如何在使用HTMLEditorKit构建的HTML编辑器中提供用于更改文本部件背景颜色的功能 [英] How to provide Functionalty for Changing the Background Color of Text Parts in HTML Editor built with HTMLEditorKit
问题描述
我的问题如下:
我想让我的小HTML编辑器的用户能够在
输入的文本使用不同的背景色.我第一次尝试
为此使用CSS样式.不同的风格定义
不同的背景色，并且通过JComboBox用户可以
在这些样式之间切换.在选择样式后
HTMLDocument内各自的位置，类型为新的HTML元素
将输入<span class="style">.
不幸的是，我无法完成这项工作.跨度元素
根本就没有创建(请参阅我关于此问题的问题).
I want to enable the user of my little HTML editor to switch between
different background colors for the text being entered. I first tried
to use CSS styles for that purpose. The different styles define
different background colors and through a JComboBox the user could
switch between these styles. Upon selection of a style in the
respective position inside the HTMLDocument a new HTML element of type
<span class="style"> would be entered.
Unfortunately I could not manage to get this work. The span elements
were simply not created (see my question regarding this problem).
之间，我看了课StyledEditorKit.ForegroundAction
了解其功能.执行后，只需修改
StyledEditorKit的输入属性在使用中设置新
前景色.随后输入的文本显示为
新的前景色.当将HTML代码写入文件时，
文本自动包含在<font color=".."> ... </font>中
HTML元素.所有这些甚至都适用于选定的文本，这可能会
遍历多个段落.在这种情况下，显然受影响
所有受影响的段落中的文本都包含在<font ...> HTML标记中.
In between I took a look at the class StyledEditorKit.ForegroundAction
to learn how this functions. Upon execution it simply modifies the
input attributes of the StyledEditorKit in use setting a new
foreground color. Text that is entered afterwards is displayed with
the new foreground color. And when writing the HTML code into a file,
the text is automagically enclosed in <font color=".."> ... </font>
HTML elements. And all that even works on selected text which might
run over multiple paragraphs. In this case obviously the affected
text inside all affected paragraphs is enclosed into <font ...> HTML tags.
我想完成设置背景的相同功能 任意文本上的颜色.但令人惊讶的是，这似乎没有 如此简单:-(
I want to accomplish the same functionality for setting the background color on arbitrary chunks of text. But surprisingly this does not seem to be so easy:-(
我没有为此目的找到预定义的动作类，类似于
Java 7 JDK中的StyledEditorKit.foregroundAction.创造
这样的课程似乎并不复杂；它几乎与
ForegroundAction和actionPerformed方法更改为设置
背景，而不是前景属性.
I didn't find a predefined action class for that purpose similar to the
StyledEditorKit.foregroundAction in the Java 7 JDK. Creating
such a class does not seem to be complex; it's almost the same as the
ForegroundAction with the actionPerformed method changed to set the
background instead of the foreground attribute.
但是如何创建设置特定背景的有效HTML代码
所包含文本的部分颜色是多少?
到目前为止，我不知道HTMLEditorKit的哪一部分执行
为HTMLDocument中的文本创建所有<font>元素
设置了前台属性.我认为从现有的代码
创建<font>元素，派生一个
创建<span style="background-color:...">的实现
元素而不是<font>元素来设置背景色
用于文本的任意区域.还是所有这些都可用，我
只是没有注意到?任何帮助将不胜感激！
But how to create valid HTML code that sets a specific background
color for parts of the contained text?
Until now I don't know which part of the HTMLEditorKit performs the
creation of all the <font> elements for text in the HTMLDocument that
has the foreground attribute set. I think from the existing code
creating the <font> elements it should not be too hard to derive an
implementation that creates <span style="background-color:...">
elements instead of <font> elements for setting the background color
for arbitrary regions of text. Or is all this already available and I
only didn't notice? Any help would be appreciated!
In between I made a significant step forward and thanks to a piece of code found here
I managed to create valid <span> elements. In the span elements I use the class attribute to assign a predefined style.
