如何在Swing中的复选框的itemStatechanged
事件中显示文本字段?
我正在尝试使用复选框和文本字段创建框架。我希望仅在选中复选框时才显示文本字段。因此,当我初始化组件时,我已将textfield.setvisible
设置为false
,并为复选框添加了addItemListener
并调用itemStateChanged
事件,并且复选框为选中后,我将setVisible
方法设置为true
。
我的SSCCE看起来像:
package ui;
public class Evaluator extends javax.swing.JFrame {
public Evaluator() {
initComponents();
}
private void initComponents() {
jCheckBox1 = new javax.swing.JCheckBox();
jTextField1 = new javax.swing.JTextField();
jTextField1.setVisible(false);
setDefaultCloseOperation(javax.swing.WindowConstants.EXIT_ON_CLOSE);
setPreferredSize(new java.awt.Dimension(800, 800));
jCheckBox1.setFont(new java.awt.Font("Tahoma", 0, 14));
jCheckBox1.setText("Properties");
jCheckBox1.addItemListener(new java.awt.event.ItemListener() {
public void itemStateChanged(java.awt.event.ItemEvent evt) {
jCheckBox1ItemStateChanged(evt);
}
});
jTextField1.setFont(new java.awt.Font("Tahoma", 0, 14));
javax.swing.GroupLayout layout = new javax.swing.GroupLayout(getContentPane());
getContentPane().setLayout(layout);
layout.setHorizontalGroup(
layout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING)
.addGroup(layout.createSequentialGroup()
.addContainerGap()
.addComponent(jCheckBox1)
.addGap(41, 41, 41)
.addComponent(jTextField1, javax.swing.GroupLayout.PREFERRED_SIZE, 109, javax.swing.GroupLayout.PREFERRED_SIZE)
.addContainerGap(155, Short.MAX_VALUE))
);
layout.setVerticalGroup(
layout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING)
.addGroup(javax.swing.GroupLayout.Alignment.TRAILING, layout.createSequentialGroup()
.addContainerGap(229, Short.MAX_VALUE)
.addGroup(layout.createParallelGroup(javax.swing.GroupLayout.Alignment.BASELINE)
.addComponent(jCheckBox1)
.addComponent(jTextField1, javax.swing.GroupLayout.PREFERRED_SIZE, 37, javax.swing.GroupLayout.PREFERRED_SIZE))
.addGap(34, 34, 34))
);
pack();
}
private void jCheckBox1ItemStateChanged(java.awt.event.ItemEvent evt) {
// TODO add your handling code here:
if(evt.getStateChange()== java.awt.event.ItemEvent.SELECTED){
jTextField1.setVisible(true);
}
}
public static void main(String args[]) {
try {
for (javax.swing.UIManager.LookAndFeelInfo info : javax.swing.UIManager.getInstalledLookAndFeels()) {
if ("Nimbus".equals(info.getName())) {
javax.swing.UIManager.setLookAndFeel(info.getClassName());
break;
}
}
} catch (ClassNotFoundException ex) {
java.util.logging.Logger.getLogger(Evaluator.class.getName()).log(java.util.logging.Level.SEVERE, null, ex);
} catch (InstantiationException ex) {
java.util.logging.Logger.getLogger(Evaluator.class.getName()).log(java.util.logging.Level.SEVERE, null, ex);
} catch (IllegalAccessException ex) {
java.util.logging.Logger.getLogger(Evaluator.class.getName()).log(java.util.logging.Level.SEVERE, null, ex);
} catch (javax.swing.UnsupportedLookAndFeelException ex) {
java.util.logging.Logger.getLogger(Evaluator.class.getName()).log(java.util.logging.Level.SEVERE, null, ex);
}
java.awt.EventQueue.invokeLater(new Runnable() {
public void run() {
new Evaluator().setVisible(true);
}
});
}
private javax.swing.JCheckBox jCheckBox1;
private javax.swing.JTextField jTextField1;
}
答案 0 :(得分:3)
基本上,您需要使框架(或父容器)无效以强制它重新布局
private void jCheckBox2ItemStateChanged(java.awt.event.ItemEvent evt) {
jTextField1.setVisible(jCheckBox2.isSelected());
invalidate();
validate();
}
<强>更新强>
我还建议您避免将整个UI添加到顶级容器中,而是使用JPanel
作为基础组件并围绕它们构建UI。准备好后,只需将基本面板添加到您需要的顶级容器中即可。
答案 1 :(得分:3)
对于一个空间中的许多组件,请使用CardLayout
,如short example所示。
这是一个更具体的例子:
import java.awt.*;
import java.awt.event.*;
import javax.swing.*;
class CardLayoutDemo {
public static void main(String[] args) {
Runnable r = new Runnable () {
public void run() {
final JCheckBox show = new JCheckBox("Have Text", false);
JPanel ui = new JPanel(new
FlowLayout(FlowLayout.CENTER, 5, 5));
ui.add( show );
final CardLayout cl = new CardLayout();
final JPanel cards = new JPanel(cl);
ui.add(cards);
cards.add(new JPanel(), "notext");
cards.add(new JTextField(8), "text");
ItemListener al = new ItemListener(){
public void itemStateChanged(ItemEvent ie) {
if (show.isSelected()) {
cl.show(cards, "text");
} else {
cl.show(cards, "notext");
}
}
};
show.addItemListener(al);
JOptionPane.showMessageDialog(null, ui);
}
};
SwingUtilities.invokeLater(r);
}
}
答案 2 :(得分:3)
很好的教训,LayoutManager
如何运作,只有GridLayout
可以毫无问题地执行此操作,但这是其属性
行或列中的最后JComponent
(部分时间约为)can't be invisible
,然后容器缩小
最简单的work_around是显示容器,然后调用包含在setVisible(false)
中的invokeLater
...... ....
import java.awt.event.ItemEvent;
import javax.swing.JCheckBox;
import javax.swing.JFrame;
import javax.swing.JPanel;
import javax.swing.JTextField;
public class Evaluator {
private JFrame frame = new JFrame();
private JPanel panel = new JPanel();
private JCheckBox checkBox = new JCheckBox();
private JTextField textField = new JTextField(10);
public Evaluator() {
checkBox.setText("Properties");
checkBox.addItemListener(new java.awt.event.ItemListener() {
@Override
public void itemStateChanged(java.awt.event.ItemEvent evt) {
if (evt.getStateChange() == ItemEvent.SELECTED) {
textField.setVisible(true);
} else {
textField.setVisible(false);
}
}
});
//panel.setLayout(new GridLayout());
//panel.setLayout(new SpringLayout());
//panel.setLayout(new BorderLayout());
//panel.setLayout(new GridBagLayout());
//panel.setLayout(new BoxLayout(panel, BoxLayout.LINE_AXIS));
panel.add(checkBox/*, BorderLayout.NORTH*/);
panel.add(textField/*, BorderLayout.SOUTH*/);
//panel.doLayout();
//textField.setVisible(false);
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
frame.add(panel);
frame.pack();
frame.setVisible(true);
java.awt.EventQueue.invokeLater(new Runnable() {
@Override
public void run() {
textField.setVisible(false);
}
});
}
public static void main(String[] args) {
java.awt.EventQueue.invokeLater(new Runnable() {
@Override
public void run() {
Evaluator evaluator = new Evaluator();
}
});
}
}