 = [[GMSMutablePath alloc]init];
}

获取 GMSPath 并创建一条蓝色折线。

Get a GMSPath and create a blue polyline.

-(void)createBluePolyline(GMSPath *path) {

       // Here create a blue poly line
      _polylineBlue = [GMSPolyline polylineWithPath:path];
      _polylineBlue.strokeColor = [UIColor blueColor];
      _polylineBlue.strokeWidth = 3;
      _polylineBlue.map = _mapView;

       // animate green path with timer
       [NSTimer scheduledTimerWithTimeInterval:0.003 repeats:true block:^(NSTimer * _Nonnull timer) {
             [self animate:path];
       }];

}

为绿色折线设置动画

向路径2添加坐标并分配到地图

Adding coordinate to path 2 and assign to map

-(void)animate:(GMSPath *)path {

    dispatch_async(dispatch_get_main_queue(), ^{
        if (i < path.count) {
            [_path2 addCoordinate:[path coordinateAtIndex:i]];
            _polylineGreen = [GMSPolyline polylineWithPath:_path2];
            _polylineGreen.strokeColor = [UIColor greenColor];
            _polylineGreen.strokeWidth = 3;
            _polylineGreen.map = _mapView;
            [arrayPolylineGreen addObject:_polylineGreen];
            i++;
        }
        else {
            i = 0;
            _path2 = [[GMSMutablePath alloc] init];

            for (GMSPolyline *line in arrayPolylineGreen) {
                line.map = nil;
            }

        }
    });
}

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