我最近在这段代码中发现了一件奇怪的事情:
import java.awt.Color;
import java.awt.Container;
import java.awt.GridBagConstraints;
import java.awt.GridBagLayout;
import java.io.IOException;
import javax.swing.BorderFactory;
import javax.swing.Box;
import javax.swing.JComponent;
import javax.swing.JFrame;
import javax.swing.JLabel;
import javax.swing.JPanel;
import javax.swing.SwingUtilities;
public class Test {
public static void main(String [] args) throws IOException {
final JFrame frame = new JFrame();
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
JPanel panel = new JPanel();
panel.setLayout(new GridBagLayout());
GridBagConstraints gbc = new GridBagConstraints();
gbc.insets.top = 5;
gbc.insets.right = 5;
add(0, 0, 1, 1, 2, 1, GridBagConstraints.BOTH, GridBagConstraints.CENTER, gbc, panel, createPanel());
add(2, 0, 1, 1, 2, 1, GridBagConstraints.BOTH, GridBagConstraints.CENTER, gbc, panel, createPanel());
add(0, 1, 1, 1, 2, 1, GridBagConstraints.BOTH, GridBagConstraints.CENTER, gbc, panel, createPanel());
add(2, 1, 1, 1, 2, 1, GridBagConstraints.BOTH, GridBagConstraints.CENTER, gbc, panel, createPanel());
add(0, 2, 1, 1, 1, 1, GridBagConstraints.BOTH, GridBagConstraints.CENTER, gbc, panel, createPanel());
add(1, 2, 1, 1, 2, 1, GridBagConstraints.BOTH, GridBagConstraints.CENTER, gbc, panel, createPanel());
add(3, 2, 1, 1, 1, 1, GridBagConstraints.BOTH, GridBagConstraints.CENTER, gbc, panel, createPanel());
add(0, 3, 1, 1, 1, 1, GridBagConstraints.BOTH, GridBagConstraints.CENTER, gbc, panel, createPanel());
add(1, 3, 1, 1, 2, 1, GridBagConstraints.BOTH, GridBagConstraints.CENTER, gbc, panel, createPanel());
add(3, 3, 1, 1, 1, 1, GridBagConstraints.BOTH, GridBagConstraints.CENTER, gbc, panel, createPanel());
add(0, 4, 1, 1, 1, 1, GridBagConstraints.BOTH, GridBagConstraints.CENTER, gbc, panel, createPanel());
add(1, 4, 1, 1, 2, 1, GridBagConstraints.BOTH, GridBagConstraints.CENTER, gbc, panel, createPanel());
add(3, 4, 1, 1, 1, 1, GridBagConstraints.BOTH, GridBagConstraints.CENTER, gbc, panel, createPanel());
add(0, 5, 1, 1, 4, 1, GridBagConstraints.BOTH, GridBagConstraints.CENTER, gbc, panel, createPanel());
frame.setContentPane(panel);
SwingUtilities.invokeLater(new Runnable() {
@Override
public void run() {
frame.pack();
frame.setLocationRelativeTo(null);
frame.setVisible(true);
}
});
}
private static void add(int gridx, int gridy, int weightx, int weighty, int gridw, int gridh, int fill, int anchor, GridBagConstraints gbc, Container container, JComponent component) {
gbc.gridx = gridx;
gbc.gridy = gridy;
gbc.weightx = weightx;
gbc.weighty = weighty;
gbc.gridwidth = gridw;
gbc.gridheight = gridh;
gbc.fill = fill;
gbc.anchor = anchor;
component.add(Box.createHorizontalStrut(5));
component.add(new JLabel("(" + gridx + "; " + gridy + ")"));
component.add(Box.createHorizontalStrut(5));
component.add(new JLabel("gridwidth = " + gridw));
component.add(Box.createHorizontalStrut(5));
container.add(component, gbc);
}
private static JPanel createPanel() {
JPanel panel1 = new JPanel();
panel1.setBackground(Color.WHITE);
panel1.setBorder(BorderFactory.createLineBorder(Color.RED));
return panel1;
}
}
以及运行时的外观:
每个面板的方括号和网格宽度中都有坐标。从最后一行可以看到，全局网格宽度为4。第1列(x = 0)中的3-5行(y = 2，y = 3，y = 4)的网格宽度等于1。但是在前两行中第一列的网格宽度等于2，应该在帧的中间进行划分，但实际上并非如此。为什么？
最佳答案
我自己发现的:
public class Test {
public static void main(String [] args) throws IOException {
final JFrame frame = new JFrame();
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
JPanel panel = new JPanel();
panel.setLayout(new BoxLayout(panel, BoxLayout.Y_AXIS));
GridBagConstraints gbc = new GridBagConstraints();
gbc.insets.top = 5;
gbc.insets.right = 5;
JPanel topPanel = new JPanel();
topPanel.setLayout(new GridBagLayout());
JPanel bottomPanel = new JPanel();
bottomPanel.setLayout(new GridBagLayout());
add(0, 0, 1, 1, 1, 1, GridBagConstraints.BOTH, GridBagConstraints.CENTER, gbc, topPanel, createPanel());
add(1, 0, 1, 1, 2, 1, GridBagConstraints.BOTH, GridBagConstraints.CENTER, gbc, topPanel, createPanel());
add(0, 0, 1, 1, 1, 1, GridBagConstraints.BOTH, GridBagConstraints.CENTER, gbc, bottomPanel, createPanel());
add(1, 0, 1, 1, 1, 1, GridBagConstraints.BOTH, GridBagConstraints.CENTER, gbc, bottomPanel, createPanel());
add(2, 0, 1, 1, 1, 1, GridBagConstraints.BOTH, GridBagConstraints.CENTER, gbc, bottomPanel, createPanel());
add(0, 2, 1, 1, 3, 1, GridBagConstraints.BOTH, GridBagConstraints.CENTER, gbc, bottomPanel, createPanel());
panel.add(topPanel);
panel.add(bottomPanel);
frame.setContentPane(panel);
SwingUtilities.invokeLater(new Runnable() {
@Override
public void run() {
frame.pack();
frame.setLocationRelativeTo(null);
frame.setVisible(true);
}
});
}
private static void add(int gridx, int gridy, int weightx, int weighty, int gridw, int gridh, int fill, int anchor, GridBagConstraints gbc, Container container, JComponent component) {
gbc.gridx = gridx;
gbc.gridy = gridy;
gbc.weightx = weightx;
gbc.weighty = weighty;
gbc.gridwidth = gridw;
gbc.gridheight = gridh;
gbc.fill = fill;
gbc.anchor = anchor;
component.add(Box.createHorizontalStrut(5));
component.add(new JLabel("(" + gridx + "; " + gridy + ")"));
component.add(Box.createHorizontalStrut(5));
component.add(new JLabel("gridwidth = " + gridw));
component.add(Box.createHorizontalStrut(5));
container.add(component, gbc);
}
private static JPanel createPanel() {
JPanel panel1 = new JPanel();
panel1.setBackground(Color.WHITE);
panel1.setBorder(BorderFactory.createLineBorder(Color.RED));
return panel1;
}
}
结果如下:
我所做的事情:将内容窗格划分为两个单独的面板-顶部(一行包含两个均等划分的单元格)和底部(两行:一个包含3个单元格，另一个包含1个单个宽单元格)。内容窗格现在具有BoxLayout而不是GBL，并且可以按预期工作。但是我对GridBagLayout感到失望，这是我之前的理想布局。
关于java - GridBagLayout的怪异行为，我们在Stack Overflow上找到一个类似的问题：https://stackoverflow.com/questions/32861903/