myui.java

J2ME编程的50个例子,适合掌上系统的编程

package demo;
import javax.microedition.lcdui.Graphics;
import javax.microedition.lcdui.Image;
import javax.microedition.lcdui.game.GameCanvas;

public class MyUI {
	//定义一组表示界面显示状态的数值
	public static final int UI_TITLE 		= 0;	//显示标题画面
	public static final int UI_HELP		= 1;	//显示帮助画面
	public static final int UI_BUTTON 	= 2;	//只显示按钮
	public static final int UI_HIDE 		= 3;	//隐藏界面
	public static final int UI_STATE_NUM	 = 4;	//界面状态总数
	private int m_nState = UI_TITLE;				//当前的界面类型
	
	private Image 		m_TitleImg;					//标题画面图像
	private Image		m_HelpImg;					//帮助画面图像
	private MyButton	m_Button;
	
	public MyUI(MyButton button){
		m_Button = button;
		try{				//读取标题图像
			m_TitleImg = Image.createImage("/demo/title.png");
		}
		catch (Exception ex){} 
		try{				//读取帮助图像
			m_HelpImg = Image.createImage("/demo/help.png");
		}
		catch (Exception ex){} 
	}
	/*****
	 * 获取当前的界面显示类型
	 * @返回:当前界面的显示类型
	 */
	public int getState(){
		return m_nState;
	}
	/*****
	 * 设置当前的界面显示类型,并进行出错处理
	 * @参数 nType.........要设置的显示类型
	 */
	public void setState( int state ){
		if( state < 0 || state >= UI_STATE_NUM )
			return;
		m_nState = state;		
	}
	public MyButton getButton(){
		return m_Button;
	}
	/*****
	 * 处理按键的输入
	 * @参数 keyStates.....当前的按键状态
	 * @返回所选按钮的类型
	 */
	public int Input( int keyStates ){
		int type = -1;
		switch( m_nState ){
		case UI_TITLE:
		case UI_BUTTON:
			{
				type = m_Button.Input(keyStates);
				switch(type){
				case MyButton.BUTTON_CONTINUE:
				case MyButton.BUTTON_START:
					setState(UI_HIDE);
					break;
				case MyButton.BUTTON_HELP:
					setState(UI_HELP);
				}
			}
			break;
		case UI_HELP:
			if( ( keyStates & GameCanvas.FIRE_PRESSED ) != 0 )
				setState(UI_TITLE);
			break;
		case UI_HIDE:
			break;
		}
		return type;
	}
	/*****
	 * 显示界面内容
	 * @参数 g.............对应显示屏幕
	 * @参数 scrWidth......屏幕的宽
	 * @参数 scrHeight.....屏幕的高
	 */
	public void Paint( Graphics g, int scrWidth, int scrHeight ){
		int x = scrWidth;
		int y = scrHeight;
		switch( m_nState ){
		case UI_TITLE:				//显示标题画面
			if( m_TitleImg != null ){
				x = ( x - m_TitleImg.getWidth() ) / 2;
				y = ( y - m_TitleImg.getHeight() ) / 2;
				g.drawImage(m_TitleImg, x, y, 0 );
			}
			m_Button.Paint(g, scrWidth, scrHeight);
			break;
		case UI_HELP:				//显示帮助画面
			if( m_HelpImg != null ){
				x = ( x - m_HelpImg.getWidth() ) / 2;
				y = ( y - m_HelpImg.getHeight() ) / 2;
				g.drawImage(m_HelpImg, x, y, 0 );
			}
			break;
		case UI_BUTTON:				//只显示按钮
			m_Button.Paint(g, scrWidth, scrHeight);
			break;
		case UI_HIDE:				//隐藏界面
			break;
		}
	}
}