我试图创建一个程序，你按下开始，一个新的JFrame出现3个按钮，你必须在使用随机点击它后切换按钮，我相当新的java所以我不知道该怎么做。谢谢
package code;
import java.awt.FlowLayout;
import java.awt.Font;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import java.util.Random;
import javax.swing.JButton;
import javax.swing.JFrame;
import javax.swing.Timer;
public class StartListener implements java.awt.event.ActionListener {
private int counter;
private Game Ga;
private JFrame z;
private int x;
public StartListener(Game a, int co){
Ga=a;
counter = co;
}
public void actionPerformed(ActionEvent e) {
Timer time = new Timer(10000,new Time(Ga));
time.start();
z = new JFrame("Sequence game");
FlowLayout fl = new FlowLayout(0, 50, 40);
z.getContentPane().setLayout(fl);
z.setVisible(true);
JButton a = new JButton("A");
Font f = a.getFont();
Font myFont = f.deriveFont(Font.BOLD, f.getSize()*4);
a.setSize(200,100);
a.setVisible(true);
JButton b = new JButton("B");
b.setVisible(true);
b.setSize(200,100);
JButton c = new JButton("C");
c.setVisible(true);
c.setSize(200,100);
z.getContentPane().add(a);
z.getContentPane().add(b);
z.getContentPane().add(c);
z.pack();
Random r = new Random();
x=r.nextInt(3);
figure(a,b,c,x,myFont,f);}
public void figure(JButton a,JButton b, JButton c, int x, Font myFont,Font f){
if(x==0){
a.setEnabled(true);
b.setEnabled(false);
c.setEnabled(false);
a.setFont(myFont);
b.setFont(f);
c.setFont(f);
x =buttonA(a);
figure(a,b,c,x,myFont,f);
;}
else if(x==1){
a.setEnabled(false);
b.setEnabled(true);
c.setEnabled(false);
a.setFont(f);
c.setFont(f);
b.setFont(myFont);
x = buttonB(b);
figure(a,b,c,x,myFont,f);
}
else if(x==2){
a.setEnabled(false);
b.setEnabled(false);
c.setEnabled(true);
a.setFont(f);
b.setFont(f);
c.setFont(myFont);
x = buttonC(c);
figure(a,b,c,x,myFont,f);
}
}
public int buttonA(JButton a){
Random r = new Random();
int rand = 0;
a.addActionListener(new Something(Ga));
rand = r.nextInt(3);
return rand;
}
public int buttonB(JButton b){
Random r = new Random();
int rand = 0;
b.addActionListener(new Something(Ga));
rand=r.nextInt(3);
return rand;
}
public int buttonC(JButton c){
Random r = new Random();
int rand=0;
c.addActionListener(new Something(Ga));
rand = r.nextInt(3);
return rand;
}
}
这里是Something的代码
package code;
import java.awt.Font;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
public class Something implements ActionListener {
private Game G;
public Something(Game a){
G = a;
}
public void actionPerformed(ActionEvent e) {
// TODO Auto-generated method stub
G.increment();
}
}
这是错误：
Exception in thread "AWT-EventQueue-0" java.lang.StackOverflowError
at java.awt.Component.enable(Unknown Source)
at java.awt.Component.setEnabled(Unknown Source)
at javax.swing.JComponent.setEnabled(Unknown Source)
at javax.swing.AbstractButton.setEnabled(Unknown Source)
答案 0 :(得分：2)
您的figure方法会不断地递归调用自身，或直到堆栈空间耗尽。解决方案：摆脱那些递归调用。另外，你真的不想继续向JButtons添加多个ActionListener，所有这些都表明你需要重构并重新设计整个程序。
您需要更改类中字段的状态，并使用该字段的状态来决定在ActionListener中执行的操作。
例如：
import java.awt.Dimension;
import java.awt.Font;
import java.awt.GridLayout;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import java.util.ArrayList;
import java.util.List;
import javax.swing.*;
@SuppressWarnings("serial")
public class SwapButtons extends JPanel {
private static final Font ACTIVE_FONT = new Font(Font.DIALOG, Font.BOLD, 15);
private static final String[] BTN_TEXT = { "Monday", "Tuesday", "Wednesday" };
private static final int EXTRA_WIDTH = 50;
private List<AbstractButton> buttonList = new ArrayList<>();
private int buttonIndex = 0;
public SwapButtons() {
setLayout(new GridLayout(1, 0, 5, 0));
BtnListener btnListener = new BtnListener();
for (int i = 0; i < BTN_TEXT.length; i++) {
JButton button = new JButton(BTN_TEXT[i]);
button.addActionListener(btnListener);
buttonList.add(button); // add to ArrayList
add(button); // add to GUI
}
setActiveButton();
setBorder(BorderFactory.createEmptyBorder(5, 5, 5, 5));
}
@Override
public Dimension getPreferredSize() {
Dimension superSz = super.getPreferredSize();
if (isPreferredSizeSet()) {
return superSz;
}
// give preferred size extra width so gui can handle larger fonts
int prefW = superSz.width + EXTRA_WIDTH;
int prefH = superSz.height;
return new Dimension(prefW, prefH);
}
private void setActiveButton() {
// iterate through buttonList, turning on the "active" button
// as determined by the buttonIndex variable
for (int i = 0; i < buttonList.size(); i++) {
if (i == buttonIndex) {
buttonList.get(i).setFont(ACTIVE_FONT);
buttonList.get(i).setEnabled(true);
} else {
buttonList.get(i).setFont(null);
buttonList.get(i).setEnabled(false);
}
}
}
private class BtnListener implements ActionListener {
@Override
public void actionPerformed(ActionEvent e) {
// show which button pressed
System.out.println("Button Pressed: " + e.getActionCommand());
// advance button index so that next button can be activated
buttonIndex++;
// but change index to 0 if buttonList size is reached
buttonIndex %= buttonList.size();
// activate the next button:
setActiveButton();
}
}
private static void createAndShowGui() {
SwapButtons mainPanel = new SwapButtons();
JFrame frame = new JFrame("Swap Buttons");
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(new Runnable() {
public void run() {
createAndShowGui();
}
});
}
}