第23章 定制文本组件

第23章 定制文本组件

　　Swing文本建立在由javax.swing.text包的类和接口提供的一个复杂的下层构件之上。一般使用Swing文本组件(在前两章中介绍)不要求对Swing文本包有很深的了解。但如果要定制文本组件，则要对javax.swing.text包有一个基本的掌握。本章提供了定制通用任务的例子。如彩色文本、设置字符和段落属性、实现定制视图等。

23.1 概览

　　与其他Swing组件一样，文本组件由一个模型(Document接口的一个实现)和一个UI代表（javax.swing.plaf.basic.BasicTextUI类的一个扩展）组成。文本组件还使用一个编辑器工具包(EditorKit类的一个扩展）和一个视图(View类的一个扩展)。图23-1示出了一个类图，这个类图说明了Swing文本域、这个域模型、UI代表、编辑器工具包和视图之间的静态关系(注：23.4节“视图”讨论了视图，所有的文本组件都有一个或多个视图)。其他的Swing文本组件有类似的类图。

23.2 属性集和风格常量

例23-1 使用属性集

---

import java.awt.*;
import java.awt.event.*;
import javax.swing.*;
import javax.swing.text.*;
import java.util.*;
import java.io.FileReader;

public class Test extends JFrame {
private JTextPane textPane = new JTextPane();
private StyledDocument document =
(StyledDocument)textPane.getDocument();

public Test() {
Container contentPane = getContentPane();
readFile("text.txt");
setAttributes();

textPane.setFont(new Font("Dialog", Font.PLAIN, 18));
contentPane.add(new JScrollPane(textPane),
BorderLayout.CENTER);
}
private void setAttributes() {
SimpleAttributeSet attributes = new SimpleAttributeSet();

StyleConstants.setForeground(attributes, Color.blue);
StyleConstants.setUnderline(attributes, true);

document.setCharacterAttributes(5,9,attributes,false);

StyleConstants.setForeground(attributes, Color.red);
StyleConstants.setStrikeThrough(attributes, false);

document.setCharacterAttributes(15,9,attributes,true);
}
private void readFile(String filename) {
EditorKit kit = textPane.getEditorKit();
try {
kit.read(new FileReader(filename), document, 0);
}
catch(Exception ex) {
ex.printStackTrace();
}
}
public static void main(String args[]) {
GJApp.launch(new Test(),
"Setting Attributes",300,300,450,300);
}
}
class GJApp extends WindowAdapter {
static private JPanel statusArea = new JPanel();
static private JLabel status = new JLabel(" ");
static private ResourceBundle resources;

static {
resources = ResourceBundle.getBundle(
"GJApp", Locale.getDefault());
};

private GJApp() {}

public static void launch(final JFrame f, String title,
final int x, final int y,
final int w, int h) {
f.setTitle(title);
f.setBounds(x,y,w,h);
f.setVisible(true);

statusArea.setBorder(BorderFactory.createEtchedBorder());
statusArea.setLayout(new FlowLayout(FlowLayout.LEFT,0,0));
statusArea.add(status);
status.setHorizontalAlignment(JLabel.LEFT);

f.setDefaultCloseOperation(
WindowConstants.DISPOSE_ON_CLOSE);

f.addWindowListener(new WindowAdapter() {
public void windowClosed(WindowEvent e) {
System.exit(0);
}
});
}
static public JPanel getStatusArea() {
return statusArea;
}
static public void showStatus(String s) {
status.setText(s);
}
static Object getResource(String key) {
if(resources != null) {
return resources.getString(key);
}
return null;
}
}

---

 

23.3 定制动作

 

