Java简单图形编程

package gridlayout;

import java.awt.GridLayout;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;

import javax.swing.ButtonGroup;
import javax.swing.JButton;
import javax.swing.JCheckBox;
import javax.swing.JFrame;
import javax.swing.JLabel;
import javax.swing.JOptionPane;
import javax.swing.JPanel;
import javax.swing.JPasswordField;
import javax.swing.JRadioButton;
import javax.swing.JTextField;

public class Demo1 extends JFrame {
	//定义个控件
	private JPanel[] ps = new JPanel[5]; //定义并分配了空间，没分配空间就操作会报空指针异常
	private JLabel l1, l2, l3, l4;
	private JTextField tf1;
	private JPasswordField pwf1;
	private JButton btn1, btn2;
	private JRadioButton rb1, rb2;
	private JCheckBox cb1, cb2;
	private ButtonGroup bg1, bg2;
	
	public Demo1() {
		//初始化各控件
		for (int i = 0; i < ps.length; i++) {
			ps[i] = new JPanel();
		}
		l1 = new JLabel("用户名：");
		l2 = new JLabel("密码：");
		l3 = new JLabel("性别：");
		l4 = new JLabel("爱好：");
		tf1 = new JTextField(15);
		pwf1 = new JPasswordField(15);
		btn1 = new JButton("登录");
		btn2 = new JButton("取消");
		rb1 = new JRadioButton("男");
		rb2 = new JRadioButton("女");
		bg1 = new ButtonGroup(); //使用单选按钮时，要使用ButtonGroup！复选按钮（框）不用！
		bg1.add(rb1);
		bg1.add(rb2);
		cb1 = new JCheckBox("唱歌");
		cb2 = new JCheckBox("跳舞");		

		//设置布局，LayoutManager manager = new GridLayout(行rows，列cols);
		setLayout(new GridLayout(5, 1));
		
		//控件添加到面板Jpanel
		ps[0].add(l1);
		ps[0].add(tf1);
		ps[1].add(l2);
		ps[1].add(pwf1);
		ps[2].add(l3);
		ps[2].add(rb1); //注意：不能添加bg1，它算是对象的容器
		ps[2].add(rb2);
		ps[3].add(l4);
		ps[3].add(cb1);
		ps[3].add(cb2);
		ps[4].add(btn1);
		ps[4].add(btn2);
		
		for (int i = 0; i < ps.length; i++) {
			add(ps[i]);//或写成this.add(ps[i]));原因见下
		}
		
		//用匿名内部类来监听事件源产生的事件
		btn2.addActionListener(new ActionListener() {
			//实现ActionListener的actionPerformed方法
			@Override
			public void actionPerformed(ActionEvent e) {
				JOptionPane.showMessageDialog(null, "即将关闭"); //弹出提示框
				dispose(); //dispose方法是关闭窗体，并释放一部分资源
			}
		});
		
		//设置JFrame窗体的各属性,(注：因为这些都是父类JFrame的方法，没有歧义时，我就省略了this，不想写一些多余的)
		setTitle("GridLayout测试");
		setSize(500, 400);
		setLocation(300, 100);
		setVisible(true); //设置窗体可见，不能忘了！
		//使用 System exit 方法退出应用程序。仅在应用程序中使用。如果不写，控制台会一直运行，不会退出
		setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE); 
	}
	public static void main(String[] args) {
		Demo1 demo1 = new Demo1();
	}
}

package borderlayout;

import java.awt.BorderLayout;
import javax.swing.JButton;
import javax.swing.JComboBox;
import javax.swing.JFrame;
import javax.swing.JLabel;
import javax.swing.JPanel;
import javax.swing.JScrollPane;
import javax.swing.JTextArea;
import javax.swing.JTextField;

public class Demo2 extends JFrame {
    private JLabel l1;
    private JTextArea ta1;
    private JScrollPane sp1;
    private JComboBox<String> cb1;
    private JTextField tf1;
    private JButton btn1;
    private JPanel p1;

    public Demo2() {
        //初始化
        l1 = new JLabel("聊天界面");
        ta1 = new JTextArea(); //不写参数，会自动调节大小
        sp1 = new JScrollPane(ta1);
        String[] strs = {"非匿名", "匿名"};
        cb1 = new JComboBox<String>(strs);
        tf1 = new JTextField(15);
        btn1 = new JButton("发送");
        p1 = new JPanel();

        p1.add(cb1);
        p1.add(tf1);
        p1.add(btn1);

        add(l1, BorderLayout.NORTH);
        add(sp1, BorderLayout.CENTER);
        add(p1, BorderLayout.SOUTH);

        setTitle("BorderLayout测试");
        setSize(500, 400);
        setLocation(300, 100);
        setVisible(true);
        setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE); 
    }
    public static void main(String[] args) {
        Demo2 demo2 = new Demo2();
    }
}