Java作业四 图形用户界面程序设计和多线程

目录

• 一、简单的计算器
• 二、实现笑脸哭脸的切换
• 三、多线程绘图

掌握窗体、容器组件、基本组件、菜单的创建和设置；熟悉图形绘制方法和程序结构。

掌握多线程控制程序编程方法。

一、简单的计算器

开发一个加、减、乘、除四则运算器。用户界面如下图：

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

/** 继承 JFrame就可以使你定义的这个类成为一个窗体
 * 可以对窗体的属性进行扩展并且可以定义自己需要的特殊操作方法
 * */
public class JCalculator extends JFrame
{
    JPanel fPanel;
    JPanel sPanel;
    JTextField tfFirstOp;
    JTextField tfSecondOp;
    JTextField tfResult;
    JButton btnAdd;
    JButton btnMinus;
    JButton btnMultiply;
    JButton btnDivide;
    String str;
    Double op1;
    Double op2;
    Double rst;

    public JCalculator()
    {
        //创建父面板，表格布局，四行一列
        fPanel = new JPanel();
        fPanel.setLayout(new GridLayout(4,1));

        //加入第一操作数
        tfFirstOp = new JTextField();
        fPanel.add(tfFirstOp);

        //加入第二操作数
        tfSecondOp = new JTextField();
        fPanel.add(tfSecondOp);

        //创建子面板容纳四个按钮
        sPanel = new JPanel();
        sPanel.setLayout(new GridLayout(1,1));

        //将四个按钮放到子面板
        btnAdd = new JButton("+");
        btnMinus = new JButton("-");
        btnMultiply = new JButton("×");
        btnDivide = new JButton("÷");
        sPanel.add(btnAdd);
        sPanel.add(btnMinus);
        sPanel.add(btnMultiply);
        sPanel.add(btnDivide);
        btnAdd.setForeground(Color.red);
        btnMinus.setForeground(Color.red);
        btnMultiply.setForeground(Color.red);
        btnDivide.setForeground(Color.red);

        //将子面板放到父面板
        fPanel.add(sPanel);

        //将结果栏放到父面板
        tfResult = new JTextField();
        fPanel.add(tfResult);

        //将父面板放进窗体
        add(fPanel);

        //为四个按钮添加监听事件
        myListener listener = new myListener();
        btnAdd.addActionListener(listener);
        btnMinus.addActionListener(listener);
        btnMultiply.addActionListener(listener);
        btnDivide.addActionListener(listener);
    }

    private class myListener implements ActionListener
    {
        @Override
        public void actionPerformed(ActionEvent e)
        {
            //处理每个按钮对应的事件
            if(e.getSource()==btnAdd)
            {
                str = tfFirstOp.getText();
                op1 = Double.parseDouble(str.trim());
                str = tfSecondOp.getText();
                op2 = Double.parseDouble(str.trim());
                rst = op1 + op2;
                tfResult.setText(rst+"");
            }

            if(e.getSource()==btnMinus)
            {
                str = tfFirstOp.getText();
                op1 = Double.parseDouble(str.trim());
                str = tfSecondOp.getText();
                op2 = Double.parseDouble(str.trim());
                rst = op1 - op2;
                tfResult.setText(rst+"");
            }

            if(e.getSource()==btnMultiply)
            {
                str = tfFirstOp.getText();
                op1 = Double.parseDouble(str.trim());
                str = tfSecondOp.getText();
                op2 = Double.parseDouble(str.trim());
                rst = op1 * op2;
                tfResult.setText(rst+"");
            }

            if(e.getSource()==btnDivide)
            {
                str = tfFirstOp.getText();
                op1 = Double.parseDouble(str.trim());
                str = tfSecondOp.getText();
                op2 = Double.parseDouble(str.trim());
                rst = op1 / op2;
                tfResult.setText(rst+"");
            }
        }
    }

    public static void main(String args[])
    {
        //主方法入口
        JCalculator frm = new JCalculator();
        frm.setTitle("A Simple Calculator");
        frm.setSize(400,300);
        frm.setLocation(300,300);
        frm.setVisible(true);
    }

