buttonsprite.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;
import javax.microedition.lcdui.game.Sprite;


public class ButtonSprite extends Sprite{
	//精灵状态值
	public static final int BUTTON_WALK 	= 0;			//WALK按钮
	public static final int BUTTON_TALK	= 1;			//TALK按钮
	public static final int BUTTON_SLEEP = 2;				//SLEEP按钮
	public static final int BUTTON_MUSIC	= 3;			//MUSIC按钮
	public static final int BUTTON_TYPE_NUM	= 4;
	private int m_nCurButton = BUTTON_WALK;
	public ButtonSprite(Image img, int frameWidth, int frameHeight){
		super(img, frameWidth, frameHeight );
		defineReferencePixel(frameWidth/2, frameHeight/2);
		setVisible(false);
	}
	//响应按键,返回所选按钮的种类
	public int Input(int keyStates){
		if( ( keyStates & GameCanvas.FIRE_PRESSED ) != 0 )
		{
			if( isVisible() )
			{//按下按钮
				setVisible(false);
				return m_nCurButton;
			}
			else
			{//调出按钮
				setVisible(true);
				return -1;
			}
		}
		if( isVisible() )
		{//选择按钮
			if( ( keyStates & GameCanvas.UP_PRESSED ) != 0 )
				m_nCurButton --;
			if( ( keyStates & GameCanvas.DOWN_PRESSED ) != 0 )
				m_nCurButton ++;
			if( m_nCurButton < 0 )
				m_nCurButton = 0;
			else if( m_nCurButton >= BUTTON_TYPE_NUM )
				m_nCurButton = BUTTON_TYPE_NUM - 1;
		}
		return -1;
	}
	//显示所有按钮
	public void PaintAll(Graphics g, int scrWidth, int scrHeight){
		if( isVisible() == false )
			return;
		int x = scrWidth/2 - getWidth()/2;
		int y = scrHeight/2 -getHeight() * 2 - 20;
		for( int n = 0; n < BUTTON_TYPE_NUM; n ++ ){
			setPosition( x, y);
			setFrame(n);
			paint(g);
			if( n == m_nCurButton ){
				g.drawRect(x-1, y-1, 
					getWidth()+2, getHeight()+2);
			}
			y = y + getHeight() + 10;
		}	
	}
}