Ionic2应用程序中的Google地图

Question

我正在构建一个Ionic2应用程序，其中有一个Google地图。 我需要：

1. 绘制多边形
2. 计算它的面积
3. 应该能够删除多边形

基本上，我需要完全按照这里的同一个解决方案：calculate area of a drawn polygon on google map javascript

到目前为止，我转换了打字稿中的整个代码，它几乎可以工作。但有一个问题：

• 当我完成第一次绘制多边形时，区域显示在UI上。如果在这一点上，我修改我的形状区域不更新。看到gif图像。
• 如果我点击地图上的任何地方，然后再绘制形状并对其进行修改，则会针对每个后续修改计算面积。

我在做什么错？

我的组件代码：

import { Component } from '@angular/core'; 
import { NavController, Platform } from 'ionic-angular'; 


@Component({ 
    templateUrl: 'build/pages/start/start.html' 
}) 

export class StartPage { 

    selectedShape: any; 

    constructor(private navController : NavController, private platform : Platform) { 

    this.initializeMap(); 

    } 

    clearSelection = (shape): void => { 

    if(shape) { 
     shape.setEditable(false); 
     shape = null; 
     this.selectedShape=shape 
    } 
    } 

    setSelection = (shape): void => { 

    this.clearSelection(shape); 
    var shape = shape; 
    this.selectedShape=shape; 

    console.log(shape.getPath()) 

    shape.setEditable(true); 
    google.maps.event.addListener(shape.getPath(), 'set_at',()=>{this.calcar(shape)}); 
    google.maps.event.addListener(shape.getPath(), 'insert_at',()=>{this.calcar(shape)}); 
    } 

    calcar= (shape): void => { 

    var shape = shape 

    var area = google.maps.geometry.spherical.computeArea(shape.getPath()); 
    document.getElementById("area").innerHTML = "Area =" + area.toFixed(2); 

    this.selectedShape=shape 
    } 

    deleteSelectedShape =(): void => { 

    if (this.selectedShape) { 
     this.selectedShape.setMap(null); 
    } 
    } 

    initializeMap =(): void => { 

    var newShape 
    var map 
    var drawingManager 

    this.platform.ready().then(() => { 
     var minZoomLevel = 15; 

     map = new google.maps.Map(document.getElementById('map_canvas'), { 
     zoom: minZoomLevel, 
     center: new google.maps.LatLng(52.5200, 13.4050), 
     mapTypeId: google.maps.MapTypeId.ROADMAP, 
     disableDefaultUI: true, 
     zoomControl: true  
     }); 

     var polyOptions = { 
     strokeWeight: 0, 
     fillOpacity: 0.45, 
     editable: true 
     }; 

     drawingManager = new google.maps.drawing.DrawingManager({ 
     drawingControl: true, 
     drawingControlOptions: { 
      drawingModes: [ 
      google.maps.drawing.OverlayType.POLYGON, 
      ] 
     }, 
     polygonOptions: polyOptions, 
     map: map 
     }); 

     google.maps.event.addListener(drawingManager, 'overlaycomplete', (e) => { 

     this.selectedShape=e.overlay 

     if (e.type != google.maps.drawing.OverlayType.MARKER) { 
     // Switch back to non-drawing mode after drawing a shape. 
     drawingManager.setDrawingMode(null); 

     // Add an event listener that selects the newly-drawn shape when the user 
     // mouses down on it. 
     newShape = e.overlay; 
     newShape.type = e.type; 

     google.maps.event.addListener(newShape, 'click',()=> { 

     this.setSelection(newShape); 


     }); 

     var area = google.maps.geometry.spherical.computeArea(newShape.getPath()); 
     document.getElementById("area").innerHTML = "Area =" + area.toFixed(2); 

    () => {this.setSelection(newShape);} 
    } 
    }); 

     google.maps.event.addListener(map, 'click', ()=>{this.clearSelection(newShape);}); 
     google.maps.event.addDomListener(document.getElementById('delete-button'), 'click', ()=>{this.deleteSelectedShape();}); 

    }); 

    } 

} 

Answer 1

你的错误就设在这里：

var area = google.maps.geometry.spherical.computeArea(newShape.getPath()); 
    document.getElementById("area").innerHTML = "Area =" + area.toFixed(2); 

() => {this.setSelection(newShape);} <== this line 
} 

你不叫setSelection功能。这是一样的：

function() { 
    this.setSelection(newShape); 
}; 

您需要使用以下方法：

this.setSelection(newShape); 

又见working plunker