单击按钮时如何显示颜色选择器? [英] How to display a color selector when clicking a button?

问题描述

我正在制作一个程序来绘制一些形状并用颜色填充它们.我需要更改线条"颜色，并希望用户能够选择颜色.

I'm making a program that draws some shapes and fills them with color. I need to change the 'line' color, and want the user to be able to select the color.

如何在单击选择颜色"按钮时设置一组按钮下方出现的颜色?是否可以将选择器嵌入到按钮下方的 UI 中(而不是在窗口中弹出)?

How can I, when clicking a button "Choose Color", have a set of colours appear below the button? Is it possible for the selector to be embedded in the UI below the button (and not pop up in a window)?

我想显示一个类似于 Paint 的颜色选择器.

I want to display a color selector like in Paint.

推荐答案

这里是一个颜色选择按钮类:

Here is a colour selection button class:

• 显示当前选择的颜色
• 按下时打开 JColorChooser 对话框
• 选择颜色时触发事件

以这种方式使用它:

ColorChooserButton colorChooser = new ColorChooserButton(Color.WHITE);
colorChooser.addColorChangedListener(new ColorChangedListener() {
    @Override
    public void colorChanged(Color newColor) {
            // do something with newColor ...
    }
});

    import java.awt.Color;
    import java.awt.Graphics2D;
    import java.awt.event.ActionEvent;
    import java.awt.event.ActionListener;
    import java.awt.image.BufferedImage;
    import java.util.ArrayList;
    import java.util.List;

    import javax.swing.ImageIcon;
    import javax.swing.JButton;
    import javax.swing.JColorChooser;

    public class ColorChooserButton extends JButton {

        private Color current;

        public ColorChooserButton(Color c) {
            setSelectedColor(c); 
            addActionListener(new ActionListener() {
                @Override
                public void actionPerformed(ActionEvent arg0) {
                    Color newColor = JColorChooser.showDialog(null, "Choose a color", current);
                    setSelectedColor(newColor);
                }
            });
        }

        public Color getSelectedColor() {
            return current;
        }

        public void setSelectedColor(Color newColor) {
            setSelectedColor(newColor, true);
        }

        public void setSelectedColor(Color newColor, boolean notify) {

            if (newColor == null) return;

            current = newColor;
            setIcon(createIcon(current, 16, 16));
            repaint();

            if (notify) {
                // Notify everybody that may be interested.
                for (ColorChangedListener l : listeners) {
                    l.colorChanged(newColor);
                }
            }
        }

        public static interface ColorChangedListener {
            public void colorChanged(Color newColor);
        }

        private List<ColorChangedListener> listeners = new ArrayList<ColorChangedListener>();

        public void addColorChangedListener(ColorChangedListener toAdd) {
            listeners.add(toAdd);
        }

        public static  ImageIcon createIcon(Color main, int width, int height) {
            BufferedImage image = new BufferedImage(width, height, java.awt.image.BufferedImage.TYPE_INT_RGB);
            Graphics2D graphics = image.createGraphics();
            graphics.setColor(main);
            graphics.fillRect(0, 0, width, height);
            graphics.setXORMode(Color.DARK_GRAY);
            graphics.drawRect(0, 0, width-1, height-1);
            image.flush();
            ImageIcon icon = new ImageIcon(image);
            return icon;
        }
    }

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