AndroidHive Login/Registration tutorial modification

If you tried implementing the code from AndroidHive's tutorial (found here: http://www.androidhive.info/2012/01/android-login-and-registration-with-php-mysql-and-sqlite/), then you might have gotten a android.os.NetworkOnMainThreadException error when attempting to log in or register via the phone app. To fix this, you must use AsyncTasks to run the code that retrieves info from the website.

In LoginActivity.java, add this class:

private class MyAsyncTask extends AsyncTask<String, Void, JSONObject> {

	protected JSONObject doInBackground(String... params) {
		UserFunctions userFunction = new UserFunctions();
		if (params.length != 2)
			return null;
		JSONObject json = userFunction.loginUser(params[0], params[1]);
		return json;
	}

	protected void onPostExecute(JSONObject json) {
		try {
            if (json != null && json.getString(KEY_SUCCESS) != null) {
                loginErrorMsg.setText("");
                String res = json.getString(KEY_SUCCESS);
                if(Integer.parseInt(res) == 1){
                    // user successfully logged in
                    // Store user details in SQLite Database
                    DatabaseHandler db = new DatabaseHandler(getApplicationContext());
                    JSONObject json_user = json.getJSONObject("user");

                    // Clear all previous data in database
                    UserFunctions userFunction = new UserFunctions();
                    userFunction.logoutUser(getApplicationContext());
                    db.addUser(json_user.getString(KEY_NAME), json_user.getString(KEY_EMAIL), json.getString(KEY_UID), json_user.getString(KEY_CREATED_AT));

                    // Launch Dashboard Screen
                    Intent dashboard = new Intent(getApplicationContext(), DashboardActivity.class);

                    // Close all views before launching Dashboard
                    dashboard.addFlags(Intent.FLAG_ACTIVITY_CLEAR_TOP);
                    startActivity(dashboard);

                    // Close Login Screen
                    finish();
                }else{
                    // Error in login
                    loginErrorMsg.setText("Incorrect username/password");
                }
            }
        } catch (JSONException e) {
            e.printStackTrace();
        }
	}
}

Then, inside the onCreate method, change the login button's OnClickListener so its onClick method looks like this:

public void onClick(View view) {
    String email = inputEmail.getText().toString();
    String password = inputPassword.getText().toString();
    new MyAsyncTask().execute(email, password);
}

Do the same sort of thing in RegisterActivity.java. Add this class:

private class MyAsyncTask extends AsyncTask<String, Void, JSONObject> {

	protected JSONObject doInBackground(String... params) {
		UserFunctions userFunction = new UserFunctions();
		if (params.length != 3)
			return null;
		JSONObject json = userFunction.registerUser(params[0], params[1], params[2]);
		return json;
	}

	protected void onPostExecute(JSONObject json) {
		// check for login response
        try {
            if (json != null && json.getString(KEY_SUCCESS) != null) {
                registerErrorMsg.setText("");
                String res = json.getString(KEY_SUCCESS);
                if(Integer.parseInt(res) == 1){
                    // user successfully registred
                    // Store user details in SQLite Database
                    DatabaseHandler db = new DatabaseHandler(getApplicationContext());
                    JSONObject json_user = json.getJSONObject("user");

                    // Clear all previous data in database
                    UserFunctions userFunction = new UserFunctions();
                    userFunction.logoutUser(getApplicationContext());
                    db.addUser(json_user.getString(KEY_NAME), json_user.getString(KEY_EMAIL), json.getString(KEY_UID), json_user.getString(KEY_CREATED_AT));
                    // Launch Dashboard Screen
                    Intent dashboard = new Intent(getApplicationContext(), DashboardActivity.class);
                    // Close all views before launching Dashboard
                    dashboard.addFlags(Intent.FLAG_ACTIVITY_CLEAR_TOP);
                    startActivity(dashboard);
                    // Close Registration Screen
                    finish();
                }else{
                    // Error in registration
                    registerErrorMsg.setText("Error occured in registration");
                }
            }
        } catch (JSONException e) {
            e.printStackTrace();
        }
	}
}

And change the register button listener's onClick method to this:

public void onClick(View view) {
    String name = inputFullName.getText().toString();
    String email = inputEmail.getText().toString();
    String password = inputPassword.getText().toString();
    new MyAsyncTask().execute(name, email, password);
}

Try running the app now, and it should work!