为网格创建一个绘制矩形（用黑色填充）的Java函数 [英] Creating a draw rectangle (filled with black color) function in Java for a grid

问题描述

我在我的程序中创建了一个网格。下面是用于创建网格的代码。

  import java.awt.Graphics; 
 
 import javax.swing.JComponent; 
 import javax.swing.JFrame; 
 $ b $ class类Grid继承JComponent {
 public void paint（Graphics g）{
 g.drawRect（10，10，800，500）; （int i = 10; i <= 800; i + = 10）
 
 
 g.drawLine（i，10，i，510）; （int i = 10;i≤500; i + = 10）
 
 
 g.drawLine（10，i，810，i）; 
 
 
 
 public class CoreControl {
 
 public static void main（String [] a）{
 JFrame window = new JFrame （）; 
 window.setSize（840,560）; 
 window.setDefaultCloseOperation（JFrame.EXIT_ON_CLOSE）; 
 window.getContentPane（）。add（new Grid（））; 
 window.setVisible（true）; 
} 
 
} 
  

我想要做的是创建一个函数，该函数将根据我给出的坐标绘制一个矩形（填充黑色）。基本上我想用黑色填充网格的某些单元格，我的想法是在单元格坐标上绘制黑色填充的矩形。我试图制作另一个名为drawRectangle的类，并在主函数中调用它，就像window.getContentPane（）。add（new drawRectangle（））一样， ）;然而，这并没有工作（只有drawRectangle显示，而不是网格）。

我也想重复使用这个函数来保持创建矩形。

如何创建这个函数？

另外如果你知道一个更好的方法，我应该构造这个程序请让我知道（我是新来的Java，所以我打开任何建议）。

解决方案

1. 不要使用 paint ，使用 paintComponent 并且不要忘记调用 super .paintComponent


2. JComponent 可能不是最佳选择， JPanel 可能是更好的选择


3. > ？

您可以查看执行自定义绘画和 2D图形为mo详细信息。

我建议不要试图让第二个组件执行填充。只需在网格类中提供一个方法，该方法提供单元格的x / y位置（以网格方式）并填充 paintComponent 方法中的单元格

以示例更新

  import java.awt.Color; 
 import java.awt.EventQueue; 
 import java.awt.Graphics; 
 import java.awt.Point; 
 import java.util.ArrayList; 
 import java.util.List; 
 import javax.swing.JFrame; 
 import javax.swing.JPanel; 
 import javax.swing.UIManager; 
 import javax.swing.UnsupportedLookAndFeelException; 
 
 public class CoreControl {
 
 public static class Grid extends JPanel {
 
 private List< Point> fillCells; 
 
 public Grid（）{
 fillCells = new ArrayList<>（25）; 
 
 
 @Override 
 protected void paintComponent（Graphics g）{
 super.paintComponent（g）; 
 for（Point fillCell：fillCells）{
 int cellX = 10 +（fillCell.x * 10）; 
 int cellY = 10 +（fillCell.y * 10）; 
 g.setColor（Color.RED）; 
 g.fillRect（cellX，cellY，10，10）; 
} 
 g.setColor（Color.BLACK）; 
 g.drawRect（10，10，800，500）; （int i = 10; i <= 800; i + = 10）
 
 {
 g.drawLine（i，10，i，510）; 
 
 
 $ b（int i = 10; i <= 500; i + = 10）{
 g.drawLine（10，i，810，i）; 
 
 
 
 public void fillCell（int x，int y）{
 fillCells.add（new Point（x，y））; 
 repaint（）; 
 
 
 
 $ b public static void main（String [] a）{
 EventQueue.invokeLater（new Runnable（）{
 @Override 
 public void run（）{
 try {
 UIManager.setLookAndFeel（UIManager.getSystemLookAndFeelClassName（））; 
} catch（ClassNotFoundException | InstantiationException | IllegalAccessException | UnsupportedLookAndFeelException ex）{ 
} 
 
