Question

所以我将这个面板定位在我的框架的顶部（NORTH）侧，称为menupanel。在这个面板里面，我还有另外两个面板--topPanel和botPanel（红色和黑色）。在这两个面板内部有几个按钮（在此示例中为标签）。我想在两个面板（机器人和顶部）上添加滚动（水平）。

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You can see an image here

Answer 1

您要将组件添加到多个容器中：

scrollT = new JScrollPane(topPanel);  // topPanel added to scroll pane
scrollT.setHorizontalScrollBarPolicy(JScrollPane.HORIZONTAL_SCROLLBAR_ALWAYS);
scrollB = new JScrollPane(botPanel);  // botPanel added to scroll pane
scrollB.setHorizontalScrollBarPolicy(JScrollPane.HORIZONTAL_SCROLLBAR_ALWAYS);
menupanel.add(scrollT); // scrollpanes added to menupanel -- without Borderlayout constants?
menupanel.add(scrollB);

menupanel.add( topPanel, BorderLayout.NORTH );  // topPanel added to menupanel
menupanel.add( botPanel, BorderLayout.SOUTH );

这不允许用于Swing GUI。

而是将topPanel和botPanel添加到JScrollPanes，将JScrollPanes添加到GUI的其余部分，但不要将topPanel和botPanel重新添加到任何内容。

另一个问题 - 你限制了topPanel和botPanel的大小，这会使它们不能滚动 - 避免这样做。如果您需要约束某些内容的大小，请执行滚动窗格的视口或滚动窗格本身。

如，

import java.awt.Dimension;
import java.awt.GridLayout;

import javax.swing.*;

public class ScrollPaneFun2 extends JPanel {

    private static final int PREF_W = 500;

    public ScrollPaneFun2() {
        JPanel topPanel = new JPanel(new GridLayout(0, 1));
        JPanel botPanel = new JPanel(new GridLayout(0, 1));

        for (int i = 0; i < 3; i++) {
            JPanel innerTopPanel = new JPanel(new GridLayout(1, 0, 3, 0));
            JPanel innerBotPanel = new JPanel(new GridLayout(1, 0, 3, 0));
            for (int j = 0; j < 50; j++) {
                innerTopPanel.add(new JLabel("Text " + (i + 1)));
                innerBotPanel.add(new JLabel("Text " + (i + 1)));
            }
            topPanel.add(innerTopPanel);
            botPanel.add(innerBotPanel);
        }

        JScrollPane topScrollPane = new JScrollPane(topPanel);
        JScrollPane botScrollPane = new JScrollPane(botPanel);
        topScrollPane.setHorizontalScrollBarPolicy(JScrollPane.HORIZONTAL_SCROLLBAR_ALWAYS);
        botScrollPane.setHorizontalScrollBarPolicy(JScrollPane.HORIZONTAL_SCROLLBAR_ALWAYS);

        setLayout(new GridLayout(0, 1));
        add(topScrollPane);
        add(botScrollPane);
    }

    @Override
    public Dimension getPreferredSize() {
        if (isPreferredSizeSet()) {
            return super.getPreferredSize();
        }
        int height = super.getPreferredSize().height;
        return new Dimension(PREF_W, height);
    }

    private static void createAndShowGui() {
        JFrame frame = new JFrame("ScrollPaneFun2");
        frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
        frame.getContentPane().add(new ScrollPaneFun2());
        frame.pack();
        frame.setLocationRelativeTo(null);
        frame.setVisible(true);
    }

    public static void main(String[] args) {
        SwingUtilities.invokeLater(() -> createAndShowGui());
    }
}

2张带有卷轴的JPanel

1 个答案: