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Displays a map of the south Pacific Ocean with an animation of red and green
polylines changing their position and size.
Get started
Before you can try the sample code, you must configure your development environment.
For more information, seeMaps SDK for iOS code samples.
View the code
Swift
importGoogleMapsimportUIKitfinalclassPolylinesViewController:UIViewController{privatelazyvarstyles:[GMSStrokeStyle]={letgreenStyle=GMSStrokeStyle.gradient(from:.green,to:UIColor.green.withAlphaComponent(0))letredStyle=GMSStrokeStyle.gradient(from:UIColor.red.withAlphaComponent(0),to:.red)return[greenStyle,redStyle,GMSStrokeStyle.solidColor(UIColor(white:0,alpha:0))]}()privatevarpathLength:Double=0privatevarpos:Double=0privatevarpolylines:[GMSPolyline]=[]privatelazyvarmapView:GMSMapView={letcamera=GMSCameraPosition(latitude:-30,longitude:-175,zoom:3)returnGMSMapView(frame:.zero,camera:camera)}()overridefuncloadView(){view=mapViewmapView.accessibilityElementsHidden=true}overridefuncviewDidLoad(){super.viewDidLoad()varpath=GMSMutablePath()path.addLatitude(-33.866901,longitude:151.195988)path.addLatitude(-18,longitude:179)path.addLatitude(21.291982,longitude:-157.821856)path.addLatitude(37.423802,longitude:-122.091859)path.addLatitude(-12,longitude:-77)path.addLatitude(-33.866901,longitude:151.195988)path=path.pathOffset(byLatitude:-30,longitude:0)pathLength=path.length(of:.geodesic)/21foriin0..<30{letpolyline=GMSPolyline(path:path.pathOffset(byLatitude:Double(i)*1.5,longitude:0))polyline.strokeWidth=8polyline.geodesic=truepolyline.map=mapViewpolylines.append(polyline)}animatePath()}// Updates the path style every 0.1 seconds.privatefuncanimatePath(){polylines.forEach{ifletpath=$0.path{$0.spans=GMSStyleSpansOffset(path,styles,[NSNumber(value:pathLength)],.geodesic,pos)}}pos-=50000DispatchQueue.main.asyncAfter(deadline:DispatchTime.now()+0.1){self.animatePath()}}}
The Maps SDK for iOS sample app is available as adownload archivefromGitHub.
Follow these steps to install and try the Maps SDK for iOS sample app.
Rungit clone https://github.com/googlemaps-samples/maps-sdk-for-ios-samples.gitto clone the samples repository into a local directory.
Open a terminal window, navigate to the directory where you cloned the sample files, and
drill down into the GoogleMaps directory:
Swift
cd maps-sdk-for-ios-samples-main/GoogleMaps-Swiftpod installopen GoogleMapsSwiftDemos.xcworkspace
Objective-C
cd maps-sdk-for-ios-samples-main/GoogleMapspod installopen GoogleMapsDemos.xcworkspace
In Xcode, press the compile button tobuild the appwith the current scheme. The build produces an error, prompting you to enter your API key
in theSDKConstants.swiftfile for Swift orSDKDemoAPIKey.hfile for Objective-C.
Edit theSDKConstants.swiftfile for Swift orSDKDemoAPIKey.hfile for Objective-C and paste your API key into the definition of either theapiKeyorkAPIKeyconstant. For example:
Swift
static let apiKey = "YOUR_API_KEY"
Objective-C
staticNSString*constkAPIKey=@"YOUR_API_KEY";
In theSDKConstants.swiftfile (Swift) orSDKDemoAPIKey.hfile (Objective-C), remove the following line, because it's used to register the user-defined issue:
Swift
#error (Register for API Key and insert here. Then delete this line.)
Objective-C
#error Register for API Key and insert here.
Build and run the project. The iOS simulator window appears, showing
a list ofMaps SDK Demos.
Choose one of the options displayed, to experiment with a feature of the
Maps SDK for iOS.
If prompted to allow GoogleMapsDemos to access your location, chooseAllow.
