Swing中如何实现快捷键绑定和修改

在许许多多市面上常见的桌面软件中, 可以使用快捷键操作， 比如像微信一样,使用Alt+A 可以打开截图窗口，如果不习惯于Alt+A按键时，还可以打开设置去修改。

如果在swing中也想实现一个快捷键绑定和修改的操作，那么应该如何操作？

一、实现思路

1.1创建事件Action

创建一个Action 对象，实现actionPerformed方法即可。
// 该事件触发时， 会弹出bindKeyMapButton按钮上绑定的按键值。

   Action actionListener = new AbstractAction() {@Overridepublic void actionPerformed(ActionEvent e) {MessageUtil.ok(bindKeyMapButton, "Key:" + SwingCoreUtil.keyStroke2Str((KeyStroke) bindKeyMapButton.getClientProperty("activeKeyStroke")));}};

1.2.为按钮绑定默认快捷键

创建一个KeyStroke按键，绑定键盘Ctrl+Q ,那么键盘按下Ctrl+Q时，会触发事件Action

        KeyStroke defaultKeyStroke = KeyStroke.getKeyStroke("ctrl Q");bindKeyMapButton.getInputMap(JComponent.WHEN_IN_FOCUSED_WINDOW).put(defaultKeyStroke, "active");bindKeyMapButton.getActionMap().put("active", actionListener);bindKeyMapButton.putClientProperty("activeKeyStroke", defaultKeyStroke);

1.3. 创建Jtextfield来监听键盘事件

当键盘被按下时，记录符合要求的按键值，并显示文本到输入框内。

   keymapText.addKeyListener(new KeyAdapter() {private KeyStroke keyStroke;@Overridepublic void keyPressed(KeyEvent e) {keyStroke = null;// 无ctrl/shift/alt 组合键if (e.getModifiersEx() == 0 || e.getKeyCode() == KeyEvent.VK_UNDEFINED) {keyStroke = null;} else {keyStroke = KeyStroke.getKeyStrokeForEvent(e);}}@Overridepublic void keyReleased(KeyEvent e) {if (keyStroke == null) {return;}int keyCode = keyStroke.getKeyCode();// 禁止某些键if (keyCode == KeyEvent.VK_CONTROL || keyCode == KeyEvent.VK_SHIFT|| keyCode == KeyEvent.VK_ALT || keyCode == KeyEvent.VK_ALT_GRAPH|| keyCode == KeyEvent.VK_SCROLL_LOCK || keyCode == KeyEvent.VK_PRINTSCREEN) {return;}String keyStrokeText = SwingCoreUtil.keyStroke2Str(keyStroke);keymapText.setText(keyStrokeText);keymapText.putClientProperty("bindKeyStroke", keyStroke);}});

1.4. 监听Jtextfield文本变化更新button的按键绑定

对button移除按键操作，并绑定Jtextfield中设置的新按键值。

        keymapText.getDocument().addDocumentListener(new ChangeDocumentListener() {@Overridepublic void update(DocumentEvent e) {bindKeyMapButton.getInputMap(JComponent.WHEN_IN_FOCUSED_WINDOW).remove((KeyStroke)                   bindKeyMapButton.getClientProperty("activeKeyStroke"));KeyStroke keyStroke = (KeyStroke) keymapText.getClientProperty("bindKeyStroke");if (keyStroke != null) {bindKeyMapButton.putClientProperty("activeKeyStroke", keyStroke);bindKeyMapButton.getInputMap(JComponent.WHEN_IN_FOCUSED_WINDOW).put(keyStroke, "active");}}});

