Question

我正在开发Ionic应用程序。我的应用程序是从USGS获取数据json api地震，然后在Google地图上设置坐标。我正在遍历数组以创建标记。一切正常，但是当我单击任何图标标记时，都会得到重复的标题！

export class HomePage implements OnInit {
  protected points: { lng: number, lat: number }[] = [];

  items: any
  pet: string = "Today";
  map: GoogleMap;
  mags: number;

  constructor(
    private http: HTTP) {

  }

  async ngOnInit() {

    this.getData()

  }

  async getData() {

   this.http.get(`https://earthquake.usgs.gov/earthquakes/feed/v1.0/summary/all_hour.geojson`, {}, {}).then(data => {

      this.items = JSON.parse(data.data)
      let earth = JSON.parse(data.data)

      console.log(this.items)

      for (let datas of earth['features']) {

        this.points.push({ lng: datas.geometry.coordinates[0], lat: datas.geometry.coordinates[1] });

        let mag = datas.properties.place
        let title = datas.properties.title

       /// Marker icon

        let dest = this.points.map((coords) => {
          return this.map.addMarker({
            position: coords,
            icon: this.mags_icons
            title : title
          }).then((marker: Marker) => {

            marker.on(GoogleMapsEvent.MARKER_CLICK).subscribe(() => {

            });

          });
        });




        this.map = GoogleMaps.create('map_canvas');
      }

    })
  }

}

Answer 1

标记的实例化方式看起来不正确，因为在功能集合的每次迭代中，预置标记都在重新创建（这就是我猜测title引用相同标记的原因值）。

给出示例，以下示例演示了如何创建标记并设置title来引用适当的功能ptoperty：

getData() {
    this.http
      .get(
        `https://earthquake.usgs.gov/earthquakes/feed/v1.0/summary/all_hour.geojson`,{},{}
      )
      .then(data => {
        let geojson = JSON.parse(data.data);
        for (let feature of geojson["features"]) {
          let markerProps = {
            title: feature.properties.title,
            position: {
              lng: feature.geometry.coordinates[0],
              lat: feature.geometry.coordinates[1]
            }
          };

          let marker = this.map.addMarker(markerProps).then(marker => {
            marker.on(GoogleMapsEvent.MARKER_CLICK).subscribe(() => {
              //...
            });
          });
        }
      });
}

另一种选择是利用map.addMarkerSync函数：

let geojson = JSON.parse(data.data);
for (let feature of geojson["features"]) {
    let markerProps = {
      title: feature.properties.title,
      position: {
          lng: feature.geometry.coordinates[0],
          lat: feature.geometry.coordinates[1]
      }
    };

    let marker = this.map.addMarkerSync(markerProps);
    marker.on(GoogleMapsEvent.MARKER_CLICK).subscribe(() => {
        //...
    });
}

Google地图标记标题重复

1 个答案: