我必須創建一個具有精確顏色的圓形按鈕。

我做了很多研究才能做到這一點，我快到了！

我選擇使用圓形邊框，因為否則對我來說似乎不可能：/（我是 Java 新手）。

所以我只需要找到一種方法來將按鈕（文本）內容的背景設定為正確的顏色，我就完成了。（我目前只有邊框并禁用背景以查看圓形部分，因此文本的背景為空......）

結果：

Java JButton 設定文本背景色

預期結果：

Java JButton 設定文本背景色

我已經嘗試過論文：

import java.awt.Color;
import java.awt.EventQueue;
import java.awt.Font;
import java.awt.Graphics;
import java.awt.Graphics2D;
import java.awt.GridBagLayout;
import java.awt.RenderingHints;
import java.awt.geom.RoundRectangle2D;
import javax.swing.JButton;
import javax.swing.JFrame;
import javax.swing.JPanel;
import javax.swing.border.EmptyBorder;

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 TestPane());
                frame.pack();
                frame.setLocationRelativeTo(null);
                frame.setVisible(true);
            }
        });
    }

    public class TestPane extends JPanel {

        public TestPane() {
            setBorder(new EmptyBorder(32, 32, 32, 32));
            setLayout(new GridBagLayout());
            add(new Button("This is a test"));
        }

    }

    public class BrandColors {

        public static final Color TEXT_ON_SECOUNDARY = Color.WHITE;
        public static final Color SECOUNDARY = Color.RED;
    }

    public class Button extends JButton {

        private int xPadding = 10;

        public Button(String text) {
            super(text);
            this.init();
        }

        private void init() {
            this.setFont(new Font("Arial", Font.PLAIN, 16));
            this.setForeground(BrandColors.TEXT_ON_SECOUNDARY);

            this.setContentAreaFilled(false);
            this.setBorderPainted(false);

            this.setBackground(BrandColors.SECOUNDARY);
            this.setOpaque(false);
        }

        @Override
        protected void paintComponent(Graphics g) {
            Graphics2D g2d = (Graphics2D) g.create();
            RenderingHints hints = new RenderingHints(
                    RenderingHints.KEY_ANTIALIASING, RenderingHints.VALUE_ANTIALIAS_ON
            );
            g2d.setRenderingHints(hints);
            g2d.setColor(getBackground());
            g2d.fill(new RoundRectangle2D.Double(0, 0, getWidth() - 1, getHeight() - 1, 15, 15));
            g2d.setColor(getForeground());
            super.paintComponent(g2d);
            g2d.dispose();
        }

    }
}

現在，這里的技巧是知道這paintComponent也將呈現文本，所以我們需要在呼叫之前繪制背景super.paintComponent

UI 委托示例...

現在，Swing 的特性之一是它的“可插拔外觀和感覺”。這允許您修改組件的“外觀和感覺”，而無需修改其余代碼。

以下示例顯示了一種為特定實體設定 UI 委托的方法 JButton

Java JButton 設定文本背景色

import java.awt.Color;
import java.awt.EventQueue;
import java.awt.Graphics;
import java.awt.Graphics2D;
import java.awt.GridBagConstraints;
import java.awt.GridBagLayout;
import java.awt.Insets;
import java.awt.RenderingHints;
import java.awt.geom.RoundRectangle2D;
import javax.swing.AbstractButton;
import javax.swing.JButton;
import javax.swing.JComponent;
import javax.swing.JFrame;
import javax.swing.JPanel;
import javax.swing.border.EmptyBorder;
import javax.swing.plaf.basic.BasicButtonUI;

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 TestPane());
                frame.pack();
                frame.setLocationRelativeTo(null);
                frame.setVisible(true);
            }
        });
    }

    public class TestPane extends JPanel {

        public TestPane() {
            setBorder(new EmptyBorder(32, 32, 32, 32));
            setLayout(new GridBagLayout());

            GridBagConstraints gbc = new GridBagConstraints();
            gbc.gridwidth = GridBagConstraints.REMAINDER;
            gbc.insets = new Insets(4, 4, 4, 4);

            JButton button = new JButton("This is a normal button");
            add(button, gbc);
            JButton superButton = new JButton("This is a super button");
            superButton.setUI(new RoundedButtonUI());
            add(superButton, gbc);
        }

    }

    public class BrandColors {
        public static final Color TEXT_ON_SECOUNDARY = Color.WHITE;
        public static final Color SECOUNDARY = Color.RED;
    }

    public class RoundedButtonUI extends BasicButtonUI {
        @Override
        protected void installDefaults(AbstractButton b) {
            super.installDefaults(b);
            b.setOpaque(false);
            b.setBackground(BrandColors.SECOUNDARY);
            b.setForeground(BrandColors.TEXT_ON_SECOUNDARY);
        }

        @Override
        public void paint(Graphics g, JComponent c) {
            Graphics2D g2d = (Graphics2D) g.create();
            RenderingHints hints = new RenderingHints(
                    RenderingHints.KEY_ANTIALIASING, RenderingHints.VALUE_ANTIALIAS_ON
            );
            g2d.setRenderingHints(hints);
            g2d.setColor(c.getBackground());
            g2d.fill(new RoundRectangle2D.Double(0, 0, c.getWidth() - 1, c.getHeight() - 1, 15, 15));
            g2d.setColor(c.getForeground());
            super.paint(g, c);
            g2d.dispose();
        }

    }
}

影響 UI 中的所有按鈕

如果要更改 UI 中的所有按鈕，而無需更改任何相關代碼，則可以將 UI 委托設定為所有按鈕使用的默認 UI 委托

為此，我必須進行一些額外的更改。首先，委托類需要在它自己的檔案中（請注意包名）并且我必須實作該static方法createUI

package stackoverflow;

import java.awt.Graphics;
import java.awt.Graphics2D;
import java.awt.RenderingHints;
import java.awt.geom.RoundRectangle2D;
import javax.swing.AbstractButton;
import javax.swing.JComponent;
import javax.swing.plaf.ComponentUI;
import javax.swing.plaf.basic.BasicButtonUI;

public class RoundedButtonUI extends BasicButtonUI {

    private static RoundedButtonUI shared;

    public static ComponentUI createUI(JComponent c) {
        if (shared != null) {
            return shared;
        }
        shared = new RoundedButtonUI();
        return shared;
    }

    @Override
    protected void installDefaults(AbstractButton b) {
        super.installDefaults(b);
        b.setOpaque(false);
        b.setBackground(BrandColors.SECOUNDARY);
        b.setForeground(BrandColors.TEXT_ON_SECOUNDARY);
    }

    @Override
    public void paint(Graphics g, JComponent c) {
        Graphics2D g2d = (Graphics2D) g.create();
        RenderingHints hints = new RenderingHints(RenderingHints.KEY_ANTIALIASING, RenderingHints.VALUE_ANTIALIAS_ON);
        g2d.setRenderingHints(hints);
        g2d.setColor(c.getBackground());
        g2d.fill(new RoundRectangle2D.Double(0, 0, c.getWidth() - 1, c.getHeight() - 1, 15, 15));
        g2d.setColor(c.getForeground());
        super.paint(g, c);
        g2d.dispose();
    }

}

現在，在你做任何其他事情之前，我需要安裝它，UIManager.getDefaults().put(new JButton().getUIClassID(), "stackoverflow.RoundedButtonUI");. 這應該在您呼叫任何其他 UI 相關代碼之前完成（并且在您設定外觀之后，如果您正在這樣做）

然后我就可以正常運行代碼了

Java JButton 設定文本背景色

import java.awt.EventQueue;
import java.awt.GridBagConstraints;
import java.awt.GridBagLayout;
import java.awt.Insets;
import javax.swing.JButton;
import javax.swing.JFrame;
import javax.swing.JPanel;
import javax.swing.UIManager;
import javax.swing.border.EmptyBorder;

public class Test {

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

    public Test() {
        EventQueue.invokeLater(new Runnable() {
            @Override
            public void run() {
                UIManager.getDefaults().put(new JButton().getUIClassID(), "stackoverflow.RoundedButtonUI");
                JFrame frame = new JFrame();
                frame.add(new TestPane());
                frame.pack();
                frame.setLocationRelativeTo(null);
                frame.setVisible(true);
            }
        });
    }

    public class TestPane extends JPanel {

        public TestPane() {
            setBorder(new EmptyBorder(32, 32, 32, 32));
            setLayout(new GridBagLayout());

            GridBagConstraints gbc = new GridBagConstraints();
            gbc.gridwidth = GridBagConstraints.REMAINDER;
            gbc.insets = new Insets(4, 4, 4, 4);

            JButton button = new JButton("This is a normal button");
            add(button, gbc);
            JButton superButton = new JButton("This is a super button");
            add(superButton, gbc);
        }

    }

}

請注意

為了以這種方式安裝新的 UI 委托，您必須提供完全限定的類名，即完整的包路徑和類名。

在我上面的例子中，我使用stackoverflow作為我的包名（我很懶），所以安裝看起來像UIManager.getDefaults().put(new JButton().getUIClassID(), "stackoverflow.RoundedButtonUI");

轉載請註明出處，本文鏈接：https://www.uj5u.com/net/401897.html

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JavaJButton設定文本背景色

UI 委托示例...

影響 UI 中的所有按鈕

請注意