使用KeyListener更改字符串背景并在键释放时将其设置回来 键入Tutor计划
我已经存货了几个小时现在大声笑，没有乐趣，但这就是为什么..我有一个打字的应用程序，这是将按钮键盘的背景设置为不同的颜色，以免在打字时说黄色（如突出显示）按下按键每个按钮都会突出显示，当释放时它会将背景设置为白色..好吧，我的KeyListener我认为它没有任何焦点但我似乎失去了一些东西或没有看到它发生在哪里..
我不得不注释掉添加监听器，因为给出了空指针的exception。
我真的希望有人可以看到我不能或我错过的东西..这是一个可运行的代码，这将使你们更容易理解发生了什么，并能够自己测试，看看我的意思..
import java.awt.BorderLayout; import java.awt.Color; import java.awt.Dimension; import java.awt.Font; import java.awt.GradientPaint; import java.awt.Graphics; import java.awt.Graphics2D; import java.awt.GridBagConstraints; import java.awt.GridBagLayout; import java.awt.RenderingHints; import java.awt.event.ActionEvent; import java.awt.event.ActionListener; import java.awt.event.KeyEvent; import java.awt.event.KeyListener; import javax.swing.JButton; import javax.swing.JFrame; import javax.swing.JLabel; import javax.swing.JPanel; import javax.swing.JTextField; import javax.swing.JTextArea; public class typeTutor extends JFrame implements KeyListener { //Individual keyboard rows String firstRow[] = {"~", "1", "2", "3", "4", "5", "6", "7", "8", "9", "0", "-", "+", "fill", "BackSpace"}; String secondRow[] = {"Tab", "Q", "W", "E", "R", "T", "Y", "U", "I", "O", "P", "[", "]", "\\"}; String thirdRow[] = {"Caps", "A", "S", "D", "F", "G", "H", "J", "K", "L", ":", "\"", "fill", "fill", "Enter"}; String fourthRow[] = {"Shift", "Z", "X", "C", "V", "B", "N", "M", ",", ".", "?", "blank", "^"}; String fifthRow[] = {"blank", "blank", "fill", "fill", "fill", "fill", "fill", "fill", "fill", "fill", "", ""}; private JTextField textField; //Individual keyboard rows /* String firstRow[] = {"~","1","2","3","4","5","6","7","8","9","0","-","+","BackSpace"}; String secondRow[] = {"Tab","Q","W","E","R","T","Y","U","I","O","P","[","]","\\"}; String thirdRow[] = {"Caps","A","S","D","F","G","H","J","K","L",":","\"","Enter"}; String fourthRow[] = {"Shift","Z","X","C","V","B","N","M",",",".","?"," ^" }; String fifthRow[]={" " ,"" }; */ String strText = ""; //all keys without shift key press String noShift="`1234567890-=qwertyuiop[]\\asdfghjkl;'zxcvbnm,./"; //special characters on keyboard that has to be addressed during key press String specialChars ="~-+[]\\;',.?"; int keycode; JTextArea text = new JTextArea(); //Jbuttons corresponding to each individual rows JButton first[]; JButton second[]; JButton third[]; JButton fourth[]; JButton fifth[]; //default color of the button to be repainted when key released Color cc = new JButton().getBackground(); //Driver main method to start the application public static void main(String[] args) { //launch typing tutor typeTutor a = new typeTutor(); a.setVisible(true); } // No argument constructor to create frame public typeTutor() { super("Type Tutor - My JAC444"); JPanel contentPane = new JPanel() { @Override protected void paintComponent(Graphics grphcs) { Graphics2D g2d = (Graphics2D) grphcs; Dimension d = this.getSize(); g2d.setRenderingHint(RenderingHints.KEY_ANTIALIASING, RenderingHints.VALUE_ANTIALIAS_ON); GradientPaint gp = new GradientPaint(0, 0, getBackground().brighter().brighter(), 0, d.height, getBackground().darker().darker()); g2d.setPaint(gp); g2d.fillRect(0, 0, d.width, d.height); super.paintComponent(grphcs); } }; contentPane.setOpaque(false); setContentPane(contentPane); //textField = new JTextField(80); //text.setEditable(true); TextFieldHandler handler = new TextFieldHandler(); //set the info label on top JLabel info = new JLabel(" Type some text using your keyboard.The keys you press will be highlighted and text will be displayed.
