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import java.awt.Component;
import java.awt.Container;
import java.awt.Dimension;
import java.awt.Insets;
import java.awt.LayoutManager;
import javax.swing.JFrame;
import javax.swing.JLabel;
import javax.swing.JTextField;
public class FormLayoutTester {
public static void main(String[] args) {
JFrame frame = new JFrame();
frame.setLayout(new FormLayout());
frame.add(new JLabel("A"));
frame.add(new JTextField(15));
frame.add(new JLabel("AA"));
frame.add(new JTextField(20));
frame.add(new JLabel("AAAA"));
frame.add(new JTextField(10));
frame.add(new JLabel("AAAAAA"));
frame.add(new JTextField(2));
frame.add(new JLabel("AAAAAAAA"));
frame.add(new JTextField(5));
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
frame.pack();
frame.setVisible(true);
}
}
/**
* A layout manager that lays out components along a central axis
*/
class FormLayout implements LayoutManager {
private int left;
private int right;
private int height;
private static final int GAP = 6;
public Dimension preferredLayoutSize(Container parent) {
Component[] components = parent.getComponents();
left = 0;
right = 0;
height = 0;
for (int i = 0; i < components.length; i += 2) {
Component cleft = components[i];
Component cright = components[i + 1];
Dimension dleft = cleft.getPreferredSize();
Dimension dright = cright.getPreferredSize();
left = Math.max(left, dleft.width);
right = Math.max(right, dright.width);
height = height + Math.max(dleft.height, dright.height);
}
return new Dimension(left + GAP + right, height);
}
public Dimension minimumLayoutSize(Container parent) {
return preferredLayoutSize(parent);
}
public void layoutContainer(Container parent) {
preferredLayoutSize(parent); // Sets left, right
Component[] components = parent.getComponents();
Insets insets = parent.getInsets();
int xcenter = insets.left + left;
int y = insets.top;
for (int i = 0; i < components.length; i += 2) {
Component cleft = components[i];
Component cright = components[i + 1];
Dimension dleft = cleft.getPreferredSize();
Dimension dright = cright.getPreferredSize();
int height = Math.max(dleft.height, dright.height);
cleft.setBounds(xcenter - dleft.width, y + (height - dleft.height) / 2,
dleft.width, dleft.height);
cright.setBounds(xcenter + GAP, y + (height - dright.height) / 2,
dright.width, dright.height);
y += height;
}
}
public void addLayoutComponent(String name, Component comp) {
}
public void removeLayoutComponent(Component comp) {
}
}
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