Как рисовать фигуры из массиваList в JPanel?

Question

Мне поручено рисовать массивList форм в java.

Я чувствую, у меня есть большая часть этого прямо, однако

Последний метод в ShapeChooserPanel я не могу узнать, как напечатать Shapes в массиве, он должен нарисовать текущую форму на месте мыши была нажата.

Мой код ниже

Основной класс:

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

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 * 

    for(int i = 0; i < 4; i++) { 
     Xs[i] = x; 
     Ys[i] = 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.add(new Shape(currentX, currentY, SQUARE,Color.cyan)); 

     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.getActionCommand().equals("Red Circle")){ 
      shapes.add(new Shape(currentX, currentY, CIRCLE, Color.red)); 

      } 

      if (me.getActionCommand().equals("Cyan Square")){ 
       shapes.add(new Shape(currentX, currentY, SQUARE, Color.cyan)); 
      } 

      if(me.getActionCommand().equals("Green Triangle")){ 
       shapes.add(new Shape(currentX, currentY, TRIANGLE, Color.green)); 

      } 

      if(me.getActionCommand().equals("Blue Box")){ 
       shapes.add(new Shape(currentX, currentY, BOX, 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 
    } 
} 
} 

И Shape.java

import java.awt.Color; 
import java.awt.Graphics; 

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 getX() { 

     return x; 
    } 

    public int getY() { 

     return y; 
    } 

    public int getType() { 

     return type; 
    } 

    public Color getColor() { 

     return c; 
    } 



} 

Answer 1

В классе DrawingPanel вам нужен метод Li ke addShape(...), который добавит объект Shape в ArrayList. Затем в методе paintComponent(...) вы перебираете ArrayList для рисования каждой фигуры в списке.

Посмотрите пример Draw On Component, найденный в Custom Painting Approaches для рабочего примера.

Пример только рисует прямоугольники, поэтому ваш код будет немного более активным, так как вам нужно будет проверить, какой тип фигуры вы хотите нарисовать.