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如何将焦点设置为图像或标签?[Java Swing]

focus image-processing swing java

Kirito · 技术社区 · 2 年前

假设我有几个图像,每个图像都在一个标签中,有没有一种方法可以通过单击其中一个图像或标签来设置焦点,并对单击的图像进行一些图像处理(模糊、黑白…)。

谢谢你的帮助

0 回复 | 直到 2 年前

MadProgrammer 2 年前

你可以。。。

使用 JButton 相反,这是他们设计的目的。。。

import java.awt.EventQueue;
import java.awt.GridLayout;
import java.awt.Image;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import java.awt.image.BufferedImage;
import java.io.IOException;
import java.util.logging.Level;
import java.util.logging.Logger;
import javax.imageio.ImageIO;
import javax.swing.ImageIcon;
import javax.swing.JButton;
import javax.swing.JFrame;
import javax.swing.JPanel;

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

    public Main() {
        EventQueue.invokeLater(new Runnable() {
            @Override
            public void run() {
                try {
                    JFrame frame = new JFrame();
                    frame.add(new TestPane());
                    frame.pack();
                    frame.setLocationRelativeTo(null);
                    frame.setVisible(true);
                } catch (IOException ex) {
                    Logger.getLogger(Main.class.getName()).log(Level.SEVERE, null, ex);
                }
            }
        });
    }

    public class TestPane extends JPanel {

        public TestPane() throws IOException {
            setLayout(new GridLayout(-1, 3));
            for (int index = 1; index < 13; index++) {
                BufferedImage image = ImageIO.read(getClass().getResource("/images/Cute" + index + ".png"));
                Image scaled = image.getScaledInstance(50, -1, Image.SCALE_SMOOTH);
                JButton btn = new JButton(new ImageIcon(scaled));
                btn.putClientProperty("image", image);
                add(btn);
                btn.addActionListener(new ActionListener() {
                    @Override
                    public void actionPerformed(ActionEvent e) {
                        JButton btn = (JButton) e.getSource();
                        BufferedImage img = (BufferedImage) btn.getClientProperty("image");
                        // Do stuff
                    }
                });
            }
        }

    }
}

看见 How to Use Buttons, Check Boxes, and Radio Buttons

不想要按钮“填充”效果吗?

这变得有点复杂,但并非不可能。。。

import java.awt.Component;
import java.awt.EventQueue;
import java.awt.Graphics;
import java.awt.Graphics2D;
import java.awt.GridLayout;
import java.awt.Image;
import java.awt.RenderingHints;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import java.awt.event.FocusEvent;
import java.awt.event.FocusListener;
import java.awt.image.BufferedImage;
import java.io.IOException;
import java.util.logging.Level;
import java.util.logging.Logger;
import javax.imageio.ImageIO;
import javax.swing.ImageIcon;
import javax.swing.JButton;
import javax.swing.JFrame;
import javax.swing.JPanel;
import javax.swing.UIManager;
import javax.swing.border.AbstractBorder;
import javax.swing.border.EmptyBorder;

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

    public Main() {
        EventQueue.invokeLater(new Runnable() {
            @Override
            public void run() {
                try {
                    JFrame frame = new JFrame();
                    frame.add(new TestPane());
                    frame.pack();
                    frame.setLocationRelativeTo(null);
                    frame.setVisible(true);
                } catch (IOException ex) {
                    Logger.getLogger(Main.class.getName()).log(Level.SEVERE, null, ex);
                }
            }
        });
    }

    public class TestPane extends JPanel {

        public TestPane() throws IOException {
            setLayout(new GridLayout(-1, 3));
            for (int index = 1; index < 13; index++) {
                BufferedImage image = ImageIO.read(getClass().getResource("/images/Cute" + index + ".png"));
                Image scaled = image.getScaledInstance(50, -1, Image.SCALE_SMOOTH);
                JButton btn = new JButton();
                btn.addFocusListener(new FocusListener() {
                    @Override
                    public void focusGained(FocusEvent e) {
                        // Focus.color is for MacOS, Button.focus should work under
                        // most other look and feels
                        btn.setBorder(new RoundBorder());
                    }

                    @Override
                    public void focusLost(FocusEvent e) {
                        btn.setBorder(new EmptyBorder(1, 1, 1, 1));
                    }
                });
                btn.setBorder(new EmptyBorder(1, 1, 1, 1));
                btn.setIcon(new ImageIcon(scaled));
                btn.putClientProperty("image", image);
                add(btn);
                btn.addActionListener(new ActionListener() {
                    @Override
                    public void actionPerformed(ActionEvent e) {
                        JButton btn = (JButton) e.getSource();
                        BufferedImage img = (BufferedImage) btn.getClientProperty("image");
                        // Do stuff
                    }
                });
            }
        }

        public class RoundBorder extends AbstractBorder {
            @Override
            public void paintBorder(Component c, Graphics g, int x, int y, int width, int height) {
                Graphics2D g2d = (Graphics2D) g.create();
                g2d.setRenderingHint(RenderingHints.KEY_ANTIALIASING, RenderingHints.VALUE_ANTIALIAS_ON);
                g2d.setRenderingHint(RenderingHints.KEY_INTERPOLATION, RenderingHints.VALUE_INTERPOLATION_BICUBIC);
                g2d.setRenderingHint(RenderingHints.KEY_ALPHA_INTERPOLATION, RenderingHints.VALUE_ALPHA_INTERPOLATION_QUALITY);
                g2d.setRenderingHint(RenderingHints.KEY_COLOR_RENDERING, RenderingHints.VALUE_COLOR_RENDER_QUALITY);
                g2d.setRenderingHint(RenderingHints.KEY_DITHERING, RenderingHints.VALUE_DITHER_ENABLE);
                g2d.setRenderingHint(RenderingHints.KEY_RENDERING, RenderingHints.VALUE_RENDER_QUALITY);
                g2d.setRenderingHint(RenderingHints.KEY_ANTIALIASING, RenderingHints.VALUE_ANTIALIAS_ON);
                g2d.setRenderingHint(RenderingHints.KEY_INTERPOLATION, RenderingHints.VALUE_INTERPOLATION_BILINEAR);
                g2d.setRenderingHint(RenderingHints.KEY_INTERPOLATION, RenderingHints.VALUE_INTERPOLATION_BICUBIC);
                g2d.setColor(UIManager.getColor("Focus.color"));
                g2d.drawRoundRect(x, y, width - 1, height - 1, 20, 20);
            }
        }

    }
}

为什么要用按钮?

它们是为这个目的而建造的;他们表现出专注;他们在“采取行动”时提供反馈,从而导致
免费支持键盘输入;你可以 标签 在按钮之间,用键盘“操作”它们——你甚至可以不费吹灰之力地设置键盘快捷键。

但是

你可以。。。

使用 JList ,这将允许您使用箭头键进行导航

import java.awt.BorderLayout;
import java.awt.Component;
import java.awt.EventQueue;
import java.awt.Image;
import java.awt.event.MouseAdapter;
import java.awt.event.MouseEvent;
import java.awt.image.BufferedImage;
import java.io.IOException;
import java.util.logging.Level;
import java.util.logging.Logger;
import javax.imageio.ImageIO;
import javax.swing.DefaultListCellRenderer;
import javax.swing.DefaultListModel;
import javax.swing.ImageIcon;
import javax.swing.JFrame;
import javax.swing.JList;
import javax.swing.JPanel;
import javax.swing.JScrollPane;

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

    public Main() {
        EventQueue.invokeLater(new Runnable() {
            @Override
            public void run() {
                try {
                    JFrame frame = new JFrame();
                    frame.add(new TestPane());
                    frame.pack();
                    frame.setLocationRelativeTo(null);
                    frame.setVisible(true);
                } catch (IOException ex) {
                    Logger.getLogger(Main.class.getName()).log(Level.SEVERE, null, ex);
                }
            }
        });
    }

    public class TestPane extends JPanel {

        public TestPane() throws IOException {
            setLayout(new BorderLayout());
            DefaultListModel<BufferedImage> model = new DefaultListModel<>();
            for (int index = 1; index < 13; index++) {
                BufferedImage image = ImageIO.read(getClass().getResource("/images/Cute" + index + ".png"));
                model.addElement(image);
            }

            JList list = new JList(model);
            list.setCellRenderer(new BufferedImageListRenderer());
            list.setLayoutOrientation(JList.HORIZONTAL_WRAP);
            list.setVisibleRowCount(4);

            list.addMouseListener(new MouseAdapter() {
                @Override
                public void mouseClicked(MouseEvent e) {
                    BufferedImage image = (BufferedImage)list.getSelectedValue();
                    // Do stuff
                }
            });
            list.setSelectedIndex(0);

            add(new JScrollPane(list));
        }

        protected class BufferedImageListRenderer extends DefaultListCellRenderer {
            @Override
            public Component getListCellRendererComponent(JList<?> list, Object value, int index, boolean isSelected, boolean cellHasFocus) {
                super.getListCellRendererComponent(list, value, index, isSelected, cellHasFocus);
                if (value instanceof BufferedImage) {
                    setText(null);
                    // This is expensive, I'd normally have it cached somewhere
                    Image scaled = ((BufferedImage)value).getScaledInstance(50, -1, Image.SCALE_SMOOTH);
                    setIcon(new ImageIcon(scaled));
                }
                return this;
            }
        }

