How to retain EditText data on orientation change?

Give the element an id and Android will manage it for you.

android:id="@id/anything"

in onConfigurationChanged method, first get the data of both the edit texts in global variables and then call setContentView method. Now set the saved data again into the edit texts.

A better approach is to let android handle the orientation change. Android will automatically fetch the layout from the correct folder and display it on the screen. All you need to do is to save the input values of the edit texts in the onSaveInsanceState() method and use these saved values to initialize the edit texts in the onCreate() method.
Here is how you can achieve this:

@Override
protected void onCreate (Bundle savedInstanceState)
{
    super.onCreate(savedInstanceState);
    setContentView(R.layout.login_screen);
    ...
    ...
    String userName, password;
    if(savedInstanceState!=null)
    {
        userName = savedInstanceState.getString("user_name");
        password= savedInstanceState.getString("password");
    }

    if(userName != null)
        userNameEdtTxt.setText(userName);
    if(password != null)
        passEdtTxt.setText(password);
}

>

@Override
    protected void onSaveInstanceState (Bundle outState)
    {
        outState.putString("user_name", userNameEdtTxt.getText().toString());
        outState.putString("password",  passEdtTxt.getText().toString());
    }

By default, Edittext save their own instance when changing orientation.

Be sure that the 2 Edittexts have unique IDs and have the same IDs in both Layouts.

That way, their state should be saved and you can let Android handle the orientation change.

If you are using a fragment, be sure it has a unique ID also and you dont recreate it when recreating the Activity.