例23-2 实现定制动作

---

import java.io.File;
import javax.swing.*;
import javax.swing.text.*;
import java.awt.*;
import java.awt.event.*;
import java.util.*;
import java.io.FileReader;

public class Test extends JFrame {
private JTextPane textPane = new JTextPane();
private StyledDocument document =
(StyledDocument)textPane.getDocument();
private StyledEditorKit kit =
(StyledEditorKit)textPane.getEditorKit();
private JColorChooser chooser = new JColorChooser();
private int CharacterMode = 0, ParagraphMode = 1;

public Test() {
Container contentPane = getContentPane();
readFile("text.txt");

textPane.setFont(new Font("Dialog", Font.PLAIN, 18));

contentPane.add(new JScrollPane(textPane),
BorderLayout.CENTER);

setJMenuBar(createMenuBar());
}
private JMenuBar createMenuBar() {
JMenuBar menuBar = new JMenuBar();
JMenu editMenu = new JMenu("Edit");

editMenu.add(new ForegroundFromChooserAction(
"Character Foreground Color ... ",
CharacterMode));

editMenu.add(new ForegroundFromChooserAction(
"Paragraph Foreground Color ... ",
ParagraphMode));

menuBar.add(editMenu);
return menuBar;
}
private void readFile(String filename) {
try {
kit.read(new FileReader(filename), document, 0);
}
catch(Exception ex) {
ex.printStackTrace();
}
}
public static void main(String args[]) {
GJApp.launch(new Test(),
"Custom Actions",300,300,650,275);
}
class ForegroundFromChooserAction
extends StyledEditorKit.StyledTextAction {

protected Color fg;
protected JColorChooser chooser = new JColorChooser();
protected int mode;

public ForegroundFromChooserAction(String nm, int mode) {
super(nm);
this.mode = mode;
}
public void actionPerformed(ActionEvent e) {
JEditorPane editor = getEditor(e);
if (editor != null) {
AttributeSet attributes =
textPane.getCharacterAttributes();
Color c =
StyleConstants.getForeground(attributes);

Color fg = chooser.showDialog(Test.this,
"Choose Color for Text",
c == null ? Color.black : c);
/*
if ((e != null) && (e.getSource() == editor)) {
String s = e.getActionCommand();
try {
fg = Color.decode(s);
}
catch(NumberFormatException ex) {
ex.printStackTrace();
}
}
*/
if (fg != null) {
MutableAttributeSet attr =
new SimpleAttributeSet();
StyleConstants.setForeground(attr, fg);

if(mode == CharacterMode)
setCharacterAttributes(editor, attr, false);
else
setParagraphAttributes(editor, attr, false);

textPane.setCaretPosition(
textPane.getSelectionStart());
} else {
Toolkit.getDefaultToolkit().beep();
}
}
}
}
}
class GJApp extends WindowAdapter {
static private JPanel statusArea = new JPanel();
static private JLabel status = new JLabel(" ");
static private ResourceBundle resources;

static {
resources = ResourceBundle.getBundle(
"GJApp", Locale.getDefault());
};

private GJApp() {}

public static void launch(final JFrame f, String title,
final int x, final int y,
final int w, int h) {
f.setTitle(title);
f.setBounds(x,y,w,h);
f.setVisible(true);

statusArea.setBorder(BorderFactory.createEtchedBorder());
statusArea.setLayout(new FlowLayout(FlowLayout.LEFT,0,0));
statusArea.add(status);
status.setHorizontalAlignment(JLabel.LEFT);

f.setDefaultCloseOperation(
WindowConstants.DISPOSE_ON_CLOSE);

f.addWindowListener(new WindowAdapter() {
public void windowClosed(WindowEvent e) {
System.exit(0);
}
});
}
static public JPanel getStatusArea() {
return statusArea;
}
static public void showStatus(String s) {
status.setText(s);
}
static Object getResource(String key) {
if(resources != null) {
return resources.getString(key);
}
return null;
}
}

---

23.4 视图

 

例23-3 实现一个定制视图

---

import javax.swing.*;
import javax.swing.event.*;
import javax.swing.text.*;
import java.awt.*;
import java.awt.event.*;
import java.util.*;

public class Test extends JFrame {
JEditorPane editorPane = new JEditorPane();
Vector positions = new Vector();
Position.Bias bias = Position.Bias.Forward;

class CustomView extends WrappedPlainView {
public CustomView(Element elem) {
super(elem);
}
public void paint(Graphics g, Shape a) {
super.paint(g,a);

Enumeration e = positions.elements();
Position p;

while(e.hasMoreElements()) {
try {
p = (Position)e.nextElement();
int offset = p.getOffset();

Shape s = modelToView(p.getOffset(), a, bias);
Rectangle r = s.getBounds();

// black border
g.setColor(Color.black);
g.drawRect(r.x, r.y, 6, 6);

// red fill
g.setColor(Color.red);
g.fillRect(r.x+1, r.y+1, 5, 5);
}
catch(BadLocationException ex) {
ex.printStackTrace();
}
}
}
};
class CustomEditorKit extends DefaultEditorKit
implements ViewFactory {
public ViewFactory getViewFactory() {
return this;
}
public View create(Element elem) {
return new CustomView(elem);
}
};
public Test() {
JPanel panel = new JPanel();
JButton button = new JButton("Insert Position");
Container contentPane = getContentPane();
panel.add(button);

editorPane.setEditorKit(new CustomEditorKit());
editorPane.setFont(new Font("Serif", Font.ITALIC, 36));

contentPane.add(panel, BorderLayout.NORTH);
contentPane.add(editorPane, BorderLayout.CENTER);

button.addActionListener(new ActionListener() {
public void actionPerformed(ActionEvent e) {
try {
Document doc = editorPane.getDocument();
int p = editorPane.getCaretPosition();

positions.addElement(doc.createPosition(p));
editorPane.repaint();
}
catch(BadLocationException ex) {
ex.printStackTrace();
}
}
});
}
public static void main(String args[]) {
GJApp.launch(new Test(),
"Custom Text Views",300,300,450,300);
}
}
class GJApp extends WindowAdapter {
static private JPanel statusArea = new JPanel();
static private JLabel status = new JLabel(" ");

public static void launch(final JFrame f, String title,
final int x, final int y,
final int w, int h) {
f.setTitle(title);
f.setBounds(x,y,w,h);
f.setVisible(true);

statusArea.setBorder(BorderFactory.createEtchedBorder());
statusArea.setLayout(new FlowLayout(FlowLayout.LEFT,0,0));
statusArea.add(status);
status.setHorizontalAlignment(JLabel.LEFT);

f.setDefaultCloseOperation(
WindowConstants.DISPOSE_ON_CLOSE);

f.addWindowListener(new WindowAdapter() {
public void windowClosed(WindowEvent e) {
System.exit(0);
}
});
}
static public JPanel getStatusArea() {
return statusArea;
}
static public void showStatus(String s) {
status.setText(s);
}
}

---

23.5 风格和风格的相关内容

 

例23-4 使用风格的相关内容

---

import java.io.File;
import javax.swing.*;
import javax.swing.text.*;
import javax.swing.event.*;
import java.awt.*;
import java.awt.event.*;
import java.util.*;
import java.io.FileReader;

public class Test extends JFrame {
private JTextPane textPane = new JTextPane();
private Hashtable actionTable = new Hashtable();
private JCheckBoxMenuItem titleItem, bodyItem;

public Test() {
Container contentPane = getContentPane();

textPane.setEditorKit(new ChapterEditorKit());
textPane.setFont(new Font("Dialog", Font.PLAIN, 18));

// must load action table after setting editor kit ...
loadActionTable();

readFile("text.txt");

contentPane.add(new JScrollPane(textPane),
BorderLayout.CENTER);
contentPane.add(GJApp.getStatusArea(),BorderLayout.SOUTH);

setJMenuBar(createMenuBar());
}
private JMenuBar createMenuBar() {
JMenuBar menuBar = new JMenuBar();
JMenu editMenu = new JMenu("Edit"),
styleMenu = new JMenu("Paragraph Styles");

styleMenu.add(getAction(ChapterStyleContext.titleStyle));
styleMenu.add(getAction(ChapterStyleContext.bodyStyle));

