如何绘制形状的arrayList Java [英] How to paint an arrayList of shapes Java

问题描述

我的任务是如何在 java 中绘制一个 arrayList 形状.

I am tasked with how to paint an arrayList of shapes in java.

我觉得我大部分都是对的，但是有两种方法我很困惑

I feel i have most of it right, there are two methods i am confused about however

ShapeChooserPanel中的方法叫public void setPoints(int x, int y)

由于 Xs 和 Ys 是数组，我将如何设置 x 和 y 值?

Since Xs and Ys are arrays, how would i set the x and y values?

另一个是ShapeChooserPanel中的final方法，我不知道如何打印数组中的形状，它应该在鼠标点击的地方绘制当前形状.

And the other is one is the final method in ShapeChooserPanel I cannot find out how to print the Shapes in the array, It should paint the current shape at the place the mouse was clicked.

我的代码在下面

主类:

import javax.swing.JFrame;

public class Lab2 {

    public static void main (String[] args) {


    JFrame myFrame = new JFrame("Lab 2");

    myFrame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
    myFrame.add(new ShapeChooserPanel());
    myFrame.pack();
    myFrame.setVisible(true);








    }
}

ShapeChooserPanel 类

ShapeChooserPanel class

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

public class ShapeChooserPanel extends JPanel {

private int currentX;
private int currentY;
private Color currentColor;
private int currentShape;
private JButton clearBtn;
private JRadioButton circle, square, triangle, box;
private DrawingPanel drawingPanel;
private JPanel controlsPanel;
//constants representing shape choice
private final int CIRCLE = 0;
private final int SQUARE = 1;
private final int TRIANGLE = 2;
private final int BOX = 3;
//constant delta used for setting distance between points
private final int DELTA = 25;
private int[] Xs;
private int[] Ys;
//store all the shapes to be painted UNCOMMENT when you have Shape.java defined
ArrayList<Shape> shapes;

public ShapeChooserPanel(){
    //provide some default values paints a circle at (10,10) in blue
    currentX = 10;
    currentY = 10;
    Xs = new int[4];//we will use all 4 points for the square, but only the first 3 for the triangle
    Ys = new int[4];
    setPoints(currentX,currentY);
    currentShape = CIRCLE;
    currentColor = Color.red;
    shapes = new ArrayList<Shape>();
    //instantiate the controls panel and set its layout to display everything in a single column
    controlsPanel = new JPanel();
    controlsPanel.setLayout(new BoxLayout(controlsPanel, BoxLayout.Y_AXIS));


    //TODO: add clear button *
    // TODO: define radio buttons *

    clearBtn = new JButton("Clear");
    clearBtn.addActionListener(new ClearListener());

    circle = new JRadioButton("Red Circle");
    circle.addActionListener(new ShapeListener());

    square = new JRadioButton("Cyan Square");
    square.addActionListener(new ShapeListener());

    triangle = new JRadioButton("Green Triangle");
    triangle.addActionListener(new ShapeListener());

    box = new JRadioButton("Blue Box");
    box.addActionListener(new ShapeListener());

    ButtonGroup group = new ButtonGroup();
    group.add(clearBtn);
    group.add(circle);
    group.add(square);
    group.add(triangle);
    group.add(box);

    controlsPanel.add(clearBtn);
    controlsPanel.add(circle);
    controlsPanel.add(square);
    controlsPanel.add(triangle);
    controlsPanel.add(box);



    //TODO: add radio buttons to group *
    //TODO add listeners to radio buttons *
    //TODO: add radio buttons to controls panel *

    drawingPanel = new DrawingPanel();

    drawingPanel.setBorder(BorderFactory.createLineBorder(Color.black));
    //TODO: set a border around the drawing panel *
    drawingPanel.setPreferredSize(new Dimension(200,200));
    drawingPanel.addMouseListener(new PanelListener());

    add(drawingPanel);
    add(controlsPanel);
    setPreferredSize(new Dimension (300,400));
}//end constructor

public void setPoints(int x, int y) {
    //TODO: set Xs and Ys *

    Xs[0] = x;
    Ys[0] = y;

