Java Lanterna - how can I get input from a textbox?

Question

I'm a relatively new Java programmer (about two months experience) and I can't figure out how to get the data inputted into a Lanterna (a library for creating terminal user interfaces) textbox into a string for later use.

Here is my code:

//Variables (that I can't seem to populate)
final String usernameIn = null;
final String passwordIn = null;

//Username panel, contains Label and TextBox
Panel username = new Panel(new Border.Invisible(), Panel.Orientation.HORISONTAL);
username.addComponent(new Label("Username: "));
username.addComponent(new TextBox(null, 15));
addComponent(username);

//Password panel, contains label and PasswordBox
Panel password = new Panel(new Border.Invisible(), Panel.Orientation.HORISONTAL);
password.addComponent(new Label("Password: "));
password.addComponent(new PasswordBox(null, 15));
addComponent(password);

//Controls panel, contains Button w/ action
Panel controls = new Panel(new Border.Invisible(), Panel.Orientation.HORISONTAL);
controls.addComponent(new Button("Login", new Action()
{
    public void doAction() {
        MessageBox.showMessageBox(getOwner(), "Alert", "You entered the username " + usernameIn + " and password " + passwordIn + ".");
    }
}));
addComponent(controls);

Any help would be really appreciated. I have looked all over for information but there really isn't much on Lanterna and it's the only up-to-date Java library that I could find allowing me to make terminal applications. Please note: I'm aware there's nothing in the above code that'll process the inputted data, I left out all of my attempts as they caused pages upon pages of errors (which is to be expected when using the wrong functions).

Answer 1

I got a look into the Lanterna code: TextBox has a getText() method.

As an idea:

Panel username = new Panel(new Border.Invisible(), Panel.Orientation.HORISONTAL);
username.addComponent(new Label("Username: "));
TextBox userBox = new TextBox(null, 15);
username.addComponent(userBox);
addComponent(username);
// ... and later elsewhere 
usernameIn = userBox.getText();

Shure, you need a reference to userBox to get the content later elsewhere in your code.

Lanterna has also a ComponentListener interface to response if a value changed:

Panel username = new Panel(new Border.Invisible(), Panel.Orientation.HORISONTAL);
username.addComponent(new Label("Username: "));
TextBox userBox = new TextBox(null, 15);
userBox.addComponentListener(new ComponentListener() {
    void onComponentValueChanged(InteractableComponent component) {
         usernameIn = ((TextBox)component).getText();
    }
});

username.addComponent(userBox);
addComponent(username);

That seems even cleaner.

Answer 2

There are no addComponent() method in TextBox class, Lanterna ver3.0.0-beta2. So use readInput() in Screen. Below sample represent when user press enter, get text from TextBox.

private Screen screen;
private TextBox textBox; 
private final String emptyString = "";
...
public String getText() throws IOException {
    String result = null;
    KeyStroke key = null;
    while ((key = screen.readInput()).getKeyType() != KeyType.Enter) {
        textBox.handleKeyStroke(key);
       // use only one of handleInput() or handleKeyStroke() 
        textBox.setText(textBox.getText()); 
    }
    result = textBox.getText();
    textBox.setText(emptyString);
    return result;