使用GridBagLayout的奇怪行为，网格位置被部分忽略

Question

我对GridBagLayout有一个非常奇怪的问题，布局似乎＆＃34;调整＆＃34;网格位置使组件在整齐的列中对齐 - 正是我不想要的。我希望我的组件以砖墙方式对齐，但我得到一个棋盘布局。

此示例重现案例：

public class GBLayout extends JPanel {

    public GBLayout() {
        setLayout(new GridBagLayout());
        for (int y=0; y<10; ++y) {
            int offset = y & 1;
            if (offset != 0) {
                GridBagConstraints c = new GridBagConstraints(
                        0, y, // x, y
                        1, 1, // w, h
                        0D, 0D,
                        GridBagConstraints.NORTHWEST, GridBagConstraints.HORIZONTAL,
                        new Insets(2, 2, 2, 2),
                        0, 0);
                add(new JLabel("!"), c);
            }
            for (int x=0; x<10; ++x) {
                int bx = x * 2 + offset;
                int by = y;
                JButton b = new JButton("(" + bx + ", " + by + ")");
                GridBagConstraints c = new GridBagConstraints(
                        bx, by, // x, y
                        2, 1, // w, h
                        1D, 0D,
                        GridBagConstraints.NORTHWEST, GridBagConstraints.HORIZONTAL,
                        new Insets(2, 2, 2, 2),
                        0, 0);
                add(b, c);
            }
        }
    }

    public static void main(String[] args) {
        SwingUtilities.invokeLater(new Runnable() {
            @Override
            public void run() {
                GBLayout panel = new GBLayout();
                JFrame frame = new JFrame("Test");
                frame.setLayout(new BorderLayout());
                frame.add(panel, BorderLayout.CENTER);
                frame.pack();
                frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
                frame.setVisible(true);
            }
        });
    }
}

目前看起来如何：

预期布局是一堵砖墙（大约，我手动编辑）：

在最左边的专栏中，只有在GridBagLayout似乎对我的组件放置位置有自己的想法之后才会听从。是什么导致这种情况，我该如何解决它？

Answer 1

这会给你带来理想的效果，在我的电脑上看起来像这样：

import java.awt.BorderLayout;
import java.awt.GridBagConstraints;
import java.awt.GridBagLayout;
import java.awt.Insets;

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

public class GBLayout extends JPanel {

    public GBLayout() {
        GridBagLayout gridBagLayout = new GridBagLayout();
        gridBagLayout.columnWeights = new double[] {1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1};
        setLayout(gridBagLayout);
        for (int y=0; y<10; ++y) {
            int offset = y & 1;
            if (offset != 0) {
                GridBagConstraints c = new GridBagConstraints(
                        0, y, // x, y
                        1, 1, // w, h
                        0D, 0D,
                        GridBagConstraints.NORTHWEST, GridBagConstraints.HORIZONTAL,
                        new Insets(2, 2, 2, 2),
                        0, 0);
                add(new JLabel("!"), c);
            }
            for (int x=0; x<10; ++x) {
                int bx = x * 2 + offset;
                int by = y;
                JButton b = new JButton("(" + bx + ", " + by + ")");
                GridBagConstraints c = new GridBagConstraints(
                        bx, by, // x, y
                        2, 1, // w, h
                        1D, 1D,
                        GridBagConstraints.NORTHWEST, GridBagConstraints.HORIZONTAL,
                        new Insets(2, 2, 2, 2),
                        0, 0);
                add(b, c);
            }
        }
    }

    public static void main(String[] args) {
        SwingUtilities.invokeLater(new Runnable() {
            @Override
            public void run() {
                GBLayout panel = new GBLayout();
                JFrame frame = new JFrame("Test");
                frame.setLayout(new BorderLayout());
                frame.add(panel, BorderLayout.CENTER);
                frame.pack();
                frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
                frame.setVisible(true);
            }
        });
    }
}

诀窍是将表columnWeights设置为1，因为没有它，colums可以有不同的大小，一些列可以拉伸到按钮宽度，或者粉碎到0。