直接从 Oracle 的关于制作内部框架的 Java 教程复制并粘贴此代码:(注释是 Oracle 的,不是我的。)在右边距标记错误位置和注释“此处发生错误”。计算机说 MyInternalFrame “无法解析输入”。
package components;
import javax.swing.JInternalFrame;
import javax.swing.JDesktopPane;
import javax.swing.JMenu;
import javax.swing.JMenuItem;
import javax.swing.JMenuBar;
import javax.swing.JFrame;
import javax.swing.KeyStroke;
import java.awt.event.*;
import java.awt.*;
public class InternalFrameDemo extends JFrame
implements ActionListener {
JDesktopPane desktop;
public InternalFrameDemo() {
super("InternalFrameDemo");
//Make the big window be indented 50 pixels from each edge
//of the screen.
int inset = 50;
Dimension screenSize = Toolkit.getDefaultToolkit().getScreenSize();
setBounds(inset, inset,
screenSize.width - inset*2,
screenSize.height - inset*2);
//Set up the GUI.
desktop = new JDesktopPane(); //a specialized layered pane
createFrame(); //create first "window"
setContentPane(desktop);
setJMenuBar(createMenuBar());
//Make dragging a little faster but perhaps uglier.
desktop.setDragMode(JDesktopPane.OUTLINE_DRAG_MODE);
}
protected JMenuBar createMenuBar() {
JMenuBar menuBar = new JMenuBar();
//Set up the lone menu.
JMenu menu = new JMenu("Document");
menu.setMnemonic(KeyEvent.VK_D);
menuBar.add(menu);
//Set up the first menu item.
JMenuItem menuItem = new JMenuItem("New");
menuItem.setMnemonic(KeyEvent.VK_N);
menuItem.setAccelerator(KeyStroke.getKeyStroke(
KeyEvent.VK_N, ActionEvent.ALT_MASK));
menuItem.setActionCommand("new");
menuItem.addActionListener(this);
menu.add(menuItem);
//Set up the second menu item.
menuItem = new JMenuItem("Quit");
menuItem.setMnemonic(KeyEvent.VK_Q);
menuItem.setAccelerator(KeyStroke.getKeyStroke(
KeyEvent.VK_Q, ActionEvent.ALT_MASK));
menuItem.setActionCommand("quit");
menuItem.addActionListener(this);
menu.add(menuItem);
return menuBar;
}
//React to menu selections.
public void actionPerformed(ActionEvent e) {
if ("new".equals(e.getActionCommand())) { //new
createFrame();
} else { //quit
quit();
}
}
//Create a new internal frame.
protected void createFrame() {
MyInternalFrame frame = new MyInternalFrame(); //Error occurs here//
frame.setVisible(true); //necessary as of 1.3
desktop.add(frame);
try {
frame.setSelected(true);
} catch (java.beans.PropertyVetoException e) {}
}
//Quit the application.
protected void quit() {
System.exit(0);
}
/**
* Create the GUI and show it. For thread safety,
* this method should be invoked from the
* event-dispatching thread.
*/
private static void createAndShowGUI() {
//Make sure we have nice window decorations.
JFrame.setDefaultLookAndFeelDecorated(true);
//Create and set up the window.
InternalFrameDemo frame = new InternalFrameDemo();
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
//Display the window.
frame.setVisible(true);
}
public static void main(String[] args) {
//Schedule a job for the event-dispatching thread:
//creating and showing this application's GUI.
javax.swing.SwingUtilities.invokeLater(new Runnable() {
public void run() {
createAndShowGUI();
}
});
}
}