当展示一组JRadioButtons时,初始状态下没有一个被选中(除非您通过编程强制执行)。我希望能够在用户已经选择其中一个之后,将按钮重新放回到该状态,即没有任何一个按钮被选中。
然而,使用通常的方法并不能达到所需的效果:对每个按钮调用“setSelected(false)”无效。有趣的是,当按钮没有放入ButtonGroup时,它确实起作用-不幸的是,后者是JRadioButtons互斥所必需的。
此外,使用javax.swing.ButtonGroup的setSelected(ButtonModel, boolean)方法也不能满足我的要求。
我编写了一个小程序来演示这种效果:两个单选按钮和一个JButton。单击JButton应取消选中单选按钮,以便窗口看起来与首次弹出时完全相同。
有什么想法吗?谢谢!
然而,使用通常的方法并不能达到所需的效果:对每个按钮调用“setSelected(false)”无效。有趣的是,当按钮没有放入ButtonGroup时,它确实起作用-不幸的是,后者是JRadioButtons互斥所必需的。
此外,使用javax.swing.ButtonGroup的setSelected(ButtonModel, boolean)方法也不能满足我的要求。
我编写了一个小程序来演示这种效果:两个单选按钮和一个JButton。单击JButton应取消选中单选按钮,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);
}
}
有什么想法吗?谢谢!