public class Aktor extends greenfoot.Actor{}

/** initiates "ask" with mouse click on world */
public void act()
{
    if (Greenfoot.mouseClicked(null))
    {
        String answer = ask("Hey");
    }
}
/** returns keyboard input from user */
public String ask(String prompt)
{
    String output = ""; // for the user's input (to be returned)
    
    // the background for dialog area
    Actor panel = new Aktor();
    GreenfootImage frame = new GreenfootImage(800, 80);
    frame.setColor(new Color(192, 80, 80));
    frame.fill();
    panel.setImage(frame);
    
    // the prompt
    Actor text = new Aktor();
    GreenfootImage txt = new GreenfootImage(prompt, 28, Color.YELLOW, new Color(0, 0, 0, 0));
    text.setImage(txt);
    
    // the keyboard input string area
    Actor input = new Aktor();
    GreenfootImage area = new GreenfootImage(600, 36);
    area.setColor(Color.DARK_GRAY);
    area.fill();
    txt = new GreenfootImage(output, 28, Color.WHITE, new Color(0, 0, 0, 0));
    GreenfootImage copy = new GreenfootImage(area);
    copy.drawImage(txt, 20, 2);
    input.setImage(copy);
    
    // add dialog actors into world
    addObject(panel, 400, 560);
    addObject(text, 400, 540);
    addObject(input, 400, 580);
    
    // show new actors
    repaint();
    
    // get input
    do
    {
        String key = Greenfoot.getKey();
        if (key == null) continue;
        if ("enter".equals(key)) break;
        if ("backspace".equals(key) && output.length() > 0)
        {
            output = output.substring(0, output.length()-1);
        }
        if ("space".equals(key))
        {
            key = " ";
        }
        if (key.length() == 1 && key.charAt(0) > 31 && key.charAt(0) < 127)
        {
            output = output+key;
        }
        txt = new GreenfootImage(output, 28, Color.WHITE, Color.DARK_GRAY);
        copy = new GreenfootImage(area);
        copy.drawImage(txt, 20, 2);
        input.setImage(copy);
        Greenfoot.delay(1); // repaints AND updates keyboard buffer
    } while (true);
    
    // remove dialog actors from world
    removeObject(panel);
    removeObject(text);
    removeObject(input);
    
    // return string entered via keyboard
    return output;
}