为什么按UP键时面板会消失？
这是我制作游戏的代码。目前我并不担心游戏功能如何让我更加担心每次按下UP按钮时面板消失，有时我也会点击左按钮。有没有解释，任何人都可以帮助我理解为什么会这样？我觉得它与我的if语句有关但我不太确定。此外，我正在搞乱关键的听众，如果你能给我一些关于主要听众的建议，比如一些dos和donts，我真的很感激帮助!!
import javax.swing.*;
import java.applet.*;
import java.awt.event.*;
import java.awt.*;
public class Game extends Applet implements ActionListener,KeyListener {
Image image;
MediaTracker tr;
JLabel label,computerLabel;
JPanel panel,computerPanel;
Button start,up,down;
Label result;
Dimension SIZE = new Dimension(50,50);
int x = 0;
int y = 0;
int w = 100;
int q = 100;
int WIDTH = 50;
int HEIGHT = 50;
//Player Integers
int zeroPosX,zeroPosY,xLeft,xUp;
//Computer integers
int compZeroPosX,compZeroPosY,compXLeft,compXUp;
//--------------------------------------
public void init() {
setLayout(new FlowLayout());
start = new Button("Start");
up = new Button("UP");
down = new Button("LEFT");
//PlayerPiece stuff
ImageIcon icon = new ImageIcon("playerpiece.png");
label = new JLabel(icon);
panel = new JPanel();
label.setVisible(true);
panel.add(label);
panel.setPreferredSize(SIZE);
//ComputerPiece Stuff
ImageIcon computerIcon = new ImageIcon("computerPiece.png");
computerPanel = new JPanel();
computerLabel = new JLabel(computerIcon);
computerLabel.setVisible(true);
computerPanel.add(computerLabel);
computerPanel.setPreferredSize(SIZE);
//===============================================
result = new Label("=========");
addKeyListener(this);
setSize(650,650);
up.addActionListener(this);
down.addActionListener(this);
start.addActionListener(this);
label.setSize(WIDTH,HEIGHT);
label.setLocation(0,0);
add(computerPanel);
add(panel);
add(start);
add(up);
add(down);
add(result);
}
//--------------------------------------
public void paint(Graphics g) {
Graphics2D firstLayer = (Graphics2D)g;
Graphics2D secondLayer = (Graphics2D)g;
Graphics2D thirdLayer = (Graphics2D)g;
secondLayer.setColor(Color.BLACK);
for(x=100; x<=500; x+=100)
for(y=100; y <=500; y+=100)
{
firstLayer.fillRect(x,y,WIDTH,HEIGHT);
}
for(w=150; w<=500; w+=100)
for(q=150; q <=500; q+=100)
{
secondLayer.fillRect(w,q,WIDTH,HEIGHT);
}
}
//--------------------------------------
public void actionPerformed(ActionEvent ae) {
int [] range = {50,0,0,0,0};
int selection = (int)Math.random()*5 ;
//~~~~~~~~~~~~~~~~~~~~~~~~~
//PlayerPositioning
zeroPosX = panel.getX();
zeroPosY = panel.getY();
xLeft = zeroPosX - 50;
xUp = zeroPosY - 50;
//ComputerPositioning
compZeroPosX = computerPanel.getX();
compZeroPosY = computerPanel.getY();
compXLeft = compZeroPosX - range[selection];
compXUp = compZeroPosY - range[selection];
//~~~~~~~~~~~~~~~~~~~~~~~~~~
Button user = (Button)ae.getSource();
//Starting the game
if(user.getLabel() == "Start") {
result.setText("=========");
//playersetup
label.setLocation(0,0);
panel.setLocation(300,500);
//============================
//npc setup
computerLabel.setLocation(0,0);
computerPanel.setLocation(500,300);
}
if(compZeroPosX >= 150) {
if(compZeroPosY >= 150) {
if(zeroPosX >= 150) {
if(zeroPosY >=150) {
if(user.getLabel() == "UP") {
panel.setLocation(zeroPosX,xUp);
}
else
computerPanel.setLocation(compZeroPosX,compXUp);
if(user.getLabel() == "LEFT") {
panel.setLocation(xLeft,zeroPosY);
}
else
computerPanel.setLocation(compXLeft,compZeroPosY);
if(panel.getX() < 150)
result.setText("GAME-OVER");
if(panel.getY() < 150)
result.setText("GAME-OVER");
}
}
}
}
}
@Override
public void keyPressed(KeyEvent kp) {
int keycode = kp.getKeyCode();
switch (keycode) {
case KeyEvent.VK_W:
panel.setLocation(xLeft,zeroPosY);
break;
}
}
@Override
public void keyReleased(KeyEvent kr) {
}
@Override
public void keyTyped(KeyEvent kt) {
}
}
1 个答案:
答案 0 :(得分：3)
问题和建议：
- 您将AWT（例如，小程序，按钮，标签）与Swing（例如，JPanel，JLabel）混合危险地且不需要。坚持使用Swing并摆脱AWT的所有残余。
- 你直接在顶级窗口绘画，这里是Applet，这是一件很危险的事情。唐＆＃39;吨。按照Swing图形教程，在JPanel的paintComponent方法中进行绘制。
- 你没有在你的绘画方法覆盖中调用超级方法，这是另一个危险的事情，另一个迹象表明你在没有阅读重要的相关教程的情况下尝试这样做。
- 请勿使用
==或!=来比较字符串。请改用equals(...)或equalsIgnoreCase(...)方法。理解==检查两个对象引用是否相同而不是您感兴趣的内容。另一方面，这些方法检查两个字符串是否具有相同顺序的相同字符，以及＃39;这里重要的是什么。 - 您尝试直接设置组件（如JPanel）的位置，而不考虑布局管理器。不要这样做。而是移动逻辑（非组件）实体并在图形中显示移动。
您可以在此处找到指向Swing教程和其他Swing资源的链接：Swing Info
稍后我们可以说出为什么你应该避免各种口味的小程序......
