1.原理
????????原理非常簡單：就是一個(gè)JLabel和JPanel荣挨。Jlabel顯示標(biāo)題文字以及標(biāo)明控件當(dāng)前是處于展開還是折疊狀態(tài)的圖片植旧；而JPanel主要就一個(gè)作用——承載控件的容器艇潭。JLabel通過響應(yīng)鼠標(biāo)事件來控制JPanel是否顯示。這樣就可以達(dá)到折疊或展開的效果。
2.代碼
public class JShrinkablePanel extends JPanel {
private JLabellabel;
private Stringtitle ="";
private JPanelcontentPanel =null;
private boolean isExpanded =true;
private JListlist =new JList();
private IconiconExpand =null;
private IconiconCollapse =null;
public JShrinkablePanel(String title, JPanel contentPanel) {
super();
this.title = title;
this.contentPanel = contentPanel;
initComponents();
initComponentsStatus();
initLayout();
initResources();
unRegisterEvents();
registerEvents();
}
private void initComponents() {
this.label =new JLabel();
}
private void initComponentsStatus() {
this.label.setHorizontalAlignment(JLabel.LEFT);
this.label.setVerticalAlignment(JLabel.CENTER);
this.label.setVerticalTextPosition(JLabel.CENTER);
this.label.setBackground(this.list.getSelectionBackground());
this.iconExpand =new ImageIcon("src/Resources/Expand.png");
this.iconCollapse =new ImageIcon("src/Resources/Collapse.png");
}
private void initLayout() {
this.setLayout(new GridBagLayout());
this.add(this.label,new GridBagConstraints(0,0,1,1,1,0, GridBagConstraints.WEST, GridBagConstraints.HORIZONTAL,new Insets(0,0,0,0),0,0));
this.add(this.contentPanel,new GridBagConstraints(0,1,1,1,1,0, GridBagConstraints.WEST, GridBagConstraints.HORIZONTAL,new Insets(0,0,0,0),0,0));
}
private void initResources() {
this.label.setIcon(this.iconExpand);
this.label.setText(this.title);
}
private void unRegisterEvents() {
this.label.removeMouseListener(this.mouseListener);
}
private void registerEvents() {
this.label.addMouseListener(this.mouseListener);
}
private MouseListenermouseListener =new MouseAdapter() {
@Override
public void mouseClicked(MouseEvent e) {
isExpanded = !isExpanded;
panelVisible();
}
@Override
public void mouseEntered(MouseEvent e) {
label.setOpaque(true);
label.repaint();
}
@Override
public void mouseExited(MouseEvent e) {
label.setOpaque(false);
label.repaint();
}
};
private void panelVisible() {
this.contentPanel.setVisible(this.isExpanded);
this.label.setIcon(this.isExpanded ?this.iconExpand :this.iconCollapse);
}
public static void main(String[] args) {
JFrame jf =new JFrame("JShrinkablePanel");
jf.setBounds(400,200,400,300);
jf.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
JPanel panel=new JPanel();
panel.add(new JButton("Just for show"));
panel.setBorder(BorderFactory.createTitledBorder("Border"));
JShrinkablePanel scrollPane=new JShrinkablePanel("TestJShrinkablePanel",panel);
jf.add(scrollPane);
jf.setVisible(true);
}
}
3.效果
panel展開鼠標(biāo)在標(biāo)題Label上
panel展開鼠標(biāo)沒在標(biāo)題Label上
panel折疊鼠標(biāo)在標(biāo)題Label上
panel折疊鼠標(biāo)沒在標(biāo)題Label上
