Login.java

package me.emkaha.e_amikomv31.activity;

import android.app.Activity;
import android.content.Intent;
import android.support.v7.app.AppCompatActivity;
import android.os.Bundle;
import android.view.View;
import android.widget.Button;
import android.widget.EditText;
import android.widget.Toast;

import com.android.volley.AuthFailureError;
import com.android.volley.Request;
import com.android.volley.Response;
import com.android.volley.VolleyError;
import com.android.volley.toolbox.StringRequest;

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

import java.util.HashMap;
import java.util.Map;

import me.emkaha.e_amikomv31.R;
import me.emkaha.e_amikomv31.app.AppConfig;
import me.emkaha.e_amikomv31.app.AppController;
import me.emkaha.e_amikomv31.helper.SessionManager;

public class Login extends Activity {

    private Button btnLogin;
    private EditText txtUsername, txtPassword;
    private SessionManager sessionManager;

    String uName, name, status, foto;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_login);btnLogin = (Button) findViewById(R.id.btnLogin);
        txtUsername = (EditText) findViewById(R.id.txtUsername);
        txtPassword = (EditText) findViewById(R.id.txtPassword);

        // Session Manager
        sessionManager = new SessionManager(getApplicationContext());

        // status user
        Toast.makeText(getApplicationContext(), "User Login Status: " + sessionManager.isLoggedIn(), Toast.LENGTH_SHORT).show();

        // Login button click event
        btnLogin.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View view) {
                // Tag used to cancel the request
                String tag_string_req = "req_login";

                StringRequest request = new StringRequest(Request.Method.POST, AppConfig.URL_LOGIN, new Response.Listener<String>() {
                    @Override
                    public void onResponse(String response) {
                        try {
                            JSONObject jsonObject = new JSONObject(response);
                            if (jsonObject.names().get(0).equals("dsn")) {
                                uName = jsonObject.getString("dsn");
                                name = jsonObject.getString("nama");
                                status = jsonObject.getString("jabatan");
                                foto = jsonObject.getString("foto");
                                sessionManager.createLoginSession(uName, name, status, foto);
                                Toast.makeText(getApplicationContext(), uName + "; " + name, Toast.LENGTH_SHORT).show();
                                Intent i = new Intent(getApplicationContext(), MainActivity.class);
                                startActivity(i);
                                finish();
                            } else if (jsonObject.names().get(0).equals("mhs")){
                                uName = jsonObject.getString("mhs");
                                name = jsonObject.getString("nama");
                                status = jsonObject.getString("jabatan");
                                foto = jsonObject.getString("foto");
                                sessionManager.createLoginSession(uName, name, status, foto);
                                Toast.makeText(getApplicationContext(), uName + "; " + name, Toast.LENGTH_SHORT).show();
                                Intent j = new Intent(getApplicationContext(), MainActivity.class);
                                startActivity(j);
                                finish();
                            } else if (jsonObject.names().get(0).equals("error")){
                                Toast.makeText(getApplicationContext(), jsonObject.getString("error"),Toast.LENGTH_SHORT).show();
                            } else {
                                Toast.makeText(getApplicationContext(), jsonObject.getString("empty"),Toast.LENGTH_SHORT).show();
                            }
                        } catch (JSONException e) {
                            e.printStackTrace();
                        }

                    }
                }, new Response.ErrorListener() {
                    @Override
                    public void onErrorResponse(VolleyError error) {

                    }
                }){
                    @Override
                    protected Map<String, String> getParams() throws AuthFailureError {
                        HashMap<String, String> hashMap = new HashMap<String, String>();
                        hashMap.put("username", txtUsername.getText().toString());
                        hashMap.put("password", txtPassword.getText().toString());

                        return hashMap;
                    }
                };

                AppController.getAppController().addToRequestQueue(request, tag_string_req);
            }
        });
    }

    @Override
    public void onBackPressed() {
//        super.onBackPressed();
    }
}