学习GridBagLayout,问题在于名称标签和组合框没有显示在面板顶部,但我已将其锚定到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();
}
}