}

运行截图

二、实现笑脸哭脸的切换

编写一个“变脸”程序：程序运行后出现一张笑脸，鼠标点击一次则变成哭脸，再点击一次又变成笑脸，依次轮换。

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

public class SmileToCry extends JFrame
{
    public static int i = 0;
    public static  boolean bool = true;

    @Override
    public void paint(Graphics g)
    {
        //这一步操作会调用父类update();update()方法中paint()方法为空操作
        super.paint(g);
        
        g.setColor(Color.red);
        if(bool)
        {
            g.drawOval(50,50,80,100);
            g.drawArc(70,80,14,7,0,180);
            g.drawArc(110,80,14,7,0,180);
            g.drawArc(70,110,40,20,180,180);
            g.drawString("I'm Smiling!",30,55);
        }
        else
        {
            g.drawOval(50,50,80,100);
            g.drawArc(70,80,14,7,180,180);
            g.drawArc(110,80,14,7,180,180);
            g.drawArc(70,110,40,20,0,180);
            g.drawString("I'm Crying!",30,55);
        }
    }

    public static void main(String[] args)
    {
        SmileToCry stc = new SmileToCry();
        stc.setTitle("Click to change face");
        stc.setBounds(200,200,200,200);
        stc.addMouseListener(new MouseAdapter()
        {
            @Override
            public void mouseClicked(MouseEvent e)
            {
                super.mouseClicked(e);
                i++;
                if (i%2 == 1)
                {
                    bool = false;
                }
                else
                {
                    bool = true;
                }
                stc.repaint();
            }
        });

        stc.setVisible(true);
    }

}

运行截图

三、多线程绘图

利用鼠标事件启动多个线程在多个窗体中同时绘制动画。

思路：程序运行后每点击一次按钮出现一个窗体。

import javax.swing.*;
import java.awt.*;
import java.awt.event.MouseAdapter;
import java.awt.event.MouseEvent;
import java.util.Arrays;

//继承JFrame,并且实现Runnable接口
public class ThreadCartoon extends JFrame implements Runnable
{
    int X;
    int Y;
    public static boolean bool = true;

    //构造方法，实现JFram的初始化,传参设置三个窗体出现的位置
    public ThreadCartoon(int x,int y)
    {
        X = x;
        Y = y;
        this.setBounds(X,Y,300,200);
        setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
        this.setTitle("动画演示");
    }

    @Override
    public void paint(Graphics g)
    {
        super.paint(g);
        g.setColor(Color.red);
        if (bool)
        {
            g.drawRect(40,50,150,100);
        }
        else
        {
            g.drawOval(40,50,150,100);
        }
        bool = !bool;
        try
        {
            Thread.sleep(1000);
        }
        catch (InterruptedException e){}
        repaint();
    }

    @Override
    public void run()
    {
        //线程要做的事，创建窗体，并且调用paint方法绘制动画
        ThreadCartoon tc = new ThreadCartoon(X,Y);
        tc.setVisible(true);
    }

    public static void main(String[] args)
    {
        //x，y是每个子窗体的坐标
        final int[] x = new int[20];
        Arrays.fill(x,300);
        final int y = 300;

        JFrame f1 = new JFrame("初始界面");
        f1.setBounds(1000,100,200,200);
        JButton btn = new JButton("start");
        btn.addMouseListener(new MouseAdapter() {
            @Override
            public void mouseClicked(MouseEvent e) {
                super.mouseClicked(e);
                Thread t = new Thread(new ThreadCartoon(x[0], y));
                x[0] +=300;
                t.start();
            }
        });
        f1.add(btn);
        f1.setVisible(true);

    }

}

运行截图