Question

我的任务是如何在java中绘制形状的arrayList。

我觉得我的大部分都是正确的

ShapeChooserPanel中的最后一个方法我无法找到如何在数组中打印Shapes，它应该在单击鼠标的位置绘制当前形状。

我的代码在

下面

主要课程：

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
    }
}
}

和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

在DrawingPanel类中，您需要一个像addShape(...)这样的方法，它会将一个Shape对象添加到ArrayList中。然后在paintComponent(...)方法中迭代ArrayList以绘制列表中的每个形状。

查看Custom Painting Approaches中找到的Draw On Component示例，了解有关工作示例的信息。

该示例仅绘制矩形，因此您的代码将更加复杂，因为您需要检查要绘制的形状类型。

如何＆＃34;画＆＃34;从arrayList到JPanel的形状？

1 个答案: