【发布时间】：2016-05-27 13:33:25
【问题描述】：
我正在尝试在用 Java 生成的 html 文档中实现用户可选择的文本对齐方式。我试过了：
JMenuItem leftAlignMenuItem =
new JMenuItem(new StyledEditorKit.AlignmentAction("Left Align", StyleConstants.ALIGN_LEFT));
JMenuItem centerMenuItem =
new JMenuItem(new StyledEditorKit.AlignmentAction("Center", StyleConstants.ALIGN_CENTER));
JMenuItem rightAlignMenuItem =
new JMenuItem(new StyledEditorKit.AlignmentAction("Right Align", StyleConstants.ALIGN_RIGHT));
以及这个主题的各种变体。选择菜单项会使文本在文本窗格中正确对齐，并将适当的 html 标记添加到保存的文档中。问题是，一旦添加了标签，单击另一个对齐菜单项并不会更改它，因此无法多次更改默认（左）的文本对齐方式并保存更改。
我知道我不是第一个遇到此问题的人，但到目前为止我还没有找到任何解决方案，因此我们将不胜感激。
这是我的“M”CVE，不幸的是它仍然很大，但我无法删除更多代码，否则它不会显示问题：
package aligntest;
import java.awt.*;
import java.awt.event.*;
import javax.swing.*;
import javax.swing.text.*;
import javax.swing.text.html.HTMLDocument;
import javax.swing.text.html.HTMLEditorKit;
import javax.swing.JFrame;
public class AlignTest extends JFrame implements ActionListener {
private HTMLDocument doc; // Stores the formatted text.
private JTextPane textPane = new JTextPane(); // The Pane itself.
String FilePath = ""; // Stores the file path.
public AlignTest() { // This method is called automatically when the app is launched.
HTMLEditorKit editorKit = new HTMLEditorKit();
doc = (HTMLDocument)editorKit.createDefaultDocument();
init(); // Calls interface method below.
}
public static void main(String[] args) {
AlignTest editor = new AlignTest();
}
public void init(){
JMenuBar menuBar = new JMenuBar();
getContentPane().add(menuBar, BorderLayout.NORTH);
JMenu fileMenu = new JMenu("File");
JMenu alignMenu = new JMenu("Text Align");
menuBar.add(fileMenu);
menuBar.add(alignMenu);
JMenuItem openItem = new JMenuItem("Open"); //
JMenuItem saveItem = new JMenuItem("Save"); //
openItem.addActionListener(this);
saveItem.addActionListener(this);
fileMenu.add(openItem);
fileMenu.add(saveItem);
JMenuItem leftAlignMenuItem = new JMenuItem(new StyledEditorKit.AlignmentAction("Left Align", StyleConstants.ALIGN_LEFT));
JMenuItem centerMenuItem = new JMenuItem(new StyledEditorKit.AlignmentAction("Center", StyleConstants.ALIGN_CENTER));
JMenuItem rightAlignMenuItem = new JMenuItem(new StyledEditorKit.AlignmentAction("Right Align", StyleConstants.ALIGN_RIGHT));
leftAlignMenuItem.setText("Left");
centerMenuItem.setText("Center");
rightAlignMenuItem.setText("Right");
alignMenu.add(leftAlignMenuItem);
alignMenu.add(centerMenuItem);
alignMenu.add(rightAlignMenuItem);
textPane = new JTextPane(doc); // Create object from doc and set this as value of textPane.
textPane.setContentType("text/html"); // textPane holds html.
JScrollPane scrollPane = new JScrollPane(textPane); // textPane in JScrollPane to allow scrolling if more text than space.
Dimension screenSize = Toolkit.getDefaultToolkit().getScreenSize(); // Get screen size to use below.
Dimension scrollPaneSize = new Dimension(1*screenSize.width/2,1*screenSize.height/2); // Together with next line, sets dimensions of textPane relative to screen size.
scrollPane.setPreferredSize(scrollPaneSize);
getContentPane().add(scrollPane, BorderLayout.SOUTH);
pack();
setLocationRelativeTo(null);
show(); // Actually displays the interface.
}
public void actionPerformed(ActionEvent ae) { // Method called with action commands from interface objects above. Which action depends on the text of the interface element.
String actionCommand = ae.getActionCommand();
if (actionCommand.compareTo("Open") == 0){ // Calls method when action command received.
openDocument();
} else if (actionCommand.compareTo("Save") == 0){
saveDocument();
}
}
public void saveDocument(){
String FP = FilePath; // This paragraph calls Save As instead of Save if file not already saved.
String unsaved = "";
int saved = FP.compareTo(unsaved);
if (saved == 0) {
saveDocumentAs();
} else {
save();
}
}
public void saveDocumentAs(){
JFileChooser SaveDialog = new javax.swing.JFileChooser();
int returnVal = SaveDialog.showSaveDialog(this);
if (returnVal == JFileChooser.APPROVE_OPTION) {
java.io.File saved_file = SaveDialog.getSelectedFile();
FilePath = saved_file.toString();
save();
}
}
public void save(){
try {
WriteFile objPane = new WriteFile(FilePath, false);
String PaneText = textPane.getText(); // Gets text from Title Pane.
objPane.writeToFile(PaneText);
}
catch (Exception ex) {
}
}
public void openDocument(){
JFileChooser OpenDialog = new javax.swing.JFileChooser(); // Creates file chooser object.
int returnVal = OpenDialog.showOpenDialog(this); // Defines 'returnVal' according to what user clicks in file chooser.
if (returnVal == JFileChooser.APPROVE_OPTION) { // Returns value depending on whether user clicks 'yes' or 'OK' etc.
java.io.File file = OpenDialog.getSelectedFile(); // Gets path of selected file.
FilePath = file.toString( ); // Converts path of selected file to String.
// The problem seems to be related to the code that starts here...
try {
ReadFile readPane = new ReadFile(FilePath); // Creates "readPane" object from "FilePath" string, using my ReadFile class.
String[] aryPane = readPane.OpenFile(); // Creates string array "aryPane" from "readPane" object.
int i; // Creates integer variable "i".
String PaneText = "";
for (i=0; i < aryPane.length; i++) { // Creates a for loop with starting "i" value of 0, adding 1 to i each time round and ending when i = the number of lines in the aryLines array.
PaneText = PaneText + aryPane[i]; // Add present line to "PaneText".
}
textPane.setText(PaneText); // Displays "PaneText" in "TextPane".
} catch (Exception ex) {
// and ends here. This code also calls ReadFile, so code in that class may be at fault.
}
}
}
}
它还必须调用以下两个类中的方法才能工作：
package aligntest;
import java.io.IOException;
import java.io.FileReader;
import java.io.BufferedReader;
public class ReadFile {
private String path;
public ReadFile(String file_path) {
path = file_path;
}
public String[] OpenFile() throws IOException {
FileReader fr = new FileReader(path);
BufferedReader textReader = new BufferedReader(fr);
int numberOfLines = readLines( );
String[] textData = new String[numberOfLines];
int i;
for (i=0; i < numberOfLines; i++) {
textData[i] = textReader.readLine();
}
textReader.close( );
return textData;
}
int readLines() throws IOException {
FileReader file_to_read = new FileReader(path);
BufferedReader bf = new BufferedReader(file_to_read);
String aLine;
int numberOfLines = 0;
while ((aLine = bf.readLine()) != null) {
numberOfLines++;
}
bf.close();
return numberOfLines;
}
}
&
package aligntest;
import java.io.File;
import java.io.FileWriter;
import java.io.PrintWriter;
import java.io.IOException;
public class WriteFile {
private String path;
private boolean append_to_file = false;
public WriteFile(String file_path) {
path = file_path;
}
public WriteFile(String file_path, boolean append_value) {
path = file_path;
}
public WriteFile(File SectionPath, boolean success) {
throw new UnsupportedOperationException("Not yet implemented");
}
public void writeToFile( String textLine ) throws IOException {
FileWriter write = new FileWriter(path, append_to_file);
PrintWriter print_line = new PrintWriter(write);
print_line.printf( "%s" + "%n" , textLine);
print_line.close();
}
}
问题似乎与打开文档（第 126 - 138 行）或“ReadFile”类有关：在另一个程序中查看保存的文件时，我可以看到标签正在更改，直到文档关闭，然后再次使用“AlignTest”打开。在此之后，任何对齐更改都不会反映在 html 中。
希望有人能提供帮助。
编辑：这是由“AlignTest”生成的一些 html。如果将其粘贴到文本文件中，然后在“AlignTest”中打开，它应该会重现问题：“AlignTest”无法更改对齐标签。
<html>
<head>
<meta id="_moz_html_fragment">
</head>
<body>
<p align="right" style="margin-top: 0pt">
Another
</p>
</body>
</html>
【问题讨论】：
-
发布MCVE。请务必将您的代码复制粘贴到新项目，并确保在将其发布到此处之前编译并运行。
-
感谢 user1803551。我现在已经发布了我希望通过 MCVE 的内容。
-
"第 126 - 138 行" 哪些是？
-
aLineinreadLines未使用，debuginAlignTest也未使用。他们有什么需要吗？ -
回应你的其他cmets：我会马上去标记我认为可能有问题的行（我匆忙中没有注意到这里没有行号！）。 aLine 用于获取行数的循环中，在我的实际程序中的其他地方需要调试，但这里不需要 - 我应该有，现在将删除它。
标签： java html swing jtextpane text-alignment