我正在尝试制作一个弹出面板,该面板在JToggleButton的帮助下激活。我希望当选择toggleButton并在取消切换时隐藏时,我希望将jpanel添加到另一个jpanel中。
我已经声明了jtogglebutton并使用了itemListener。但是发生的事情是,当我选择togglebutton时,如果我取消选择并再次选择了一个面板时,再次添加了另一个jpanel,则在5次点击之后,什么也不会出现。
。public static JPanel createDesignButtons(){
designButtonsPanel.setOpaque(false);
BoxLayout boxLayout = new BoxLayout(designButtonsPanel, BoxLayout.LINE_AXIS);
designButtonsPanel.setLayout(boxLayout);
mainButton.setIcon(Icons.venueIcon);
mainButton.setBorderPainted(false);
mainButton.setPreferredSize(new Dimension(40,40));
mainButton.addItemListener(new ItemListener() {
public void itemStateChanged(ItemEvent ev) {
if(ev.getStateChange()==ItemEvent.SELECTED){
designButtonsPanel.add(createButtonsDialog());
designButtonsPanel.validate();
} else if(ev.getStateChange()==ItemEvent.DESELECTED){
System.out.println("button is not selected");
}
}
});
designButtonsPanel.add(mainButton);
JLabel padding = new JLabel(" ");
padding.setPreferredSize(null);
JLabel divider = new JLabel("", Icons.dividerIcon, JLabel.CENTER);
divider.setPreferredSize(new Dimension(3,45));
designButtonsPanel.add(divider);
SwingUtilities.updateComponentTreeUI(designButtonsPanel);
return(designButtonsPanel);
}
上面的代码显示mainbutton是我想要动作的toggleButton,而DesignButtonPanel是父母。
。public static JPanel createButtonsDialog(){
JPanel buttonsPanel = new JPanel();
buttonsPanel.setBorder(new LineBorder(Color.gray,1));
return buttonsPanel;
}
此类显示我想添加到父面板上的面板
选择JToggleButton并在取消选择时隐藏时,如何仅添加面板一次?
问题是您继续创建JPanel
的实例。如果未选择JToggleButton
,则可以remove
JPanel
,如果选择按钮,则可以添加JPanel
的实例。请参阅此简单示例:
public class MainFrame extends JFrame {
private JPanel topPanel = new JPanel();
private JPanel centerPanel = new JPanel();
private JToggleButton toggleButton = new JToggleButton("Toggle");
public MainFrame() {
this.setVisible(true);
this.setDefaultCloseOperation(EXIT_ON_CLOSE);
this.setLayout(new BorderLayout());
this.topPanel.setPreferredSize(new Dimension(100, 100));
this.centerPanel.setPreferredSize(new Dimension(100, 100));
this.toggleButton.setPreferredSize(new Dimension(100, 100));
this.add(topPanel, BorderLayout.NORTH);
this.add(centerPanel, BorderLayout.CENTER);
this.add(toggleButton, BorderLayout.SOUTH);
this.toggleButton.addItemListener(new ItemListener() {
@Override
public void itemStateChanged(ItemEvent e) {
if(e.getStateChange() == ItemEvent.SELECTED) {
add(centerPanel, BorderLayout.CENTER);
} else {
remove(centerPanel);
}
pack();
}
});
this.pack();
this.setVisible(true);
}
}
您可以看到centerPanel
仅实例化一次。