Note : Clicking the buttons with your mouse will not perform any action.
" ); //set the bold font for info info.setFont(new Font("Verdana",Font.BOLD,12)); //set the layout and place component in place and pack it setLayout(new BorderLayout()); //Various panel for the layout JPanel jpNorth = new JPanel(); JPanel jpCenter = new JPanel(); jpCenter.setPreferredSize(new Dimension(10,10)); JPanel jpKeyboard = new JPanel(new GridBagLayout()); JPanel jpNote = new JPanel(); add(jpNorth, BorderLayout.NORTH); add(jpNote); add(jpCenter, BorderLayout.CENTER); add(jpKeyboard, BorderLayout.SOUTH); jpNorth.setLayout(new BorderLayout()); jpNorth.add(info, BorderLayout.WEST); jpNorth.add(info, BorderLayout.SOUTH); jpCenter.setLayout( new BorderLayout()); jpCenter.add(text, BorderLayout.WEST); jpCenter.add(text, BorderLayout.CENTER); jpCenter.setPreferredSize(new Dimension(10,10)); first = new JButton[firstRow.length]; second = new JButton[secondRow.length]; third = new JButton[thirdRow.length]; fourth = new JButton[fourthRow.length]; fifth = new JButton[fifthRow.length]; addKeys(jpKeyboard, 0, firstRow, first); addKeys(jpKeyboard, 1, secondRow, second); addKeys(jpKeyboard, 2, thirdRow, third); addKeys(jpKeyboard, 3, fourthRow, fourth); addKeys(jpKeyboard, 4, fifthRow, fifth); //jpCenter.setPreferredSize(new Dimension(10,10)); jpKeyboard.setPreferredSize(new Dimension(800,160)); info.setOpaque(false); jpNote.setOpaque(false); jpNorth.setOpaque(false); jpCenter.setOpaque(false); jpKeyboard.setOpaque(false); /* //add listeners //getComponent().addKeyListener(this); text.addKeyListener(this); // add listeners to all the button for(JButton b : first) b.addKeyListener(this); for(JButton b : second) b.addKeyListener(this); for(JButton b : third) b.addKeyListener(this); for(JButton b : fourth) b.addKeyListener(this); for(JButton b : fifth) b.addKeyListener(this); */ this.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE); //set non re-sizable this.setResizable(false); //set size of the content pane ie frame this.getContentPane().setPreferredSize(new Dimension(1100,350)); //set location for the frame //this.setLocation(150,150); //init and paint frame initWidgets(); pack(); this.toFront(); // brings this Window to the front and may make it the focused Window this.setLocationRelativeTo(null); // Window appears center } // Method to initialize frame component private void initWidgets() { } private class TextAreaHandler implements ActionListener { // process textfield events public void actionPerformed( ActionEvent event ) { String string = ""; // declare string to display // user pressed Enter in JTextField textField1 if ( event.getSource() == textField ) string = String.format( "%s", event.getActionCommand() ); } } // Invoked when a key has been pressed. // @see java.awt.event.KeyListener#keyPressed(java.awt.event.KeyEvent) public void keyPressed(KeyEvent evt) { keycode = evt.getKeyCode(); strText = String.format( "%s",KeyEvent.getKeyText( evt.getKeyCode() ) ); setBackground(Color.BLUE); }//end of key pressed //Invoked when a key has been released. public void keyReleased(KeyEvent evt) { keycode = evt.getKeyCode(); strText = String.format( "%s",KeyEvent.getKeyText( evt.getKeyCode() ) ); getBackground(); } public void keyTyped(KeyEvent evt) { strText = String.format( "%s", evt.getKeyChar() ); }//end of key pressed