这是我的代码:
import java.awt.BorderLayout;
import java.awt.Container;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import java.io.File;
import java.io.FileWriter;
import java.io.IOException;
import java.util.Enumeration;
import java.util.Vector;
import javax.swing.AbstractAction;
import javax.swing.Action;
import javax.swing.DefaultComboBoxModel;
import javax.swing.JComboBox;
import javax.swing.JFileChooser;
import javax.swing.JFrame;
import javax.swing.JMenu;
import javax.swing.JMenuBar;
import javax.swing.JOptionPane;
import javax.swing.JTextPane;
import javax.swing.JToolBar;
import javax.swing.text.AttributeSet;
import javax.swing.text.BadLocationException;
import javax.swing.text.MutableAttributeSet;
import javax.swing.text.SimpleAttributeSet;
import javax.swing.text.Style;
import javax.swing.text.StyleContext;
import javax.swing.text.html.HTML;
import javax.swing.text.html.HTMLDocument;
import javax.swing.text.html.HTMLEditorKit;
import javax.swing.text.html.StyleSheet;
public class SimpleEditor extends JFrame {
private static final long serialVersionUID = 1L;
private final JTextPane textPane;
private final HTMLEditorKit edtKit;
private final HTMLDocument doc;
private final StyleSheet predefStyles;
public static void main(String[] args) throws BadLocationException, IOException {
final SimpleEditor editor = new SimpleEditor();
editor.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
editor.setVisible(true);
}
public SimpleEditor() throws BadLocationException, IOException {
super("Very Simple HTML Editor");
textPane = new JTextPane();
edtKit = new HTMLEditorKit();
textPane.setEditorKit(edtKit);
predefStyles = new StyleSheet();
predefStyles.addRule(".MyStyle1 { color:#cc0000; background-color:silver }\n" +
".MyStyle2 { color:#0000cc; background-color:aqua }");
doc = new HTMLDocument(predefStyles);
textPane.setDocument(doc);
final Container content = getContentPane();
content.add(textPane, BorderLayout.CENTER);
content.add(createToolBar(), BorderLayout.NORTH);
setJMenuBar(createMenuBar());
setSize(500, 240);
}
private JToolBar createToolBar() {
final Vector<String> styleNames = new Vector<String>();
final Enumeration<?> names = predefStyles.getStyleNames();
while (names.hasMoreElements()) {
styleNames.add((String) names.nextElement());
}
final DefaultComboBoxModel<String> stylesModel =
new DefaultComboBoxModel<String>(styleNames);
final JComboBox<String> cbStyleSel = new JComboBox<String>(stylesModel);
final JToolBar bar = new JToolBar();
Action dumpAction = null;
for (final Action act : edtKit.getActions()) {
if (act.getValue(Action.NAME).equals("dump-model")) {
dumpAction = act;
break;
}
}
bar.add(dumpAction);
cbStyleSel.setEditable(false);
cbStyleSel.addActionListener(new ActionListener() {
@Override
public void actionPerformed(ActionEvent e) {
e.getSource();
@SuppressWarnings("unchecked")
final JComboBox<CondStyle> cboStyleSel = (JComboBox<CondStyle>) e.getSource();
final String selItem = (String) cboStyleSel.getSelectedItem();
final MutableAttributeSet divAttributes = new SimpleAttributeSet();
if (selItem.equals("default")) {
// This does not work!
