Logging into a website using Android app (Java)

Question

I am currently trying to make an app that would allow you to log into your account and view whatever data needs to be displayed.

I am not using webview but instead,

Answer 1

I am not sure what you are trying to do by logging the content of the WebPage there. What you need to do first is check if the "browser" has Javascript enabled but in your case this is moot because you are using your own WebView. It would still be wise to just check if JS is enabled.

The next step obviously involves using JS since I asked you to check if it is enabled. Here is the code but note I did nor test this but it is a step in the right direction:

    public void loginUser(View view) {

        InputMethodManager inputMan = (InputMethodManager) getSystemService(Context.INPUT_METHOD_SERVICE);
        imm.hideSoftInputFromWindow(layout.getWindowToken(), 0);


        webView.loadUrl("https://yourwebsite.net");
        webView.setVisibility(View.INVISIBLE);
        webView.setWebViewClient(new WebViewClient() {

            public void onPageFinished(WebView view, String url) {
                webView.loadUrl("javascript: {" + "document.getElementById('login_account').value = '" + "USERNAME" + "';" + "document.getElementById('login_password').value = '" + "PASSWORD" + "';" + "document.getElementById('submit').click();" + "};");
                 }

            public void onPageFinished2(WebView view, String url) {
                webView.loadUrl(url);
            }
        });

        webView.clearCache(true);
        webView.clearHistory();


    WebView webView2 = (WebView) this.findViewById(R.id.web_view);

    String url = "https://yourwebsite.net";
    webView2.loadUrl(url);

}

Some points to note: change the values login_account and login_password to something that a person cannot easily guess for security.

Answer 2

Here is the solution to this:

class HTTPRequest implements Runnable {

    private URL url;
    private User user;
    private Handler handler;
    private String cookie;

    //**REDEFINED CONSTRUCTOR
    HTTPRequest(Handler in_handler, User in_user) {
        try {
                        url = new URL("https://yoururl.com");

            handler = in_handler;
            user = in_user;
        } catch (MalformedURLException e) {
            e.printStackTrace();
        }
    }

    @Override
    public void run() {
        try {
            //**Preparing to open connection
            //**Using POST method
            //**Enabling Input & Output
            HttpsURLConnection conn = (HttpsURLConnection) url.openConnection();
            conn.setRequestMethod("POST");
            conn.setDoInput(true);
            conn.setDoOutput(true);

            //**Setting Headers to send with POST request
            conn.setRequestProperty("Accept", "text/html");
            conn.setRequestProperty("Accept", "text/xml");
            conn.setRequestProperty("Cookie", "upassword=" + user.getPasswordHashed() + "; ulogin=" + user.getUsername());
            conn.setRequestProperty("Content-Type", "application/x-www-form-urlencoded");
            conn.setRequestProperty("charset", "UTF-8");
            conn.setRequestProperty("User-Agent", "Mozilla/5.0");

            //**READING RESPONSE FROM THE SERVER:
            //**IF LOGIN WAS SUCCESSFUL, SEND MESSAGE WITH XML DATA BACK TO UI THREAD, ELSE SEND NULL TO UI THREAD
            BufferedReader input = new BufferedReader(new InputStreamReader(conn.getInputStream()));

            if (isLoginSuccess(input)) {
                StringBuilder response = new StringBuilder();
                String tempString;
                while ((tempString = input.readLine()) != null) {
                    response.append(tempString);
                }
                input.close();
                conn.disconnect();

                Message msg = Message.obtain();
                msg.obj = response.toString();
                handler.sendMessage(msg);
            } else if (!isLoginSuccess(input)) {
                input.close();
                conn.disconnect();
                Message msg = Message.obtain();
                msg.obj = "Wrong";
                handler.sendMessage(msg);
            }

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

    //**LOGIN IS SUCCESSFUL WHEN THE RESPONSE'S FIRST LINE EQUALS XML DECLARATION
    //**RETURNS TRUE IF THAT IS THE CASE, MEANING YOU HAVE SUCCESSFULLY LOGGED IN
    private boolean isLoginSuccess(BufferedReader input) throws IOException {
        String LoginSuccess = "<?xml version=\"1.0\" encoding=\"utf-8\"?>";

        String response = input.readLine();
        return response.equals(LoginSuccess);
    }
}

MainActivity.java:

public class MainActivity extends AppCompatActivity {

    public static final String EXTRA_MESSAGE = "Message 1";
    public static final String EXTRA_MESSAGE_2 = "Message 2";
    Handler mainHandler;
    Thread thread;
    User user;

    EditText etUsername;
    EditText etPassword;
    CheckBox cbRememberMe;
    Button btLogin;

    SharedPreferences preferences;
    SharedPreferences.Editor SPEditor;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setTheme(R.style.LoginPageTheme);
        setContentView(R.layout.activity_main);

        //**DECLARATION OF SHARED PREFERENCES
        preferences = getApplicationContext().getSharedPreferences("Preferences", MODE_PRIVATE);
        SPEditor = preferences.edit();
        SPEditor.apply();

        //**HANDLER INSTANTIATING AND HANDLING MESSAGES FROM HTTPRequest
        mainHandler = new Handler(Looper.getMainLooper()) {
            @Override
            public void handleMessage(@NonNull Message msg) {
                String message = msg.obj.toString();
                thread.interrupt();
                if (!message.equals("Wrong")) {
                    if (cbRememberMe.isChecked()) {
                        user.RememberLoginSuccess(preferences);
                    }
                    Intent intent = new Intent(getApplicationContext(), ProfilePageActivity.class);
                    intent.putExtra(EXTRA_MESSAGE, message);
                    intent.putExtra(EXTRA_MESSAGE_2, user);
                    startActivity(intent);
                    finish();
                } else {
                    etUsername.setError("Wrong username or password");
                    etUsername.setText("");
                    etPassword.setText("");
                }
            }
        };

        etUsername = findViewById(R.id.et_username);
        etPassword = findViewById(R.id.et_password);
        cbRememberMe = findViewById(R.id.cb_rememberMe);
        btLogin = findViewById(R.id.bt_login);

        btLogin.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                String temp_user = etUsername.getText().toString();
                String temp_pass = etPassword.getText().toString();
                if (!TextUtils.isEmpty(temp_user) && !TextUtils.isEmpty(temp_pass)) {
                    user = new User(etUsername.getText().toString(), etPassword.getText().toString());
                    thread = new Thread(new HTTPRequest(mainHandler, user));
                    thread.start();
                } else {
                    etUsername.setError("Please, fill-out the form");
                    etUsername.setText("");
                    etPassword.setText("");
                }
            }
        });
    }
}