}

private class ClearListener implements ActionListener{
    public void actionPerformed(ActionEvent ae){
        shapes.removeAll(shapes);
        drawingPanel.repaint();
    }
}
private class PanelListener implements MouseListener {
    public void mouseClicked(MouseEvent me) {

        currentX = me.getX();
        currentY = me.getY();
        //TODO: find coordinates of this mouse click *

        //TODO: add a new shape to the shapes list*

        shapes.addAll(shapes);

        setPoints(currentX, currentY);
        //TODO: call setPoints with current x and y values *
        drawingPanel.repaint();
    }
    public void mouseExited(MouseEvent me){}
    public void mouseEntered(MouseEvent me){}
    public void mouseReleased(MouseEvent me){}
    public void mousePressed(MouseEvent me){}
}
//Class to listen for radio button changes
private class ShapeListener implements ActionListener{
    public void actionPerformed(ActionEvent me){
        //TODO: determine which radio button was clicked *

        if(me.getSource() == circle){
            currentShape = CIRCLE;
            currentColor = Color.red;

          }

          if(me.getSource() == square){
              currentShape = SQUARE;
                currentColor = Color.cyan;

          }

          if(me.getSource() == triangle){
              currentShape = TRIANGLE;
                currentColor = Color.green;

          }

          if(me.getSource() == box){
              currentShape = BOX;
                currentColor = Color.blue;

          }


        //TODO: set current shape and color *
        drawingPanel.repaint();
    }
}
private class DrawingPanel extends JPanel {
    public void paintComponent(Graphics g) {
        super.paintComponent(g);



        //TODO: paint all the shapes in our list
    }
}
}

还有我的 Shape 类

and my Shape class

import java.awt.Color;

public class Shape  {

private int x,y;
private int type;
private Color c;

public Shape(int x, int y, int type, Color c) {
    this.x = x;
    this.y = y;
    this.type = type;
    this.c = c;

}

public int x(int x) {

    return x;
}

public int y(int y) {

    return y;
}

public int type(int type) {

    return type;
}

public Color c(Color c) {

    return c;
}
}

推荐答案

你可以...

定义一个抽象"；形状的概念，它具有基本属性(位置和大小)并且可以自己绘制...

You could...

Define an "abstract" concept of a shape, which has the basic properties (location and size) and which can paint itself...

public abstract class Shape {

    private int x, y;
    private int width, height;
    private Color c;

    public Shape(int x, int y, int width, int height, Color c) {
        this.x = x;
        this.y = y;
        this.c = c;
        this.width = width;
        this.height = height;
    }

    public int getHeight() {
        return height;
    }

    public int getWidth() {
        return width;
    }

    public int getX() {
        return x;
    }

    public int getY() {
        return y;
    }

    public Color getColor() {
        return c;
    }

    public abstract void paint(Graphics2D g2d);
}

然后您可以实现各个形状...

Then you can implement the individual shapes...

public class Rectangle extends Shape {

    public Rectangle(int x, int y, int width, int height, Color c) {
        super(x, y, width, height, c);
    }

    @Override
    public void paint(Graphics2D g2d) {
        g2d.setColor(getColor());
        g2d.drawRect(getX(), getY(), getWidth(), getHeight());
    }
}

public class Oval extends Shape {

    public Oval(int x, int y, int width, int height, Color c) {
        super(x, y, width, height, c);
    }

    @Override
    public void paint(Graphics2D g2d) {
        g2d.setColor(getColor());
        g2d.drawOval(getX(), getY(), getWidth(), getHeight());
    }
}

然后，您可以根据需要简单地调用每个Shape实例的paint方法...

Then, you can simply call the paint method of each instance of Shape as required...

public class TestPane extends JPanel {

    private List<Shape> shapes;

    public TestPane() {
        shapes = new ArrayList<>(25);
        shapes.add(new Rectangle(10, 10, 20, 20, Color.RED));
        shapes.add(new Oval(15, 15, 40, 20, Color.RED));
    }

    @Override
    public Dimension getPreferredSize() {
        return new Dimension(200, 200);
    }

    @Override
    protected void paintComponent(Graphics g) {
        super.paintComponent(g);
        for (Shape shape : shapes) {
            Graphics2D g2d = (Graphics2D) g.create();
            shape.paint(g2d);
            g2d.dispose();
        }
    }

}

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