changebetscreen.java

利用javame开发的

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package example.fruitmachine;

import javax.microedition.lcdui.*;


class ChangeBetScreen
    extends Form
    implements CommandListener
{
    private final FruitMachineMIDlet midlet;
    private final Account account;
    private final TextField betField;
    private final Command changeCommand;
    private final Command cancelCommand;
    private boolean isHolding;   // can't increase bet if HOLDs are pressed
    private int previousBet;


    ChangeBetScreen(FruitMachineMIDlet midlet,
                    Image logoImage,
                    Account account)
    {
        super("Change Bet");
        this.midlet = midlet;
        this.account = account;

        append(logoImage);
        betField = new TextField("Bet:", "", 3, TextField.NUMERIC);
        append(betField);
        changeCommand = new Command("Change", Command.SCREEN, 2);
        addCommand(changeCommand);
        cancelCommand = new Command("Cancel", Command.EXIT, 2);
        addCommand(cancelCommand);

        setCommandListener(this);
    }

    
    public void commandAction(Command c, Displayable d)
    {
        if (c == changeCommand)
        {
            try
            {
                int bet = Integer.parseInt(betField.getString());
                if (isHolding && (bet > previousBet))
                {
                    betField.setString(
                        Integer.toString(account.getCurrentBet()));
                    ErrorScreen.showError("Can't hold AND increase bet");
                }
                else
                {
                    account.setCurrentBet(bet);
                    midlet.changeBetScreenDone();
                }
            }
            catch (NumberFormatException e)
            {
                betField.setString(Integer.toString(account.getCurrentBet()));
            }
        }
        else if (c == cancelCommand)
        {
            midlet.changeBetScreenDone();
        }
    }


    void updateValues(boolean isHolding, int previousBet)
    {
        this.isHolding = isHolding;
        this.previousBet = previousBet;
        betField.setString(Integer.toString(account.getCurrentBet()));
    }
}