在地圖上繪製折線

顯示南太平洋的地圖，並以紅色和綠色多邊形動畫變更位置和大小。

開始使用

請務必先設定開發環境，再試用程式碼範例。詳情請參閱 Maps SDK for iOS 程式碼範例。

查看程式碼

Swift

import GoogleMaps
import UIKit

final class PolylinesViewController: UIViewController {
  private lazy var styles: [GMSStrokeStyle] = {
    let greenStyle = GMSStrokeStyle.gradient(from: .green, to: UIColor.green.withAlphaComponent(0))
    let redStyle = GMSStrokeStyle.gradient(from: UIColor.red.withAlphaComponent(0), to: .red)
    return [greenStyle, redStyle, GMSStrokeStyle.solidColor(UIColor(white: 0, alpha: 0))]
  }()
  private var pathLength: Double = 0
  private var pos: Double = 0
  private var polylines: [GMSPolyline] = []

  private lazy var mapView: GMSMapView = {
    let camera = GMSCameraPosition(latitude: -30, longitude: -175, zoom: 3)
    return GMSMapView(frame: .zero, camera: camera)
  }()

  override func loadView() {
    view = mapView
    mapView.accessibilityElementsHidden = true
  }

  override func viewDidLoad() {
    super.viewDidLoad()

    var path = 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) / 21
    for i in 0..<30 {
      let polyline = GMSPolyline(path: path.pathOffset(byLatitude: Double(i) * 1.5, longitude: 0))
      polyline.strokeWidth = 8
      polyline.geodesic = true
      polyline.map = mapView
      polylines.append(polyline)
    }
    animatePath()
  }

  // Updates the path style every 0.1 seconds.
  private func animatePath() {
    polylines.forEach {
      if let path = $0.path {
        $0.spans = GMSStyleSpansOffset(path, styles, [NSNumber(value: pathLength)], .geodesic, pos)
      }
    }
    pos -= 50000

    DispatchQueue.main.asyncAfter(deadline: DispatchTime.now() + 0.1) {
      self.animatePath()
    }
  }
}
PolylinesViewController.swift

Objective-C

#import "GoogleMapsDemos/Samples/PolylinesViewController.h"

#import <GoogleMaps/GoogleMaps.h>

static CLLocationCoordinate2D kSydneyAustralia = {-33.866901, 151.195988};
static CLLocationCoordinate2D kHawaiiUSA = {21.291982, -157.821856};
static CLLocationCoordinate2D kFiji = {-18, 179};
static CLLocationCoordinate2D kMountainViewUSA = {37.423802, -122.091859};
static CLLocationCoordinate2D kLimaPeru = {-12, -77};
static bool kAnimate = true;

@implementation PolylinesViewController {
  NSArray *_styles;
  NSArray *_lengths;
  NSArray *_polys;
  double _pos, _step;
  GMSMapView *_mapView;
}

- (void)tick {
  for (GMSPolyline *poly in _polys) {
    poly.spans = GMSStyleSpansOffset(poly.path, _styles, _lengths, kGMSLengthGeodesic, _pos);
  }
  _pos -= _step;
  if (kAnimate) {
    __weak id weakSelf = self;
    dispatch_after(dispatch_time(DISPATCH_TIME_NOW, NSEC_PER_SEC / 10), dispatch_get_main_queue(),
                   ^{
                     [weakSelf tick];
                   });
  }
}

- (void)initLines {
  if (!_polys) {
    NSMutableArray *polys = [NSMutableArray array];
    GMSMutablePath *path = [GMSMutablePath path];
    [path addCoordinate:kSydneyAustralia];
    [path addCoordinate:kFiji];
    [path addCoordinate:kHawaiiUSA];
    [path addCoordinate:kMountainViewUSA];
    [path addCoordinate:kLimaPeru];
    [path addCoordinate:kSydneyAustralia];
    path = [path pathOffsetByLatitude:-30 longitude:0];
    _lengths = @[ @([path lengthOfKind:kGMSLengthGeodesic] / 21) ];
    for (int i = 0; i < 30; ++i) {
      GMSPolyline *poly = [[GMSPolyline alloc] init];
      poly.path = [path pathOffsetByLatitude:(i * 1.5) longitude:0];
      poly.strokeWidth = 8;
      poly.geodesic = YES;
      poly.map = _mapView;
      [polys addObject:poly];
    }
    _polys = polys;
  }
}