private class TextFieldHandler implements ActionListener { // process textfield events public void actionPerformed( ActionEvent event ) { String string = ""; // declare string to display // user pressed Enter in JTextField textField1 if ( event.getSource() == text ) strText = String.format( "%s", event.getActionCommand() ); } } protected void addKeys(JPanel parent, int row, String[] keys, JButton[] buttons) { GridBagConstraints gbc = new GridBagConstraints(); gbc.gridy = row; gbc.gridx = 0; gbc.fill = GridBagConstraints.BOTH; int gap = 0; for (int index = 0; index < keys.length; index++) { String key = keys[index]; if ("blank".equalsIgnoreCase(key)) { gbc.gridx++; } else if ("fill".equalsIgnoreCase(key)) { gbc.gridwidth++; gap++; } else { //System.out.println("Add " + key); JButton btn = new JButton(key); buttons[index] = btn; parent.add(btn, gbc); gbc.gridx += gap + 1; gbc.gridwidth = 1; gap = 0; } } } }//end of class 如果你们需要更多的澄清或有任何疑问，请告诉我，我会提供尽可能多的信息。 我真的很感谢你的帮助，当你有库存并且无法找到问题的答案时，你会感到多么沮丧..不好玩！ 🙁
大多数键的简单解决方案：
要遵循的步骤：
- 创建一个按键值作为键的地图
- 根据按键获取按钮
- 将返回按钮的颜色更改为蓝色
- 在键释放时执行相同的操作并将颜色设置为白色
代码段：
Map map=new HashMap(); public void keyPressed(KeyEvent evt) { keycode = evt.getKeyCode(); strText = String.format("%s", KeyEvent.getKeyText(evt.getKeyCode())); JButton btn = map.get(keycode); if (btn != null) { map.get(keycode).setBackground(Color.BLUE); } }// end of key pressed public void keyReleased(KeyEvent evt) { keycode = evt.getKeyCode(); strText = String.format("%s", KeyEvent.getKeyText(evt.getKeyCode())); JButton btn = map.get(keycode); if (btn != null) { map.get(keycode).setBackground(Color.WHITE); } } protected void addKeys(JPanel parent, int row, String[] keys, JButton[] buttons) { GridBagConstraints gbc = new GridBagConstraints(); gbc.gridy = row; gbc.gridx = 0; gbc.fill = GridBagConstraints.BOTH; int gap = 0; for (int index = 0; index < keys.length; index++) { String key = keys[index]; if ("blank".equalsIgnoreCase(key)) { gbc.gridx++; } else if ("fill".equalsIgnoreCase(key)) { gbc.gridwidth++; gap++; } else { // System.out.println("Add " + key); JButton btn = new JButton(key); buttons[index] = btn; parent.add(btn, gbc); gbc.gridx += gap + 1; gbc.gridwidth = 1; gap = 0; System.out.println(key); btn.setBackground(Color.WHITE); map.put(getKeyCode(key), btn); } } } private int getKeyCode(String key) { if (key.equals("BackSpace")) { return KeyEvent.VK_BACK_SPACE; } else if (key.equals("Tab")) { return KeyEvent.VK_TAB; } else if (key.equals("Caps")) { return KeyEvent.VK_CAPS_LOCK; } else if (key.equals("Enter")) { return KeyEvent.VK_ENTER; } else if (key.equals("Shift")) { return KeyEvent.VK_SHIFT; } else if (key.equals("")) { return KeyEvent.VK_SPACE; } else if (key.equals("+")) { return KeyEvent.VK_EQUALS; }else if (key.equals(":")) { return KeyEvent.VK_SEMICOLON; }else if (key.equals("\"")) { return KeyEvent.VK_QUOTE; }else if (key.equals("?")) { return KeyEvent.VK_SLASH; }else if (key.equals("~")) { return KeyEvent.VK_BACK_QUOTE; } else if (key.equals("^")) { return KeyEvent.VK_UP; } else if (key.equals("v")) { return KeyEvent.VK_DOWN; } else if (key.equals("<")) { return KeyEvent.VK_LEFT; } else if (key.equals(">")) { return KeyEvent.VK_RIGHT; } else { return (int) key.charAt(0); } }
完整代码 （如果您收到错误。上面提到了更改）
