从距离矩阵Javascript API的回调函数访问类属性
这是我的代码:从距离矩阵Javascript API的回调函数访问类属性,javascript,google-distancematrix-api,Javascript,Google Distancematrix Api,这是我的代码: declare var google; var service = new google.maps.DistanceMatrixService(); class BranchesPage { public branches: any = []; public allBranches: any = []; public travelDetails: any = []; constructor(){ this.getBranches();
declare var google;
var service = new google.maps.DistanceMatrixService();
class BranchesPage {
public branches: any = [];
public allBranches: any = [];
public travelDetails: any = [];
constructor(){
this.getBranches();
}
getBranches(){
this.travelDetails = [];
this.branchProvider.getBranches()
.subscribe(data => {
this.allBranches = data;
this.getBranchDistanceAndTime();
loadingBranches.dismiss();
}, err => {
console.log(err);
});
}
getBranchDistanceAndTime(){
for(let branch of this.allBranches){
this.getTravelDetails(branch);
}
}
getTravelDetails(branch){
service.getDistanceMatrix(
{
origins: [new google.maps.LatLng(6.870128,79.880340)],
destinations: [new google.maps.LatLng(branch.lat, branch.lng)],
travelMode: 'DRIVING'
}, this.callback);
}
callback(response, status) {
let travelDetailsObject;
if (status == 'OK') {
var origins = response.originAddresses;
var destinations = response.destinationAddresses;
for (var i = 0; i < origins.length; i++) {
var results = response.rows[i].elements;
for (var j = 0; j < results.length; j++) {
var element = results[j];
var distance = element.distance.text;
var duration = element.duration.text;
var from = origins[i];
var to = destinations[j];
travelDetailsObject = {
distance: distance,
duration: duration
}
}
}
console.log(travelDetailsObject)//this works perfectly retrieving the correct distances and durations
this.travelDetails.push(travelDetailsObject); //error is on this line
}
}
google;
var service=new google.maps.DistanceMatrixService();
类分支页面{
公共分支机构:任何=[];
公共所有分支机构:任何=[];
公共旅行详情:任何=[];
构造函数(){
这个.getBranchs();
}
getBranchs(){
this.travelDetails=[];
this.branchProvider.getBranchs()
.订阅(数据=>{
this.allbranchs=数据;
这个.getBranchDistanceAndTime();
loadingbranchs.disclose();
},err=>{
控制台日志(err);
});
}
getBranchDistanceAndTime(){
for(让此的分支。所有分支){
此.getTravelDetails(分支);
}
}
getTravelDetails(分支){
service.getDistanceMatrix(
{
来源:[新google.maps.LatLng(6.870128,79.880340)],
目的地:[新建google.maps.LatLng(branch.lat,branch.lng)],
travelMode:“驾驶”
},这是回调);
}
回调(响应、状态){
让我们的目标成为现实;
如果(状态=‘正常’){
var origins=response.originAddresses;
var destinations=response.destinationaddress;
对于(变量i=0;i
我无法从回调函数访问我的travelDetails属性,因为它引发以下异常uncaughtTypeError:无法读取null的属性“travelDetails”
由于某种原因,this
关键字在回调函数中不可用。有什么解决方法吗?我已经在这个问题上纠缠了一天多了。如果有任何帮助,我们将不胜感激
谢谢各位
PS:在任何人询问之前,
branch.lat
和branch.lng
正在按预期返回值。请尝试(r,s)=>{this.callback(r,s)}而不是this.callback
@tymeJV非常感谢您的回复。现在不存在错误,但我无法从回调函数外部访问推送元素。当我在函数外部输入console.log时,它会记录一个空数组:(这是一个异步函数-取决于您尝试访问它的时间,数组中可能有数据,也可能没有数据。getBranchDistanceAndTime
如果您想知道何时完成,应该进行回调或返回承诺。