- (void)viewDidLoad {
  [super viewDidLoad];
  GMSCameraPosition *camera = [GMSCameraPosition cameraWithLatitude:-30 longitude:-175 zoom:3];
  GMSMapView *mapView = [GMSMapView mapWithFrame:CGRectZero camera:camera];
  mapView.accessibilityElementsHidden = YES;
  self.view = mapView;
  _mapView = mapView;

  CGFloat alpha = 1;
  UIColor *green = [UIColor colorWithRed:0 green:1 blue:0 alpha:alpha];
  UIColor *greenTransp = [UIColor colorWithRed:0 green:1 blue:0 alpha:0];
  UIColor *red = [UIColor colorWithRed:1 green:0 blue:0 alpha:alpha];
  UIColor *redTransp = [UIColor colorWithRed:1 green:0 blue:0 alpha:0];
  GMSStrokeStyle *grad1 = [GMSStrokeStyle gradientFromColor:green toColor:greenTransp];
  GMSStrokeStyle *grad2 = [GMSStrokeStyle gradientFromColor:redTransp toColor:red];
  _styles = @[
    grad1,
    grad2,
    [GMSStrokeStyle solidColor:[UIColor colorWithWhite:0 alpha:0]],
  ];
  _step = 50000;
  [self initLines];
  [self tick];
}

@end
PolylinesViewController.m

在本機執行完整的範例應用程式

您可以從 GitHub 下載 Archives ，取得 Maps SDK for iOS 範例應用程式。請按照下列步驟安裝及試用 Maps SDK for iOS 範例應用程式。

  1. 執行 git clone https://github.com/googlemaps-samples/maps-sdk-for-ios-samples.git 將範例存放區複製到本機目錄。

  2. 開啟終端機視窗，前往複製範例檔案的目錄，然後深入 GoogleMaps 目錄：

    Swift

    cd maps-sdk-for-ios-samples-main/GoogleMaps-Swift
pod install
open GoogleMapsSwiftDemos.xcworkspace

    Objective-C

    cd maps-sdk-for-ios-samples-main/GoogleMaps
pod install
open GoogleMapsDemos.xcworkspace
  3. 在 Xcode 中按下編譯按鈕，即可使用目前的企劃書建構應用程式。建構作業會產生錯誤，提示您在 SDKConstants.swift 檔案 (Swift) 或 SDKDemoAPIKey.h 檔案 (Objective-C) 中輸入 API 金鑰。
  4. 取得 API 金鑰，並在啟用 Maps SDK for iOS 的專案中使用。
  5. 編輯 Swift 的 SDKConstants.swift 檔案或 Objective-C 的 SDKDemoAPIKey.h 檔案，然後將 API 金鑰貼到 apiKey 或 kAPIKey 常數的定義中。例如：

    Swift

    static let apiKey = "YOUR_API_KEY"

    Objective-C

    static NSString *const kAPIKey = @"YOUR_API_KEY";
  6. 在 SDKConstants.swift 檔案 (Swift) 或 SDKDemoAPIKey.h 檔案 (Objective-C) 中，移除下列行，因為這會用來註冊使用者定義的問題：

    Swift

    #error (Register for API Key and insert here. Then delete this line.)

    Objective-C

    #error Register for API Key and insert here.
  7. 建構並執行專案。iOS 模擬器視窗隨即顯示 Maps SDK 示範清單。
  8. 選擇其中一個顯示的選項，即可試用 Maps SDK for iOS 的功能。
  9. 如果系統提示您允許 GoogleMapsDemos 存取您的位置，請選擇「允許」。