Java，设置按钮的颜色而不是 macOS 上的边框？

Question

我正在尝试将随机 colors 分配给我的鼠标点击按钮。 该操作本身似乎有效，但它并没有为我的按钮着色 - 而是边框：,(（仅供参考，我刚刚开始学习编码，所以我为我的“2+2=4”技能道歉）

它也不会让我在 If 语句或其他任何地方执行 setBorderPainted(false) 。

这是我的代码：

import javax.swing.border.Border;
import javax.xml.transform.Source;
import java.awt.*;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import java.util.Random;

public class buttonTest extends JFrame implements ActionListener {

    JPanel p = new JPanel();
    Random rand = new Random();
    Button one, two, three, four, five, six, seven, eight, nine;


    public static void main(String[] args) {

        new buttonTest();
    }

    public buttonTest() {
        super("ColourButton(2.0)");
        setSize(500, 500);

        setDefaultCloseOperation(EXIT_ON_CLOSE);

        one = new Button("one");
        two = new Button("two");
        three = new Button("three");
        four = new Button("four");
        five = new Button("five");
        six = new Button("six");
        seven = new Button("seven");
        eight = new Button("eight");
        nine = new Button("nine");

        float r = rand.nextFloat();
        float g = rand.nextFloat();
        float b = rand.nextFloat();

        Color randColor = new Color(r, g, b);


        p.setLayout(new GridLayout(3, 3));
        p.add(one);
        p.add(two);
        p.add(three);
        p.add(four);
        p.add(five);
        p.add(six);
        p.add(seven);
        p.add(eight);
        p.add(nine);

        one.addActionListener(this);
        two.addActionListener(this);
        three.addActionListener(this);
        four.addActionListener(this);
        five.addActionListener(this);
        six.addActionListener(this);
        seven.addActionListener(this);
        eight.addActionListener(this);
        nine.addActionListener(this);


        add(p);
        setVisible(true);
    }

    @Override
    public void actionPerformed(ActionEvent e) {
        String clickedbutton = e.getActionCommand();
        System.out.println(clickedbutton + " button clicked.");


        float r = rand.nextFloat();
        float g = rand.nextFloat();
        float b = rand.nextFloat();

        Color randColor = new Color(r, g, b);


        if (e.getSource() == one) {
            one.setBackground(new Color(r,g,b));

        } else if (e.getSource() == two) {
            two.setBackground(new Color(r,g,b));

        } else if (e.getSource() == three) {
            three.setBackground(new Color(r,g,b));

        } else if (e.getSource() == four) {
            four.setBackground(new Color(r,g,b));

        } else if (e.getSource() == five) {
            five.setBackground(new Color(r,g,b));

        } else if (e.getSource() == six) {
            six.setBackground(new Color(r,g,b));

        } else if (e.getSource() == seven) {
            seven.setBackground(new Color(r,g,b));

        } else if (e.getSource() == eight) {
            eight.setBackground(new Color(r,g,b));

        } else {
            nine.setBackground(new Color(r,g,b));
        }


        }

    }

Answer 1

“长”答案将涉及创建您自己的 UI 委托 class，它允许您完全控制按钮的外观，但对于如此简单的事情来说，这似乎需要付出很多努力。

开始的地方是查看setBorderPainted和setContentAreaFilled 。 通常，这将允许您删除平台 UI 委托完成的所有自定义，但在我的测试中，我还需要使用setOpaque(true)

import java.awt.Color;
import java.awt.EventQueue;
import java.awt.GridLayout;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import java.util.Random;
import javax.swing.JButton;
import javax.swing.JFrame;
import javax.swing.JPanel;

public class Test {

    public static void main(String[] args) {
        new Test();
    }

    public Test() {
        EventQueue.invokeLater(new Runnable() {
            @Override
            public void run() {
                JFrame frame = new JFrame();
                frame.add(new ButtonTest());
                frame.pack();
                frame.setLocationRelativeTo(null);
                frame.setVisible(true);
            }
        });
    }

    public class ButtonTest extends JPanel implements ActionListener {

        Random rand = new Random();
        JButton buttons[];

        public ButtonTest() {
            buttons = new JButton[9];
            setLayout(new GridLayout(3, 3));
            for (int i = 0; i < buttons.length; i++) {
                buttons[i] = new JButton(Integer.toString(i));

                buttons[i].setBorderPainted(false);
                // This may not be needed, but shouldn't hurt
                buttons[i].setContentAreaFilled(false);
                // This is what fixed the issue for me
                // But you might need to consider providing a "default"
                // background color OR change this in the `actionPerformed`
                // method
                buttons[i].setOpaque(true);

                buttons[i].addActionListener(this);
                add(buttons[i]);
            }
        }

        @Override
        public void actionPerformed(ActionEvent e) {
            if (!(e.getSource() instanceof JButton)) {
                return;
            }
            String clickedbutton = e.getActionCommand();
            System.out.println("You clicked " + clickedbutton);

            float r = rand.nextFloat();
            float g = rand.nextFloat();
            float b = rand.nextFloat();

            JButton button = (JButton) e.getSource();

            button.setBackground(new Color(r, g, b));
        }
    }
}

Answer 2

使用button.setBorderPainted(false); 对于所有的 JButtons，它应该去掉边框。 但是，如果那不是您所说的，那么我不明白您要做什么； 您的 JButton 在单击时会被着色，而不是边框。

此外，为了减少您的代码，我强烈建议创建一个 JButton 数组来保存您的所有 JButton，这样您就不需要编写代码来初始化和设置每个独立 JButton 的颜色。

这是我写的修改后的代码：

 import java.awt.*;
 import java.awt.event.ActionEvent;
 import java.awt.event.ActionListener;
 import java.util.Random;
 import javax.swing.*;

 public class ButtonTest extends JFrame implements ActionListener {

JPanel p = new JPanel();
Random rand = new Random();
JButton buttons[];


public static void main(String[] args) {

    new ButtonTest();
}

public ButtonTest() {
    super("ColourButton(2.0)");
    setSize(500, 500);

    setDefaultCloseOperation(EXIT_ON_CLOSE);

    buttons = new JButton[9];
    p.setLayout(new GridLayout(3, 3));
    for (int i = 0; i < buttons.length; i++)
    {
        buttons[i] = new JButton(Integer.toString(i));
        buttons[i].setBorderPainted(false);
        buttons[i].addActionListener(this);
        p.add(buttons[i]);
    }
    
    add(p);
    setVisible(true);
}

@Override
public void actionPerformed(ActionEvent e) {
    String clickedbutton = e.getActionCommand();
    System.out.println(clickedbutton + " button clicked.");

    float r = rand.nextFloat();
    float g = rand.nextFloat();
    float b = rand.nextFloat();

    JButton button = (JButton)e.getSource();

    button.setBackground(new Color(r,g,b));
    button.setForeground(new Color(0, 0, 0, 250));
}
}