Java学习笔记（9）：图形接口

一：第一个图形——按钮

import javax.swing.*;
import java.awt.*;
import java.awt.event.*;

public class tx implements ActionListener {
    
    //实现ActionListener接口
    JButton button;//创建按钮

    public static void main(String[] args) {
    
    
        tx gui = new tx();
        gui.go();
    }

    public void go()
    {
    
    
        JFrame frame = new JFrame();
       button = new JButton("click me");//按钮上的文本显示

        button.addActionListener(this);//向按钮注册

        frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);//在窗口关闭时结束程序

        frame.getContentPane().add(BorderLayout.CENTER,button);//将按钮放在中心
        
        frame.setSize(300,300);//设置出现在你屏幕的那个窗口多大

        frame.setVisible(true);
    }
    public void actionPerformed(ActionEvent event)//actionPerformed不能改喔
    {
    
    
        button.setText("ywq i love you");
    }
}

二：第二个图形——双重按钮加变色变文本内容

/*目标： 设置两个独立按钮：需要分别创建不同的指令接受类 class 类名 implements ActionListener{}
 //实现label的按钮接受信息
    class LabelListener implements ActionListener
    {
        public void actionPerformed(ActionEvent event)
        {
        }
    }
    //实现改变颜色的按钮接受信息
    class ColorListener implements ActionListener
    {
        public void actionPerformed(ActionEvent event)
        {
        }
    } 
*/

//图形设置及打印，ht类
import javax.swing.*;
import java.awt.*;

public class ht extends JPanel{
    
      //注意要继承JPanel
    public void paintComponent(Graphics g){
    
    
        Graphics2D g2d = (Graphics2D) g;

        //设置随机颜色
        int red = (int) (Math.random()*255);
        int green = (int) (Math.random()*255);
        int blue = (int) (Math.random()*255);
        Color startColor = new Color(red,green,blue);

        //设置随机颜色
        red = (int) (Math.random()*255);
        green = (int) (Math.random()*255);
        blue = (int) (Math.random()*255);
        Color endColor = new Color(red,green,blue);

        //设置渐变
        GradientPaint gradient = new GradientPaint(70,70,startColor,150,150,endColor);
        g2d.setPaint(gradient);
        //画出图形
        g2d.fillOval(70,70,100,100);
    }
}

//主类
import javax.swing.*;
import java.awt.*;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;

public class gui3c{
    
    
    public static int i = 1;

    public static int getI() {
    
    
        return i;
    }

    public static void setI(int i) {
    
    
        gui3c.i = i+1;
    }

    JFrame frame;
    JLabel label;
    public static void main(String[] args) {
    
    
        gui3c gui = new gui3c();
        gui.go();
    }

    public void go()
    {
    
    
        //常规设置
        frame =new JFrame();
        frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);

        //创建color按钮
        JButton colorButton = new JButton("change color");
        colorButton.addActionListener(new ColorListener());

        //创建label按钮
        JButton labelButton = new JButton("change label");
        labelButton.addActionListener(new LabelListener());

        //设置label
        ht draw =new ht();
        label = new JLabel("i am a label");

        //将label，label按钮，color按钮和ht中的图形加入frame
        frame.getContentPane().add(BorderLayout.SOUTH,colorButton);
        frame.getContentPane().add(BorderLayout.EAST,labelButton);
        frame.getContentPane().add(BorderLayout.CENTER,draw);
        frame.getContentPane().add(BorderLayout.WEST,label);

        //设置图形的大小
        frame.setSize(300,300);
        frame.setVisible(true);
    }

    //实现label的按钮
    class LabelListener implements ActionListener
    {
    
    
        public void actionPerformed(ActionEvent event)
        {
    
    
            //改变文本内容
            label.setText("于文晴小宝贝我爱你"+"*"+i);
            setI(i);
        }
    }
    //实现改变颜色的按钮
    class ColorListener implements ActionListener
    {
    
    
        public void actionPerformed(ActionEvent event)
        {
    
    
            //每次repaint（）都会执行paintComponent里面的指令
            frame.repaint();
        }
    }
}

值得注意的是：
1.JFrame的用法
2.按钮创建JButton，文本创建JLabel
单个按钮与多个按钮ActionListener的写法不同