使用Sencha Touch的移动应用程序-JSON请求生成语法错误 [英] Mobile Application Using Sencha Touch - JSON Request Generates Syntax Error

问题描述

我开始使用Sencha Touch玩一些游戏.

I started playing a bit with Sencha Touch.

因此，我基于其中一个示例构建了一个非常简单的应用程序，以了解其运行方式.

So I've built a really simple application based on one of the examples just to see how it goes.

基本上，它创建一个JSON请求，该请求执行Last.FM Web服务以获取用户位置附近的音乐事件.

Basically it creates a JSON Request which executes a Last.FM web service to get music events near the user's location.

这是JSON代码:

var makeJSONPRequest = function() {
        Ext.util.JSONP.request({
        url: 'http://ws.audioscrobbler.com/2.0/',
            params: {
                method: 'geo.getEvents',
                location: 'São+Paulo+-+SP',
                format: 'json',
                callback: 'callback',
                api_key: 'b25b959554ed76058ac220b7b2e0a026'
            },
            callback: function(result) {
                var events = result.data.events;
                if (events) {
                    var html = tpl.applyTemplate(events);
                    Ext.getCmp('content').update(html);                        
                }
                else {
                    alert('There was an error retrieving the events.');
                }
                Ext.getCmp('status').setTitle('Events in Sao Paulo, SP');
            }
        })
    };

但是每次我尝试运行它时，都会出现以下异常:

But every time I try to run it, I get the following exception:

未捕获到的SyntaxError:意外令牌:

Uncaught SyntaxError: Unexpected token :

有人知道吗?

推荐答案

几件事.首先，"Uncaught SyntaxError: Unexpected token :"表示浏览器JavaScript引擎抱怨放置在错误位置的冒号":".

A couple of things. First of all the "Uncaught SyntaxError: Unexpected token :" means the browser javascript engine is complaining about a colon ":" that has been put in the wrong place.

问题很可能出在返回的JSON中.由于服务器返回的所有内容都将通过javascript中的eval("{JSON HTTP RESULT}")函数运行，因此最有可能的问题是您的问题在某个地方.

The problem will most likely be in the returned JSON. Since whatever the server returns will be run though the eval("{JSON HTTP RESULT}") function in javascript, the most likely thing is that your problem is in there somewhere.

我已经将您的代码放在了一个sencha测试工具上，并发现了一些问题.

I've put your code on a little sencha test harness and found a couple of problems with it.

首先:我的浏览器对location: 'São+Paulo+-+SP',中的弯曲ã"不太满意，因此我不得不将其更改为location: 'Sao+Paulo,+Brazil',，并且可以从audioscribbler API中返回正确的结果.

First: My browser was not too happy with the "squiggly ã" in location: 'São+Paulo+-+SP', so I had to change this to location: 'Sao+Paulo,+Brazil', which worked and returned the correct results from the audioscribbler API.

第二步::我注意到您在请求参数中添加了callback: 'callback',行，该行更改了HTTP结果的性质并返回JSON，如下所示:

Second: I notice you added a callback: 'callback', line to your request parameters, which changes the nature of the HTTP result and returns the JSON as follows:

callback({ // a function call "callback(" gets added here
   "events":{
      "event":[
         {
            "id":"1713341",
            "title":"Skank",
            "artists":{
               "artist":"Skank",
               "headliner":"Skank"
            },
         // blah blah more stuff
      "@attr":{
         "location":"Sao Paulo, Brazil",
         "page":"1",
         "totalpages":"1",
         "total":"2"
      }
   }
}) // the object gets wrapped with extra parenthesis here

我认为您应该使用callbackKey: 'callback'，而不是这样做. rel ="nofollow"> http://dev.sencha.com/deploy/touch/examples/ajax/index.js .

Instead of doing that I think you should be using the callbackKey: 'callback' that comes with the example in http://dev.sencha.com/deploy/touch/examples/ajax/index.js.

例如这样的东西:

   Ext.util.JSONP.request({
        url: 'http://ws.audioscrobbler.com/2.0/',
            params: {
                method: 'geo.getEvents',
                location: 'Sao+Paulo,+Brazil',
                format: 'json',
                api_key: 'b25b959554ed76058ac220b7b2e0a026'
            },
            callbackKey: 'callback',
            callback: function(result) {
                 // Output result to console (Firebug/Chrome/Safari)
                 console.log(result);
                 // Handle error logic
                 if (result.error) {
                    alert(result.error)
                    return;
                 }
                 // Continue your code
                var events = result.data.events;
                // ...
            }
        });

对我有用，所以希望对您也有用. Cherio.

That worked for me so hopefully it'll work for you too. Cherio.

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