java - 在 JAVA GUI 中添加随机形状矩形、椭圆形和线条

Question

嘿，我正在尝试设计一个 GUI 程序 ShapeFactory，它具有要生成的按钮:

a.具有随机颜色的随机矩形。

b.具有随机颜色的随机椭圆。

c.具有随机颜色的随机线。

每当用户单击按钮时，相应的形状就会添加到 JFrame 中已绘制的形状中。

我一直在尝试将 ActionListener 与绘制方法连接起来

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

public class ShapeFactory extends JFrame implements ActionListener{

    public static void main(String[] args) {
        new ShapeFactory();
}

    JButton ranRects = new JButton("Random Rectangles");
    JButton ranElli = new JButton("Random Ellipses");
    JButton ranLines = new JButton("Random Lines");
    Graphics g;
    Color c;
    ArrayList shapeList = new ArrayList( );

public ShapeFactory(){
    super("Shape Factory");
    setLayout(new FlowLayout());
    setSize(600,400);
    setDefaultCloseOperation(WindowConstants.EXIT_ON_CLOSE);

    add(ranRects);
    add(ranElli);
    add(ranLines);

    JPanel nPanel = new JPanel (new GridLayout(1,3));
    nPanel.add(ranRects);
    nPanel.add(ranElli);
    nPanel.add(ranLines);

    add(nPanel);


    ranRects.addActionListener(this);

    ranElli.addActionListener(this);        

    ranLines.addActionListener(this);


    setVisible(true);
}

    public void paint (Graphics g) {

        super.paint(g);

    if (d == 1) {
        paintRect(g);
        shapeList.add(d);
        }

    else if (d == 2) {
        paintOval(g);
        shapeList.add(d);
        }

    else if (d == 3 ) {
        paintLine(g);
        shapeList.add(d);
        }
} 

    public void paintRect(Graphics g) {

        int rectX1 = (int)(Math.random() * getWidth() / 4.0);
        int rectY1 = (int)(Math.random() * getHeight()/ 4.0);
        int rectX2 = (int)(Math.random() * getWidth());
        int rectY2 = (int)(Math.random() * getHeight());
        c = new Color( (int) (Math.random() * 255) , (int) (Math.random() * 255) , (int) (Math.random() * 255));
        g.setColor(c);
        g.fillRect(rectX1,rectY2,rectX2,rectY2);
    }
    public void paintOval(Graphics g) {

        int ciX1 = (int)(Math.random() * getWidth() / 4.0);
        int ciY1 = (int)(Math.random() * getHeight()/ 4.0);
        int ciX2 = (int)(Math.random() * getWidth());
        int ciY2 = (int)(Math.random() * getHeight());
        c = new Color( (int) (Math.random() * 255) , (int) (Math.random() * 255) , (int) (Math.random() * 255));
        g.setColor(c);
        g.fillOval(ciX1,ciY1,ciX2,ciY2);
    }
    public void paintLine(Graphics g) {

        int lineX1 = (int)(Math.random() * getWidth() / 4.0);
        int lineY1 = (int)(Math.random() * getHeight()/ 4.0);
        int lineX2 = (int)(Math.random() * getWidth());
        int lineY2 = (int)(Math.random() * getHeight());
        c = new Color( (int) (Math.random() * 255) , (int) (Math.random() * 255) , (int) (Math.random() * 255));
        g.setColor(c);
        g.drawLine(lineX1,lineY1,lineX2,lineY2);
    }

    public void actionPerformed(ActionEvent e) {
        Object source = e.getSource();

        if (source == ranRects) { 
            d = 1;
        }
        else if (source == ranElli) {
            d = 2; 
        }
        else if (source == ranLines) {
            d = 3;

        }
        repaint();  

    }

}

Answer 1

因此，一种解决方案是使用 3 个成员变量来跟踪每种类型需要绘制多少个形状。单击按钮后，您只需增加相应的变量，然后在 paint 方法中多次调用 paintOval 或任何形状。在这种情况下，您的 paint 方法可能如下所示:

public void paint(Graphics g) {
    super.paint(g);
    for (int i = 0; i < this.numberOfRects; i++)
        paintRect(g);
    for (int i = 0; i < this.numberOfEllis; i++)
        paintOval(g);
    for (int i = 0; i < this.numberOfLines; i++)
        this.paintLine(g);
}

actionPerformed 像这样:

public void actionPerformed(ActionEvent e) {
    Object source = e.getSource();
    if (source == ranRects) {
        this.numberOfRects++;
    } else if (source == ranElli) {
        this.numberOfEllis++;
    } else if (source == ranLines) {
        this.numberOfLines++;
    }
    repaint();
}

