JavaSwing組件布局管理器之FlowLayout（流式布局）入門教程

package awtDemo;
import java.awt.BorderLayout;
import java.awt.Dimension;
import java.awt.FlowLayout;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import java.util.HashMap;
import java.util.Map;
import javax.swing.JButton;
import javax.swing.JComboBox;
import javax.swing.JFrame;
import javax.swing.JLabel;
import javax.swing.JPanel;
import javax.swing.JTextField;
/*
 * @功能：演示FlowLayout布局管理器的用法
 * @版本：20150609
 */
@SuppressWarnings("serial")
public class FlowLayoutDemo extends JFrame {
 FlowLayout contentPanelLayout = new FlowLayout();
 Map<String, Integer> alignmentMap = new HashMap<String, Integer>();
 JPanel configPanel = new JPanel();
 JPanel contentPanel = new JPanel();
 JComboBox<String> alignmentComboBox = new JComboBox<String> ();
 JTextField textHgap = new JTextField("10");
 JTextField textVgap = new JTextField("20");
 MyListener myListener = new MyListener();
 public FlowLayoutDemo() {
 //init
 alignmentMap.put("LEFT", 0);
 alignmentMap.put("CENTER", 1);
 alignmentMap.put("RIGHT", 2);
 alignmentMap.put("LEADING", 3);
 alignmentMap.put("TRAILING", 4);
 //設(shè)置面板
 configPanel.setLayout(new FlowLayout());
 configPanel.add(new JLabel("對(duì)齊方式"));
 for (String alignment : alignmentMap.keySet()) {
 alignmentComboBox.addItem(alignment);
 }
 configPanel.add(alignmentComboBox);
 configPanel.add(new JLabel("水平間距"));
 configPanel.add(textHgap);
 configPanel.add(new JLabel("垂直間距"));
 configPanel.add(textVgap);
 JButton actionBtn = new JButton("Action!!!");
 actionBtn.addActionListener(myListener);
 configPanel.add(actionBtn);
 //展示面板
 contentPanel.setLayout(contentPanelLayout);
 contentPanel.add(new JButton("Button 1"));
 contentPanel.add(new JButton("Button 2"));
 contentPanel.add(new JButton("Button 3"));
 contentPanel.add(new JButton("Button 4"));
 //主窗體
 setLayout(new BorderLayout());
 add("North",configPanel);
 add("South", contentPanel);
 }
 class MyListener implements ActionListener
 {
 public void actionPerformed(ActionEvent e)
 {
 String alignmentStr = alignmentComboBox.getSelectedItem().toString();
 int alignment = alignmentMap.get(alignmentStr);
 contentPanelLayout.setAlignment(alignment);
 int hgap = Integer.valueOf(textHgap.getText());
 int vgap = Integer.valueOf(textVgap.getText());
 contentPanelLayout.setHgap(hgap);
 contentPanelLayout.setVgap(vgap);
 contentPanel.updateUI();
 }
 }
 public static void main(String[] args) {
 // TODO Auto-generated method stub
 FlowLayoutDemo window = new FlowLayoutDemo();
 window.setTitle("FlowLayoutDemo - www.jb51.net");
 // 該代碼依據(jù)放置的組件設(shè)定窗口的大小使之正好能容納你放置的所有組件
 window.setPreferredSize(new Dimension(500, 200));
 window.pack();
 window.setVisible(true);
 window.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
 window.setLocationRelativeTo(null); // 讓窗體居中顯示
 }
}