ini

  public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_login);

        inputEmail = (EditText) findViewById(R.id.email);
        inputPassword = (EditText) findViewById(R.id.password);
        btnLogin = (Button) findViewById(R.id.btnLogin);
        btnLinkToRegister = (Button) findViewById(R.id.btnLinkToRegisterScreen);


        pDialog = new ProgressDialog(this);
        pDialog.setCancelable(false);


        db = new SQLiteHandler(getApplicationContext());


        session = new SessionManager(getApplicationContext());


        if (session.isLoggedIn()) {
            Intent intent = new Intent(LoginActivity.this, MainActivity.class);
            startActivity(intent);
            finish();
        }


        btnLogin.setOnClickListener(new View.OnClickListener() {

            public void onClick(View view) {
                String email = inputEmail.getText().toString().trim();
                String password = inputPassword.getText().toString().trim();


                if (!email.isEmpty() && !password.isEmpty()) {
                    checkLogin(email, password);
                } else {
                    Toast.makeText(getApplicationContext(),
                            "Please enter the credentials!", Toast.LENGTH_LONG)
                            .show();
                }
            }

        });

        btnLinkToRegister.setOnClickListener(new View.OnClickListener() {

            public void onClick(View view) {
                Intent i = new Intent(getApplicationContext(),
                        RegisterActivity.class);
                startActivity(i);
                finish();
            }
        });

    }

    private void checkLogin(final String email, final String password) {
        String tag_string_req = "req_login";

        pDialog.setMessage("Logging in ...");
        showDialog();

        StringRequest strReq = new StringRequest(Method.POST,
                AppConfig.URL_LOGIN, new Response.Listener<String>() {

            @Override
            public void onResponse(String response) {
                Log.d(TAG, "Login Response: " + response.toString());
                hideDialog();

                try {
                    JSONObject jObj = new JSONObject(response);
                    boolean error = jObj.getBoolean("error");


                    if (!error) {
                        session.setLogin(true);
                        String uid = jObj.getString("uid");

                        JSONObject user = jObj.getJSONObject("user");
                        String name = user.getString("name");
                        String email = user.getString("email");
                        String created_at = user
                                .getString("created_at");

                        db.addUser(name, email, uid, created_at);

                        Intent intent = new Intent(LoginActivity.this,
                                MainActivity.class);
                        startActivity(intent);
                        finish();
                    } else {

                        String errorMsg = jObj.getString("error_msg");
                        Toast.makeText(getApplicationContext(),
                                errorMsg, Toast.LENGTH_LONG).show();
                    }
                } catch (JSONException e) {

                    e.printStackTrace();
                    Toast.makeText(getApplicationContext(), "Json error: " + e.getMessage(), Toast.LENGTH_LONG).show();

                }

            }
        }, new Response.ErrorListener() {

            @Override
            public void onErrorResponse(VolleyError error) {
                Log.e(TAG, "Login Error: " + error.getMessage());
                Toast.makeText(getApplicationContext(),
                        error.getMessage(), Toast.LENGTH_LONG).show();
                hideDialog();
            }
        }) {

            @Override
            protected Map<String, String> getParams() {
                // Posting parameters to login url
                Map<String, String> params = new HashMap<String, String>();
                params.put("email", email);
                params.put("password", password);

                return params;
            }

        };

        AppController.getInstance().addToRequestQueue(strReq, tag_string_req);
    }

    private void showDialog() {
        if (!pDialog.isShowing())
            pDialog.show();
    }

    private void hideDialog() {
        if (pDialog.isShowing())
            pDialog.dismiss();
    }