public class LoginActivity extends AppCompatActivity {

EditText username, password;
String Username, Password;
Context ctx = this;
String NAME = null, ADDRESS= null, MOBILE_NUMBER = null,USERNAME = null, PASSWORD = null, EMAIL = null;

@Override
protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_login);
    username = (EditText) findViewById(R.id.login_username);
    //mEmailView.setPaintFlags(mEmailView.getPaintFlags() | Paint.UNDERLINE_TEXT_FLAG);
    password = (EditText) findViewById(R.id.login_password);
    //mPasswordView.setPaintFlags(mPasswordView.getPaintFlags() | Paint.UNDERLINE_TEXT_FLAG)


}

 public void login_register(View v) {
    startActivity(new Intent(LoginActivity.this, RegisterActivity.class));
}

public void login_signin(View v) {
    Username = username.getText().toString();
    Password = password.getText().toString();
    BackGround b = new BackGround();
    b.execute(Username, Password);
}

class BackGround extends AsyncTask<String, String, String> {
    /**Button btn_register = (Button) findViewById(R.id.btn_register);
     btn_register.setOnClickListener(new OnClickListener() {
    @Override public void onClick(View v) {
    Intent i = new Intent(LoginActivity.this,RegisterActivity.class);
    startActivity(i);
    }
    }); */

    /** Button btn_signin = (Button) findViewById(R.id.btn_signin);
     btn_signin.setOnClickListener(new OnClickListener() {
    @Override public void onClick(View view) {
    Intent i = new Intent(LoginActivity.this,MenuActivity.class);
    startActivity(i);
    //buttonnya dsni tapi aksinya dibawah
    /** attemptLogin();
    }
    }); */

@Override
protected String doInBackground(String... params) {
    String username = params[0];
    String password = params[1];
    String data = "";
    int tmp;

    try {
        URL url = new URL("http://10.0.2.2/MYCODE/konserfutsal/login.php");
        String urlParams = "username="+username+"&password="+password;

        HttpURLConnection httpURLConnection = (HttpURLConnection) url.openConnection();
        httpURLConnection.setDoOutput(true);
        OutputStream os = httpURLConnection.getOutputStream();
        os.write(urlParams.getBytes());
        os.flush();
        os.close();

        InputStream is = httpURLConnection.getInputStream();
        while ((tmp = is.read()) != -1) {
            data += (char) tmp;
        }

        is.close();
        httpURLConnection.disconnect();

        return data;
    } catch (MalformedURLException e) {
        e.printStackTrace();
        return "Exception: " + e.getMessage();
    } catch (IOException e) {
        e.printStackTrace();
        return "Exception: " + e.getMessage();
    }
}
    @Override
    protected void onPostExecute (String s){
        String err = null;
        try {
            JSONObject root = new JSONObject(s);
            JSONObject user_data = root.getJSONObject("user_data");
            NAME = user_data.getString("name");
            EMAIL = user_data.getString("email");
            ADDRESS = user_data.getString("address");
            MOBILE_NUMBER = user_data.getString("mobile_number");
            USERNAME = user_data.getString("username");
            PASSWORD = user_data.getString("password");

        } catch (JSONException e) {
            e.printStackTrace();
            err = "Exception: " + e.getMessage();
        }

        Intent i = new Intent(ctx, MenuActivity.class);
        i.putExtra("name", NAME);
        i.putExtra("email", EMAIL);
        i.putExtra("address", ADDRESS);
        i.putExtra("mobile_number", MOBILE_NUMBER);
        i.putExtra("username", USERNAME);
        i.putExtra("password", PASSWORD);
        i.putExtra("err", err);
        startActivity(i);

    }
}
}

public class RegisterActivity extends AppCompatActivity {
EditText name, password, username, email, mobile_number, address;
String Name, Password, Username, Email, Mobile_number, Address;
Button btn_back;
Context ctx=this;
@Override
protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_register);
    name = (EditText) findViewById(R.id.register_name);
    email = (EditText) findViewById(R.id.register_email);
    address = (EditText) findViewById(R.id.register_address);
    mobile_number = (EditText) findViewById(R.id.register_mobile_number);
    username = (EditText) findViewById(R.id.register_username);
    password = (EditText) findViewById(R.id.register_pass);

    btn_back = (Button) findViewById(R.id.register_btn_back);
    btn_back.setOnClickListener(new View.OnClickListener() {
        @Override
        public void onClick(View v) {
            finish();
        }
    });
    }

public void register_register (View V){
        Name = name.getText().toString();
        Email = email.getText().toString();
        Address = address.getText().toString();
        Mobile_number = mobile_number.getText().toString();
        Username = username.getText().toString();
        Password = password.getText().toString();
        Background b = new Background();
        b.execute(Name, Email, Address, Mobile_number, Username, Password);
    }
 class Background extends AsyncTask<String, String, String> {
        @Override
        protected String doInBackground(String... params) {
            String name = params[0];
            String email = params[1];
            String address = params[2];
            String mobile_number = params[3];
            String username = params[4];
            String password = params[5];
            String data="";
            int tmp;

            try {
                URL url = new URL("http://10.0.2.2/MYCODE/konserfutsal/register.php");
                String urlParams = "name="+name+"&email="+email+"&address="+address+"&mobile_number="+mobile_number+"&username="+username+"&password="+password;

                HttpURLConnection httpURLConnection = (HttpURLConnection) url.openConnection();
                httpURLConnection.setDoOutput(true);
                OutputStream os = httpURLConnection.getOutputStream();
                os.write(urlParams.getBytes());
                os.flush();
                os.close();
                InputStream is = httpURLConnection.getInputStream();
                while((tmp=is.read())!=-1){
                    data+= (char)tmp;
                }
                is.close();
                httpURLConnection.disconnect();

                return data;

            } catch (MalformedURLException e) {
                e.printStackTrace();
                return "Exception: "+e.getMessage();
            } catch (IOException e) {
                e.printStackTrace();
                return "Exception: "+e.getMessage();
            }
        }

    @Override
    protected void onPostExecute(String s) {
        if(s.equals("")){
            s="Data saved successfully.";
        }
        Toast.makeText(ctx, s, Toast.LENGTH_LONG).show();
    }


}
}

<uses_permission android:name="android.permission.INETERNET" />
<uses-permission android:name="android.permission.ACCESS_NETWORK_STATE" />
<uses-permission android:name="android.permission.ACCESS_WIFI_STATE" />