基于MIDP实现Dialog组件[2]

    private int mCount, mMaximum;
    private int mInterval;

    private int mWidth, mHeight, mX, mY, mRadius;
    private String mMessage;
    private boolean run = false;

    public WaitCanvas(String message, boolean run)
    {
        this.mMessage = message;
        mCount = 0;
        mMaximum = 36;
        mInterval = 100;

        mWidth = getWidth();
        mHeight = getHeight();

        // Calculate the radius.
        int halfWidth = (mWidth - mRadius) / 2;
        int halfHeight = (mHeight - mRadius) / 2;
        mRadius = Math.min(halfWidth, halfHeight);

        //   Calculate the location.
        mX = halfWidth - mRadius / 2;
        mY = halfHeight - mRadius / 2;

        //   Create a Timer to update the display.
        if (run)
        {
            TimerTask task = new TimerTask()
            {
                public void run()
                {
                    mCount = (mCount + 1) % mMaximum;
                    repaint();
                }
            };
            Timer timer = new Timer();

            timer.schedule(task, 0, mInterval);
        }
    }

    public void paint(Graphics g)
    {
        int theta = -(mCount * 360 / mMaximum);

        // Clear the whole screen.
        g.setColor(255, 255, 255);
        g.fillRect(0, 0, mWidth, mHeight);

        // Now draw the pinwheel.
        g.setColor(128, 128, 255);
        g.drawArc(mX, mY, mRadius, mRadius, 0, 360);
        g.fillArc(mX, mY, mRadius, mRadius, theta + 90, 90);
        g.fillArc(mX, mY, mRadius, mRadius, theta + 270, 90);

        // Draw the message, if there is a message.
        if (mMessage != null)
        {
            g.drawString(mMessage, mWidth / 2, mHeight, Graphics.BOTTOM
                    | Graphics.HCENTER);
        }
    }

}

    过控制boolean run的值可以决定是不是让这个画面动起来。下面两个例子是Dialog的子类，他们实现了它的抽象方法。我直接给出代码：
import javax.microedition.lcdui.*;

public class ConfirmationDialog extends Dialog implements CommandListener
{

    public static final int YES = 0;
    public static final int NO = 1;
    protected Canvas canvas;
    protected Command noCommand;
    protected Command yesCommand;
    private String message;
    private String yesLabel;
    private String noLabel;

    public ConfirmationDialog(Display display, String message)
    {
        this(display, message, null, null);
    }