Question

我正在尝试使用android httpget调用此URL以获得方向的json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“

基本上这就是我到目前为止所做的：

1）我首先创建了一个asynctask，以便调用google指令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Activity中，我将执行异步任务，将url：

传递给它

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

其中urlString是StringBuilder。我尝试用几种方法构建该地址，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，这是 http connectionjava.lang.NegativeArraySizeException中的错误< / em> ，我无法从谷歌检索json数据。如何正确格式化该网址？我的目标是获得与这个家伙相同的结果（在json部分）：http://blog.synyx.de/2010/06/routing-driving-directions-on-android-part-1-get-the-route/

谢谢！

Answer 1

我终于明白了！我改变了调用google webservice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();

用另一种方式调用google webservice：

        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“锁定”InputStreamReader中的输入流，缓冲读取器内的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，我可以记录所需的结果。我想了解的一件事是为什么httpclient不起作用，而httpURLConnection则改为。谁能帮我？

Answer 2

只是删除有问题的代码，因为它没有在任何地方使用过吗？

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

//StringBuffer buffer = new StringBuffer(lenght);

在android中调用httpget时出错（检索谷歌指示）

2 个答案: