public class Register extends AppCompatActivity {

private static final String TAG = Register.class.getSimpleName();
ProgressDialog progressDialog;
private EditText signupInputName, signupInputEmail, signupInputPassword;
public Button btnSignUp;
public Button btnLinkLogin;
private SQLiteHandler db;


@Override
protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_register);
    Toolbar toolbar = (Toolbar) findViewById(R.id.toolbar);
    setSupportActionBar(toolbar);

    progressDialog = new ProgressDialog(this);
    progressDialog.setCancelable(false);
    SessionManager  session = new SessionManager(getApplicationContext());
    db = new SQLiteHandler(getApplicationContext());

    // Check if user is already logged in or not
    if (session.isLoggedIn()) {
        // User is already logged in. Take him to main activity
        Intent intent = new Intent(Register.this,
                Matchboard.class);
        startActivity(intent);
        finish();
    }

    signupInputName = (EditText) findViewById(R.id.name);
    signupInputEmail = (EditText) findViewById(R.id.email);
    signupInputPassword = (EditText) findViewById(R.id.password);
    btnSignUp = (Button) findViewById(R.id.btnRegister);
    btnLinkLogin = (Button) findViewById(R.id.btnLinkToLoginScreen);


    btnSignUp.setOnClickListener(new View.OnClickListener() {
        @Override
        public void onClick(View view) {
            String name = signupInputName.getText().toString().trim();
            String email = signupInputEmail.getText().toString().trim();
            String password = signupInputPassword.getText().toString().trim();

            if (!name.isEmpty() && !email.isEmpty() && !password.isEmpty()) {
                registerUser(name, email, password);
            } else {
                Toast.makeText(getApplicationContext(),
                        "Please enter your details!", Toast.LENGTH_SHORT).show();
            }
        }
    });
    btnLinkLogin.setOnClickListener(new View.OnClickListener() {
        @Override
        public void onClick(View view) {

            Intent i = new Intent(getApplicationContext(),Login.class);
            startActivity(i);
            finish();
        }
    });
}




private void registerUser(final String name,  final String email, final String password) {
    // Tag used to cancel the request
    String tag_string_req = "req_register";

    progressDialog.setMessage("Adding you ...");
    showDialog();

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

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

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

                if (!error) {

                    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");

                    // Inserting row in users table
                    db.addUser(name, email, uid, created_at);

                     Toast.makeText(getApplicationContext(), "Hi "+name+",You are successfully Added!", Toast.LENGTH_SHORT).show();

                    // Launch login activity
                    Intent intent = new Intent(
                            Register.this,
                            Login.class);
                    startActivity(intent);
                    finish();

                } else {

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

        }
    }, new Response.ErrorListener() {

        @Override
        public void onErrorResponse(VolleyError error) {
            Log.e(TAG, "Registration Error: " + error.getMessage());
            Toast.makeText(getApplicationContext(),
                    error.getMessage(), Toast.LENGTH_SHORT).show();
            hideDialog();
        }
    }) {
        @Override
        protected Map<String, String> getParams() {
            // Posting params to register url
            Map<String, String> params = new HashMap<String, String>();
            params.put("name", name);
            params.put("email", email);
            params.put("password", password);

            return params;
        }
    };
    // Adding request to request queue
    AppController.getInstance().addToRequestQueue(strReq, tag_string_req);
}

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

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