import javax.microedition.midlet.*;
import javax.microedition.lcdui.*;
import java.util.* ;
public class Navigator
{
	final public static int MAIN_SCREEN = 1 ;
	final public static int USERDATA_SCREEN = 2 ;
	final public static int UPDATEUSERDATA_SCREEN = 3 ;
	
	public static MIDlet midlet ;
	public static Display display ;
	public static int current ;
	
	public static void show(Object obj)
	{
		switch(current)
		{
			case MAIN_SCREEN :
				display.setCurrent(MainScreen.getInstance()) ;
				break ;
			case USERDATA_SCREEN :
				display.setCurrent(new UserDataScreen((Vector)obj)) ;
				break ;
			case UPDATEUSERDATA_SCREEN :
				display.setCurrent(UpdateUserDataScreen.getInstance()) ;
				break ;
		}
		
	}
	public static void flow(String cmd)
	{
		switch(current)
		{
			case MAIN_SCREEN :
				if(cmd.equals("離開"))
				{
					midlet.notifyDestroyed() ;
				}else if(cmd.equals("增加數據"))
				{
					current = UPDATEUSERDATA_SCREEN ;
					show(null) ;
				}
				break ;
			case USERDATA_SCREEN :
				if(cmd.equals("離開"))
				{
					midlet.notifyDestroyed() ;
				}else if(cmd.equals("回主功能"))
				{
					current = MAIN_SCREEN ;
					show(null) ;
				}
				break ;
			case UPDATEUSERDATA_SCREEN :
				if(cmd.equals("回主功能"))
				{
					current = MAIN_SCREEN ;
					show(null) ;
				}
				break ;
		}
		
	}
}