Java核心技术（高级Swing）三文本构件

所有文本构件都可以绘制和编辑存储在实现了Document接口的类的模型对象中的数据。JTextField和JTextArea构件使用的是

PlainDocument，该构件只储存普通文本的行序列，而不进行任何格式化。JEditorPane可以展示和编辑各种格式的样式文本，特别

是HTML，StyleDocument接口描述了对样式、字体和颜色的额外需求，而HTMLDocument类实现了这个接口。

文本构件中的修改跟踪

应该让文档来通知我们数据发生变化，方法是在文档上安装文档监听器DocumentListener。

格式化的输入框

JFormattedTextField类，当格式化文本框失去焦点时，格式器会检查用户输入的文本字符串。失去焦点的默认行为称为提交或回复。

过滤器：防止用户键入非法字符。过滤器可以拦截插入命令，并修改字符串或放弃插入操作。通过过滤机制避免所有无效字符串是不可

能的。

校验器：在任意JComponent上附着，可以就无效输入对用户发出警告。必须扩展InputVerifier类并定义verify方法。如果该构件失

去焦点，那么校验器就会被查询。如果校验器报告该构件无效，那么该构件就会立即重新获得焦点，用户就被强制要求在进行其他输入之前先

订正刚输入的内容。

标准格式器：NumberFormat类、DateFormat类、DefaultFormatter类、MaskFormatter类。

定制格式器：需要扩展DefaultFormatter类，并覆盖String valueToString(Object value)、

Object stringToValue(String text)。

JSpinner构件

JSpinner是包含一个文本框以及两个在文本框旁边的小按钮的构件。当点击按钮时，文本框的值就会递增或递减。微调器中的值可以是

数字、日期、列表中的值，或是更为普遍的情况，即前驱和后继可以确定的任何值序列。可以用微调器迭代任何值集合，只需将一个

SpinnerListModel传递给JSpinner构造器即可。通过定义自已的微调器模型，可以在微调器中显示任意的序列，需要扩展

AbstractSpinnerModel类并定义Object getValue();void setValue(Object value);Object getNextValue();

Object getPreviousVaule().

