我收到此错误的ItemListener和ItemEvent行。我把**放在哪里。无法解析为类型?
import java.awt.FlowLayout;
import java.awt.Font;
import java.awt.event.ActionListener;
import java.awt.event.ActionEvent;
import javax.swing.JFrame;
import javax.swing.JButton;
import javax.swing.JCheckBox;
import javax.swing.Icon;
import javax.swing.ImageIcon;
import javax.swing.JOptionPane;
import javax.swing.JTextField;
public class gui extends JFrame {
private JTextField tf;
private JCheckBox boldbox;
private JCheckBox italicbox;
public gui() {
super("The title");
setLayout(new FlowLayout());
tf = new JTextField("This is a sentence", 20);
tf.setFont(new Font("Serif", Font.PLAIN, 14));
add(tf);
boldbox = new JCheckBox("bold");
italicbox = new JCheckBox("italic");
add(boldbox);
add(italicbox);
HandlerClass handler = new HandlerClass();
boldbox.addItemListener(handler);
italicbox.addItemListener(handler);
}
private class HandlerClass implements *ActionListener* {
public void itemStateChanged(*ActionEvent* event) {
Font font = null;
if (boldbox.isSelected()&& italicbox.isSelected())
font = new Font("Serif", Font.BOLD + Font.ITALIC, 14);
else if(boldbox.isSelected())
font = new Font("Serif", Font.BOLD, 14);
else if(italicbox.isSelected())
font = new Font("Serif", Font.ITALIC, 14);
else font = new Font("Serif", Font.PLAIN, 14);
tf.setFont(font);
}
}
}
你能帮我理解为什么我会得到那个错误吗?领导该教程的人不会得到这些错误。
编辑:
import java.awt.FlowLayout;
import java.awt.Font;
import java.awt.event.ActionListener;
import java.awt.event.ActionEvent;
import javax.swing.JFrame;
import javax.swing.JButton;
import javax.swing.JCheckBox;
import javax.swing.Icon;
import javax.swing.ImageIcon;
import javax.swing.JOptionPane;
import javax.swing.JTextField;
public class gui extends JFrame {
private JTextField tf;
private JCheckBox boldbox;
private JCheckBox italicbox;
public gui() {
super("The title");
setLayout(new FlowLayout());
tf = new JTextField("This is a sentence", 20);
tf.setFont(new Font("Serif", Font.PLAIN, 14));
add(tf);
boldbox = new JCheckBox("bold");
italicbox = new JCheckBox("italic");
add(boldbox);
add(italicbox);
HandlerClass handler = new HandlerClass();
boldbox.addActionListener(handler);
italicbox.addActionListener(handler);
}
private class HandlerClass implements ActionListener {
@Override
public void ActionPerformed(ActionEvent event) {
Font font = null;
if (boldbox.isSelected()&& italicbox.isSelected())
font = new Font("Serif", Font.BOLD + Font.ITALIC, 14);
else if(boldbox.isSelected())
font = new Font("Serif", Font.BOLD, 14);
else if(italicbox.isSelected())
font = new Font("Serif", Font.ITALIC, 14);
else font = new Font("Serif", Font.PLAIN, 14);
tf.setFont(font);
}
}
}
什么是'ItemListener'和'ItemEvent'?你是否错过了他们的进口报告和/或他们的实际定义? – luk2302