当然，您需要将 3 个成员变量添加到类中。

<小时/>

如果您想存储形状位置和颜色，我建议创建一个新类将它们存储在某种List中。您可以创建一个内部类 Shape 来存储形状属性，例如位置、大小和颜色。

private class Shape{
    public int x1;
    public int y1;
    public int x2;
    public int y2;
    public Color color;
}

然后您可以为每种类型的形状添加成员变量:

private List<Shape> rectList = new ArrayList<>();
private List<Shape> ovalList = new ArrayList<>();
private List<Shape> lineList = new ArrayList<>();

我会推荐一种添加形状的方法，如下所示:

public void addRect(){
    //Create new Shape
    Shape shape = new Shape();

    //Set shape's properties
    shape.x1 = (int) (Math.random() * getWidth() / 4.0);
    shape.x2 = (int) (Math.random() * getHeight() / 4.0);
    shape.y1 = (int) (Math.random() * getWidth());
    shape.y2 = (int) (Math.random() * getHeight());
    shape.color =  new Color((int) (Math.random() * 255), (int) (Math.random() * 255), (int) (Math.random() * 255));

    //Add the shape to the list
    this.rectList.add(shape);
} 

并调用actionListener中的方法

public void actionPerformed(ActionEvent e) {
    Object source = e.getSource();
    if (source == ranRects) {
        addRect();
    } else if (source == ranElli) {
        addOval();
    } else if (source == ranLines) {
        addLine();
    }
    repaint();
}

要绘制它们，您只需迭代每种形状类型的列表即可:

public void paint(Graphics g) {
    super.paint(g);
    for (Shape s: rectList )
        paintRect(g, s);
    //...
    //Add loops for all shapes
}

public void paintRect(Graphics g, Shape shape) {
    g.setColor(shape.color);
    g.fillRect(shape.x1, shape.y1, shape.x2, shape.y2);
}

最后你应该得到这样的结果:

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

public class ShapeFactory extends JFrame implements ActionListener {

    public static void main(String[] args) {
        new ShapeFactory();
    }

    JButton ranRects = new JButton("Random Rectangles");
    JButton ranElli = new JButton("Random Ellipses");
    JButton ranLines = new JButton("Random Lines");
    private List<Shape> rectList = new ArrayList<>();
    private List<Shape> ovalList = new ArrayList<>();
    private List<Shape> lineList = new ArrayList<>();

    private class Shape{
        public int x1;
        public int y1;
        public int x2;
        public int y2;
        public Color color;
    }

    public ShapeFactory() {
        super("Shape Factory");
        setLayout(new FlowLayout());
        setSize(600, 400);
        setDefaultCloseOperation(WindowConstants.EXIT_ON_CLOSE);

        add(ranRects);
        add(ranElli);
        add(ranLines);

        JPanel nPanel = new JPanel(new GridLayout(1, 3));
        nPanel.add(ranRects);
        nPanel.add(ranElli);
        nPanel.add(ranLines);

        add(nPanel);


        ranRects.addActionListener(this);

        ranElli.addActionListener(this);

        ranLines.addActionListener(this);


        setVisible(true);
    }

    public void paint(Graphics g) {
        super.paint(g);
        for (Shape s: rectList )
            paintRect(g, s);
        //...
        //Add loops for all shapes
    }

    public void paintRect(Graphics g, Shape shape) {
        g.setColor(shape.color);
        g.fillRect(shape.x1, shape.y1, shape.x2, shape.y2);
    }
    //...
    //Add paint methods for oval and lines

    public void addRect(){
        //Create new Shape
        Shape shape = new Shape();

        //Set shape's properties
        shape.x1 = (int) (Math.random() * getWidth() / 4.0);
        shape.x2 = (int) (Math.random() * getHeight() / 4.0);
        shape.y1 = (int) (Math.random() * getWidth());
        shape.y2 = (int) (Math.random() * getHeight());
        shape.color =  new Color((int) (Math.random() * 255), (int) (Math.random() * 255), (int) (Math.random() * 255));
        //Add the shape to the list

        this.rectList.add(shape);
    }
    //...
    //Add methods to add ovals and lines


    public void actionPerformed(ActionEvent e) {
        Object source = e.getSource();
        if (source == ranRects) {
            addRect();
        } else if (source == ranElli) {
            //addOval();
        } else if (source == ranLines) {
            //addLine();
        }
        repaint();
    }
}

我只实现了矩形的 paint 和 add 方法，但添加椭圆形和线条并不难。希望这有帮助