editMenu.add(styleMenu);
menuBar.add(editMenu);
return menuBar;
}
private void readFile(String filename) {
EditorKit kit = textPane.getEditorKit();
Document doc = textPane.getDocument();

try {
kit.read(new FileReader(filename), doc, 0);
}
catch(Exception ex) {
ex.printStackTrace();
}
}
private void loadActionTable() {
Action[] actions = textPane.getActions();

for(int i=0; i < actions.length; ++i) {
actionTable.put(actions[i].getValue(Action.NAME),
actions[i]);
}
}
private Action getAction(String name) {
return (Action)actionTable.get(name);
}
public static void main(String args[]) {
GJApp.launch(new Test(),
"Custom EditorKits & Style Contexts",
300,300,650,275);
}
}
class ChapterEditorKit extends StyledEditorKit {
private CaretListener caretListener = new Listener();
private static ChapterStyleContext context =
new ChapterStyleContext();

private static Action[] defaultActions = new Action[] {
new ParagraphStyleAction(
ChapterStyleContext.titleStyle,
context.getStyle(ChapterStyleContext.titleStyle)),
new ParagraphStyleAction(
ChapterStyleContext.bodyStyle,
context.getStyle(ChapterStyleContext.bodyStyle)),
};
public Action[] getActions() {
return TextAction.augmentList(super.getActions(),
defaultActions);
}
public void install(JEditorPane editorPane) {
editorPane.addCaretListener(caretListener);
}
public void deinstall(JEditorPane editorPane) {
editorPane.removeCaretListener(caretListener);
}
static class Listener implements CaretListener {
public void caretUpdate(CaretEvent e) {
int dot = e.getDot(), mark = e.getMark();

if (dot == mark) {
JTextComponent c = (JTextComponent) e.getSource();
StyledDocument document =
(StyledDocument) c.getDocument();
Element elem = document.getParagraphElement(dot);
AttributeSet set = elem.getAttributes();
String name = (String)set.getAttribute(
StyleConstants.NameAttribute);

GJApp.showStatus(name);
}
}
}
static class ParagraphStyleAction
extends StyledEditorKit.StyledTextAction {
private Style style;

public ParagraphStyleAction(String nm, Style style) {
super(nm);
this.style = style;
}
public void actionPerformed(ActionEvent e) {
setParagraphAttributes(getEditor(e), style, false);
GJApp.showStatus(style.getName());
}
}
}
class ChapterStyleContext extends StyleContext {
public static String titleStyle = "title",
bodyStyle = "body";

public static String[] defaultStyleNames = new String[] {
new String(titleStyle),
new String(bodyStyle) };

public ChapterStyleContext() {
Style root = getStyle(DEFAULT_STYLE);

for(int i=0; i < defaultStyleNames.length; ++i) {
String name = defaultStyleNames[i];
Style s = addStyle(name, root);

if(name.equals(titleStyle)) {
StyleConstants.setFontFamily(s, "Dialog");
StyleConstants.setFontSize(s, 24);
StyleConstants.setBold(s, true);
StyleConstants.setUnderline(s, true);
}
else if(name.equals(bodyStyle)) {
StyleConstants.setFontFamily(s, "Times-Roman");
StyleConstants.setFontSize(s, 16);
}
}
}
}
class GJApp extends WindowAdapter {
static private JPanel statusArea = new JPanel();
static private JLabel status = new JLabel(" ");
static private ResourceBundle resources;

static {
resources = ResourceBundle.getBundle(
"GJApp", Locale.getDefault());
};

private GJApp() {}

public static void launch(final JFrame f, String title,
final int x, final int y,
final int w, int h) {
f.setTitle(title);
f.setBounds(x,y,w,h);
f.setVisible(true);

statusArea.setBorder(BorderFactory.createEtchedBorder());
statusArea.setLayout(new FlowLayout(FlowLayout.LEFT,0,0));
statusArea.add(status);
status.setHorizontalAlignment(JLabel.LEFT);

f.setDefaultCloseOperation(
WindowConstants.DISPOSE_ON_CLOSE);

f.addWindowListener(new WindowAdapter() {
public void windowClosed(WindowEvent e) {
System.exit(0);
}
});
}
static public JPanel getStatusArea() {
return statusArea;
}
static public void showStatus(String s) {
status.setText(s);
}
static Object getResource(String key) {
if(resources != null) {
return resources.getString(key);
}
return null;
}
}