[[["Easy to understand","easyToUnderstand","thumb-up"],["Solved my problem","solvedMyProblem","thumb-up"],["Other","otherUp","thumb-up"]],[["Missing the information I need","missingTheInformationINeed","thumb-down"],["Too complicated / too many steps","tooComplicatedTooManySteps","thumb-down"],["Out of date","outOfDate","thumb-down"],["Samples / code issue","samplesCodeIssue","thumb-down"],["Other","otherDown","thumb-down"]],["Last updated 2025-09-04 UTC."],[[["\u003cp\u003eThis sample demonstrates animating the style of a polyline on a map using the Google Maps SDK for iOS.\u003c/p\u003e\n"],["\u003cp\u003eThe animation is achieved by dynamically updating the \u003ccode\u003eGMSStyleSpansOffset\u003c/code\u003e of the polylines based on position and style.\u003c/p\u003e\n"],["\u003cp\u003eThe sample code provides implementations in both Swift and Objective-C.\u003c/p\u003e\n"],["\u003cp\u003eYou can clone the sample app repository, install dependencies via CocoaPods, build the project, and run it on an iOS simulator.\u003c/p\u003e\n"],["\u003cp\u003eEnsure to obtain and configure your API key before building and running the sample app.\u003c/p\u003e\n"]]],[],null,["Displays a map of the south Pacific Ocean with an animation of red and green polylines changing their position and size.\n\nGet started\n\nBefore you can try the sample code, you must configure your development environment.\nFor more information, see [Maps SDK for iOS code samples](/maps/documentation/ios-sdk/examples).\n\nView the code \n\nSwift \n\n```swift\nimport GoogleMaps\nimport UIKit\n\nfinal class PolylinesViewController: UIViewController {\n private lazy var styles: [GMSStrokeStyle] = {\n let greenStyle = GMSStrokeStyle.gradient(from: .green, to: UIColor.green.withAlphaComponent(0))\n let redStyle = GMSStrokeStyle.gradient(from: UIColor.red.withAlphaComponent(0), to: .red)\n return [greenStyle, redStyle, GMSStrokeStyle.solidColor(UIColor(white: 0, alpha: 0))]\n }()\n private var pathLength: Double = 0\n private var pos: Double = 0\n private var polylines: [GMSPolyline] = []\n\n private lazy var mapView: GMSMapView = {\n let camera = GMSCameraPosition(latitude: -30, longitude: -175, zoom: 3)\n return GMSMapView(frame: .zero, camera: camera)\n }()\n\n override func loadView() {\n view = mapView\n mapView.accessibilityElementsHidden = true\n }\n\n override func viewDidLoad() {\n super.viewDidLoad()\n\n var path = GMSMutablePath()\n path.addLatitude(-33.866901, longitude: 151.195988)\n path.addLatitude(-18, longitude: 179)\n path.addLatitude(21.291982, longitude: -157.821856)\n path.addLatitude(37.423802, longitude: -122.091859)\n path.addLatitude(-12, longitude: -77)\n path.addLatitude(-33.866901, longitude: 151.195988)\n path = path.pathOffset(byLatitude: -30, longitude: 0)\n pathLength = path.length(of: .geodesic) / 21\n for i in 0..\u003c30 {\n let polyline = GMSPolyline(path: path.pathOffset(byLatitude: Double(i) * 1.5, longitude: 0))\n polyline.strokeWidth = 8\n polyline.geodesic = true\n polyline.map = mapView\n polylines.append(polyline)\n }\n animatePath()\n }\n\n // Updates the path style every 0.1 seconds.\n private func animatePath() {\n polylines.forEach {\n if let path = $0.path {\n $0.spans = GMSStyleSpansOffset(path, styles, [NSNumber(value: pathLength)], .geodesic, pos)\n }\n }\n pos -= 50000\n\n DispatchQueue.main.asyncAfter(deadline: DispatchTime.now() + 0.1) {\n self.animatePath()\n }\n }\n}https://github.com/googlemaps-samples/maps-sdk-for-ios-samples/blob/86408feffd008565cd2cafce8aff3dc27f1f41bb/GoogleMaps-Swift/GoogleMapsSwiftDemos/Swift/Samples/PolylinesViewController.swift#L14-L72\n \n```\n\nObjective-C \n\n```objective-c\n#import \"GoogleMapsDemos/Samples/PolylinesViewController.h\"\n\n#import \u003cGoogleMaps/GoogleMaps.h\u003e\n\nstatic CLLocationCoordinate2D kSydneyAustralia = {-33.866901, 151.195988};\nstatic CLLocationCoordinate2D kHawaiiUSA = {21.291982, -157.821856};\nstatic CLLocationCoordinate2D kFiji = {-18, 179};\nstatic CLLocationCoordinate2D kMountainViewUSA = {37.423802, -122.091859};\nstatic CLLocationCoordinate2D kLimaPeru = {-12, -77};\nstatic bool kAnimate = true;\n\n@implementation PolylinesViewController {\n NSArray *_styles;\n NSArray *_lengths;\n NSArray *_polys;\n double _pos, _step;\n GMSMapView *_mapView;\n}\n\n- (void)tick {\n for (GMSPolyline *poly in _polys) {\n poly.spans = GMSStyleSpansOffset(poly.path, _styles, _lengths, kGMSLengthGeodesic, _pos);\n }\n _pos -= _step;\n if (kAnimate) {\n __weak id weakSelf = self;\n dispatch_after(dispatch_time(DISPATCH_TIME_NOW, NSEC_PER_SEC / 10), dispatch_get_main_queue(),\n ^{\n [weakSelf tick];\n });\n }\n}\n\n- (void)initLines {\n if (!