javascript - 从自定义 panoProvider 返回异步结果

Question

我知道这个问题在 SO 上有很多很多答案，但我一直没能找到适用于这种情况的答案。我正在异步调用 Google 服务并需要返回结果:

function getCustomPanorama(pano,zoom,tileX,tileY) {
    client.getPanoramaById(pano, function(result, status) {
        return {
            location: result.location,
            links: result.links,
            copyright: result.copyright+' BUT GREY',
            tiles: {
                tileSize: result.tiles.tileSize,
                worldSize: result.tiles.worldSize,
                centerHeading: result.tiles.centerHeading,
                getTileUrl: getCustomPanoramaTileUrl
                }
            };
        });
    }

我理解上面是错误的，不会返回，觉得需要用到回调，但是不明白在哪里。请注意，我无法更改传递给 getCustomPanorama 的内容。非常感谢所有帮助。

更新:完整代码:

var panorama;
var client;

$(document).ready(function() {
    var panoramaOptions = {
        position: new google.maps.LatLng(51.52241608253253, -0.10488510131835938),
        panoProvider: getCustomPanorama
        };
    client = new google.maps.StreetViewService();
    panorama = new google.maps.StreetViewPanorama(document.getElementById("pano"), panoramaOptions);
    });

function getCustomPanorama(pano,zoom,tileX,tileY) {
    client.getPanoramaById(pano, function(result, status) {
        return {
            location: result.location,
            links: result.links,
            copyright: result.copyright+' BUT GREY',
            tiles: {
                tileSize: result.tiles.tileSize,
                worldSize: result.tiles.worldSize,
                centerHeading: result.tiles.centerHeading,
                getTileUrl: getCustomPanoramaTileUrl
                }
            };
        });
    }

更新 2:

建议肯定是我正在尝试做一些不可能的事情，因此尝试另一种涉及预缓存 getPanoramaByID() 响应的方法。

Answer 1

更改 getCustomPanorama 以获取一个额外的回调参数，并传入一个函数来执行您需要对结果执行的操作:

function getCustomPanorama(pano,zoom,tileX,tileY,callback) {
    client.getPanoramaById(pano, function(result, status) {
        var data = {
          location: result.location,
          links: result.links,
          copyright: result.copyright+' BUT GREY',
          tiles: {
              tileSize: result.tiles.tileSize,
              worldSize: result.tiles.worldSize,
              centerHeading: result.tiles.centerHeading,
              getTileUrl: getCustomPanoramaTileUrl
          }
        };
        callback(data); // call the function and pass in the data you would have returned
    });
}

getCustomPanorama(pano,zoom,tileX,tileY,function(data) {
    // do something with the results of the asynchronous call here        
});