Question

我在执行这项任务时遇到了麻烦，因为我是我的行动助手。现在，面板有2个复选框，可将字体更改为粗体或斜体。我想添加4个单选按钮，可以改变“说”的字体。任何人都可以告诉我我的动作者有什么问题吗？谢谢！

import javax.swing.*;
import java.awt.*;
import java.awt.event.*;

public class StyleOptionsPanel extends JPanel implements ActionListener, ItemListener
{
private JLabel saying;
private JCheckBox bold, italic; // have a button for style1, button for style2, button for style3
private JRadioButton style1, style2, style3, style4; //creates the buttons for each of the 4 styles
{
    bold = new JCheckBox ("Bold", true);
    italic = new JCheckBox ("Italic", true);

    style1 = new JRadioButton ("Arial", true);
    style2 = new JRadioButton ("Times New Roman", false);
    style3 = new JRadioButton ("Verdana", false);
    style4 = new JRadioButton ("Thonburi", false);

    //also check out quote options panel file for example of radio buttons.
    //after creating your radio buttons, you have to create a button group. copy line exactly from quote options panel
    //comedy = new JRadioButton ("Comedy", true); - example of assigning radio button
    //comedy.setBackground (Color.green);
    ButtonGroup group = new ButtonGroup(); //use this code for the homework
    group.add (style1);
    group.add (style2);
    group.add (style3);
    group.add (style4);

    style1.addActionListener (this);
    style2.addActionListener (this);
    style3.addActionListener (this);
    style4.addActionListener (this);

    add (style1);
    add (style2);
    add (style3);
    add (style4);
}
//-----------------------------------------------------------------
//  Sets up a panel with a label and some check boxes that
//  control the style of the label's font.
//-----------------------------------------------------------------
public StyleOptionsPanel()
{
    saying = new JLabel ("Say it with style!");
    saying.setFont (new Font ("Helvetica", Font.PLAIN, 36)); // we'll need this later

    bold = new JCheckBox ("Bold"); // what is in quotes doesn't have to match variable being created but it should be descriptive
    bold.setBackground (Color.green); // you can also set the background color of the checkbox
    italic = new JCheckBox ("Italic");
    italic.setBackground (Color.green); // this doesn't seem to change anything for me?

    //StyleListener listener = new StyleListener(); //whenever you create a textbox, you have to add a listener for it
    //bold.addActionListener (listener);
    //italic.addActionListener (listener);

    add (saying); //it matters what order these go in, it affects the way that your program looks
    add (bold);
    add (italic);
    add (style1);
    add (style2);
    add (style3);
    add (style4);

    setBackground (Color.cyan);
    setPreferredSize (new Dimension(300, 100));
}

//*****************************************************************
//  Represents the listener for both check boxes and the radio boxes.
//*****************************************************************
private class StyleListener implements ActionListener, ItemListener
{
    //--------------------------------------------------------------
    //  Updates the style of the label font style.
    //--------------------------------------------------------------
    public void itemStateChanged(ItemEvent e) 
    {
        int style = Font.PLAIN;

        if (bold.isSelected()) //this is a boolean statement, on the inside you will always expect some kind of boolean statement
            style = Font.BOLD;

        if (italic.isSelected())
            style += Font.ITALIC; // style += means that it takes whatever style the font already is and then adds the value Italic to it
        //public void actionPerformed (ActionEvent event) //also use this code in homework

        Object source = e.getSource();// TODO Auto-generated method stub

    }

    public void actionPerformed(ActionEvent e) // this is our bread and butter, it is basically what we will be changing
    {


        if (source == style1) //if (source == style1)
            saying.setText (Arial); //quote.setText(Helvetica)
        else (source == style2)
        saying.setText (TimesNewRoman);
        else (source == style3)
        saying.setText (Verdana);
        else (source == style4)
        saying.setText(Thonburi);
    }

}

@Override
public void itemStateChanged(ItemEvent e) {
    // TODO Auto-generated method stub

}

@Override
public void actionPerformed(ActionEvent e) {
    // TODO Auto-generated method stub

}

}

Answer 1

您将此作为ActionListener添加到单选按钮，但侦听器方法是在单独的StyleListener类中实现的。

Answer 2

如前所述，您正在添加错误的ActionListener。

StyleListener styleListener = new StyleListener();
style1.addActionListener(styleListener);
style2.addActionListener(styleListener);
style3.addActionListener(styleListener);
style4.addActionListener(styleListener);

你也应该对复选框

做同样的事情

bold.addItemListener(styleListener);
italic.addItemListener(styleListener);

你的主要StyleOptionsPanel不必是一个听众。

Java面板字体更改单选按钮问题

2 个答案: