7

我有JFrame一个包含一组JPanels的CardLayout. 每个JPanel都有不同的大小，我希望JFrame适应当前显示的大小JPanel（而不是JPanel适应 的大小JFrame）。

我怎样才能做到这一点？

4

4 回答 4

15

一般是：如果您有布局问题，请始终使用适当的 LayoutManager 来解决。永远不要调整组件的大小提示来达到您的目标。

在这种情况下，调整 CardLayout 就特别容易。默认情况下，它会将其 prefSize 计算为所有卡的 prefSize 的最大值。只需子类化并实现以返回当前可见卡片的 prefSize（加上插图）：

public static class MyCardLayout extends CardLayout {

    @Override
    public Dimension preferredLayoutSize(Container parent) {

        Component current = findCurrentComponent(parent);
        if (current != null) {
            Insets insets = parent.getInsets();
            Dimension pref = current.getPreferredSize();
            pref.width += insets.left + insets.right;
            pref.height += insets.top + insets.bottom;
            return pref;
        }
        return super.preferredLayoutSize(parent);
    }

    public Component findCurrentComponent(Container parent) {
        for (Component comp : parent.getComponents()) {
            if (comp.isVisible()) {
                return comp;
            }
        }
        return null;
    }

}

使用它（借用@mKorbel 的示例），主要方法干净地缩小了：

private static void createAndShowUI() {
    final CardLayout cardLayout = new MyCardLayout();
    final JPanel cardHolder = new JPanel(cardLayout);
    final JFrame frame = new JFrame("MultiSizedPanels");
    JLabel[] labels = {
        new JLabel("Small Label", SwingConstants.CENTER),
        new JLabel("Medium Label", SwingConstants.CENTER),
        new JLabel("Large Label", SwingConstants.CENTER)};

    for (int i = 0; i < labels.length; i++) {
        int padding = 50 * (i + 1);
        Border lineBorder = BorderFactory.createCompoundBorder(
            BorderFactory.createLineBorder(Color.blue),
            BorderFactory.createEmptyBorder(padding, padding, padding, padding));
        labels[i].setBorder(lineBorder);
        JPanel containerPanel = new JPanel();
        containerPanel.add(labels[i]);
        cardHolder.add(containerPanel, String.valueOf(i));
    }
    JButton nextButton = new JButton("Next");
    nextButton.addActionListener(new ActionListener() {

        @Override
        public void actionPerformed(ActionEvent e) {
            cardLayout.next(cardHolder);
            frame.pack();
        }
    });
    JPanel btnHolder = new JPanel();
    btnHolder.add(nextButton);

    frame.add(cardHolder, BorderLayout.CENTER);
    frame.add(btnHolder, BorderLayout.SOUTH);
    frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
    frame.pack();
    frame.setLocation(150, 150);
    frame.setVisible(true);
}
于 2011-11-27T15:40:28.273 回答
4

这里是SSCCE。

1）对于大小的连续增加/减少，你应该寻找一些动画API。

或者

2) 如果没有任何后台任务输出到 GUI，您可以在调整JFrame. Thread#sleep(int)在这种情况下，您将通过使用包裹到Runnable线程来延迟增加/减少。

3) 在 EDT 期间直接使用的通知（不适用于 OP）Thread#sleep(int)将冻结 GUI，直到延迟结束。

import java.awt.*;
import java.awt.event.*;
import javax.swing.*;
import javax.swing.border.Border;
//based on HFOE http://stackoverflow.com/questions/5414177/change-size-of-jpanel-using-cardlayout/5414770#5414770
public class MultiSizedPanels {

    private static void createAndShowUI() {
        final CardLayout cardLayout = new CardLayout();
        final JPanel cardHolder = new JPanel(cardLayout);
        final JFrame frame = new JFrame("MultiSizedPanels");
        JLabel[] labels = {
            new JLabel("Small Label", SwingConstants.CENTER),
            new JLabel("Medium Label", SwingConstants.CENTER),
            new JLabel("Large Label", SwingConstants.CENTER)};

        for (int i = 0; i < labels.length; i++) {
            int padding = 50;
            Dimension size = labels[i].getPreferredSize();
            size = new Dimension(size.width + 2 * (i + 1) * padding, size.height + 2 * (i + 1) * padding);
            labels[i].setPreferredSize(size);
            Border lineBorder = BorderFactory.createLineBorder(Color.blue);
            labels[i].setBorder(lineBorder);
            JPanel containerPanel = new JPanel();
            if (i == 1) {
                containerPanel.setPreferredSize(new Dimension(300, 200));
                containerPanel.add(labels[i], BorderLayout.CENTER);
                cardHolder.add(containerPanel, String.valueOf(i));
            } else if (i == 2) {
                containerPanel.setPreferredSize(new Dimension(600, 400));
                containerPanel.add(labels[i], BorderLayout.CENTER);
                cardHolder.add(containerPanel, String.valueOf(i));
            } else {
                containerPanel.setPreferredSize(new Dimension(800, 600));
                containerPanel.add(labels[i], BorderLayout.CENTER);
                cardHolder.add(containerPanel, String.valueOf(i));
            }
        }
        JButton nextButton = new JButton("Next");
        nextButton.addActionListener(new ActionListener() {

            public void actionPerformed(ActionEvent e) {
                cardLayout.next(cardHolder);
                Dimension dim = new Dimension();
                for (Component comp : cardHolder.getComponents()) {
                    if (comp.isVisible() == true) {
                        dim = comp.getPreferredSize();
                    }
                }
                frame.setPreferredSize(dim);
                java.awt.EventQueue.invokeLater(new Runnable() {

                    public void run() {
                        frame.pack();
                    }
                });
            }
        });
        JPanel btnHolder = new JPanel();
        btnHolder.add(nextButton);

        frame.add(cardHolder, BorderLayout.CENTER);
        frame.add(btnHolder, BorderLayout.SOUTH);
        frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
        frame.pack();
        frame.setLocation(150, 150);
        frame.setVisible(true);
    }

    public static void main(String[] args) {
        java.awt.EventQueue.invokeLater(new Runnable() {

            public void run() {
                createAndShowUI();
            }
        });
    }
}
于 2011-11-26T16:51:36.420 回答
2

I think you may have the wrong layout manager for what you want to do (leaving aside, for the moment, that I am not sure you want to do what you say you want to do).

I have not yet found documentation on what I suspect, which is that CardLayout resizes all of its children to the size of its container. I did find the following comment for its "layoutContainer" method:

         * Each component in the <code>parent</code> container is reshaped
         * to be the size of the container, minus space for surrounding
         * insets, horizontal gaps, and vertical gaps.

I think this is reasonable behavior, since it would be very annoying for a user to have the panel size jump around as panels are traversed.

If this is really the behavior you want, then I think you want a different layout manager. And since it is unusual behavior for a UI in general, you may well not find a standard one to do this particular 'feature', so you may have to write your own.

于 2011-11-26T12:38:10.837 回答
0 
Try this code this may help you.




protected void paintComponent(Graphics g) {
if (getModel().isArmed()) {
      g.setColor(Color.lightGray);
} else {
     g.setColor(getBackground());
}
g.fillOval(0, 0, getSize().width-1, getSize().height-1);
System.out.println("width is "+getSize().width+"height is "+getSize().height);
super.paintComponent(g);
}
protected void paintBorder(Graphics g) {
g.setColor(getForeground());
g.drawOval(0, 0, getSize().width-1, getSize().height-1);
}
Shape shape;
public boolean contains(int x, int y) {
if (shape == null || !shape.getBounds().equals(getBounds())) {
     shape = new Ellipse2D.Float(0, 0, getWidth(), getHeight());
}
return shape.contains(x, y);
}}
于 2013-02-05T07:11:26.380 回答