日期:2014-05-20  浏览次数:20793 次

只求一个Sprite使用的最简单实例
能让我知道Sprite怎么用就行。

------解决方案--------------------
Sprite,精灵,顾名思义,专用来代表游戏中的动画角色,比如飞机,坦克等等。在MIDP1.0中,我们必须自己写专门的类来实现Sprite,幸运的是,MIDP2.0为Sprite提供了强力支持,可以创建静态,动态,不透明和透明的Sprite,下面我们准备在上次的GameCanvas基础上添加一个Sprite并让它动起来。

Sprite的主要构造方法有:

Sprite(Image):构造一个单幅图案的Sprite;

Sprite(Image, int width, int height):构造一个动画Sprite,图片将按照指定大小被分为N个Frame,通过setFrame(int index)就可以让Sprite动起来。

下边是例子
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package tank.midp.core;
import javax.microedition.lcdui.*;
import javax.microedition.lcdui.game.*;
public class TankGameCanvas extends GameCanvas implements Runnable {
// 控制方向:
private static int INDEX_OF_UP = 0;
private static int INDEX_OF_DOWN = 1;
private static int INDEX_OF_LEFT = 3;
private static int INDEX_OF_RIGHT = 2;
private boolean isPlay; // Game Loop runs when isPlay is true
private long delay; // To give thread consistency
private int currentX, currentY; // To hold current position of the 'X '
private int width; // To hold screen width
private int height; // To hold screen height
private Sprite spriteTank; // our sprite!
// Constructor and initialization
public TankGameCanvas() {
super(true);
width = getWidth();
height = getHeight();
currentX = width / 2;
currentY = height / 2;
delay = 20;
// init sprite:
try {
Image image = Image.createImage( "/res/img/player1.png "); // 注意路径
spriteTank = new Sprite(image, 16, 16); // 大小是16x16
} catch (Exception e) {
e.printStackTrace();
}
}
// Automatically start thread for game loop
public void start() {
isPlay = true;
new Thread(this).start();
}
public void stop() {
isPlay = false;
}
// Main Game Loop
public void run() {
Graphics g = getGraphics();
while (isPlay) {
input();
drawScreen(g);
try {
Thread.sleep(delay);
} catch (InterruptedException ie) {
}
}
}
// Method to Handle User Inputs
private void input() {
int keyStates = getKeyStates();
// Left
if ((keyStates & LEFT_PRESSED) != 0) {
currentX = Math.max(0, currentX - 1);
spriteTank.setFrame(INDEX_OF_LEFT);
}
// Right
if ((keyStates & RIGHT_PRESSED) !=0 ) {
if ( currentX + 5 < width)
currentX = Math.min(width, currentX + 1);
spriteTank.setFrame(INDEX_OF_RIGHT);
}
// Up
if ((keyStates & UP_PRESSED) != 0) {
currentY = Math.max(0, currentY - 1);
spriteTank.setFrame(INDEX_OF_UP);
}
// Down
if ((keyStates & DOWN_PRESSED) !=0) {
if ( currentY + 10 < height)
currentY = Math.min(height, currentY + 1);
spriteTank.setFrame(INDEX_OF_DOWN);
}
}
// Method to Display Graphics
private void drawScreen(Graphics g) {
g.setColor(0); // black
g.fillRect(0, 0, getWidth(), getHeight());
// 画一个Sprite非常简单:
spriteTank.setPosition(currentX, currentY);
spriteTank.paint(g);
flushGraphics();