public class TextDemo extends JFrame {public static void main(String[] args){new TextDemo().setVisible(true);}public TextDemo(){setTitle("TextDemo");setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);setSize(WIDTH, HEIGHT);northPanel = new JPanel();//跟踪文本构件MyDocumentListener myDocumentListener = new MyDocumentListener();northPanel.add(new JLabel("Red:"));redField = new JTextField("255", 3);redField.getDocument().addDocumentListener(myDocumentListener);northPanel.add(redField);northPanel.add(new JLabel("Green:"));greenField = new JTextField("255", 3);greenField.getDocument().addDocumentListener(myDocumentListener);northPanel.add(greenField);northPanel.add(new JLabel("Blue:"));blueField = new JTextField("255", 3);blueField.getDocument().addDocumentListener(myDocumentListener);northPanel.add(blueField);setColor();centerPanel = new JPanel();//格式化文本设置过滤器filterFormattedTextField = new JFormattedTextField(new InternationalFormatter(NumberFormat.getIntegerInstance()){protected DocumentFilter getDocumentFilter(){return filter;}private DocumentFilter filter = new MyFilter();});filterFormattedTextField.setValue(new Integer(1000));//格式化文本设置校验器verifiedFormattedTextField = new JFormattedTextField(NumberFormat.getIntegerInstance());verifiedFormattedTextField.setValue(new Integer(1000));verifiedFormattedTextField.setInputVerifier(new MyVerifier());centerPanel.add(new JLabel("Filter:"));centerPanel.add(filterFormattedTextField);centerPanel.add(new JLabel("Verified:"));centerPanel.add(verifiedFormattedTextField);//格式化文本try{MaskFormatter formatter = new MaskFormatter("###-##-####");formatter.setPlaceholderCharacter(' ');formattedTextField = new JFormattedTextField(formatter);formattedTextField.setValue("078-25-4646");centerPanel.add(new JLabel("Mask:"));centerPanel.add(formattedTextField);}catch (Exception e) {e.printStackTrace();}southPanel = new JPanel();boundSpinner = new JSpinner(new SpinnerNumberModel(5, 0, 10, 0.5));southPanel.add(boundSpinner);String[] fonts = GraphicsEnvironment.getLocalGraphicsEnvironment().getAvailableFontFamilyNames();fontSpinner = new JSpinner(new SpinnerListModel(fonts){public Object getNextValue() {return super.getPreviousValue();}public Object getPreviousValue() {return super.getNextValue();}});southPanel.add(fontSpinner);//定制JSpinnerspinner = new JSpinner(new MySpinnerModel("meat"));southPanel.add(spinner);add(northPanel, BorderLayout.NORTH);add(centerPanel, BorderLayout.CENTER);add(southPanel, BorderLayout.SOUTH);pack();}private void setColor(){try{int red = Integer.parseInt(redField.getText().trim());int green = Integer.parseInt(greenField.getText().trim());int blue = Integer.parseInt(blueField.getText().trim());northPanel.setBackground(new Color(red, green, blue));}catch (Exception e) {}}//跟踪文本框的修改private class MyDocumentListener implements DocumentListener{public void changedUpdate(DocumentEvent event) {}public void insertUpdate(DocumentEvent event) {setColor();}public void removeUpdate(DocumentEvent event) {setColor();}}//设置过滤器private class MyFilter extends DocumentFilter{public void insertString(FilterBypass fb, int offset, String string, AttributeSet attr) throws BadLocationException{System.out.println("string:" + string);StringBuilder builder = new StringBuilder(string);for(int i=builder.length()-1;i>=0;i--){int cp = builder.codePointAt(i);if(!Character.isDigit(cp) && cp != '-'){builder.deleteCharAt(i);if(Character.isSupplementaryCodePoint(cp)){i--;builder.deleteCharAt(i);}}}super.insertString(fb, offset, builder.toString(), attr);}public void replace(FilterBypass fb, int offset, int length, String string, AttributeSet attr) throws BadLocationException{if(string != null){StringBuilder builder = new StringBuilder(string);for(int i=builder.length()-1;i>=0;i--){int cp = builder.codePointAt(i);if(!Character.isDigit(cp)&&cp!='-'){builder.deleteCharAt(i);if(Character.isSupplementaryCodePoint(cp)){i--;builder.deleteCharAt(i);}}}string = builder.toString();}super.replace(fb, offset, length, string, attr);}}//设置校验器private class MyVerifier extends InputVerifier{public boolean verify(JComponent component) {JFormattedTextField field = (JFormattedTextField)component;return field.isEditable();}}//自定义微调器private class MySpinnerModel extends AbstractSpinnerModel{public MySpinnerModel(String word) {this.word = word;}public Object getNextValue() {int[] codePoints = toCodePointArray(word);for(int i = codePoints.length - 1;i>0;i--){if(codePoints[i-1]<codePoints[i]){int j = codePoints.length - 1;while(codePoints[i-1]>codePoints[j])j--;swap(codePoints, i - 1, j);reverse(codePoints, i, codePoints.length - 1);return new String(codePoints, 0, codePoints.length);}}reverse(codePoints, 0, codePoints.length - 1);return new String(codePoints, 0, codePoints.length);}public Object getPreviousValue() {int[] codePoints = toCodePointArray(word);for(int i = codePoints.length - 1;i>0;i--){if(codePoints[i-1]>codePoints[i]){int j = codePoints.length - 1;while(codePoints[i-1]<codePoints[j])j--;swap(codePoints, i - 1, j);reverse(codePoints, i, codePoints.length - 1);return new String(codePoints, 0, codePoints.length);}}reverse(codePoints, 0, codePoints.length - 1);return new String(codePoints, 0, codePoints.length);}public Object getValue() {return word;}public void setValue(Object value) {if(!(value instanceof String))throw new IllegalArgumentException();word = (String)value;fireStateChanged();}private int[] toCodePointArray(String str){int[] codePoints = new int[str.codePointCount(0, str.length())];for(int i = 0, j = 0;i < str.length();i++, j++){int cp = str.codePointAt(i);if(Character.isSupplementaryCodePoint(cp))i++;codePoints[j] = cp;}return codePoints;}private void swap(int[] a, int i, int j){int temp = a[i];a[i] = a[j];a[j] = temp;}private void reverse(int[] a, int i, int j){while(i<j){swap(a, i, j);i++;j--;}}private String word;}private JTextField redField;private JTextField greenField;private JTextField blueField;private JPanel northPanel;private JPanel centerPanel;private JFormattedTextField filterFormattedTextField;private JFormattedTextField verifiedFormattedTextField;private JFormattedTextField formattedTextField;private JPanel southPanel;private JSpinner boundSpinner;private JSpinner fontSpinner;private JSpinner spinner;private static final int WIDTH = 500;private static final int HEIGHT = 400;}