【Java 基础学习-面向对象-08绘图拓展】

• 目的

• 绘制一个画图界面，设置两种按钮，分别是绘图按钮与颜色按钮

• 实现绘制不同颜色的各种图形

• DrawUI .java

import javax.swing.*;
import java.awt.*;
    public class DrawUI {
    DrawListen dl = new DrawListen();
    //创建监听器对象
    String[] btnstrs ={"直线","矩形","圆形","点击三角形","等腰三角形","多边形","实心矩形","实心圆"};
    //定义一个图形数组
    String[] colorstrs ={"红","橘","黄","绿","蓝","白","紫","黑"};
    //定义一个颜色数组
public void initUI() {
    JFrame jf = new JFrame();
    //创建窗体
    jf.setTitle("绘制图形");//标题
    jf.setSize(1000, 1000);//大小
    jf.setDefaultCloseOperation(3);//操作选项
    jf.setLayout(new FlowLayout());//流式布局
    for(int i=0;i< btnstrs.length;i++){
    //循环执行“按钮字符次数”次
        JButton btn=new JButton();
        //创建按钮对象
        btn.setText(btnstrs[i]);
        //按钮字符数组的字符-赋值给按钮
        btn.setActionCommand("shapeOP");
        //按钮设置命令为绘制图形操作
        jf.add(btn);
        //窗体添加按钮
        btn.addActionListener(dl);
        //按钮添加动作监听器
    }
    for(int i=0;i< colorstrs.length;i++){
     //循环执行“颜色字符次数”次
        JButton btn =new JButton();
        //创建按钮对象
        btn.setText(colorstrs[i]);
        //颜色字符数组的颜色字符-赋值给按钮
        btn.setActionCommand("colorOP");
        //按钮设置命令为颜色操作
        jf.add(btn);
        //窗体添加按钮
        btn.addActionListener(dl);
        //按钮添加动作监听器
    }
    jf.setVisible(true);//可视化
jf.addMouseListener(dl);
//窗体添加鼠标监听器
dl.setGraphics(jf.getGraphics());
//画布与监听器绑定



}

public static void main(String[]args){
    DrawUI drawUI=new DrawUI();
    drawUI.initUI();

}
}

• DrawListen.java

import javax.swing.*;
import java.awt.*;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import java.awt.event.MouseEvent;
import java.awt.event.MouseListener;
public class DrawListen implements MouseListener,ActionListener {
//画画监听器类实现动作和鼠标监听器接口
//一个类可以实现多个接口
    private int x1, y1, x2, y2;
    private Graphics g;
    //属性封装
    public void setGraphics(Graphics g) {
        this.g=g;
    }
    //设置set方法
private String btnStr;
//封装按钮字符属性
public void actionPerformed(ActionEvent e){
    System.out.println("按钮被点击了");
    String action=e.getActionCommand();
    //按钮命令转化为动作属性
    if(action.equals("shapeOP")){
        JButton btn = (JButton) e.getSource();
        //按钮获取来源，与DrawUI界面联系起来
        btnStr = btn.getText();}
    else if
    (action.equals("colorOP")) {
        JButton btn =(JButton) e.getSource();
        //
        String colorstr = btn.getText();
        switch (colorstr){
            case"红":g.setColor(Color.red);break;
            case"橘":g.setColor(Color.orange);break;
            case"黄":g.setColor(Color.yellow);break;
            case"绿":g.setColor(Color.green);break;
            case"蓝":g.setColor(Color.blue);break;
            case"白":g.setColor(Color.white);break;
            case"紫":g.setColor(Color.magenta);break;
            case"黑":g.setColor(Color.BLACK);break;
        }
    }
}
int count=0;
int x3,y3,x4,y4,x5,y5;
    @Override
    public void mouseClicked(MouseEvent e) {
        System.out.println("点击");
        int x=e.getX();
        int y=e.getY();
        g.fillOval(x-2,y-2,4,4);
    if(btnStr.equals("点击三角形")){
        if(count==0){x3=x;y3=y;count++;}
        else if (count==1) {x4=x;y4=y;g.drawLine(x3,y3,x4,y4);count++;}
        else if (count==2) {x5=x;y5=y;g.drawLine(x3,y3,x5,y5);g.drawLine(x4,y4,x5,y5);count=0;}
    } else if (btnStr.equals("多边形")) { }


    }


    @Override
    public void mousePressed(MouseEvent e) {
    System.out.println("按下");
    x1=e.getX();
    y1=e.getY();
    }

    @Override
    public void mouseReleased(MouseEvent e) {
    System.out.println("释放");
    x2=e.getX();
    y2=e.getY();
    if(btnStr.equals("直线")){
        g.drawLine(x1,y1,x2,y2);
    } else if (btnStr.equals("矩形")) {
        g.drawLine(x1,y1,x2,y1);
        g.drawLine(x1,y1,x1,y2);
        g.drawLine(x2,y1,x2,y2);
        g.drawLine(x1,y2,x2,y2);
    } else if (btnStr.equals("等腰三角形")) {
        g.drawLine((x1+x2)/2,y1,x1,y2);
        g.drawLine((x1+x2)/2,y1,x2,y2);
        g.drawLine(x1,y2,x2,y2);
    } else if (btnStr.equals("圆形")) {
        g.fillOval(x2-x1,y2-y1,100,100);

    } else if (btnStr.equals("多边形")) {
        g.drawLine(x1,y1,(x1+x2)/2,(3*y1-y2)/2);
        g.drawLine((x1+x2)/2,(3*y1-y2)/2,x2,y1);
        g.drawLine(x2,y1,x2,y2);
        g.drawLine(x2,y2,(x1+x2)/2,(3*y2-y1)/2);
        g.drawLine((x1+x2)/2,(3*y2-y1)/2,x1,y2);
        g.drawLine(x1,y2,x1,y1);
    }

    }




    @Override
    public void mouseEntered(MouseEvent e) {
        System.out.println("进入");
    }
    @Override
    public void mouseExited(MouseEvent e) {
        System.out.println("退出");
    }
}