_polys) {\n NSMutableArray *polys = [NSMutableArray array];\n GMSMutablePath *path = [GMSMutablePath path];\n [path addCoordinate:kSydneyAustralia];\n [path addCoordinate:kFiji];\n [path addCoordinate:kHawaiiUSA];\n [path addCoordinate:kMountainViewUSA];\n [path addCoordinate:kLimaPeru];\n [path addCoordinate:kSydneyAustralia];\n path = [path pathOffsetByLatitude:-30 longitude:0];\n _lengths = @[ @([path lengthOfKind:kGMSLengthGeodesic] / 21) ];\n for (int i = 0; i \u003c 30; ++i) {\n GMSPolyline *poly = [[GMSPolyline alloc] init];\n poly.path = [path pathOffsetByLatitude:(i * 1.5) longitude:0];\n poly.strokeWidth = 8;\n poly.geodesic = YES;\n poly.map = _mapView;\n [polys addObject:poly];\n }\n _polys = polys;\n }\n}\n\n- (void)viewDidLoad {\n [super viewDidLoad];\n GMSCameraPosition *camera = [GMSCameraPosition cameraWithLatitude:-30 longitude:-175 zoom:3];\n GMSMapView *mapView = [GMSMapView mapWithFrame:CGRectZero camera:camera];\n mapView.accessibilityElementsHidden = YES;\n self.view = mapView;\n _mapView = mapView;\n\n CGFloat alpha = 1;\n UIColor *green = [UIColor colorWithRed:0 green:1 blue:0 alpha:alpha];\n UIColor *greenTransp = [UIColor colorWithRed:0 green:1 blue:0 alpha:0];\n UIColor *red = [UIColor colorWithRed:1 green:0 blue:0 alpha:alpha];\n UIColor *redTransp = [UIColor colorWithRed:1 green:0 blue:0 alpha:0];\n GMSStrokeStyle *grad1 = [GMSStrokeStyle gradientFromColor:green toColor:greenTransp];\n GMSStrokeStyle *grad2 = [GMSStrokeStyle gradientFromColor:redTransp toColor:red];\n _styles = @[\n grad1,\n grad2,\n [GMSStrokeStyle solidColor:[UIColor colorWithWhite:0 alpha:0]],\n ];\n _step = 50000;\n [self initLines];\n [self tick];\n}\n\n@end \nhttps://github.com/googlemaps-samples/maps-sdk-for-ios-samples/blob/86408feffd008565cd2cafce8aff3dc27f1f41bb/GoogleMaps/GoogleMapsDemos/Samples/PolylinesViewController.m#L16-L98\n\n \n```\n\nRun the full sample app locally\n\nThe Maps SDK for iOS sample app is available as a\n[download archive](https://github.com/googlemaps-samples/maps-sdk-for-ios-samples/archive/main.zip)\nfrom [GitHub](https://github.com/googlemaps-samples/maps-sdk-for-ios-samples/tree/main/GoogleMaps).\nFollow these steps to install and try the Maps SDK for iOS sample app.\n\n1. Run `git clone https://github.com/googlemaps-samples/maps-sdk-for-ios-samples.git` to clone the samples repository into a local directory.\n2. Open a terminal window, navigate to the directory where you cloned the sample files, and\n drill down into the GoogleMaps directory:\n\n Swift \n\n cd maps-sdk-for-ios-samples-main/GoogleMaps-Swift\n pod install\n open GoogleMapsSwiftDemos.xcworkspace\n\n Objective-C \n\n cd maps-sdk-for-ios-samples-main/GoogleMaps\n pod install\n open GoogleMapsDemos.xcworkspace\n\n3. In Xcode, press the compile button to [build the app](https://developer.apple.com/documentation/xcode/building-and-running-an-app) with the current scheme. The build produces an error, prompting you to enter your API key in the `SDKConstants.swift` file for Swift or`SDKDemoAPIKey.h` file for Objective-C.\n4. [Get an API key](/maps/documentation/ios-sdk/get-api-key) from your project with the [Maps SDK for iOS enabled](/maps/documentation/ios-sdk/cloud-setup#enabling-apis).\n5. Edit the `SDKConstants.swift` file for Swift or`SDKDemoAPIKey.h` file for Objective-C and paste your API key into the definition of either the `apiKey` or `kAPIKey` constant. For example: \n\n Swift \n\n ```scdoc\n static let apiKey = \"YOUR_API_KEY\"\n ```\n\n Objective-C \n\n ```objective-c\n static NSString *const kAPIKey = @\"YOUR_API_KEY\";\n ```\n6. In the `SDKConstants.swift` file (Swift) or`SDKDemoAPIKey.h` file (Objective-C), remove the following line, because it's used to register the user-defined issue: \n\n Swift \n\n ```text\n #error (Register for API Key and insert here. Then delete this line.)\n ```\n\n Objective-C \n\n ```text\n #error Register for API Key and insert here.\n ```\n7. Build and run the project. The iOS simulator window appears, showing a list of **Maps SDK Demos**.\n8. Choose one of the options displayed, to experiment with a feature of the Maps SDK for iOS.\n9. If prompted to allow GoogleMapsDemos to access your location, choose **Allow**."]]
