如何在Android中使用Java从php获取Json？

Question

I want to go through json and check each name to see if what I type in edittext will match with what i have in my json from get_user.php...

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


        JSONArray jArray = new JSONArray( );

        @Override protected void onPreExecute()
        { super.onPreExecute();
            pDialog = new ProgressDialog(LoginWithAccount.this);
            pDialog.setMessage("Attempting for login...");
            pDialog.setIndeterminate(false);
            pDialog.setCancelable(true);
            pDialog.show(); }
        @Override
        protected String doInBackground(String... params) {
            int success;
           //here i will get the name and password from my edittexts
            String username = EditName.getText().toString();
            String password = EditPassword.getText().toString();
            try {  
                List<NameValuePair> params2 = new ArrayList<NameValuePair>();

                params2.add(new BasicNameValuePair("nume", username));
                params2.add(new BasicNameValuePair("parola", password));
                Log.d("request!", "starting");
                JSONObject json = jsonParser.makeHttpRequest( LOGIN_URL, "POST", params2);
                Log.d("Login attempt", json.toString());
                success = json.getInt(TAG_SUCCESS);

                String nume_json, parola_json;

                if (success == 1)
                {
                    Log.d("Successfully Login!", json.toString());
                   // return json.getString(TAG_MESSAGE);
                    for(int i = 0 ; i<jArray.length() ;i++)
                    {Log.d("here1", json.toString());
                        json = jArray.getJSONObject(i);
                        nume_json = json.getString("nume");
                        parola_json = json.getString("parola");
                   //     Toast.makeText(LoginWithAccount.this,     nume_json, Toast.LENGTH_SHORT).show();
                        if ( EditName.getText().toString().matches(nume_json)&& EditPassword.getText().toString().matches(parola_json))
                        {  Log.d("yess", json.toString());
                            get_user_json = true;
                        }
                    }

                }
                else
                {
                  //  get_user_json = false;
                    return json.getString(TAG_MESSAGE);

                }
            } catch (JSONException e) {
                e.printStackTrace();
            }
            return null;
         }
        protected void onPostExecute(String message)
        { pDialog.dismiss();
            if (message != null)
            { Toast.makeText(LoginWithAccount.this, message, Toast.LENGTH_LONG).show();
            }
        }
    }

What am I doing wrong? I can't go through the json to check each name, my json has only names and passwords, but I can't check them.

Answer 1

why are you not waiting for the complete result to be fetched from the url? should not it be checked in onPostExecute? and why are you getting edittext values inside the doinbackground method? the ui related things should be done in other places. Using a common public static variable to store them and then using them would be a better approach. Let's say you have an activity Login.java and you have an AsyncTask class LoginAsyncTask.java. Now, get the values of edittexts(that is your id and password) in two variables. Now instantiate an object of the loginasynctask class and send the context, uid and pwd values in it's constructor. In onPreexecute of the asynctask, create your progressdialog. In doinbackground hit the url you need to hit, to get the values. Use connection timeout, socket timeout and general exception. Create another method for parsing the json return. Create a simple arraylist to store all the returned and parsed values. In onpostExecute call this json parsing method. Now, run a loop and check for the match. Use an interface method for creating a proper callback to your activity. If a match was found set a (maybe boolean or a string "success" or "failure")value to the parameter of the interface's method. Implement the interface on the activity and in the overridden method check for the value came(that boolean or string). Take action accordingly. Hope this helps.