final Style defStyle = StyleContext.getDefaultStyleContext().getStyle(StyleContext.DEFAULT_STYLE);
divAttributes.addAttribute(HTML.Tag.CONTENT, defStyle);
textPane.setCharacterAttributes(divAttributes, true);
} else {
divAttributes.addAttribute(HTML.Attribute.CLASS, selItem.substring(1));
final MutableAttributeSet tagAttributes = new SimpleAttributeSet();
tagAttributes.addAttribute(HTML.Tag.SPAN, divAttributes);
textPane.setCharacterAttributes(tagAttributes, false);
}
textPane.requestFocusInWindow();
}
});
bar.add(cbStyleSel);
return bar;
}
/**
* Extracts the style attributes except the style's name
* @param aStyle The style to be processed
* @return The visual attributes extracted from the style
*/
AttributeSet extractStyleAttribs(Style aStyle) {
final MutableAttributeSet attribs = new SimpleAttributeSet();
final Enumeration<?> attribNames = aStyle.getAttributeNames();
while (attribNames.hasMoreElements()) {
final Object attribName = attribNames.nextElement();
if (attribName == Style.NameAttribute) {
continue;
}
attribs.addAttribute(attribName, aStyle.getAttribute(attribName));
}
return attribs;
}
private JMenuBar createMenuBar() {
final JMenuBar menubar = new JMenuBar();
final JMenu mnuFile = new JMenu("File");
menubar.add(mnuFile);
final SaveAction actSave = new SaveAction();
mnuFile.add(actSave);
return menubar;
}
class SaveAction extends AbstractAction {
private static final long serialVersionUID = 1L;
public SaveAction() {
super("Save");
}
@Override
public void actionPerformed(ActionEvent ev) {
final JFileChooser chooser = new JFileChooser();
if (chooser.showSaveDialog(SimpleEditor.this) != JFileChooser.APPROVE_OPTION)
return;
final File file = chooser.getSelectedFile();
if (file == null)
return;
FileWriter writer = null;
try {
writer = new FileWriter(file);
textPane.write(writer);
} catch (final IOException ex) {
JOptionPane.showMessageDialog(SimpleEditor.this,
"File Not Saved", "ERROR",
JOptionPane.ERROR_MESSAGE);
} finally {
if (writer != null) {
try {
writer.close();
} catch (final IOException x) {
}
}
}
}
}
}
到目前为止一切顺利！我对这种解决方案的唯一问题是，我无法实现将<span>元素中包含的文本切换回普通"文本的操作.文字，即未放置在<span>元素内的文字.
这应该没什么大不了的，但是不幸的是我无法弄清楚如何才能做到这一点.任何想法都将非常受欢迎！
So far so good! My only problem with this solution is that I couldn't manage to implement the switch back from text enclosed in <span> elements to "normal" text, i.e. text that is not placed inside of <span> elements.
This should be no big deal but unfortunately I couldn't figure out how I can accomplish that. Any ideas would be very welcome!
推荐答案
我明白了！而且非常简单；-)
要使用<span>元素从样式化的文本条目中退回，我只需要从当前文本的输入属性中删除HTML.Tag.SPAN属性.这是通过以下步骤完成的:
I got it! And it's sooo simple;-)
To switch back from the styled text entry using <span> elements I only had to remove the HTML.Tag.SPAN attribute from the input attributes of the current text. This is accomplished as follows:
edtKit.getInputAttributes().removeAttribute(HTML.Tag.SPAN);
因此，我在(已更新的)问题中发布的示例代码中的ActionListener代码现在看起来如下:
So the code for the ActionListener in the example code I posted in my (updated) question now looks as follows:
cbStyleSel.addActionListener(new ActionListener() {
@Override
public void actionPerformed(ActionEvent e) {
e.getSource();
@SuppressWarnings("unchecked")
final JComboBox<CondStyle> cboStyleSel = (JComboBox<CondStyle>) e.getSource();
final String selItem = (String) cboStyleSel.getSelectedItem();
if (selItem.equals("default")) {
edtKit.getInputAttributes().removeAttribute(HTML.Tag.SPAN);
} else {
final MutableAttributeSet divAttributes = new SimpleAttributeSet();
divAttributes.addAttribute(HTML.Attribute.CLASS, selItem.substring(1));
final MutableAttributeSet tagAttributes = new SimpleAttributeSet();
tagAttributes.addAttribute(HTML.Tag.SPAN, divAttributes);
textPane.setCharacterAttributes(tagAttributes, false);
}
textPane.requestFocusInWindow();
}
});
关于实现该功能的问题，我发布了多个问题(请参见此处和
I had posted multiple questions regarding my problems implementing that functionality (see here, and here) but got no answers. Maybe the issue was too trivial;-)
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