 Grid grid = new Grid（）; 
 JFrame window = new JFrame（）; 
 window.setSize（840，560）; 
 window.setDefaultCloseOperation（JFrame.EXIT_ON_CLOSE）; 
 window.add（grid）; 
 window.setVisible（true）; 
 grid.fillCell（0，0）; 
 grid。 fillCell（79，0）; 
 grid.fillCell（0，49）; 
 grid.fillCell（79，49）; 
 grid.fil lCell（39,24）; 
} 
}）; 
} 
} 
  

I have created a grid in my program. Below is the code used to create the grid.

import java.awt.Graphics;

import javax.swing.JComponent;
import javax.swing.JFrame;

class Grid extends JComponent {
    public void paint(Graphics g) {
        g.drawRect (10, 10, 800, 500);    

        for (int i = 10; i <= 800; i+= 10)
            g.drawLine (i, 10, i, 510);

        for (int i = 10; i <= 500; i+= 10)
            g.drawLine (10, i, 810, i);
    }
}

public class CoreControl {

    public static void main(String[] a) {
        JFrame window = new JFrame();
        window.setSize(840,560);
        window.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
        window.getContentPane().add(new Grid());
        window.setVisible(true);
    }

}

What I want to do is to create a function which will draw a rectangle (filled with black color) based on the coordinates that I give it. Basically I want to populate certain cells of the grid with black color and my idea is to draw black filled rectangles on the cell coordinates. How do I make this function?

I tried making another class called drawRectangle and called it in the main function like so window.getContentPane().add(new drawRectangle()); however that did not work (only drawRectangle shows up and not the grid).

I also want to be able to use this function repeatedly to keep creating rectangles.

How do I do create this function?

Also if you know a better way that I should structure this program please let me know (I am new to Java so I am open to any suggestions).

解决方案

1. Don't use paint, use paintComponent and don't forget to call super.paintComponent
2. JComponent may not be the best choice, JPanel is probably a better choice
3. What's wrong with Graphics#fillRect(int, int, int, int)?

You might to take a look at Performing Custom Painting and 2D Graphics for more details.

I'd advice against trying to have a second component to performing the filling. Simply provide a method in you grid class that supplies the cell's x/y position (in grid terms) and fill the cell within the paintComponent method

Updated with example

import java.awt.Color;
import java.awt.EventQueue;
import java.awt.Graphics;
import java.awt.Point;
import java.util.ArrayList;
import java.util.List;
import javax.swing.JFrame;
import javax.swing.JPanel;
import javax.swing.UIManager;
import javax.swing.UnsupportedLookAndFeelException;

public class CoreControl {

    public static class Grid extends JPanel {

        private List<Point> fillCells;

        public Grid() {
            fillCells = new ArrayList<>(25);
        }

        @Override
        protected void paintComponent(Graphics g) {
            super.paintComponent(g);
            for (Point fillCell : fillCells) {
                int cellX = 10 + (fillCell.x * 10);
                int cellY = 10 + (fillCell.y * 10);
                g.setColor(Color.RED);
                g.fillRect(cellX, cellY, 10, 10);
            }
            g.setColor(Color.BLACK);
            g.drawRect(10, 10, 800, 500);

            for (int i = 10; i <= 800; i += 10) {
                g.drawLine(i, 10, i, 510);
            }

            for (int i = 10; i <= 500; i += 10) {
                g.drawLine(10, i, 810, i);
            }
        }

        public void fillCell(int x, int y) {
            fillCells.add(new Point(x, y));
            repaint();
        }

    }

    public static void main(String[] a) {
        EventQueue.invokeLater(new Runnable() {
            @Override
            public void run() {
                try {
                    UIManager.setLookAndFeel(UIManager.getSystemLookAndFeelClassName());
                } catch (ClassNotFoundException | InstantiationException | IllegalAccessException | UnsupportedLookAndFeelException ex) {
                }

                Grid grid = new Grid();
                JFrame window = new JFrame();
                window.setSize(840, 560);
                window.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
                window.add(grid);
                window.setVisible(true);
                grid.fillCell(0, 0);
                grid.fillCell(79, 0);
                grid.fillCell(0, 49);
                grid.fillCell(79, 49);
                grid.fillCell(39, 24);
            }
        });
    }
}

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