我重构了代码，生成了一个最小的、可复制的示例。

问题-我无法从面板中删除卡(我在出现问题的代码中进行了注释，请参阅类"ClearCardEventListener"(。

下面是完整的代码。

在运行程序之前，您需要下载一个映像并将其添加到resources文件夹=https://ibb.co/MNccGS0

运行程序
点击"添加卡片"按钮(这将在面板上添加2个心形图像图标(

点击"清除卡"按钮(这是问题所在，我无法从面板上移除卡(

package debug.debug;
import java.awt.Insets;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import java.util.ArrayList;
import java.util.Arrays;
import java.util.Collections;
import java.util.List;
import javax.swing.ImageIcon;
import javax.swing.JButton;
import javax.swing.JFrame;
import javax.swing.JLabel;
import javax.swing.JPanel;
public class App extends JFrame {
public static void main(String[] args) {
App app = new App();
Insets insets = app.getInsets();
app.setSize(300 + insets.left + insets.right,
300 + insets.top + insets.bottom);
}
JPanel panel;
JButton clearCardButton;
JButton addCardButton;
List<Card> playerCards = new ArrayList<Card> ();
Deck deck = new Deck();
public App() {
setTitle("BlackJack Game");
setVisible(true);
setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
setLocationRelativeTo(null);
panel = new JPanel();
add(panel);
panel.setLayout(null);
addCardButton = new JButton("Add card");
clearCardButton = new JButton("Clear card");
panel.add(addCardButton);
panel.add(clearCardButton);
addCardButton.addActionListener(new AddCardEventListener(this, this.deck));
clearCardButton.addActionListener(new ClearCardEventListener(this, this.deck));
addCardButton.setBounds(150, 50, addCardButton.getPreferredSize().width, addCardButton.getPreferredSize().height);
clearCardButton.setBounds(150, 100, clearCardButton.getPreferredSize().width, clearCardButton.getPreferredSize().height);
}
public JPanel getPanel() {
return panel;
}
public void addPlayerCard(Card card) {
playerCards.add(card);
}
public List<Card> getPlayerCards() {
return playerCards;
}
public List<JLabel> getPlayerCardLabels() {
List<JLabel> playerCardLabels = new ArrayList<JLabel> ();
for (int i = 0; i<this.getPlayerCards().size(); i++) {
playerCardLabels.add(this.getPlayerCards().get(i).getCardLabel());
}
return playerCardLabels;
}
}
class AddCardEventListener implements ActionListener {
private App app;
private Deck deck;
AddCardEventListener(App app, Deck deck) {
this.app = app;
this.deck = deck;
}
public void actionPerformed(ActionEvent arg0) {
// Player gets a card
app.addPlayerCard(deck.getCard());
// Display that player's card
app.getPanel()
.add(app.getPlayerCards().get(0).getCardLabel()).setBounds(0, 0, 72, 96);
}
}
class ClearCardEventListener implements ActionListener {
private App app;
private Deck deck;
ClearCardEventListener(App app, Deck deck) {
this.app = app;
this.deck = deck;
}
public void actionPerformed(ActionEvent arg0) {
System.out.println("DEBUG: " + app.getPlayerCards().get(0).getCardLabel());
/***
* 
* NOT ABLE TO REMOVE CARD, WHY ???
* 
*/
app.getPlayerCards().get(0).getCardLabel().setIcon(null);
app.getPlayerCards().get(0).getCardLabel().revalidate();
app.getPlayerCards().get(0).getCardLabel().repaint();
app.getPanel().remove(app.getPlayerCards().get(0).getCardLabel());
}
}
class Card {
private String suit;
private String rank;
private int value;
public void setSuit(String suit) {
this.suit = suit;
}
public void setRank(String rank) {
this.rank = rank;
}
public void setValue(int value) {
this.value = value;
}
public String getSuit() {
return suit;
}
public String getRank() {
return rank;
}
public int getValue() {
return value;
}
// Hardcoded for debugging, so every card image is a 2 of hearts
public JLabel getCardLabel() {
return new JLabel(new ImageIcon(getClass()
.getResource("/cards/2h.png")));
}
}
class Deck {
private final String RANKS[] = {
"Ace",
"Deuce",
"Three",
"Four",
"Five",
"Six",
"Seven",
"Eight",
"Nine",
"Ten",
"Jack",
"Queen",
"King"
};
private final String SUITS[] = {
"Spades",
"Hearts",
"Diamonds",
"Clubs"
};
private Card[] deck;
static private int cardPosition = 0;
public Deck() {
deck(); // Create the deck
shuffle(); // shuffle the deck
}
public Card[] deck() {
deck = new Card[52];
for (int x = 0; x<deck.length; x++) {
String rankTemp = RANKS[x % 13];
String suitTemp = SUITS[x / 13];
deck[x] = new Card();
deck[x].setRank(rankTemp);
deck[x].setSuit(suitTemp);
deck[x].setValue((x % 13) + 1);
if (deck[x].getValue() > 10)
deck[x].setValue(10);
else if (deck[x].getValue() == 1)
deck[x].setValue(11);
}
return deck;
}
public void shuffle() {
Collections.shuffle(Arrays.asList(deck()));
}
public Card[] getDeck() {
return deck;
}
public Card getCard() {
return deck[cardPosition++];
}
}

问题#1

每次调用Card#getCardLabel时，它都在创建一个新的JLabel实例。。。

class Card {
// Hardcoded for debugging, so every card image is a 2 of hearts
public JLabel getCardLabel() {
return new JLabel(new ImageIcon(getClass()
.getResource("/cards/2h.png")));
}
}

这意味着当你做…

app.getPanel().add(app.getPlayerCards().get(0).getCardLabel()).setBounds(0, 0, 72, 96);

而且。。。

System.out.println("DEBUG: " + app.getPlayerCards().get(0).getCardLabel());

而且。。。

app.getPlayerCards().get(0).getCardLabel().setIcon(null);
app.getPlayerCards().get(0).getCardLabel().revalidate();
app.getPlayerCards().get(0).getCardLabel().repaint();
app.getPanel().remove(app.getPlayerCards().get(0).getCardLabel());

每个调用实际上都是创建一个JLabel的新实例，因此屏幕上的调用与您试图修改的调用无关。

因此，您的Card#getCardLabel应该只创建一个JLabelONCE，这也被称为"懒惰加载"。。。

class Card {
private JLabel label;
//...
// Hardcoded for debugging, so every card image is a 2 of hearts
public JLabel getCardLabel() {
if (label == null) {
// Simple image for demonstration purposes
BufferedImage img = new BufferedImage(100, 150, BufferedImage.TYPE_INT_RGB);
Graphics2D g2d = img.createGraphics();
g2d.setColor(Color.WHITE);
g2d.fillRect(0, 0, 100, 150);
g2d.setColor(Color.RED);
g2d.drawLine(0, 0, 100, 150);
g2d.drawLine(100, 0, 0, 150);
g2d.dispose();
label = new JLabel(new ImageIcon(img));
}
return label;
}
}

问题#2

Swing是惰性的(好吧，它是"优化的"(，这意味着添加或删除组件本身不会触发布局或绘制过程。这样做是为了让你可以对UI进行大规模更改，而不是让它尝试更新每个更改，这会非常慢。

这意味着，当您添加或删除组件时，还应该调用repaint来触发新的绘制过程(我也建议使用revalidate，但您没有使用任何布局管理器，所以它对您没有任何帮助(

app.getPanel().remove(app.getPlayerCards().get(0).getCardLabel());
app.getPanel().repaint();

无法从jpanel中删除组件

问题#1

问题#2

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