java布局的麻烦

Question

我曾经有一个带有2个组件的jframe,每个组件占用了宽度的一半和所有高度:

我用一个2列1行的gridlayout实现了这个目的,效果很好.虽然现在我想在右边的组件下面添加第三个组件:

有谁知道我怎么能做到这一点？

Answer 1

您可以尝试嵌套一些JPanels,例如:

有一个主窗格,FlowLayout其中包含左窗格和右窗格.

在右侧窗格中有一个BoxLayout或GridLayout用于按住顶部和底部窗格.

在下面的示例代码中,它给出了以下输出

我添加了一些边框颜色,所以你可以看到它是如何工作的,我添加了一些标签,因为我太懒了,无法覆盖getPreferredSize()每个JPanel,但我想这会让你知道如何从这里开始.

import java.awt.Color;
import java.awt.Dimension;
import java.awt.FlowLayout;
import java.awt.GridLayout;

import javax.swing.BorderFactory;
import javax.swing.JFrame;
import javax.swing.JLabel;
import javax.swing.JPanel;
import javax.swing.SwingUtilities;

public class LayoutExample {
    private JFrame frame;
    private JPanel pane;
    private JPanel leftPane;
    private JPanel rightPane;
    private JPanel topPane;
    private JPanel bottomPane;
    public static void main (String args[]) {
        SwingUtilities.invokeLater(new Runnable() {
            @Override
            public void run() {
                new LayoutExample().createAndShowGui();
            }
        });
    }

    public void createAndShowGui() {
        frame = new JFrame("Layout Example");
        pane = new JPanel();
        leftPane = new JPanel() {
            @Override
            public Dimension getPreferredSize() {
                return new Dimension(200, 300); 
            }
        };
        rightPane = new JPanel() {
            @Override
            public Dimension getPreferredSize() {
                return new Dimension(200, 300);
            }
        };
        topPane = new JPanel();
        bottomPane = new JPanel();

        pane.setLayout(new FlowLayout());
        rightPane.setLayout(new GridLayout(2, 1, 5, 5));

        rightPane.add(topPane);
        rightPane.add(bottomPane);

        pane.add(leftPane);
        pane.add(rightPane);
        pane.setBorder(BorderFactory.createLineBorder(Color.green));
        leftPane.setBorder(BorderFactory.createLineBorder(Color.red));
        topPane.setBorder(BorderFactory.createLineBorder(Color.black));
        bottomPane.setBorder(BorderFactory.createLineBorder(Color.magenta));

        frame.setContentPane(pane);
        frame.pack();
        frame.setVisible(true);
        frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
    }
}

注意:为了在上面的示例中在左右窗格上获得相同的维度,我必须覆盖该getPreferredSize()方法,因为我使用了a FlowLayout,在这种情况下,为了避免这样做,最好使用2中的任何一个@LukkasRotter在下面的回答中提出的建议.

Answer 2

使用嵌套布局,即两个网格布局,或使用GridBagLayout.

例

import java.awt.Color;
import java.awt.GridBagConstraints;
import java.awt.GridBagLayout;
import java.awt.GridLayout;
import java.awt.Insets;

import javax.swing.BorderFactory;
import javax.swing.JFrame;
import javax.swing.JPanel;

public class Example {

    public static void main(String[] args) {
        new Example().createAndShowGUI();
    }

    public void createAndShowGUI() {
        JPanel nestedPanel = new JPanel(new GridLayout(2, 1, 10, 10));
        nestedPanel.add(createBorderedPanel());
        nestedPanel.add(createBorderedPanel());

        JPanel nestedPanelContainer = new JPanel(new GridLayout(1, 2, 10, 10));
        nestedPanelContainer.setBorder(BorderFactory.createTitledBorder("Nested GridLayouts"));
        nestedPanelContainer.add(createBorderedPanel());
        nestedPanelContainer.add(nestedPanel);

        JPanel gridBagPanel = new JPanel(new GridBagLayout());
        gridBagPanel.setBorder(BorderFactory.createTitledBorder("GridBagLayout"));
        GridBagConstraints constraints = new GridBagConstraints();
        constraints.fill = GridBagConstraints.BOTH;
        constraints.weightx = 1;
        constraints.weighty = 1;
        constraints.gridheight = 2;
        constraints.insets = new Insets(5, 5, 5, 5);
        gridBagPanel.add(createBorderedPanel(), constraints);
        constraints.gridheight = 1;
        constraints.gridx = 1;
        gridBagPanel.add(createBorderedPanel(), constraints);
        constraints.gridy = 1;
        gridBagPanel.add(createBorderedPanel(), constraints);

        JPanel contentPane = new JPanel(new GridLayout(1, 2, 5, 5));
        contentPane.add(nestedPanelContainer);
        contentPane.add(gridBagPanel);

        JFrame frame = new JFrame();
        frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
        frame.setContentPane(contentPane);
        frame.setSize(800, 600);
        frame.setVisible(true);
    }

    private JPanel createBorderedPanel() {
        JPanel panel = new JPanel();
        panel.setBorder(BorderFactory.createLineBorder(Color.BLACK));
        return panel;
    }

}