Question

我正在尝试解析一些JSON数据，但我的应用程序没有做任何事情，因为我似乎无法从URL获得任何响应，我试图以几种不同的方式打开URL连接，但它仍然是相同的。例如：

urlMy=new URL(string);
    URLConnection tc = urlMy.openConnection();
    BufferedReader in = new BufferedReader(new InputStreamReader(
            tc.getInputStream()));
    String line=in.readLine();

不会返回任何内容，它甚至会忽略我在该代码下面编写的函数中的所有内容。

或者

    urlMy=new URL(examp);
InputStream   inputStream = urlMy.openConnection().getInputStream();
InputStreamReader reader = new InputStreamReader(inputStream);
BufferedReader bR = new BufferedReader(reader);

同样的事情。这个函数被调用，就像它从未发生过一样，每个函数都执行后，所以它不在无限循环中，但是在这个示例代码之后的这个函数中的每一位代码都被忽略了。如果我删除此代码用于阅读网址，其他工作。

Answer 1

尝试使用AsyncTask，尝试类似：

class MyAsyncTask extends AsyncTask<String, String, Void> {

    private ProgressDialog progressDialog = new ProgressDialog(MainActivity.this);
    InputStream inputStream = null;
    String result = ""; 

    protected void onPreExecute() {
        progressDialog.setMessage("Downloading your data...");
        progressDialog.show();
        progressDialog.setOnCancelListener(new OnCancelListener() {
            public void onCancel(DialogInterface arg0) {
                MyAsyncTask.this.cancel(true);
            }
        });
    }

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

        String url_select = "http://yoururlhere.com"

                ArrayList<NameValuePair> param = new ArrayList<NameValuePair>();

        try {
            // Set up HTTP post

            // HttpClient is more then less deprecated. Need to change to URLConnection
            HttpClient httpClient = new DefaultHttpClient();

            HttpPost httpPost = new HttpPost(url_select);
            httpPost.setEntity(new UrlEncodedFormEntity(param));
            HttpResponse httpResponse = httpClient.execute(httpPost);
            HttpEntity httpEntity = httpResponse.getEntity();

            // Read content & Log
            inputStream = httpEntity.getContent();
        } catch (UnsupportedEncodingException e1) {
            Log.e("UnsupportedEncodingException", e1.toString());
            e1.printStackTrace();
        } catch (ClientProtocolException e2) {
            Log.e("ClientProtocolException", e2.toString());
            e2.printStackTrace();
        } catch (IllegalStateException e3) {
            Log.e("IllegalStateException", e3.toString());
            e3.printStackTrace();
        } catch (IOException e4) {
            Log.e("IOException", e4.toString());
            e4.printStackTrace();
        }
        // Convert response to string using String Builder
        try {
            BufferedReader bReader = new BufferedReader(new InputStreamReader(inputStream, "iso-8859-1"), 8);
            StringBuilder sBuilder = new StringBuilder();

            String line = null;
            while ((line = bReader.readLine()) != null) {
                sBuilder.append(line + "\n");
            }

            inputStream.close();
            result = sBuilder.toString();

        } catch (Exception e) {
            Log.e("StringBuilding & BufferedReader", "Error converting result " + e.toString());
        }
    } // protected Void doInBackground(String... params)


    protected void onPostExecute(Void v) {

        //parse JSON data
        try{
            JSONArray jArray = new JSONArray(result);

            for(i=0; i < jArray.length(); i++) {

                JSONObject jObject = jArray.getJSONObject(i);

                String name = jObject.getString("name");
                String tab1_text = jObject.getString("tab1_text");
                int active = jObject.getInt("active");


            } // End Loop

            this.progressDialog.dismiss();

        } catch (JSONException e) {

            Log.e("JSONException", "Error: " + e.toString());

        } // catch (JSONException e)


    } // protected void onPostExecute(Void v)

} //class MyAsyncTask extends AsyncTask<String, String, Void>

Answer 2

在上一次Google I / O中，Google发布了一个名为Volley的新库。它对HTTP请求来说很快，非常容易使用，您可以将其设置为返回准备好解析的JSONObjects。 https://developers.google.com/events/io/sessions/325304728

从URL读取JSON数据

2 个答案: