您好我正在用Java创建一个带有GUI的刽子手游戏，当我将字母的JButtons添加到GUI时我遇到了问题，因为它们没有出现。不知道为什么。我开始添加按钮的代码位于GamePanel类中，游戏，GameWord，GameMain和GameFrame类以及GamePanel类的部分未显示，因为它们不需要理解和回答问题。
GamePanel类：
//some imports were omitted because they are irrelevant to the post
import java.awt.Graphics;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import javax.swing.JPanel;
import javax.swing.JButton;
public class GamePanel extends JPanel implements ActionListener
{
//some declarations were omitted because they are irrelevant to the post
private JButton a;
private JButton b;
private JButton c;
private JButton d;
private JButton e;
private JButton f;
private JButton g;
private JButton h;
private JButton i;
private JButton j;
private JButton k;
private JButton l;
private JButton m;
private JButton n;
private JButton o;
private JButton p;
private JButton q;
private JButton r;
private JButton s;
private JButton t;
private JButton u;
private JButton v;
private JButton w;
private JButton x;
private JButton y;
private JButton z;
public GamePanel(Game aGame)
{
// certain initialization's were omitted because they are irrelevant
this.addLetters();
}
public void paint(Graphics g)
{
//paint code goes here some parts were omitted as they are irrelevant to the post
repaint();
}
public void addLetters()
{
a = new JButton("A");
b = new JButton("B");
c = new JButton("C");
d = new JButton("D");
e = new JButton("E");
f = new JButton("F");
g = new JButton("G");
h = new JButton("H");
i = new JButton("I");
j = new JButton("J");
k = new JButton("K");
l = new JButton("L");
m = new JButton("M");
n = new JButton("N");
o = new JButton("O");
p = new JButton("P");
q = new JButton("Q");
r = new JButton("R");
s = new JButton("S");
t = new JButton("T");
u = new JButton("U");
v = new JButton("V");
w = new JButton("W");
x = new JButton("X");
y = new JButton("Y");
z = new JButton("Z");
a.addActionListener(this);
b.addActionListener(this);
c.addActionListener(this);
d.addActionListener(this);
e.addActionListener(this);
f.addActionListener(this);
g.addActionListener(this);
h.addActionListener(this);
i.addActionListener(this);
j.addActionListener(this);
k.addActionListener(this);
l.addActionListener(this);
m.addActionListener(this);
n.addActionListener(this);
o.addActionListener(this);
p.addActionListener(this);
q.addActionListener(this);
r.addActionListener(this);
s.addActionListener(this);
t.addActionListener(this);
u.addActionListener(this);
v.addActionListener(this);
w.addActionListener(this);
x.addActionListener(this);
y.addActionListener(this);
z.addActionListener(this);
a.setBounds(340, 250, 5, 5);
b.setBounds(350, 250, 5, 5);
c.setBounds(360, 250, 5, 5);
d.setBounds(370, 250, 5, 5);
e.setBounds(380, 250, 5, 5);
f.setBounds(390, 250, 5, 5);
g.setBounds(400, 250, 5, 5);
h.setBounds(410, 250, 5, 5);
i.setBounds(420, 250, 5, 5);
j.setBounds(430, 250, 5, 5);
k.setBounds(440, 250, 5, 5);
l.setBounds(450, 250, 5, 5);
m.setBounds(460, 250, 5, 5);
n.setBounds(340, 350, 5, 5);
o.setBounds(350, 350, 5, 5);
p.setBounds(360, 350, 5, 5);
q.setBounds(370, 350, 5, 5);
r.setBounds(380, 350, 5, 5);
s.setBounds(390, 350, 5, 5);
t.setBounds(400, 350, 5, 5);
u.setBounds(410, 350, 5, 5);
v.setBounds(420, 350, 5, 5);
w.setBounds(430, 350, 5, 5);
x.setBounds(440, 350, 5, 5);
y.setBounds(450, 350, 5, 5);
z.setBounds(460, 350, 5, 5);
a.setVisible(true);
b.setVisible(true);
c.setVisible(true);
d.setVisible(true);
e.setVisible(true);
f.setVisible(true);
g.setVisible(true);
h.setVisible(true);
i.setVisible(true);
j.setVisible(true);
k.setVisible(true);
l.setVisible(true);
m.setVisible(true);
n.setVisible(true);
o.setVisible(true);
p.setVisible(true);
q.setVisible(true);
r.setVisible(true);
s.setVisible(true);
t.setVisible(true);
u.setVisible(true);
v.setVisible(true);
w.setVisible(true);
x.setVisible(true);
y.setVisible(true);
z.setVisible(true);
this.add(a);
this.add(b);
this.add(c);
this.add(d);
this.add(e);
this.add(f);
this.add(g);
this.add(h);
this.add(i);
this.add(j);
this.add(k);
this.add(l);
this.add(m);
this.add(n);
this.add(o);
this.add(p);
this.add(q);
this.add(r);
this.add(s);
this.add(t);
this.add(u);
this.add(v);
this.add(w);
this.add(x);
this.add(y);
this.add(z);
}
public void actionPerformed(ActionEvent e)
{
//actionPerformed code omitted because it is irrelevant
}
}
答案 0 :(得分：1)
（实际上并不是答案;只是为了向您展示使用循环实现现有逻辑的容易程度）
int x = 340;
for (char c = 'A'; c <= 'Z'; ++c, x += 10) {
JButton button = new JButton(Character.toString(c));
final char lower = Character.toLowercase(c);
button.addActionListener(new ActionListener() {
@Override public void actionPerformed(ActionEvent e) {
game.checkGuess(lower);
}
});
button.setBounds(x, 250, 5, 5);
button.setVisible(true);
this.add(button);
}
请注意，我已经定义了一个匿名的每个按钮ActionListener，因此无需保留对数组中按钮的引用。
答案 1 :(得分：-1)
我发现你必须打电话给$('body').on('click', '.username', function(e) {
console.log('hello!');
});
它才能显示按钮，而super.paint(g);你需要拨打void addLetters()，这样你就可以设置尺寸和位置按钮。我还通过循环添加了按钮以消除不必要的重复。我的this.setLayout(null);和paint()方法位于
paint（）方法
addLetters()addLetters（）方法
/**
* paint the graphics to the screen
*/
public void paint(Graphics g)
{
//paint code goes here some parts were omitted as they are irrelevant to the post
super.paint(g);
repaint();
}
答案 2 :(得分：-2)
我是安迪·特纳在评论中提到的第二个：你的代码有很多不必要的重复，因为你没有使用数组和/或集合，比如ArrayLists，但正如他所指出的那样，这不是你麻烦的原因。
一个问题是你在组件上使用setBounds(...)但忘记了布局管理器通常会忽略边界，位置和大小属性。请记住，JPanels默认使用FlowLayout，因此将根据此布局管理器和组件的首选大小放置和调整组件，并忽略您的边界。一种解决方案是使用null布局，但这导致丑陋的GUI在除了一个平台之外的所有平台上看起来很糟糕，并且难以调试和维护。不，学会使用然后使用布局管理器。请记住，您可以嵌套JPanel，每个都使用自己的布局，从而使用简单的布局管理器实现复杂的布局。
此外，你要重写JPanel的paint方法，但不要调用super的方法，这可能会导致严重的副作用。而是覆盖paintComponent，而不是绘制，并在覆盖中调用super的方法。
关于测试代码的注意事项，调用super.paint(g);作为paint方法的第一行显示按钮，但位置错误。
请注意，不是直接在JPanel上绘制，而是使用挂钩创建BufferedImages，创建图像的ImageIcons，然后通过调用JLabel上的setIcon(...)在JLabel中绘制它们。
例如，您可以使用JPanel保存GridLayout中的按钮：
import java.awt.BorderLayout;
import java.awt.Dimension;
import java.awt.Font;
import java.awt.GridLayout;
import java.util.ArrayList;
import java.util.List;
import javax.swing.*;
public class Hangman2 extends JPanel {
private static final int GAP = 5;
// best to create ImageIcons where you draw your Hangman in, and
// then display it in a JLabel by calling setIcon(...) on the label.
private JLabel imageLabel = new JLabel();
private List<Icon> iconList = createIcons();
public Hangman2() {
JLabel titleLabel = new JLabel("Welcome to Hangman", SwingConstants.CENTER);
titleLabel.setFont(titleLabel.getFont().deriveFont(Font.BOLD, 40f));
JPanel buttonPanel = createButtonPanel();
setBorder(BorderFactory.createEmptyBorder(GAP, GAP, GAP, GAP));
setLayout(new BorderLayout());
add(titleLabel, BorderLayout.PAGE_START);
add(buttonPanel, BorderLayout.PAGE_END);
// placeholder component just to show something in the center of the GUI
add(Box.createRigidArea(new Dimension(200, 200)), BorderLayout.CENTER);
}
private List<Icon> createIcons() {
List<Icon> iconList = new ArrayList<>();
// TODO: create hangman drawing icons and place into array
return iconList;
}
private JPanel createButtonPanel() {
int rows = 2;
int cols = 16;
JPanel buttonPanel = new JPanel(new GridLayout(rows, cols, GAP, GAP));
// number of empty JLabels in the beginning and end of the bottom row
int labelCount = (2 * 16 - ('Z' - 'A' + 1)) / 2;
for (char c = 'A'; c <= 'Z'; c++) {
if (c - 'A' == cols) { // at 2nd row, add empty JLabels
for (int i = 0; i < labelCount; i++) {
buttonPanel.add(new JLabel());
}
}
JButton button = new JButton("" + c);
buttonPanel.add(button);
}
for (int i = 0; i < labelCount; i++) {
buttonPanel.add(new JLabel());
}
return buttonPanel;
}
private static void createAndShowGui() {
JFrame frame = new JFrame("Hangman");
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
frame.getContentPane().add(new Hangman2());
frame.pack();
frame.setLocationRelativeTo(null);
frame.setVisible(true);
}
public static void main(String[] args) {
SwingUtilities.invokeLater(() -> createAndShowGui());
}
}