如何在 ng-bootstrap 模态中居中 ngx-leaflet 地图

Question

我想在 ng-bootstrap 模式中显示一个 ngx-leaflet 地图，以一个确定的点为中心。地图被封装在这样一个组件中：

HTML

<div class="modal-header">
  <h4 class="modal-title">Map</h4>
  <button type="button" class="close" aria-label="Close" 
      (click)="activeModal.dismiss('Cross click')">
      <span aria-hidden="true">&times;</span>
  </button>
</div>

<div class="modal-body">
  <div id="map" 
    leaflet
    [leafletOptions]="options"
    [leafletLayersControl]="layersControl"></div>
</div>

<div class="modal-footer">
  <button type="button" class="btn btn-outline-dark" (click)="activeModal.close('Close click')">Close</button>
</div>

TS

 constructor(public activeModal: NgbActiveModal) { }

  ngOnInit() {
  }

  streetMap = L.tileLayer('http://{s}.google.com/vt/lyrs=m&x={x}&y={y}&z={z}', {
    maxZoom: 20,
    subdomains: ['mt0', 'mt1', 'mt2', 'mt3']
  });

  hybridMap = L.tileLayer('http://{s}.google.com/vt/lyrs=s,h&x={x}&y={y}&z={z}', {
    maxZoom: 20,
    subdomains: ['mt0', 'mt1', 'mt2', 'mt3']
  });

  vehicleMarker = L.marker([40.4168, -3.703790], {
    icon: L.icon({
      iconSize: [25, 41],
      iconAnchor: [13, 41],
      iconUrl: 'assets/marker-icon.png',
      shadowUrl: 'assets/marker-shadow.png'
    })
  });

  layersControl = {
    baseLayers: {
      'Map view': this.streetMap,
      'Map hybrid': this.hybridMap
    },
    overlays: {
      'Vehicle': this.vehicleMarker
    }
  };

  options = {
    layers: [this.streetMap, this.vehicleMarker],
    zoom: 5,
    center: L.latLng([40.4168, -3.703790])
  };

在另一个组件中，我这样打开模式：

constructor(private modalService: NgbModal) { }

ngOnInit() {
}

openMap() {
    this.modalService.open(MapComponent);
}

模态外一切正常（地图以给定点为中心）但是当我在模态内渲染地图时地图不居中。我该如何解决这个问题？

我发现在小屏幕（如 Galaxy S5 360x460）中地图显示良好（居中）。

Answer 1

传单对页面布局和大小的变化非常敏感。一般当页面布局发生变化时需要调用Map.invalidateSize().

ngx-leaflet 自动跟踪 window 调整大小事件并为您调用 invalidateSize()，因此您通常不必担心。但是，当您使用 Bootstrap 或 JQuery 之类的东西独立于调整 window 的大小来操作页面布局时，您可能需要手动调用它。

首先，使用 README 中的说明获取对地图的引用： https://github.com/Asymmetrik/ngx-leaflet#getting-a-reference-to-the-map

<div leaflet
     [leafletOptions]="options"
     (leafletMapReady)="onMapReady($event)">
</div>

map: Map;
onMapReady(map: Map) {
   this.map = map;
}

然后，每当您 open/show/resize 地图模态时添加对 this.map.invalidateSize() 的调用。

如果这没有帮助，请在 GitHub 上提供一个重现问题的 angular CLI 项目，我可以仔细查看。

Answer 2

我是 Parham，为了解决 Angular 6 和 bootstrap Modal 中的这个问题，请使用此说明。今天用这条指令解决了我的问题。要更正此问题，应该在事件 (leafletMouseOver) 中使用方法 this.map.invalidateSize();。请从这里查看此示例代码。

    /* // In style.css add this class map */
.map {
  position: relative !important;
  width: 100%; height: 600px;
  margin: 2px;
  padding: 2px;
}

/*--------------------------------------------------------------------*/

// In Angular component .ts file

import { Component, EventEmitter, OnInit, Output } from '@angular/core';
import * as L from 'leaflet';

@Component({
  selector: 'app-map-control',
  template: 
    `<div class="map" leaflet
      (leafletMapReady)="onMapReady($event)"
      [leafletOptions]="options"
      (leafletMouseOver)="refreshMap()"
      style="border: black solid 1px;">
    </div>`
})

export class MapControlComponent {

  constructor() { }

  public map: L.Map = null;
  private latoLong: L.LatLngTuple = [35.706000, 51.4025000]; // for set static lat-long to map


  // Define our base layers so we can reference them multiple times
  streetMaps = L.tileLayer('https://{s}.tile.openstreetmap.org/{z}/{x}/{y}.png', {
    detectRetina: true,
    attribution: '&copy; <a href="https://www.openstreetmap.org/copyright">OpenStreetMap</a> contributors'
  });

  // Set the initial set of displayed layers (we could also use the leafletLayers input binding for this)
  options = {
    layers: [this.streetMaps],
    zoom: 17,
    center: L.latLng(this.latoLong)
  };

  @Output() outputLatLong = new EventEmitter<L.LatLngTuple>();

  refreshMap() {
    if (this.map) {
      // this.streetMaps.redraw();
      this.map.invalidateSize();
    }
  }

  onMapReady(map: L.Map) {
    map.on('click', (eventMouse: L.LeafletMouseEvent) => {
      this.latoLong = [eventMouse.latlng.lat, eventMouse.latlng.lng];
      map.setView(this.latoLong, map.getZoom());
      this.outputLatLong.emit(this.latoLong);
    });
    this.map = map;
  }

}

在您的组件应用程序中使用：

<app-map-control (outputLatLong)="getLatLong($event)"></app-map-control>

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