问题描述
我目前正在添加功能并完成我的编程老师制作的 Hang-Man 游戏。
以下错误消息：线程“AWT-EventQueue-0”中的异常 java.lang.Stringindexoutofboundsexception：索引 0，长度为 0，字符串生成器中的每个索引的索引都在更改。每次我输入一个在游戏中正确猜出的字母时都会出现。
我已经尝试了一段时间来修复它，但我还没有能够。
package hangManSo;
import java.awt.Color;
import java.awt.Dimension;
import java.awt.FlowLayout;
import java.awt.Font;
import java.awt.Graphics;
import java.awt.Label;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import java.awt.event.MouseEvent;
import java.awt.event.MouseListener;
import java.util.Arrays;
import java.util.Random;
import javax.swing.JButton;
import javax.swing.JFrame;
import javax.swing.JLabel;
import javax.swing.JPanel;
import javax.swing.JTextField;
public class HangManSO extends JPanel implements ActionListener,MouseListener {
private int error;
JButton button;
JTextField field;
JFrame frame;
JLabel rättord;
HangManSO(JButton button,JTextField field,JFrame frame,JLabel rättord) {
this.button = button;
this.field = field;
this.frame = frame;
this.rättord = rättord;
this.addMouseListener(this);
}
static String [] ord = {"rome"};
static Random r = new Random();
static int randomNumber=r.nextInt(ord.length);
static String d = ord[randomNumber];
StringBuilder builder = new StringBuilder(d.length());
StringBuilder builderdisplay = new StringBuilder();
public void actionPerformed(ActionEvent e) {
Object source = e.getSource();
String guessedletter = field.getText();
if (source.equals(button)) {
if (!d.contains(guessedletter)) {
error++;
frame.repaint();
}
if (d.contains(guessedletter)) {
char [] randomWord = d.tochararray();
char CharGuessedLetter = guessedletter.charat(0);
//gets the index of the guessed letter in the randomword
builder.append(randomWord);
int index = builder.indexOf(String.valueOf(CharGuessedLetter));
//is supposed to set the correctly guessed letter in the correct index
builderdisplay.setCharat(index,CharGuessedLetter);
rättord.setText(builderdisplay.toString());
}
field.setText("");
}
}
public void paintComponent(Graphics g ) {
super.paintComponent(g);
if (error == 1)
g.drawLine(10,270,500,270);
if (error == 2) {
g.drawLine(10,270);
g.drawLine(200,30,200,270);
}
if (error == 3) {
g.drawLine(10,350,30);
}
if (error == 4) {
g.drawLine(10,30);
g.drawLine(200,30);
g.drawLine(250,75);
}
if (error == 5) {
g.drawLine(10,75);
g.drawLine(350,100);
}
if (error == 6) {
g.drawLine(10,100);
g.drawoval(330,100,40,40);
}
if (error == 7) {
g.drawLine(10,40);
g.drawLine(350,140,200);
}
if (error == 8) {
g.drawLine(10,200);
g.drawLine(350,390,240);
}
if (error == 9) {
g.drawLine(10,240);
g.drawLine(350,310,240);
}
if (error == 10) {
g.drawLine(10,170,400,150);
}
if (error == 11) {
g.drawLine(10,150);
g.drawLine(350,300,150);
}
if(error > 11) {
g.setFont(new Font("Calibri",Font.BOLD,26));
g.drawString("GAME OVER",225,150);
}
}
public static void main(String[] args) {
JFrame.setDefaultLookAndFeelDecorated(true);
JFrame frame = new JFrame("HangMan");
frame.setDefaultCloSEOperation(JFrame.EXIT_ON_CLOSE);
JLabel rubrikOrd = new JLabel("rätt gissade ord");
rubrikOrd.setopaque(false);
rubrikOrd.setBackground(Color.GREEN);
rubrikOrd.setBounds(10,10,20);
JLabel rättord = new JLabel();
rättord.setopaque(true);
rättord.setBackground(Color.GREEN);
rättord.setBounds(10,35,20);
JTextField field = new JTextField();
field.setVisible(true);
JButton b = new JButton("ok");
b.setBounds(370,30);
frame.add(b);
field.setSize(300,30);
field.setLocation(60,300);
field.setVisible(true);
frame.add(field);
frame.add(rättord);
frame.add(rubrikOrd);
frame.setBackground(Color.white);
frame.setSize(600,400);
HangManSO object = new HangManSO(b,field,frame,rättord);
b.addActionListener(object);
field.addActionListener(object);
frame.add(object);
frame.setVisible(true);
}
@Override
public void mouseClicked(MouseEvent e) {
System.out.println(e.getX() + " " + e.getY());
}
@Override
public void mousepressed(MouseEvent e) {
// Todo Auto-generated method stub
}
@Override
public void mouseReleased(MouseEvent e) {
// Todo Auto-generated method stub
}
@Override
public void mouseEntered(MouseEvent e) {
// Todo Auto-generated method stub
}
@Override
public void mouseExited(MouseEvent e) {
// Todo Auto-generated method stub
}
}
解决方法
代码过于复杂，让您很难看到问题所在。
您的实际问题从这一行开始，您将整个正确的单词 d 分配给 randomWord：
char [] randomWord = d.toCharArray();
//randomWord now equals `{r,o,m,e}`
然后您使用完整的正确单词并将其附加到您的 builder 字符串中：
//builder equals a blank string of 4 characters " "
builder.append(randomWord);
//builder now equals a string with 4 blank characters followed by some " rome"
System.out.print(builder.toString());
所以现在当您尝试获取字母的索引时，例如，如果您猜到了“m”，它将返回一个大索引：
//the builder string now " rome"
int index = builder.indexOf(String.valueOf(CharGuessedLetter));
//So `m` will be found at the 6th index of " rome"
System.out.print("index = " + index);
因此，当您使用索引为 6 的下一行时，它将越界，因为 builderDisplay 字符串对于单词 rome 来说只有 4 个字符长：
builderDisplay.setCharAt(index,CharGuessedLetter);
那么你能做些什么来解决这个问题？我不会给你一个确切的答案，但你应该首先考虑上面的代码，它出错的地方（append），以及如何返回正确的字符索引（使用 {{1} } 字符串)
最后的提示，下面这行会得到一个字符的正确字符索引，注意我们如何使用 d 字符串，而不是 d 字符串：
builder编辑：
关注评论。您还需要用空格填充字符串生成器以避免此问题：
int index = d.indexOf(String.valueOf(CharGuessedLetter));
另请注意，您应该检查单词中的重复字符：
//Create the hangman object
HangManSO object = new HangManSO(b,field,frame,rättord);
//Now populate the string builder with empty characters "_" or you could use a space " "
for (int i = 0; i < object.d.length(); i++) {
object.builderDisplay.append('_');
}