enemysprite.java

来自「J2ME编程的50个例子,适合掌上系统的编程」· Java 代码 · 共 53 行

package demo;
import javax.microedition.lcdui.Image;
import javax.microedition.lcdui.game.Sprite;


public class EnemySprite extends Sprite{
	private boolean m_bRight	= true;			//敌人是否向左移动的标志
	private int m_nSpeed		= 1;			//敌人的移动速率（注意不是速度）
	public EnemySprite(Image image, int frameWidth, int frameHeight) {
		super(image, frameWidth, frameHeight);
		defineReferencePixel(frameWidth / 2, frameHeight / 2);
		setVisible(false);
	}
	//产生敌人
	//参数nX、nY分别是敌人位置的横纵坐标
	//参数bLeft指定敌人方向，参数nSpeed指定敌人速率
	public void Start( int nX, int nY, boolean bRight, int nSpeed ){
		m_bRight = bRight;
		if( bRight )
			setTransform(Sprite.TRANS_MIRROR);
		else
			setTransform(Sprite.TRANS_NONE);
		setRefPixelPosition( nX, nY );
		m_nSpeed = nSpeed;
		setVisible( true );
	}
	//逻辑操作
	public void Logic( int srcWidth, int scrHeight ){
		if( !isVisible() )
			return;
		int x = getRefPixelX();
		int y = getRefPixelY();
		if( m_bRight ){
			x += m_nSpeed;
			if( x > srcWidth + getWidth()/2 )
				setVisible(false);
		}
		else{
			x -= m_nSpeed;
			if( x < - getWidth()/2 )
				setVisible(false);
		}
		setRefPixelPosition(x, y);
		
		//产生跑步动画
		int n = getFrame();
		if( n == 0 )
			setFrame(1);
		else
			setFrame(0);
	}
}