GroupLayout用法

import javax.swing.GroupLayout;
import javax.swing.JButton;
import javax.swing.JFrame;
import javax.swing.JPanel;

public class UseGroupLayout{
	public static void main(String[] args){
		JFrame frame = new JFrame();
		JPanel panel = new JPanel();
		frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
		GroupLayout layout = new GroupLayout(panel);
		panel.setLayout(layout);
		
		JButton buttonD = new JButton("D");
		JButton buttonR = new JButton("R");
		JButton buttonY = new JButton("Y");
		JButton buttonO = new JButton("O");
		JButton buttonT = new JButton("T");
		//sequential:连续的/有序的
		GroupLayout.SequentialGroup leftToRight = layout.createSequentialGroup();
		leftToRight.addComponent(buttonD);
		//Parallel:平行线
		GroupLayout.ParallelGroup columnMiddle = layout.createParallelGroup();
		columnMiddle.addComponent(buttonR);
		columnMiddle.addComponent(buttonO);
		columnMiddle.addComponent(buttonT);
		leftToRight.addGroup(columnMiddle);
		leftToRight.addComponent(buttonY);
		
		GroupLayout.SequentialGroup topToBottom = layout.createSequentialGroup();
		GroupLayout.ParallelGroup rowTop = layout.createParallelGroup();
		rowTop.addComponent(buttonD);
		rowTop.addComponent(buttonR);
		rowTop.addComponent(buttonY);
		topToBottom.addGroup(rowTop);
		topToBottom.addComponent(buttonO);
		topToBottom.addComponent(buttonT);

		layout.setHorizontalGroup(leftToRight);
		layout.setVerticalGroup(topToBottom);
		frame.add(panel);
		frame.pack();
		frame.setVisible(true);
	}
}