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我正在尝试使用 android httpget 调用此 URL 以获得 json 方向数组：http://maps.googleapis.com/maps/api/directions/json?origin=Adelaide,SA&destination=Adelaide,SA&waypoints=optimize： true%7cBarossa+Valley,SA%7cClare,SA%7cConnawarra,SA%7cMcLaren+Vale,SA&sensor=false "

基本上这是我到目前为止所做的：

1）我首先创建了一个异步任务，以便调用谷歌方向并记录检索到的结果：

public class MyTask extends AsyncTask<String, Integer, String> {

@Override
protected String doInBackground(String... params) {

InputStream is = null;

    String result = null;

try{

        HttpClient httpclient = new DefaultHttpClient();
         HttpGet httpget = new HttpGet(params[0]);
         HttpResponse response = httpclient.execute(httpget);
         HttpEntity entity = response.getEntity();
         int lenght = (int) entity.getContentLength();

         StringBuffer buffer = new StringBuffer(lenght);

         is = entity.getContent();
         }catch(Exception e){
             Log.e("log_tag", "Error in http connection"+e.toString());
        }

    try{
        BufferedReader reader = new BufferedReader(new InputStreamReader(is,"iso-8859-1"),8);

         StringBuilder sb = new StringBuilder();
         sb.append(reader.readLine() + "\n");

         String line="0";
         while ((line = reader.readLine()) != null) {
                        sb.append(line + "\n");
          }
          is.close();
        result = sb.toString();
          }catch(Exception e){
                Log.e("log_tag", "Error converting result "+e.toString());
          }

    Log.i("Result", result);


    return result;



  }


}

2）在主活动中，我将执行传递给它的异步任务 url ： 

    MyTask t = new MyTask();
    t.execute(urlString.toString());

其中 urlString 是一个 StringBuilder。我尝试以多种方式构建该地址，即使尝试使用 URLEncoder.encode(myUrl) 对其进行编码，但我总是得到一个异常，即http connectionjava.lang.NegativeArraySizeException 中的错误，我无法检索来自谷歌的 json 数据。如何正确格式化该网址？我的目标是达到与这个人相同的结果（在 json 部分）：http: //blog.synyx.de/2010/06/routing-driving-directions-on-android-part-1-get-the -路线/

谢谢！

4

2 回答 2

1

我终于明白了！我改变了调用谷歌网络服务的方式。基本上这部分：

     HttpClient httpclient = new DefaultHttpClient();
     HttpGet httpget = new HttpGet(params[0]);
     HttpResponse response = httpclient.execute(httpget);
     HttpEntity entity = response.getEntity();

用这种其他方式调用谷歌网络服务：

        HttpURLConnection urlConnection = null;
        url = new URL("http://maps.googleapis.com/maps/api/directions/json?origin=Adelaide,SA&destination=Adelaide,SA&waypoints=optimize:true%7cBarossa+Valley,SA%7cClare,SA%7cConnawarra,SA%7cMcLaren+Vale,SA&sensor=false");
        urlConnection = (HttpURLConnection) url.openConnection();
        urlConnection.setRequestMethod("GET");
        urlConnection.setDoOutput(true);
        urlConnection.setDoInput(true);
        is = urlConnection.getInputStream();
        urlConnection.connect();

然后我“链接”了 InputStreamReader 内的 Input Stream，Buffered Reader 内的 InputStreamReader，一切正常：

        InputStreamReader inputStream = new InputStreamReader(is);
        BufferedReader r = new BufferedReader(inputStream);
        String line = null;
        line = r.readLine();
        while (line!=null){

            Log.i("RESULT", line);

            line = r.readLine();

        }

通过这种方式，我能够记录所需的结果。我想了解的一件事是为什么 httpclient 不起作用，但 httpURLConnection 却起作用。谁能帮我？

于 2012-05-31T10:35:37.493 回答
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只需删除有问题的代码，因为它没有在任何地方使用？

//int lenght = (int) entity.getContentLength();

//StringBuffer buffer = new StringBuffer(lenght);
于 2012-05-31T09:52:39.220 回答