1.5. 完整示例代码

cn.note.swing.core 引用自swing-helper

import cn.note.swing.core.listener.ChangeDocumentListener;
import cn.note.swing.core.util.ButtonFactory;
import cn.note.swing.core.util.FrameUtil;
import cn.note.swing.core.util.MessageUtil;
import cn.note.swing.core.util.SwingCoreUtil;
import cn.note.swing.core.view.AbstractMigView;
import cn.note.swing.core.view.theme.ThemeFlatLaf;
import net.miginfocom.swing.MigLayout;import javax.swing.*;
import javax.swing.event.DocumentEvent;
import java.awt.event.ActionEvent;
import java.awt.event.KeyAdapter;
import java.awt.event.KeyEvent;/*** 测试keymap** @author jee* @version 1.0*/
public class KeymapV1Test extends AbstractMigView {private JTextField keymapText;private JButton bindKeyMapButton;@Overrideprotected MigLayout defineMigLayout() {return new MigLayout("center,nogrid","grow","grow");}@Overrideprotected void init() {keymapText = new JTextField();keymapText.setEditable(false);bindKeyMapButton = ButtonFactory.primaryButton("");}@Overridepublic void bindEvents() {// 绑定按钮按键Action actionListener = new AbstractAction() {@Overridepublic void actionPerformed(ActionEvent e) {MessageUtil.ok(bindKeyMapButton, "Key:" + SwingCoreUtil.keyStroke2Str((KeyStroke) bindKeyMapButton.getClientProperty("activeKeyStroke")));}};KeyStroke defaultKeyStroke = KeyStroke.getKeyStroke("ctrl Q");bindKeyMapButton.getInputMap(JComponent.WHEN_IN_FOCUSED_WINDOW).put(defaultKeyStroke, "active");bindKeyMapButton.getActionMap().put("active", actionListener);bindKeyMapButton.putClientProperty("activeKeyStroke", defaultKeyStroke);bindKeyMapButton.setText("Init BindKey:" + SwingCoreUtil.keyStroke2Str(defaultKeyStroke));// 监听按键更改keymapText.addKeyListener(new KeyAdapter() {private KeyStroke keyStroke;@Overridepublic void keyPressed(KeyEvent e) {keyStroke = null;// 无ctrl/shift/alt 组合键if (e.getModifiersEx() == 0 || e.getKeyCode() == KeyEvent.VK_UNDEFINED) {keyStroke = null;} else {keyStroke = KeyStroke.getKeyStrokeForEvent(e);}}@Overridepublic void keyReleased(KeyEvent e) {if (keyStroke == null) {return;}int keyCode = keyStroke.getKeyCode();// 禁止某些键if (keyCode == KeyEvent.VK_CONTROL || keyCode == KeyEvent.VK_SHIFT|| keyCode == KeyEvent.VK_ALT || keyCode == KeyEvent.VK_ALT_GRAPH|| keyCode == KeyEvent.VK_SCROLL_LOCK || keyCode == KeyEvent.VK_PRINTSCREEN) {return;}String keyStrokeText = SwingCoreUtil.keyStroke2Str(keyStroke);keymapText.setText(keyStrokeText);keymapText.putClientProperty("bindKeyStroke", keyStroke);}});keymapText.getDocument().addDocumentListener(new ChangeDocumentListener() {@Overridepublic void update(DocumentEvent e) {bindKeyMapButton.getInputMap(JComponent.WHEN_IN_FOCUSED_WINDOW).remove((KeyStroke) bindKeyMapButton.getClientProperty("activeKeyStroke"));KeyStroke keyStroke = (KeyStroke) keymapText.getClientProperty("bindKeyStroke");if (keyStroke != null) {bindKeyMapButton.putClientProperty("activeKeyStroke", keyStroke);bindKeyMapButton.getInputMap(JComponent.WHEN_IN_FOCUSED_WINDOW).put(keyStroke, "active");}}});}@Overrideprotected void render() {view.add(new JLabel("keymap V1:"));view.add(keymapText, "w 200!");view.add(bindKeyMapButton, "wrap");}public static void main(String[] args) {ThemeFlatLaf.install();FrameUtil.launchTest(KeymapV1Test.class);}

二、拓展

但是，就像上述操作一样，如果页面上只有一个按键绑定还好，如果有多个按键呢 ？ 每一次更改都需要去实现KeyListener 和DocumentListener ， 所以为什么大家比较认可java的核心概念：抽象、封装、继承、多态 呢？

• 继承
  普通输入框既然不能满足了， 那么扩展一个可以支持按键的输入框，但是还想具备原来输入框的一些功能，
  那么按键输入框只需要继承普通输入框即可。
• 封装与抽象
  在第4步中输入框文本变化时，需要与绑定的按钮进行交互，耦合太大了，那么如何降低耦合呢？ 可以让按键输入框释放一个事件操作，该事件操作与按钮建立绑定关系，那么这一步就是封装与抽象了。
  如何更优雅的封装与抽象，取决于代码的汇总量和阅读优秀代码的眼界。
  为什么经常想重构代码，觉得代码比较粗糙不堪呢？可能跟你的代码量上去了，阅读和抒写了更优秀的代码，所以大牛看小白的代码就是垃圾，小白看大牛的代码就是神作。
  所以，如果你是过了这境界的大牛，还望忽略前进中的小牛。
• 多态
  当确定了要创建一个按键输入框时，可能随着时间的推移或者功能上的扩展，造成它不够健壮了，但是它还占用了你喜欢的名字， 那么多态就是一个很好的解决方案了。

  比如： 在1.0的是否创建了一个KeymapTextField，2.0的时候创建一个增强版本ExtKeymapTextField
  KeymapTextField keymapTextField=new KeymapTextField(); // V1.0
  keymapTextField=new ExtKeymapTextField(); //V2.0

