在 Java Swing 中取消选择单选按钮
2022-09-01 03:01:20
显示一组 JRadioButton 时,最初不会选择任何一个(除非您以编程方式强制执行)。我希望即使在用户已经选择了按钮之后,也能够将按钮放回该状态,即,不应选择任何按钮。
但是,使用通常的可疑指标并不能提供所需的效果:在每个按钮上调用“setSelected(false)”不起作用。有趣的是,当按钮没有放入ButtonGroup时,它确实有效 - 不幸的是,后者是JRadioButtons相互排斥所必需的。
另外,使用 setSelected(ButtonModel,布尔值) - javax.swing.ButtonGroup 的方法不能做我想要的。
我整理了一个小程序来演示效果:两个单选按钮和一个JButton。单击 JButton 应取消选择单选按钮,以便窗口看起来与首次弹出时完全相同。
import java.awt.Container;
import java.awt.GridLayout;
import java.awt.event.*;
import javax.swing.*;
/**
* This class creates two radio buttons and a JButton. Initially, none
* of the radio buttons is selected. Clicking on the JButton should
* always return the radio buttons into that initial state, i.e.,
* should disable both radio buttons.
*/
public class RadioTest implements ActionListener {
/* create two radio buttons and a group */
private JRadioButton button1 = new JRadioButton("button1");
private JRadioButton button2 = new JRadioButton("button2");
private ButtonGroup group = new ButtonGroup();
/* clicking this button should unselect both button1 and button2 */
private JButton unselectRadio = new JButton("Unselect radio buttons.");
/* In the constructor, set up the group and event listening */
public RadioTest() {
/* put the radio buttons in a group so they become mutually
* exclusive -- without this, unselecting actually works! */
group.add(button1);
group.add(button2);
/* listen to clicks on 'unselectRadio' button */
unselectRadio.addActionListener(this);
}
/* called when 'unselectRadio' is clicked */
public void actionPerformed(ActionEvent e) {
/* variant1: disable both buttons directly.
* ...doesn't work */
button1.setSelected(false);
button2.setSelected(false);
/* variant2: disable the selection via the button group.
* ...doesn't work either */
group.setSelected(group.getSelection(), false);
}
/* Test: create a JFrame which displays the two radio buttons and
* the unselect-button */
public static void main(String[] args) {
JFrame frame = new JFrame();
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
RadioTest test = new RadioTest();
Container contentPane = frame.getContentPane();
contentPane.setLayout(new GridLayout(3,1));
contentPane.add(test.button1);
contentPane.add(test.button2);
contentPane.add(test.unselectRadio);
frame.setSize(400, 400);
frame.setVisible(true);
}
}
任何人的任何想法?谢谢!