package com.test; import java.awt.BorderLayout; import java.awt.Color; import java.awt.Dimension; import java.awt.Font; import java.awt.GradientPaint; import java.awt.Graphics; import java.awt.Graphics2D; import java.awt.GridBagConstraints; import java.awt.GridBagLayout; import java.awt.RenderingHints; import java.awt.event.ActionEvent; import java.awt.event.ActionListener; import java.awt.event.KeyEvent; import java.awt.event.KeyListener; import java.util.HashMap; import java.util.Map; import javax.swing.JButton; import javax.swing.JFrame; import javax.swing.JLabel; import javax.swing.JPanel; import javax.swing.JTextArea; import javax.swing.JTextField; public class typeTutor extends JFrame implements KeyListener { Map map = new HashMap(); // Individual keyboard rows String firstRow[] = { "~", "1", "2", "3", "4", "5", "6", "7", "8", "9", "0", "-", "+", "fill", "BackSpace" }; String secondRow[] = { "Tab", "Q", "W", "E", "R", "T", "Y", "U", "I", "O", "P", "[", "]", "\\" }; String thirdRow[] = { "Caps", "A", "S", "D", "F", "G", "H", "J", "K", "L", ":", "\"", "fill", "fill", "Enter" }; String fourthRow[] = { "Shift", "Z", "X", "C", "V", "B", "N", "M", ",", ".", "?", "blank", "^" }; String fifthRow[] = { "blank", "blank", "fill", "fill", "fill", "fill", "fill", "fill", "fill", "fill", "", "<", "v", ">" }; private JTextField textField; // Individual keyboard rows /* * String firstRow[] = {"~","1","2","3","4","5","6","7","8","9","0","-","+","BackSpace"}; String * secondRow[] = {"Tab","Q","W","E","R","T","Y","U","I","O","P","[","]","\\"}; String thirdRow[] * = {"Caps","A","S","D","F","G","H","J","K","L",":","\"","Enter"}; String fourthRow[] = * {"Shift","Z","X","C","V","B","N","M",",",".","?"," ^" }; String * fifthRow[]={" " ,"<" ,"v",">" }; */ String strText = ""; // all keys without shift key press String noShift = "`1234567890-=qwertyuiop[]\\asdfghjkl;'zxcvbnm,./"; // special characters on keyboard that has to be addressed during key press String specialChars = "~-+[]\\;',.?"; int keycode; JTextArea text = new JTextArea(); // Jbuttons corresponding to each individual rows JButton first[]; JButton second[]; JButton third[]; JButton fourth[]; JButton fifth[]; // default color of the button to be repainted when key released Color cc = new JButton().getBackground(); // Driver main method to start the application public static void main(String[] args) { // launch typing tutor typeTutor a = new typeTutor(); a.setVisible(true); } // No argument constructor to create frame public typeTutor() { super("Type Tutor - My JAC444"); JPanel contentPane = new JPanel() { @Override protected void paintComponent(Graphics grphcs) { Graphics2D g2d = (Graphics2D) grphcs; Dimension d = this.getSize(); g2d.setRenderingHint(RenderingHints.KEY_ANTIALIASING, RenderingHints.VALUE_ANTIALIAS_ON); GradientPaint gp = new GradientPaint(0, 0, getBackground().brighter().brighter(), 0, d.height, getBackground().darker().darker()); g2d.setPaint(gp); g2d.fillRect(0, 0, d.width, d.height); super.paintComponent(grphcs); } }; contentPane.setOpaque(false); setContentPane(contentPane); // textField = new JTextField(80); // text.setEditable(true); TextFieldHandler handler = new TextFieldHandler(); // set the info label on top JLabel info = new JLabel( " Type some text using your keyboard.The keys you press will be highlighted and text will be displayed.
Note : Clicking the buttons with your mouse will not perform any action.
