//package bushfighting;import javax.microedition.lcdui.Display;import javax.microedition.lcdui.Displayable;//這個類用于管理不同的顯示界面的切換public class DisplayManager{    protected Display mDisplay = null;    private Displayable mParent = null;//要返回的父窗口    public DisplayManager(Display display, Displayable parent)    {        mDisplay = display;        mParent = parent;    }    //設置上一級顯示的對象    public void setParent(Displayable parent)    {        mParent = parent;    }    //返回到上一級顯示    public void back()    {        mDisplay.setCurrent(mParent);    }}