GridBagLayout-垂直定位组件

Question

试图将我的JTable旁边的表单与GridBagLayout对齐，我正在努力将组件放到面板顶部。我需要价格标签和字段就在商品标签和字段下面，但我无法让它从面板底部移动。

如果我使用anchor=GridConstraints。NORTHWEST，这会将项目标签和字段移到顶部，但随后我就失去了用行_END锚定它的能力。除非有办法两者兼得？请看我试图展示我想要放置表格的区域的图片。谢谢你的帮助。

GridBagConstraints gbc = new GridBagConstraints();

// TEST COMPONENTS
JLabel lblItem = new JLabel("Item: ");
JLabel lblPrice = new JLabel("Price: ");
JLabel lblQuantity = new JLabel ("Quantity: ");

JTextField itemField = new JTextField(15);
JTextField pricePoundsField = new JTextField(3);
JTextField pricePenceField = new JTextField(2);
JTextField quantityField = new JTextField(3);

gbc.gridx = 0;
gbc.gridy = 0;
//gbc.weightx = 1.0;
//gbc.weighty = 1.0;
gbc.anchor = GridBagConstraints.LINE_START;
panelStockTable.add(jsp, gbc);

gbc.gridx = 1;
gbc.gridy = 0;
gbc.anchor = GridBagConstraints.LINE_END;
panelStockTable.add(lblItem, gbc);

gbc.gridx = 1;
gbc.gridy = 1;
panelStockTable.add(lblPrice, gbc);

gbc.anchor = GridBagConstraints.LINE_START;
gbc.gridx = 2;
gbc.gridy = 0;
panelStockTable.add(itemField, gbc);

gbc.gridx = 2;
gbc.gridy = 1;
panelStockTable.add(pricePoundsField, gbc);

Answer 1

UI越复杂，您就越希望将功能和布局隔离到它们自己的容器/类中。

这就是复合布局的概念变得非常强大的地方。与其将字段直接放在与表相同的容器中，不如使用单独的容器

在这里，右边的面板代表桌子，蓝色的面板展示了混合容器...

import java.awt.Color;
import java.awt.Dimension;
import java.awt.EventQueue;
import java.awt.GridBagConstraints;
import java.awt.GridBagLayout;
import javax.swing.JFrame;
import javax.swing.JLabel;
import javax.swing.JPanel;
import javax.swing.JTextField;
import javax.swing.UIManager;
import javax.swing.UnsupportedLookAndFeelException;

public class Test {

    public static void main(String[] args) {
        new Test();
    }

    public Test() {
        EventQueue.invokeLater(new Runnable() {
            @Override
            public void run() {
                try {
                    UIManager.setLookAndFeel(UIManager.getSystemLookAndFeelClassName());
                } catch (ClassNotFoundException | InstantiationException | IllegalAccessException | UnsupportedLookAndFeelException ex) {
                    ex.printStackTrace();
                }

                JFrame frame = new JFrame("Testing");
                frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
                frame.add(new TestPane());
                frame.pack();
                frame.setLocationRelativeTo(null);
                frame.setVisible(true);
            }
        });
    }

    public class TestPane extends JPanel {

        public TestPane() {
            setLayout(new GridBagLayout());
            GridBagConstraints gbc = new GridBagConstraints();

            JPanel stockTableProxy = new JPanel() {
                @Override
                public Dimension getPreferredSize() {
                    return new Dimension(200, 150);
                }
            };
            stockTableProxy.setBackground(Color.RED);

            gbc.gridx = 0;
            gbc.gridy = 0;
            gbc.weightx = 1.0;
            gbc.weighty = 1.0;
            gbc.fill = GridBagConstraints.BOTH;
            gbc.anchor = GridBagConstraints.LINE_START;
            add(stockTableProxy, gbc);


            JPanel fieldsPanel = new JPanel(new GridBagLayout());
            fieldsPanel.setBackground(Color.BLUE);

            // TEST COMPONENTS
            JLabel lblItem = new JLabel("Item: ");
            JLabel lblPrice = new JLabel("Price: ");
            JLabel lblQuantity = new JLabel("Quantity: ");

            JTextField itemField = new JTextField(15);
            JTextField pricePoundsField = new JTextField(3);
            JTextField pricePenceField = new JTextField(2);
            JTextField quantityField = new JTextField(3);

            gbc = new GridBagConstraints();
            gbc.gridx = 1;
            gbc.gridy = 0;
            gbc.anchor = GridBagConstraints.LINE_END;
            fieldsPanel.add(lblItem, gbc);

            gbc.gridx = 1;
            gbc.gridy = 1;
            fieldsPanel.add(lblPrice, gbc);

            gbc.anchor = GridBagConstraints.LINE_START;
            gbc.gridx = 2;
            gbc.gridy = 0;
            fieldsPanel.add(itemField, gbc);

            gbc.gridx = 2;
            gbc.gridy = 1;
            fieldsPanel.add(pricePoundsField, gbc);

            gbc.gridx = 0;
            gbc.gridy = 20;
            gbc.gridwidth = GridBagConstraints.REMAINDER;
            gbc.weighty = 1;
            fieldsPanel.add(new JLabel(), gbc);

            gbc = new GridBagConstraints();
            gbc.gridx = 1;
            gbc.gridy = 0;
            gbc.anchor = GridBagConstraints.LINE_END;
            gbc.fill = GridBagConstraints.VERTICAL;
            add(fieldsPanel, gbc);
        }

    }

}

但是等等，还有更多。。。

gbc.gridx = 0;
gbc.gridy = 20;
gbc.gridwidth = GridBagConstraints.REMAINDER;
gbc.weighty = 1;
fieldsPanel.add(new JLabel(), gbc);

这是一个小技巧，您可以使用它来强制组件移动到容器的不同边缘，在这里，我已经使用它将所有字段推到容器的顶部。

它所做的只是添加一个透明组件（在这个组件中是aJLabel），并为其提供所有剩余的空间