missilesprite.java

J2ME编程的50个例子,适合掌上系统的编程

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


public class MissileSprite extends Sprite{
	private int m_nSpeedX = 0;				//导弹X方向的移动速率
	private int m_nSpeedY = 0;				//导弹Y方向的移动速率
	MissileSprite(Image image, int frameWidth, int frameHeight){
		super( image, frameWidth, frameHeight );
		defineReferencePixel( frameWidth / 2, frameHeight / 2 );
		setVisible(false);
	}
	//设置移动速率，注意速率与速度的差别
	public void SetSpeed( int nSpeedX, int nSpeedY ){
		m_nSpeedX = nSpeedX;
		m_nSpeedY = nSpeedY;
	}
	//逻辑操作，参数scrWidth、scrHeight分别是屏幕的宽和高
	public void Logic( int scrWidth, int scrHeight ){
		if( isVisible() == false )
			return;
		int nX = getRefPixelX() + m_nSpeedX;
		int nY = getRefPixelY() + m_nSpeedY;
		setRefPixelPosition( nX, nY );
		if( getRefPixelX() < -getWidth() || 
			getRefPixelX() > scrWidth + getWidth()||
			getRefPixelY() < -getHeight() || 
			getRefPixelY() > scrHeight + getHeight() )
				setVisible(false);
	}
}