Question

我正在尝试从网页读取JSON字符串，但是获取类型为org.json.JSONObject的错误jsonexception无法转换为JSONArray。

final static String URL =“http://www2.park.se/~ts5124/”;

@Override
public void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    tv = (TextView)findViewById(R.id.text1);
    client = new DefaultHttpClient();
    new Read().execute("JSON");


    if (logged=="yes") {
        setContentView(R.layout.main);
    } else {
        setContentView(R.layout.login);
        b1 = (Button)findViewById(R.id.btn);
        name = (EditText)findViewById(R.id.name);
        pass = (EditText)findViewById(R.id.password);



        b1.setOnClickListener(new OnClickListener() {
            @Override
            public void onClick(View arg0) {
                // TODO Auto-generated method stub


                 try {
                     JSONObject json = new JSONObject();
                     HttpClient httpclient = new DefaultHttpClient();
                     HttpPost httppost = new HttpPost("http://www2.park.se/~ts5124/login.php");



                     json.put("userName", name.getText().toString());
                     json.put("password", pass.getText().toString());

                     StringEntity se;
                     se = new StringEntity(json.toString(), "UTF-8");

                     // Add your data
                     httppost.setEntity(se);
                     httppost.setHeader("Accept", "application/json");
                     httppost.setHeader("Content-type", "application/json");


                     Log.i(TAG, json.toString());

                     // Execute HTTP Post Request
                     httpclient.execute(httppost);

                 } catch (JSONException je) {


                 } catch (IOException e) {
                     // TODO Auto-generated catch block
                 }
            }
        });
    }


}

public JSONObject getData(String page) throws ClientProtocolException, IOException, JSONException {
    StringBuilder url = new StringBuilder(URL);
    url.append(page);

    HttpGet get = new HttpGet(url.toString());
     HttpResponse r = client.execute(get);
     int status = r.getStatusLine().getStatusCode();
     if (status == 200) {
        HttpEntity e = r.getEntity();
        String data = EntityUtils.toString(e);
        JSONArray timeline = new JSONArray(data);
        JSONObject last = timeline.getJSONObject(0);
        return last;
     } else {
         Log.i("JSON","Ain't workin'");
         return null;
     }
  }

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

    @Override
    protected String doInBackground(String... params) {
       try {
          json = getData("send.php");
          return json.getString(params[0]);
       } catch (ClientProtocolException e) {
          return e.toString();
       } catch (IOException e) {
          return e.toString();
       } catch (JSONException e) {
          return e.toString();
       }
    }

    @Override
    protected void onPostExecute(String result) {
       tv.setText(result);
    }
  }

http://pastebin.com/dUnmsEd6我在logcat中得到这个，当我调试时说：ors.json.JSONObject类型的jsonexception无法转换为JSONArray

Answer 1

尝试做：

JSONArray timeline = new JSONArray(data);
String s = timeline.get(0).toString();
JSONObject last = new JSONObject(s);

如果JSON String在数组中只有一个元素，请注意。如果要从服务器发布JSON字符串响应以进行分析。

尝试使用onProgressUpdate：

protected void onProgressUpdate(String... result){
tv.setText(result[0]);
}

并在最后调用doInBackground：

publishProgress(json.getString("JSON"));

Answer 2

        // getting JSON string from URL
        JSONObject json = jParser.getJSONFromUrl(uri.toString());

        try {
            //Obter objeto JSON
            clientesJSONArray = json.optJSONArray(Clientes.TABELA);

            //Se for 1 objeto não virá em JSONArray - Os objetos em JSON são separados
            //por colchetes [] - No caso de um objeto, não será array e sim um simples
            //objeto em JSON
            if(clientesJSONArray==null){
                // means item is JSONObject instead of JSONArray
                //json = obj.optJSONObject("offerRideResult");
                JSONObject obj = json.getJSONObject(Clientes.TABELA);

                Clientes oCliente = new Clientes();
                oCliente.setCliente(obj.getString(Clientes.CLIENTE));
                oCliente.setCod_cliente(obj.getInt(Clientes.COD_CLIENTE));
                oCliente.setE_mail(obj.getString(Clientes.E_MAIL));
                oCliente.setUsuario(obj.getString(Clientes.USUARIO));
                oCliente.setUsuario(obj.getString(Clientes.SENHA));


                clientesList.add(oCliente);

            }else{
                // Mais de um objeto JSON separado por colchetes [] - JSONArray ao invés JSONObject
                for (int i = 0; i < clientesJSONArray.length(); i++) {

                    JSONObject obj = clientesJSONArray.getJSONObject(i);
                    Clientes oCliente = new Clientes();
                    oCliente.setCliente(obj.getString(Clientes.CLIENTE));
                    oCliente.setCod_cliente(obj.getInt(Clientes.COD_CLIENTE));
                    oCliente.setE_mail(obj.getString(Clientes.E_MAIL));
                    oCliente.setUsuario(obj.getString(Clientes.USUARIO));
                    oCliente.setUsuario(obj.getString(Clientes.SENHA));


                    clientesList.add(oCliente);


                }
            }

类型org.json.JSONObject的jsonexception无法转换为JSONArray

2 个答案: