JSON-Daten aus PHP-Datei in Android-Anwendung lesen

Question

Ich bin nur ein Anfänger in der Entwicklung von Android-Anwendungen, ich wollte meine Anwendung mit einem Server verbinden, damit ich Daten von MySQL bekommen konnte. Also habe ich versucht, den Login-Teil zuerst zu machen, aber ich habe ein paar Probleme. Mein Code funktioniert nicht zum Lesen von JSON. meine Codes sind wie folgt: LoginActivity (MainActivity):

package ir.naserpour.sportclub; 

import android.content.Context; 
import android.graphics.Typeface; 
import android.os.AsyncTask; 
import android.os.Bundle; 
import android.support.v7.app.AppCompatActivity; 
import android.view.View; 
import android.widget.Button; 
import android.widget.CheckBox; 
import android.widget.EditText; 
import android.widget.TextView; 
import android.widget.Toast; 

import org.json.JSONArray; 
import org.json.JSONException; 
import org.json.JSONObject; 

import java.io.UnsupportedEncodingException; 

import uk.co.chrisjenx.calligraphy.CalligraphyContextWrapper; 

public class LoginActivity extends AppCompatActivity { 

    String link; 
    String response; 
     //get values 
     String username,password; 
     @Override 
     protected void attachBaseContext (Context newBase){ 
     super.attachBaseContext(CalligraphyContextWrapper.wrap(newBase)); 
    } 
     @Override 
     protected void onCreate (Bundle savedInstanceState){ 
     super.onCreate(savedInstanceState); 
     setContentView(R.layout.activity_login); 
      //define things 
      TextView menu = (TextView) findViewById(R.id.menu); 
      final EditText login_username = (EditText) findViewById(R.id.login_username); 
      final EditText login_password = (EditText) findViewById(R.id.login_password); 
      Button login_login = (Button) findViewById(R.id.login_login); 
      Button login_register = (Button)findViewById(R.id.login_register); 
      CheckBox rememberme = (CheckBox)findViewById(R.id.login_remeberme); 


     //set icon type face 
     Typeface fonticon = Typeface.createFromAsset(getAssets(), "fonts/icon.ttf"); 
     menu.setTypeface(fonticon); 

     login_login.setOnClickListener(new View.OnClickListener() { 
      @Override 
      public void onClick(View view) { 
       username = login_username.getText().toString(); 
       password = login_password.getText().toString(); 
       //check values 
       if (username.length() <1 || password.length() < 1) { 
        Toast.makeText(getApplicationContext(), "fields cannot be empty", Toast.LENGTH_SHORT).show(); 
       } else { 
        //generate link 
        link = "http://localhost:8080/login.php?username="+username+"&password="+password; 
        login(); 
        if(response=="true"){ 
         Toast.makeText(getApplicationContext(), "true", Toast.LENGTH_SHORT).show(); 
        }else if(response=="false"){ 
         Toast.makeText(getApplicationContext(), "false", Toast.LENGTH_SHORT).show(); 
        }else{ 
         Toast.makeText(getApplicationContext(), "response", Toast.LENGTH_SHORT).show(); 
        } 
       } 
      } 
     }); 


    } 

     @Override 
     protected void onPause() { 
     super.onPause(); 
     finish(); 
    } 

    public String login() { 

     new JSONParse().execute(); 
     return response; 
    } 

    public class JSONParse extends AsyncTask<String, String, JSONObject> { 


     @Override 
     public void onPreExecute() { 
      super.onPreExecute(); 
      Toast.makeText(getApplicationContext(),"getting data ...",Toast.LENGTH_SHORT).show(); 
     } 

     @Override 
     public JSONObject doInBackground(String... args) { 
      JSONParser jParser = new JSONParser(); 
      // Getting JSON from URL 
      JSONObject json = jParser.getJSONFromUrl(link); 
      return json; 
     } 

     @Override 
     public void onPostExecute(JSONObject json) { 
      try { 
       JSONArray result = json.getJSONArray("result"); 
       JSONObject c = result.getJSONObject(0); 
       try { 
        String res = new String(c.getString("response").getBytes("ISO-8859-1"), "UTF-8"); 
        response = res; 
       } catch (UnsupportedEncodingException e) { 
        e.printStackTrace(); 
       } 

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

     } 
    } 
} 

JSONParser.java:

package ir.naserpour.sportclub; 

import android.util.Log; 

import org.apache.http.HttpEntity; 
import org.apache.http.HttpResponse; 
import org.apache.http.client.ClientProtocolException; 
import org.apache.http.client.methods.HttpPost; 
import org.apache.http.impl.client.DefaultHttpClient; 
import org.json.JSONException; 
import org.json.JSONObject; 

import java.io.BufferedReader; 
import java.io.IOException; 
import java.io.InputStream; 
import java.io.InputStreamReader; 
import java.io.UnsupportedEncodingException; 

/** 
* Created by Mohammad Naserpour on 9/22/2016. 
*/ 
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; 
    } 
} 

und mein login.php Skript auch:

<?php 
define("HOST","localhost"); 
define("USERNAME","root"); 
define("PASSWORD",""); 
define("NAME","users"); 

$con = mysqli_connect(HOST,USERNAME,PASSWORD,NAME); 

$username = $_GET["username"]; 
$password = $_GET["password"]; 

$sql = "SELECT * FROM userinfo WHERE username ='$username' AND password='$password'"; 

$check = mysqli_fetch_array(mysqli_query($con,$sql)); 


if(isset($check)){ 
echo '{"result":[{"response":"true"}]}'; 
}else{ 
echo '{"result":[{"response":"false"}]}'; 
} 

mysqli_close($con); 

?> 

i wäre so glücklich, wenn ich das Problem finde. Danke.

Answer 1

siehe this Tutorial: sein ein komplettes Tutorial über Prozess Login google volley

Answer 2

Erste Verwendung: Auf Geräteseite, Verwenden Volley, ihren einfache und leicht

Zweitens zu verwenden: Auf Server, was {"result":[{"response":"true"}]} ist

jedes Problem mit {"result":true} ??

Last but not least: Haben Sie JSON schon benutzt oder ist dieser Code ein Versuch und eine Error Copy Paste aus einigen Tutorials?