"); // set the bold font for info info.setFont(new Font("Verdana", Font.BOLD, 12)); // set the layout and place component in place and pack it setLayout(new BorderLayout()); // Various panel for the layout JPanel jpNorth = new JPanel(); JPanel jpCenter = new JPanel(); jpCenter.setPreferredSize(new Dimension(10, 10)); JPanel jpKeyboard = new JPanel(new GridBagLayout()); JPanel jpNote = new JPanel(); add(jpNorth, BorderLayout.NORTH); add(jpNote); add(jpCenter, BorderLayout.CENTER); add(jpKeyboard, BorderLayout.SOUTH); jpNorth.setLayout(new BorderLayout()); jpNorth.add(info, BorderLayout.WEST); jpNorth.add(info, BorderLayout.SOUTH); jpCenter.setLayout(new BorderLayout()); jpCenter.add(text, BorderLayout.WEST); jpCenter.add(text, BorderLayout.CENTER); jpCenter.setPreferredSize(new Dimension(10, 10)); first = new JButton[firstRow.length]; second = new JButton[secondRow.length]; third = new JButton[thirdRow.length]; fourth = new JButton[fourthRow.length]; fifth = new JButton[fifthRow.length]; addKeys(jpKeyboard, 0, firstRow, first); addKeys(jpKeyboard, 1, secondRow, second); addKeys(jpKeyboard, 2, thirdRow, third); addKeys(jpKeyboard, 3, fourthRow, fourth); addKeys(jpKeyboard, 4, fifthRow, fifth); // jpCenter.setPreferredSize(new Dimension(10,10)); jpKeyboard.setPreferredSize(new Dimension(800, 160)); info.setOpaque(false); jpNote.setOpaque(false); jpNorth.setOpaque(false); jpCenter.setOpaque(false); jpKeyboard.setOpaque(false); // add listeners // getComponent().addKeyListener(this); text.addKeyListener(this); // add listeners to all the button /* * for (JButton b : first) { if (b != null) { b.addKeyListener(this); } } */ /* * for(JButton b : second) b.addKeyListener(this); for(JButton b : third) * b.addKeyListener(this); * * for(JButton b : fourth) b.addKeyListener(this); * * for(JButton b : fifth) b.addKeyListener(this); */ this.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE); // set non re-sizable this.setResizable(false); // set size of the content pane ie frame this.getContentPane().setPreferredSize(new Dimension(1100, 350)); // set location for the frame // this.setLocation(150,150); // init and paint frame initWidgets(); pack(); this.toFront(); // brings this Window to the front and may make it the focused Window this.setLocationRelativeTo(null); // Window appears center } // Method to initialize frame component private void initWidgets() { } private class TextAreaHandler implements ActionListener { // process textfield events public void actionPerformed(ActionEvent event) { String string = ""; // declare string to display // user pressed Enter in JTextField textField1 if (event.getSource() == textField) string = String.format("%s", event.getActionCommand()); } } // Invoked when a key has been pressed. // @see java.awt.event.KeyListener#keyPressed(java.awt.event.KeyEvent) public void keyPressed(KeyEvent evt) { keycode = evt.getKeyCode(); strText = String.format("%s", KeyEvent.getKeyText(evt.getKeyCode())); JButton btn = map.get(keycode); if (btn != null) { map.get(keycode).setBackground(Color.BLUE); } }// end of key pressed // Invoked when a key has been released. public void keyReleased(KeyEvent evt) { keycode = evt.getKeyCode(); strText = String.format("%s", KeyEvent.getKeyText(evt.getKeyCode())); JButton btn = map.get(keycode); if (btn != null) { map.get(keycode).setBackground(Color.WHITE); } } public void keyTyped(KeyEvent evt) { strText = String.format("%s", evt.getKeyChar()); }// end of key pressed private class TextFieldHandler implements ActionListener { // process textfield events public void actionPerformed(ActionEvent event) { String string = ""; // declare string to display // user pressed Enter in JTextField textField1 if (event.getSource() == text) strText = String.format("%s", event.getActionCommand()); } } protected void addKeys(JPanel parent, int row, String[] keys, JButton[] buttons) { GridBagConstraints gbc = new GridBagConstraints(); gbc.gridy = row; gbc.gridx = 0; gbc.fill = GridBagConstraints.BOTH; int gap = 0; for (int index = 0; index < keys.length; index++) { String key = keys[index]; if ("blank".equalsIgnoreCase(key)) { gbc.gridx++; } else if ("fill".equalsIgnoreCase(key)) { gbc.gridwidth++; gap++; } else { // System.out.println("Add " + key); JButton btn = new JButton(key); buttons[index] = btn; parent.add(btn, gbc); gbc.gridx += gap + 1; gbc.gridwidth = 1; gap = 0; System.out.println(key); btn.setBackground(Color.WHITE); map.put(getKeyCode(key), btn); } } } private int getKeyCode(String key) { if (key.equals("BackSpace")) { return KeyEvent.VK_BACK_SPACE; } else if (key.equals("Tab")) { return KeyEvent.VK_TAB; } else if (key.equals("Caps")) { return KeyEvent.VK_CAPS_LOCK; } else if (key.equals("Enter")) { return KeyEvent.VK_ENTER; } else if (key.equals("Shift")) { return KeyEvent.VK_SHIFT; } else if (key.equals("")) { return KeyEvent.VK_SPACE; } else if (key.equals("+")) { return KeyEvent.VK_EQUALS; }else if (key.equals(":")) { return KeyEvent.VK_SEMICOLON; }else if (key.equals("\"")) { return KeyEvent.VK_QUOTE; }else if (key.equals("?")) { return KeyEvent.VK_SLASH; }else if (key.equals("~")) { return KeyEvent.VK_BACK_QUOTE; } else if (key.equals("^")) { return KeyEvent.VK_UP; } else if (key.equals("v")) { return KeyEvent.VK_DOWN; } else if (key.equals("<")) { return KeyEvent.VK_LEFT; } else if (key.equals(">")) { return KeyEvent.VK_RIGHT; } else { return (int) key.charAt(0); } } }// end of class
主要问题是，重点。 KeyListener注册到的组件必须是可聚焦的，并且在可以通知关键事件之前具有焦点。
通常情况下，我建议使用Key Bindings API，但这需要您为要监视的每个键注册一个绑定，包括它的移位状态（几乎使键绑定加倍）。
另一种方法是直接向事件队列注册AWTEventListener 。
这是非常低级别的东西，但基本上意味着您将收到几乎每个通过系统的基于AWT的事件的通知。 您可以对此进行过滤以仅包含关键事件，这样可以使您的工作更轻松……
下面是一个非常简单的例子。 知道，你将收到两件（基本）的东西。 虚拟密钥代码，用于使不同的密钥板和平台成为公共已知密钥值和关键字符。
通过shift键的状态修改关键字符。 因此，您将不得不设计一种方法来查找关键代码/字符并找到与之关联的按钮……
Toolkit.getDefaultToolkit().addAWTEventListener(new AWTEventListener() { @Override public void eventDispatched(AWTEvent event) { if (event instanceof KeyEvent) { KeyEvent ke = (KeyEvent) event; switch (ke.getID()) { case KeyEvent.KEY_PRESSED: // set the various state variables, like color for this state break; case KeyEvent.KEY_RELEASED: // set the various state variables, like color for this state break; } switch (ke.getKeyCode()) { case KeyEvent.VK_SHIFT: if (ke.getKeyLocation() == KeyEvent.KEY_LOCATION_LEFT) { // left shift } else if (ke.getKeyLocation() == KeyEvent.KEY_LOCATION_RIGHT) { // right shift } break; case KeyEvent.VK_CAPS_LOCK: break; case KeyEvent.VK_DELETE: break; case KeyEvent.VK_ENTER: break; case KeyEvent.VK_UP: break; case KeyEvent.VK_DOWN: break; case KeyEvent.VK_LEFT: break; case KeyEvent.VK_RIGHT: break; default: // You could use the ke.getKeyChar() here, but remember, // the caps-lock and shift will change the char returned // the key code is safer, but that's a lot of work ;) break; } } } }, AWTEvent.KEY_EVENT_MASK);