    }
}

看见 How to Use Lists

DevilsHnd - éãã 2 年前

或者你可以。。。

只需使用你真正想要的JLabel。我只是想借钱 疯狂的程序员 编码并用JLabel替换按钮。我还添加了一个类成员JLabel变量来保存恰好被鼠标指针点击的JLabel对象。在下面的演示图像中,请参见标题栏如何指示具有当前焦点的图像。如果你碰巧想做这样的事情,图像周围的红色边框也是一个很好的指示器。

下面是一个可运行的代码:

import java.awt.Color;
import java.awt.EventQueue;
import java.awt.GridLayout;
import java.awt.Image;
import java.awt.event.MouseAdapter;
import java.awt.event.MouseEvent;
import java.awt.image.BufferedImage;
import java.io.IOException;
import java.util.logging.Level;
import java.util.logging.Logger;
import javax.imageio.ImageIO;
import javax.swing.BorderFactory;
import javax.swing.ImageIcon;
import javax.swing.JFrame;
import javax.swing.JLabel;
import javax.swing.JPanel;

public class Main {
    JFrame frame;
    JLabel labelWithFocus;
    
    public static void main(String[] args) {
        new Main();
    }

    public Main() {
        EventQueue.invokeLater(new Runnable() {
            @Override
            public void run() {
                try {
                    frame = new JFrame();
                    frame.setAlwaysOnTop(true);
                    frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
                    frame.add(new TestPane());
                    frame.pack();
                    frame.setLocationRelativeTo(null);
                    frame.setVisible(true);
                } catch (IOException ex) {
                    Logger.getLogger(Main.class.getName()).log(Level.SEVERE, null, ex);
                }
            }
        });
    }

    public JLabel getLabelWithFocus() {
        return labelWithFocus;
    }

    
    public class TestPane extends JPanel {

        private static final long serialVersionUID = 40666L;

        public TestPane() throws IOException {
            GridLayout layout = new GridLayout(-1, 3);
            layout.setHgap(40);
            layout.setVgap(15);
            setLayout(layout);
            setBackground(Color.WHITE);
            for (int index = 1; index < 13; index++) {
                BufferedImage image = ImageIO.read(getClass().getResource("/images/Cute" + index + ".png"));
                Image scaled = image.getScaledInstance(50, -1, Image.SCALE_SMOOTH);
                JLabel lbl = new JLabel(new ImageIcon(scaled));
                lbl.setName("Cute" + index + ".png");
                lbl.putClientProperty("image", image);
                add(lbl);
                lbl.addMouseListener(new MouseAdapter() {
                    @Override
                    public void mouseClicked(MouseEvent e) {
                        if (labelWithFocus != null ) {
                            labelWithFocus.setBorder(null);
                            // Drop Focus if it currently has focus and is clicked on again.
                            if (lbl.getName().equals(labelWithFocus.getName())) {
                                frame.setTitle("");
                                labelWithFocus = null;
                                return;
                            }
                        }
                        labelWithFocus = (JLabel) e.getSource();
                        BufferedImage img = (BufferedImage) labelWithFocus.getClientProperty("image");
                        lbl.setBorder(BorderFactory.createLineBorder(Color.RED, 2));
                        frame.setTitle(labelWithFocus.getName());
                        
                        // Do anything else you want...
                    }
                    
                    @Override
                    public void mouseEntered(MouseEvent e) {
                        JLabel lbl = (JLabel) e.getSource();
                        lbl.setBorder(BorderFactory.createLineBorder(Color.decode("#2eb8b8"), 1));
                    }
                    
                    @Override
                    public void mouseExited(MouseEvent e) {
                        JLabel lbl = (JLabel) e.getSource();
                         if (lbl == labelWithFocus) {
                            lbl.setBorder(BorderFactory.createLineBorder(Color.RED, 2));
                        }
                        else {
                            lbl.setBorder(null);
                        }
                    }
                });
            }
        }
    }
}