// 程序11-3
import java.awt.*;
import javax.swing.*;

public class testFlowLayout{
    JFrame frame;
    Container contentPane;
    JPanel   jp;
    FlowLayout layout;
        
    public static void main(String args[ ]){
        testFlowLayout  obj=new testFlowLayout( );
        obj.testFlow( );
        obj.changeAlign( );
    }
    
    private  static void fillComponent(Container  c){
        for(int i=0;i<3;i++)
            c.add(new JButton("Button "+i));
    }
    
    public void testFlow ( ){        
        frame=new subJFrame("testFlowLayout");
        contentPane=frame.getContentPane( );        
        jp=new JPanel( );      	// 定義一個面板
        layout=new FlowLayout( );

        fillComponent(jp);     	// 向面板中添加組件 
        contentPane.add(jp);
        layout=new FlowLayout(FlowLayout.CENTER,20,50); 
        contentPane.setLayout(layout);
        
        frame.setSize(400,200);
        frame.show( );
    }
    
    public void changeAlign( ){
        for(int i=0;i<3;i++){
            try{
                Thread.sleep(1000);     	// 睡眠1秒
            }catch(Exception e){
                e.printStackTrace( );   
            } 

            switch(i){
                case 0:
                    layout.setAlignment(FlowLayout.LEFT); 
                    break;
                case 1:
                    layout.setAlignment(FlowLayout.CENTER); 
                    break;
                case 2:
                    layout.setAlignment(FlowLayout.RIGHT); 
                    break;
            }
            layout.layoutContainer(contentPane); // 重新排列有關的組件
        }
    }
}