2.1 封装键盘输入框

JEKeymapTextField 内置封装了不可编辑 、禁止选择、监听键盘按键回显 功能，对外暴露了setKeyStrokeChangedListener 让外界可以感知实时变化的KeyStroke

import cn.note.swing.core.listener.ChangeDocumentListener;
import cn.note.swing.core.util.SwingCoreUtil;import javax.swing.*;
import javax.swing.event.DocumentEvent;
import java.awt.event.KeyEvent;
import java.awt.event.KeyListener;
import java.util.function.Consumer;/*** 快捷键绑定文本框** @author jee* @version 1.0*/
public class JEKeymapTextField extends JTextField implements KeyListener {/* 绑定按键*/private KeyStroke keyStroke;/* 快捷键改变监听*/private Consumer<KeyStroke> keyStrokeChangedListener;public JEKeymapTextField() {super.setEditable(false);// 绑定按键super.addKeyListener(this);bindEvents();}@Overridepublic void moveCaretPosition(int pos) {//nothing 禁止光标移动,即不可选择}private void bindEvents() {// 文本框内容改变时触发this.getDocument().addDocumentListener(new ChangeDocumentListener() {@Overridepublic void update(DocumentEvent e) {if (keyStrokeChangedListener != null) {keyStrokeChangedListener.accept(keyStroke);}}});}@Overridepublic void keyTyped(KeyEvent e) {//nothing}@Overridepublic void keyPressed(KeyEvent e) {// 无ctrl/shift/alt 组合键时不绑定if (e.getModifiersEx() == 0 || e.getKeyCode() == KeyEvent.VK_UNDEFINED) {keyStroke = null;} else {keyStroke = KeyStroke.getKeyStrokeForEvent(e);}}@Overridepublic void keyReleased(KeyEvent e) {if (keyStroke == null) {return;}int keyCode = keyStroke.getKeyCode();// 禁止某些键if (keyCode == KeyEvent.VK_CONTROL || keyCode == KeyEvent.VK_SHIFT|| keyCode == KeyEvent.VK_ALT || keyCode == KeyEvent.VK_ALT_GRAPH|| keyCode == KeyEvent.VK_SCROLL_LOCK || keyCode == KeyEvent.VK_PRINTSCREEN) {return;}String keyStrokeText = SwingCoreUtil.keyStroke2Str(keyStroke);super.setText(keyStrokeText);}public void setKeyStrokeChangedListener(Consumer<KeyStroke> keyStrokeChangedListener) {this.keyStrokeChangedListener = keyStrokeChangedListener;}
}

2.1 封装后测试示例

• 代码简洁
• 耦合性更低
• 逻辑更清楚
  如果对JEKeymapTextField 进行拓展增强 （非破坏性对外方法参数变更时）则不会影响KeymapV2Test代码修改。

import cn.note.swing.core.util.ButtonFactory;
import cn.note.swing.core.util.FrameUtil;
import cn.note.swing.core.util.MessageUtil;
import cn.note.swing.core.util.SwingCoreUtil;
import cn.note.swing.core.view.AbstractMigView;
import cn.note.swing.core.view.theme.ThemeFlatLaf;
import net.miginfocom.swing.MigLayout;import javax.swing.*;
import java.awt.event.ActionEvent;/*** 测试keymap** @author jee* @version 2.0*/
public class KeymapV2Test extends AbstractMigView {private JEKeymapTextField keymapText;private JButton bindKeyMapButton;@Overrideprotected MigLayout defineMigLayout() {return new MigLayout("center,nogrid","grow","grow");}@Overrideprotected void init() {keymapText = new JEKeymapTextField();bindKeyMapButton = ButtonFactory.primaryButton("");}@Overridepublic void bindEvents() {// 绑定事件按钮Action actionListener = new AbstractAction() {@Overridepublic void actionPerformed(ActionEvent e) {MessageUtil.ok(bindKeyMapButton, "Key:" + SwingCoreUtil.keyStroke2Str((KeyStroke) bindKeyMapButton.getClientProperty("activeKeyStroke")));}};KeyStroke defaultKeyStroke = KeyStroke.getKeyStroke("ctrl pressed Q");bindKeyMapButton.getInputMap(JComponent.WHEN_IN_FOCUSED_WINDOW).put(defaultKeyStroke, "active");bindKeyMapButton.getActionMap().put("active", actionListener);bindKeyMapButton.putClientProperty("activeKeyStroke", defaultKeyStroke);bindKeyMapButton.setText("Init BindKey:" + SwingCoreUtil.keyStroke2Str(defaultKeyStroke));// 监听按键更改keymapText.setKeyStrokeChangedListener(keyStroke -> {bindKeyMapButton.getInputMap(JComponent.WHEN_IN_FOCUSED_WINDOW).remove((KeyStroke) bindKeyMapButton.getClientProperty("activeKeyStroke"));bindKeyMapButton.putClientProperty("activeKeyStroke", keyStroke);bindKeyMapButton.getInputMap(JComponent.WHEN_IN_FOCUSED_WINDOW).put(keyStroke, "active");});}@Overrideprotected void render() {view.add(new JLabel("keymap V2:"));view.add(keymapText, "w 200!");view.add(bindKeyMapButton, "wrap");}public static void main(String[] args) {ThemeFlatLaf.install();FrameUtil.launchTest(KeymapV2Test.class);}
}