如何使JToolBar设计时停靠在Frame的左(右)边框

Question

JToolBar在运行时是可以用拖动使其停靠在左(右)边框的,请问怎样在设计时就使它停靠在Frame的左(右)边框?不胜感激

Answer 1

import javax.swing.JToolBar;
import javax.swing.JButton;
import javax.swing.ImageIcon;import javax.swing.JFrame;
import javax.swing.JTextArea;
import javax.swing.JScrollPane;
import javax.swing.JPanel;import java.net.URL;import java.awt.BorderLayout;
import java.awt.GridLayout;
import java.awt.Dimension;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import javax.swing.SwingConstants;public class ToolBarDemo extends JPanel
                         implements ActionListener {
    protected JTextArea textArea;
    protected String newline = "\n";
    static final private String PREVIOUS = "previous";
    static final private String UP = "up";
    static final private String NEXT = "next";    public ToolBarDemo() {
        super(new BorderLayout());        // 创建工具条 
        JToolBar toolBar = new JToolBar("Still draggable");
        addButtons(toolBar);

// 设定显示
toolBar.setOrientation(SwingConstants.VERTICAL);

        textArea = new JTextArea(5, 30);
        textArea.setEditable(false);
        JScrollPane scrollPane = new JScrollPane(textArea);        //Lay out the main panel.
        setPreferredSize(new Dimension(450, 130));
        
        // 显示在左边
        add(toolBar, BorderLayout.LINE_START);
        add(scrollPane, BorderLayout.CENTER);
    }    protected void addButtons(JToolBar toolBar) {
        JButton button = null;        //first button
        button = makeNavigationButton("Back24", PREVIOUS,
                                      "Back to previous something-or-other",
                                      "Previous");
        toolBar.add(button);        //second button
        button = makeNavigationButton("Up24", UP,
                                      "Up to something-or-other",
                                      "Up");
        toolBar.add(button);        //third button
        button = makeNavigationButton("Forward24", NEXT,
                                      "Forward to something-or-other",
                                      "Next");
        toolBar.add(button);
    }    protected JButton makeNavigationButton(String imageName,
                                           String actionCommand,
                                           String toolTipText,
                                           String altText) {
        //Look for the image.
        String imgLocation = "toolbarButtonGraphics/navigation/"
                             + imageName
                             + ".gif";
        URL imageURL = ToolBarDemo.class.getResource(imgLocation);        //Create and initialize the button.
        JButton button = new JButton();
        button.setActionCommand(actionCommand);
        button.setToolTipText(toolTipText);
        button.addActionListener(this);        if (imageURL != null) {                      //image found
            button.setIcon(new ImageIcon(imageURL, altText));
        } else {                                     //no image found
            button.setText(altText);
            System.err.println("Resource not found: "
                               + imgLocation);
        }        return button;
    }    public void actionPerformed(ActionEvent e) {
        String cmd = e.getActionCommand();
        String description = null;        // Handle each button.
        if (PREVIOUS.equals(cmd)) { //first button clicked
            description = "taken you to the previous <something>.";
        } else if (UP.equals(cmd)) { // second button clicked
            description = "taken you up one level to <something>.";
        } else if (NEXT.equals(cmd)) { // third button clicked
            description = "taken you to the next <something>.";
        }        displayResult("If this were a real app, it would have "
                        + description);
    }    protected void displayResult(String actionDescription) {
        textArea.append(actionDescription + newline);
        textArea.setCaretPosition(textArea.getDocument().getLength());
    }    /**
     * 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.
        JFrame frame = new JFrame("ToolBarDemo");
        frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);        //Create and set up the content pane.
        ToolBarDemo newContentPane = new ToolBarDemo();
        newContentPane.setOpaque(true); //content panes must be opaque
        frame.setContentPane(newContentPane);        //Display the window.
        frame.pack();
        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();
            }
        });
    }
}