java - 如何用Java制作双色 table 板

Question

在我的 Java 类(class)中，我们正在学习《Java 基础知识》一书的第 4 章。我正在做项目 4-11，它是一个黑色和红色的棋盘格，但是我得到随机颜色，我试图按照本书教我们使用 ColorPanels 和 JFrames 的方式来完成这个。这是我的代码:

package guiwindow3;
import javax.swing.*;
import java.awt.*;
import java.util.*;

public class GUIWindow3 {

    public static void main(String[] args) {

        //Objects
        JFrame theGUI = new JFrame();

        //Format GUI
        theGUI.setTitle("GUI Example");

        theGUI.setSize(500, 500);
        theGUI.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
        Container pane = theGUI.getContentPane();
        pane.setLayout(new GridLayout(8, 8));

        //Loop for grid
        Color lastColor = Color.BLACK;

        for(int i = 1; i < 8; i++) {

            for(int j = 0; j < 8; j++) {

                if((j % 2 == 1 && i %2 == 1) || (j % 2 == 0 && i % 2 == 0)) {

                    lastColor = Color.RED;

                }

                else {

                    lastColor = Color.BLACK;

                }

                ColorPanel panel = new ColorPanel(lastColor);

                pane.add(panel);

            }

        }

        theGUI.setVisible(true);

    }

}

然后对于 ColorPanel 类，我有:

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

class ColorPanel extends JPanel {

    public ColorPanel(Color lastColor) {

        setBackground(lastColor);

    }

}

Answer 1

您获得随机数的原因是您为每个 RGB 参数创建了一个随机数。相反，你可以改变这个:

for (int i = 1; i <= rows * cols; i++) {
    int red = gen.nextInt(256); //A random Red 
    int green = gen.nextInt(256); //A random Green
    int blue = gen.nextInt(256); //A random Blue
    Color backColor = new Color(red, green, blue); //Join them and you get a random color
    ColorPanel panel = new ColorPanel(backColor); //Paint the panel
    pane.add(panel);
}

对此:

Color lastColor = Color.BLACK;
for (int i = 0; i < rows; i++) {
    for (int j = 0; j < cols; j++) {
        if ((j % 2 == 1 && i % 2 == 1) || (j % 2 == 0 && i % 2 == 0)) {
            lastColor = Color.RED; //Set the color to RED
        } else {
            lastColor = Color.BLACK; //Set the color to BLACK
        }
        ColorPanel panel = new ColorPanel(lastColor); //Paint the panel with RED or BLACK color
        pane.add(panel); //Add the painted Panel
    }
}

输出是这样的:

---

编辑

获得相同输出并使 if 条件更易于阅读的另一种方法是 @dimo414 在他的 comment 中所说的:

if((j % 2 == 1 && i %2 == 1) || (j % 2 == 0 && i % 2 == 0)) is the same as if (j % 2 == i % 2)

for (int i = 0; i < rows; i++) {
    for (int j = 0; j < cols; j++) {
        if (i % 2 == j % 2) {
            lastColor = Color.RED;
        } else {
            lastColor = Color.BLACK;
        }
        ColorPanel panel = new ColorPanel(lastColor);
        pane.add(panel);
    }
}