我的jasonParser类无法从php Web Service获得响应

Question

Code:

Login Class

public class Login extends Activity  implements View.OnClickListener {
    ImageButton bLogin;
    EditText UserName;
    EditText PassWord;
    TextView Msg;
    String email, password;
    JSONParser jsonParser = new JSONParser();
    private static final String LOGIN_URL = "Example.com";
    private static final String TAG_SUCCESS = "success";
    private static final String TAG_MESSAGE = "message";
    private ProgressDialog pDialog;
    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_login);
        UserName = (EditText) findViewById(R.id.etUserName);
        PassWord = (EditText) findViewById(R.id.etPassword);
        bLogin = (ImageButton) findViewById(R.id.bLogin);
        Msg = (TextView) findViewById(R.id.tvMsg);
        bLogin.setOnClickListener(this);
    }
@Override
public boolean onCreateOptionsMenu(Menu menu) {
    // Inflate the menu; this adds items to the action bar if it is present.
    getMenuInflater().inflate(R.menu.login, menu);
    return true;
}

@Override
public boolean onOptionsItemSelected(MenuItem item) {
    // Handle action bar item clicks here. The action bar will
    // automatically handle clicks on the Home/Up button, so long
    // as you specify a parent activity in AndroidManifest.xml.
    int id = item.getItemId();
    if (id == R.id.action_settings) {
        return true;
    }
    return super.onOptionsItemSelected(item);
}

@Override
public void onClick(View v) {
    switch (v.getId()) {
        case R.id.bLogin:
            new AttemptLogin().execute();
            break;
        default:
            break;
    }
 }

AttemptLogin

class AttemptLogin extends AsyncTask<String, String, String> {

//three methods get called, first preExecture, then do in background, and once do
//in back ground is completed, the onPost execture method will be called.
boolean failure = false;

@Override
protected void onPreExecute() {
    super.onPreExecute();
    pDialog = new ProgressDialog(Login.this);
    pDialog.setMessage("Attempting login...");
    pDialog.setIndeterminate(false);
    pDialog.setCancelable(true);
    pDialog.show();

}

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

    int success;

    String username = UserName.getText().toString();

    String password = PassWord.getText().toString();

    try {

        // Building Parameters

        List<NameValuePair> params = new ArrayList<NameValuePair>();

        params.add(new BasicNameValuePair("Username", username));

        params.add(new BasicNameValuePair("Password", password));
        Log.d("request!", "starting");
        // getting product details by making HTTP request
        JSONObject json = jsonParser.makeHttpRequest(
                LOGIN_URL, "POST", params);

        // check your log for json response

   Log.d("Login attempt", json.toString());

       // Toast.makeText(Login.this,
               //(int) msg, Toast.LENGTH_LONG).show();
        // json success tag

        success = json.getInt(TAG_SUCCESS);

        if (success == -1) {
            Log.d("Login Failure!", json.getString(TAG_MESSAGE));

            return json.getString(TAG_MESSAGE);

        } else {
            Log.d("Login Successful!", json.toString());
            Intent i = new Intent(Login.this, com.Office.bilawalkhan.projectmanagment.Menu.class);
            finish();
            startActivity(i);
            return json.getString(TAG_MESSAGE);

        }
    } catch (JSONException e) {
        e.printStackTrace();

    }

    return null;


}

protected void onPostExecute(String file_url) {
    pDialog.dismiss();

    if (file_url != null) {

        Toast.makeText(Login.this, file_url, Toast.LENGTH_LONG).show();
    }
}
}
}

JSOnParser Class

public class JSONParser {
static InputStream is = null;
static JSONObject jObj = null;
static String json = "";

// constructor
public JSONParser() {

}

public JSONObject getJSONFromUrl(String url) {

    // Making HTTP request
    try {
        // defaultHttpClient
        DefaultHttpClient httpClient = new DefaultHttpClient();
        HttpPost httpPost = new HttpPost(url);
        HttpResponse httpResponse = httpClient.execute(httpPost);
        HttpEntity httpEntity = httpResponse.getEntity();
        is = httpEntity.getContent();

    } catch (UnsupportedEncodingException e) {
        e.printStackTrace();
    } catch (ClientProtocolException e) {
        e.printStackTrace();
    } catch (IOException e) {
        e.printStackTrace();
    }

    try {
        BufferedReader reader = new BufferedReader(new InputStreamReader(
                is, "iso-8859-1"), 8);
        StringBuilder sb = new StringBuilder();
        String line = null;
        while ((line = reader.readLine()) != null) {
            sb.append(line + "\n");
        }
        is.close();
        json = sb.toString();
    } catch (Exception e) {
        Log.e("Buffer Error", "Error converting result " + e.toString());
    }

    // try parse the string to a JSON object
    try {
        jObj = new JSONObject(json);
    } catch (JSONException e) {
        Log.e("JSON Parser", "Error parsing data " + e.toString());
    }

    // return JSON String
    return jObj;
}
public JSONObject makeHttpRequest(String url, String method,
                                  List<NameValuePair> params) {

    // Making HTTP request
    try {

        // check for request method
        if(method == "POST"){
            // request method is POST
            // defaultHttpClient
            DefaultHttpClient httpClient = new DefaultHttpClient();
            HttpPost httpPost = new HttpPost(url);
            httpPost.setEntity(new UrlEncodedFormEntity(params));

            HttpResponse httpResponse = httpClient.execute(httpPost);
            HttpEntity httpEntity = httpResponse.getEntity();
            is = httpEntity.getContent();

        }else if(method == "GET"){
            DefaultHttpClient httpClient = new DefaultHttpClient();
            String paramString = URLEncodedUtils.format(params, "utf-8");
            url += "?" + paramString;
            HttpGet httpGet = new HttpGet(url);

            HttpResponse httpResponse = httpClient.execute(httpGet);
            HttpEntity httpEntity = httpResponse.getEntity();
            is = httpEntity.getContent();
        }

    } catch (UnsupportedEncodingException e) {
        e.printStackTrace();
    } catch (ClientProtocolException e) {
        e.printStackTrace();
    } catch (IOException e) {
        e.printStackTrace();
    }

    try {
        BufferedReader reader = new BufferedReader(new InputStreamReader(
                is, "iso-8859-1"), 8);
        StringBuilder sb = new StringBuilder();
        String line = null;
        while ((line = reader.readLine()) != null) {
            sb.append(line + "\n");
        }
        is.close();
        json = sb.toString();
    } catch (Exception e) {
        Log.e("Buffer Error", "Error converting result " + e.toString());
    }

    // try parse the string to a JSON object
    try {
        jObj = new JSONObject(json);
    } catch (JSONException e) {
        Log.e("JSON Parser", "Error parsing data " + e.toString());
    }

    // return JSON String
    return jObj;

}
// constructor

}

Answer 1

You can refer http://www.androidhive.info/2012/01/android-login-and-registration-with-php-mysql-and-sqlite/

Or

You can use "Volley" library by google for faster and better networking . This library nicely plays with Json . This library makes easy to cancel request for url which is not possible in AsyncTask http://bon-app-etit.blogspot.in/2013/04/the-dark-side-of-asynctask.html .

Here are some examples of using Volley : http://www.androidhive.info/2014/05/android-working-with-volley-library-1/