我正在按照此处的教程开发Java applet游戏：http://www.kilobolt.com/unit-2-creating-a-game-i.html 我正在使用它作为扩展我自己的应用程序的基础。但这是问题所在。
我想将JButtons添加到applet以获取某些功能（开始，选项等）。但是当我将鼠标悬停在它们上面时，我发现它们会闪烁，如果保持不变则完全隐藏起来。我读到它与双缓冲有关，我应该使用paintComponent而不是绘画例如
public void paintComponents(Graphics g) {
super.paintComponents(g);
}
这解决了Jbuttons的闪烁问题，但是g.drawimage方法已经破裂，或者我完全不理解它，因为我试图绘制的图像没有显示。我不知道他们是隐藏还是无法加载或是什么。如果有人可以指出正确的方向，那就太好了。
public class StartingClass extends Applet implements Runnable, KeyListener, ActionListener {
private PlayerChar playerChar;
private Image image, currentSprite, character, characterDown, characterJumped, background;
private Graphics second;
private URL base;
private static Background bg1, bg2;
private JButton start, options;
private boolean running = false;
private int score;
@Override
public void init() {
setSize(800, 480);
setFocusable(true);
addKeyListener(this);
Frame frame = (Frame) this.getParent().getParent();
frame.setTitle("GraviOn-Alpha");
try {
base = getDocumentBase();
}
catch (Exception e) {
// TODO: handle exception
}
// Image Setups
character = getImage(base, "data/character.png");
characterDown = getImage(base, "data/down.png");
characterJumped = getImage(base, "data/jumped.png");
currentSprite = character;
background = getImage(base, "data/background.png");
score = 0;
}
@Override
public void start() {
bg1 = new Background(0, 0);
bg2 = new Background(2160, 0);
playerChar = new PlayerChar();
JPanel myPanel = new JPanel();
start = new JButton("Start");
start.addActionListener(this);
options = new JButton("Change Colour");
options.addActionListener(this);
myPanel.add(start);
myPanel.add(options);
myPanel.setBackground(Color.BLACK);
myPanel.setPreferredSize(new Dimension(100, 75));
this.add(myPanel);
Thread thread = new Thread(this);
thread.start();
}
@Override
public void stop() {
// TODO Auto-generated method stub
}
@Override
public void destroy() {
// TODO Auto-generated method stub
}
@Override
public void run() {
while (true) {
if (running == true) {
playerChar.moveRight();
score += 3;
start.setVisible(false);
options.setVisible(false);
}
else {
}
playerChar.update();
if (playerChar.isJumped()) {
currentSprite = characterJumped;
}
else if (playerChar.isJumped() == false && playerChar.isDucked() == false) {
currentSprite = character;
}
bg1.update();
bg2.update();
repaint();
try {
Thread.sleep(17);
}
catch (InterruptedException e) {
e.printStackTrace();
}
}
}
@Override
public void update(Graphics g) {
if (image == null) {
image = createImage(this.getWidth(), this.getHeight());
second = image.getGraphics();
}
second.setColor(getBackground());
second.fillRect(0, 0, getWidth(), getHeight());
second.setColor(getForeground());
paint(second);
g.drawImage(image, 0, 0, this);
}
@Override
public void paintComponents(Graphics g) {
super.paintComponents(g);
g.drawImage(background, bg1.getBgX(), bg1.getBgY(), this);
g.drawImage(background, bg2.getBgX(), bg2.getBgY(), this);
g.drawImage(currentSprite, playerChar.getCenterX() - 61, playerChar.getCenterY() - 63, this);
g.drawString("Score: " + score, 50, 50);
}
@Override
public void keyPressed(KeyEvent e) {
switch (e.getKeyCode()) {
case KeyEvent.VK_UP:
System.out.println("Move up");
break;
case KeyEvent.VK_DOWN:
currentSprite = characterDown;
if (playerChar.isJumped() == false) {
playerChar.setDucked(true);
playerChar.setSpeedX(0);
}
break;
case KeyEvent.VK_LEFT:
// playerChar.moveLeft();
playerChar.setMovingLeft(true);
break;
case KeyEvent.VK_RIGHT:
// playerChar.moveRight();
playerChar.setMovingRight(true);
break;
case KeyEvent.VK_SPACE:
playerChar.jump();
break;
}
}
@Override
public void keyReleased(KeyEvent e) {
switch (e.getKeyCode()) {
case KeyEvent.VK_UP:
System.out.println("Stop moving up");
break;
case KeyEvent.VK_DOWN:
currentSprite = character;
playerChar.setDucked(false);
break;
case KeyEvent.VK_LEFT:
playerChar.stopLeft();
break;
case KeyEvent.VK_RIGHT:
playerChar.stopRight();
break;
case KeyEvent.VK_SPACE:
break;
}
}
@Override
public void keyTyped(KeyEvent e) {
// TODO Auto-generated method stub
}
public static Background getBg1() {
return bg1;
}
public static Background getBg2() {
return bg2;
}
@Override
public void actionPerformed(ActionEvent e) {
if (e.getActionCommand().equals("Start")) {
running = true;
}
if (e.getActionCommand().equals("Change Colour") && character == getImage(base, "data/character.png")) {
character = getImage(base, "data/character2.png");
}
else if (e.getActionCommand().equals("Change Colour") && character == getImage(base, "data/character2.png")) {
character = getImage(base, "data/character.png");
}
repaint();
}
}
这是尝试使用paintComponents方法。我非常感谢帮助。
编辑：我已经改为使用Japplet并在Jpanel中使用paintComponent来绘制所有内容并且它工作正常，所有这些都基于JApplet - super.paint(); causes flicker。
答案 0 :(得分：1)
我已经改为使用Applet并在Jpanel中使用paintComponent绘制所有内容并且工作正常。
JPanel myPanel = new JPanel(){
@Override
public void paintComponent(Graphics g) {
super.paintComponent(g);
g.drawImage(background, bg1.getBgX(), bg1.getBgY(), this);
g.drawImage(background, bg2.getBgX(), bg2.getBgY(), this);
g.drawImage(currentSprite, playerChar.getCenterX() - 61, playerChar.getCenterY() - 63, this);
g.drawString("Score: " + score, 50, 50);
}