Waiting for Displayable to come out

Question

Well, here's the thing: I have a custom Canvas that receives some input from the user.
There's a function that, when called, sets this Canvas as the current in the Display and returns whatever the user has entered. I would like for that function to wait until the user has ok'ed or cancelled, that is, to wait until the Canvas is no longer the current.
Hard as I tried, I couldn't stop execution at that point. Perhaps I should make the Canvas a thread (Runnable), or run in one?
Thanks in advance.

Answer 1

k_i_shor is right. I just wanted to create a reusable function that only returns after the user has entered. I understand that deepspace's approach is also possible (I don't see the advantage, though).
As requested, a piece of the code (the first try with wait() and notify()):
public class PasswordScreen implements CommandListener {
  /* some things */
  public static String requestPassword(int numdigits, Display display) {
    PasswordScreen ps = new PasswordScreen(numdigits, display);
    try {
      ps.activate();
      ps.wait();
    } catch (Exception e) {
      return null;
    return ps.getPassword();
  //voila, the constructor
  public PasswordScreen(int numdig, Display display) {
    this.display = display;
    this.typed = 0;
    this.numdigits = numdig;
    chars = new char[numdigits];
    canvas = new Canvas() {
      public void paint(Graphics g) {
        /* doesn't really matter */
    canvas.addCommand(okCommand);
    canvas.addCommand(cancelCommand);
    canvas.setCommandListener(this);
  public void activate() {
    last = display.getCurrent();
    display.setCurrent(canvas);
  public String getPassword() {
    if (typed == 0) return null;
    else return new String(chars, 0, typed);
  public void commandAction(Command command, Displayable displayable) {
    //just an example:
    if (command == okCommand) {     
      this.notify();
  }No matter if I use synchronized in the commandAction or anything it calls.... In fact, the real problem seems to be that the wait() call locks the main thread execution and therefore any further processing (as I'm not using any other threads).
Thanks for the support.