java GridBagLayout锚点

学习GridBagLayout，这里的问题是，名称标签和combox没有显示在面板的顶部，但我已将其锚点设置为NORTH。 为什么？

import java.awt.GridBagConstraints; import java.awt.GridBagLayout; import java.awt.GridLayout; import javax.swing.JComboBox; import javax.swing.JFrame; import javax.swing.JLabel; import javax.swing.JPanel; import javax.swing.WindowConstants; public class Test2 { public Test2() { JFrame frame = new JFrame(); frame.setTitle("test"); frame.getContentPane().setLayout(new GridLayout(1,2)); frame.setSize(800, 600); JPanel panel1 = new JPanel(); panel1.setLayout(new GridBagLayout()); JLabel label = new JLabel("name"); GridBagConstraints gridBagConstraints = new GridBagConstraints(); gridBagConstraints.anchor = GridBagConstraints.NORTH; gridBagConstraints.weightx = 0.0; gridBagConstraints.weighty = 0.0; gridBagConstraints.gridx = 0; gridBagConstraints.gridy = 0; panel1.add(label, gridBagConstraints); String[] petStrings = { "Bird", "Cat", "Dog", "Rabbit", "Pig" }; JComboBox petList = new JComboBox(petStrings); gridBagConstraints = new GridBagConstraints(); gridBagConstraints.anchor = GridBagConstraints.NORTH; gridBagConstraints.fill = GridBagConstraints.HORIZONTAL; gridBagConstraints.weightx = 1.0; gridBagConstraints.weighty = 0.0; gridBagConstraints.gridx = 1; gridBagConstraints.gridy = 0; panel1.add(petList, gridBagConstraints); frame.getContentPane().add(panel1); frame.getContentPane().add(new JPanel()); frame.setVisible(true); frame.setDefaultCloseOperation(WindowConstants.EXIT_ON_CLOSE); } public static void main(String[] args) { new Test2(); } } 

Answer 1

你必须改变

 gridBagConstraints.weighty = 0.0; 

至

 gridBagConstraints.weighty = 1.0; 

否则为组件保留的区域会缩小到组件的大小，并且无论您在哪个方向“锚定”组件。

改变weighty后的结果如下：