/*
 * Created on 2005-3-3
 *
 * MVC模型
 */
package com.favo.ui;

import javax.microedition.lcdui.Alert;
import javax.microedition.lcdui.AlertType;
import javax.microedition.lcdui.Display;
import javax.microedition.lcdui.Displayable;

/**
 * @author Favo
 *
 * 視圖類
 */
public abstract class BaseView {
	
	public abstract Display getDisplay();
	
	/**
	 * 簡(jiǎn)單的返回包裝的屏幕對(duì)象,不要做任何準(zhǔn)備屏幕的操作!
	 */
	public abstract Displayable getScreen();
	
	/**
	 * 創(chuàng)建屏幕
	 */
	protected abstract void createView() throws Exception;
	
	/**
	 * 更新屏幕
	 */
	public abstract void updateView() throws Exception;
		
	/**
	 * 返回控制器
	 */
	public abstract BaseController getController();
	
	/**
	 * 準(zhǔn)備屏幕
	 * 返回準(zhǔn)備好的屏幕對(duì)象
	 */
	public Displayable prepareScreen() throws Exception {
		if(getScreen()==null){
			createView();
		} else {
			updateView();
		}
		return getScreen();
	}
	
	/**
	 * 顯示當(dāng)前屏幕
	 */
	public void displayScreen(){
		try{
			getDisplay().setCurrent(prepareScreen());
		} catch (Exception e) {
			e.printStackTrace();
			Alert al=new Alert("Error",e.toString()+'\n'+e.getMessage(),null,AlertType.ERROR);
			al.setTimeout(Alert.FOREVER);
			getDisplay().setCurrent(al);
		}
	}
	
}