预览窗口（如打开的应用程序的Windows 7任务栏显示）

我想为我的“主窗口”创建一个“预览窗口”，所以如果我将鼠标指针指向特定的按钮或位置，那么它会在一个小窗口中显示主窗口预览，当我点击那个“预览窗口”时它应该返回“主窗口”。 例如，Windows 7任务栏为每个打开的应用程序创建预览。 我该如何向用户提供此function？

例如

Answer 1

一个非常简单的实现。

import java.awt.*; import java.awt.image.*; import java.awt.event.*; import javax.swing.*; class ShowPreviews { class ToolTipListener extends MouseAdapter { JWindow toolTip; JLabel label; Component preview; ToolTipListener(Component preview) { this.preview = preview; } @Override public void mouseEntered(MouseEvent me) { if (toolTip==null) { toolTip = new JWindow(); label = new JLabel(); toolTip.add(label); } label.setIcon( new ImageIcon( getScaledImageOfComponent(preview, .6) ) ); toolTip.pack(); Component c = (Component)me.getSource(); int x = c.getLocationOnScreen().x+(c.getWidth()/2); int y = c.getLocationOnScreen().y+c.getHeight(); toolTip.setLocation(x,y); toolTip.setVisible(true); } @Override public void mouseExited(MouseEvent me) { toolTip.setVisible(false); toolTip.dispose(); } public Image getScaledImageOfComponent( Component component, double scale) { BufferedImage bi = new BufferedImage( (int)(component.getWidth()*scale), (int)(component.getHeight()*scale), BufferedImage.TYPE_INT_RGB); Graphics2D g = bi.createGraphics(); g.scale(scale, scale); component.paint(g); g.dispose(); return bi; } } ShowPreviews() { JPanel gui = new JPanel(new BorderLayout(2,2)); final CardLayout cards = new CardLayout(); final JPanel cardPanel = new JPanel(cards); JPanel treePanel = new JPanel(); JTree tree = new JTree(); tree.setVisibleRowCount(5); tree.expandRow(2); treePanel.add(new JScrollPane(tree)); cardPanel.add(treePanel, "tree"); JPanel labelPanel = new JPanel(new GridLayout(0,1,2,2)); for (int ii=1; ii<7; ii++) { labelPanel.add(new JLabel("Label " + ii)); } cardPanel.add(new JScrollPane(labelPanel), "label"); JToolBar uiSelectors = new JToolBar(); // we should use a ButtonGroup for the cards, // but plain buttons look better on hover. JButton treeButton = new JButton("Tree"); treeButton.addActionListener(new ActionListener(){ public void actionPerformed(ActionEvent ae) { cards.show(cardPanel, "tree"); } }); uiSelectors.add(treeButton); treeButton.addMouseListener( new ToolTipListener(treePanel)); JButton labelButton = new JButton("Label"); labelButton.addActionListener(new ActionListener(){ public void actionPerformed(ActionEvent ae) { cards.show(cardPanel, "label"); } }); uiSelectors.add(labelButton); labelButton.addMouseListener( new ToolTipListener(labelPanel)); gui.add(uiSelectors, BorderLayout.NORTH); gui.add(cardPanel, BorderLayout.CENTER); JOptionPane.showMessageDialog(null, gui); } public static void main(String[] args) { // start the GUI on the EDT SwingUtilities.invokeLater(new Runnable() { @Override public void run() { new ShowPreviews(); } }); } }