我自己，我将ImageIcons移动到JLabel网格周围，而不是直接使用绘画方法。例如，
要查看，请运行以下代码：
import java.awt.BorderLayout;
import java.awt.Color;
import java.awt.Dimension;
import java.awt.GridLayout;
import java.awt.event.*;
import java.awt.image.BufferedImage;
import java.io.IOException;
import java.net.URL;
import java.util.HashMap;
import java.util.Map;
import javax.imageio.ImageIO;
import javax.swing.*;
@SuppressWarnings("serial")
public class Game2 extends JPanel {
private static final String CPU_PATH = "https://upload.wikimedia.org/wikipedia/commons/thumb/4/4f/"
+ "Gorilla-thinclient.svg/50px-Gorilla-thinclient.svg.png";
private static final String PERSON_PATH = "https://upload.wikimedia.org/wikipedia/commons/thumb/d/d8/"
+ "Emblem-person-blue.svg/50px-Emblem-person-blue.svg.png";
private static final int SQR_WIDTH = 50;
private static final int SIDES = 10;
private static final Dimension SQR_SIZE = new Dimension(SQR_WIDTH, SQR_WIDTH);
private static final Color DARK = new Color(149, 69, 53);
private static final Color LIGHT = new Color(240, 220, 130);
private JLabel[][] labelGrid = new JLabel[SIDES][SIDES];
private Icon playerIcon;
private Icon computerIcon;
public Game2() throws IOException {
// would use images instead
playerIcon = createIcon(PERSON_PATH);
computerIcon = createIcon(CPU_PATH);
JPanel buttonPanel = new JPanel();
buttonPanel.add(new JButton(new StartAction("Start", KeyEvent.VK_S)));
buttonPanel.add(new JButton(new UpAction("Up", KeyEvent.VK_U)));
buttonPanel.add(new JButton(new LeftAction("Left", KeyEvent.VK_L)));
JPanel gameBrd = new JPanel(new GridLayout(SIDES, SIDES));
gameBrd.setBorder(BorderFactory.createLineBorder(Color.BLACK));
for (int i = 0; i < labelGrid.length; i++) {
for (int j = 0; j < labelGrid[i].length; j++) {
JLabel label = new JLabel();
label.setPreferredSize(SQR_SIZE);
label.setOpaque(true);
Color c = i % 2 == j % 2 ? DARK : LIGHT;
label.setBackground(c);
gameBrd.add(label);
labelGrid[i][j] = label;
}
}
setLayout(new BorderLayout());
add(buttonPanel, BorderLayout.PAGE_START);
add(gameBrd);
// random placement, just for example
labelGrid[4][4].setIcon(computerIcon);
labelGrid[5][5].setIcon(playerIcon);
}
private Icon createIcon(String path) throws IOException {
URL url = new URL(path);
BufferedImage img = ImageIO.read(url);
return new ImageIcon(img);
}
private abstract class MyAction extends AbstractAction {
public MyAction(String name, int mnemonic) {
super(name);
putValue(MNEMONIC_KEY, mnemonic);
}
}
private class StartAction extends MyAction {
public StartAction(String name, int mnemonic) {
super(name, mnemonic);
}
@Override
public void actionPerformed(ActionEvent e) {
// TODO start game code
}
}
// move all icons up
private class UpAction extends MyAction {
public UpAction(String name, int mnemonic) {
super(name, mnemonic);
}
@Override
public void actionPerformed(ActionEvent e) {
// collection to hold label that needs to be moved
Map<JLabel, Icon> labelMap = new HashMap<>();
for (int i = 0; i < labelGrid.length; i++) {
for (int j = 0; j < labelGrid[i].length; j++) {
Icon icon = labelGrid[i][j].getIcon();
if (icon != null) {
int newI = i == 0 ? labelGrid.length - 1 : i - 1;
labelGrid[i][j].setIcon(null);
labelMap.put(labelGrid[newI][j], icon);
}
}
}
// move the icon after the iteration complete so as not to move it twice
for (JLabel label : labelMap.keySet()) {
label.setIcon(labelMap.get(label));
}
}
}
// move all icons left
private class LeftAction extends MyAction {
public LeftAction(String name, int mnemonic) {
super(name, mnemonic);
}
@Override
public void actionPerformed(ActionEvent e) {
Map<JLabel, Icon> labelMap = new HashMap<>();
for (int i = 0; i < labelGrid.length; i++) {
for (int j = 0; j < labelGrid[i].length; j++) {
Icon icon = labelGrid[i][j].getIcon();
if (icon != null) {
int newJ = j == 0 ? labelGrid[i].length - 1 : j - 1;
labelGrid[i][j].setIcon(null);
labelMap.put(labelGrid[i][newJ], icon);
}
}
}
for (JLabel label : labelMap.keySet()) {
label.setIcon(labelMap.get(label));
}
}
}
private static void createAndShowGui() {
Game2 mainPanel = null;
try {
mainPanel = new Game2();
} catch (IOException e) {
e.printStackTrace();
System.exit(-1);
}
JFrame frame = new JFrame("Game2");
frame.setDefaultCloseOperation(JFrame.DISPOSE_ON_CLOSE);
frame.getContentPane().add(mainPanel);
frame.pack();
frame.setLocationByPlatform(true);
frame.setVisible(true);
}
public static void main(String[] args) {
SwingUtilities.invokeLater(() -> {
createAndShowGui();
});
}
}
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