---

23.6 元素

 

例23-5 元素层次

---

import javax.swing.*;
import javax.swing.event.*;
import javax.swing.text.*;
import java.awt.*;
import java.awt.event.*;
import java.util.*;
import java.io.FileReader;

public class Test extends JFrame {
private JTextComponent components[] = new JTextComponent[] {
new JTextField("initial content"), new JTextArea(10,20),
new JTextPane(), new JEditorPane(),
};
private String borderNames[] = new String[] {
"JTextField", "JTextArea", "JTextPane", "JEditorPane"
};
private JPanel textComponentPanel = new JPanel();
private ElementTreePanel treePanel =
new ElementTreePanel(components[0]);
private JSplitPane sp = new JSplitPane(
JSplitPane.HORIZONTAL_SPLIT,
new JScrollPane(textComponentPanel),
new JScrollPane(treePanel));

public Test() {
Container contentPane = getContentPane();
CaretListener listener = new Listener();

textComponentPanel.setBorder(
BorderFactory.createTitledBorder("Text Components"));

for(int i=0; i < components.length; ++i) {
JTextComponent c = (JTextComponent)components[i];

c.addCaretListener(listener);
c.setBorder(
BorderFactory.createTitledBorder(borderNames[i]));

if(i != 0) // JTextField
readFile(c, "text.txt");

if(i == 3) { // JEditorPane
JEditorPane
editorPane = (JEditorPane)c;

String url = "file:" +
System.getProperty("user.dir") +
System.getProperty("file.separator") +
"java.util.Hashtable.html";

editorPane.setEditable(false);
try {
editorPane.setPage(url);
}
catch(Exception ex) { ex.printStackTrace(); }

JScrollPane sp = new JScrollPane(c);
sp.setPreferredSize(new Dimension(450,450));
panel.add(sp);
}
else
panel.add(c);
}
sp.setDividerLocation(600);

contentPane.add(sp, BorderLayout.CENTER);
}
class Listener implements CaretListener {
public void caretUpdate(CaretEvent e) {
JTextComponent c = (JTextComponent)e.getSource();

if(c != treePanel.getEditor()) {
sp.setRightComponent(treePanel =
new ElementTreePanel(c));
}
}
}
private void readFile(JTextComponent c, String filename) {
try {
c.read(new FileReader(filename), null);
}
catch(Exception ex) {
ex.printStackTrace();
}
}
public static void main(String args[]) {
GJApp.launch(new Test(),
"Element Hierarchies",300,300,800,300);
}
}
class GJApp extends WindowAdapter {
static private JPanel statusArea = new JPanel();
static private JLabel status = new JLabel(" ");
static private ResourceBundle resources;

private GJApp() {}

public static void launch(final JFrame f, String title,
final int x, final int y,
final int w, int h) {
f.setTitle(title);
f.setBounds(x,y,w,h);
f.setVisible(true);

statusArea.setBorder(BorderFactory.createEtchedBorder());
statusArea.setLayout(new FlowLayout(FlowLayout.LEFT,0,0));
statusArea.add(status);
status.setHorizontalAlignment(JLabel.LEFT);

f.setDefaultCloseOperation(
WindowConstants.DISPOSE_ON_CLOSE);

f.addWindowListener(new WindowAdapter() {
public void windowClosed(WindowEvent e) {
System.exit(0);
}
});
}
static public JPanel getStatusArea() {
return statusArea;
}
static public void showStatus(String s) {
status.setText(s);
}
static Object getResource(String key) {
if(resources != null) {
return resources.getString(key);
}
return null;
}
}

---

23.7 本章回顾

略