对于从JTextPane中的任何偏移量获取样式感兴趣的读者，本文将提供您所需要的所有信息，并且为您提供关于C/C++结构体成员偏移量获取、HTML页面没有出现在JavaSwingJTextPane中、
对于从JTextPane中的任何偏移量获取样式感兴趣的读者，本文将提供您所需要的所有信息，并且为您提供关于C/C++ 结构体成员偏移量获取、HTML页面没有出现在Java Swing JTextPane中、Java JTextPane JScrollPane显示问题、java – JTextPane阻止在父JScrollPane中滚动的宝贵知识。
本文目录一览：- 从JTextPane中的任何偏移量获取样式
- C/C++ 结构体成员偏移量获取
- HTML页面没有出现在Java Swing JTextPane中
- Java JTextPane JScrollPane显示问题
- java – JTextPane阻止在父JScrollPane中滚动
从JTextPane中的任何偏移量获取样式
有没有一种方法可以获取Style，样式名称，甚至可以将插入时我给文本的样式Style在某个位置上甚至与之进行比较JTextPane？因为我的目的，我创建的自定义JTextPane，StyledDocument和DocumentFilter。因此，我可以选择Style用于表示常规字母，并用于表示数字的另一种样式。我还具有切换按钮，该按钮在切换时设置DocumentFilter为以不同的方式设置数字格式，而在未切换时不定期设置数字格式，因此最后您无法仅根据JTextPane''sgetText()方法区分哪些数字受到了影响。因此，唯一的方法是比较具有常规和特殊数字样式作为常量的样式。我唯一需要提出的就是如何为每个角色获取样式。
我知道有一种JTextPane''s方法可以从插入符号的位置获取AttributeSet，getCharacterAttributes()但是我认为这对我的问题没有用。
是否需要包含代码示例？我认为很难想象。如果您要我，我会包括在内。
任何输入将不胜感激。谢谢！
答案1
小编典典尝试调用StyledDocument.getCharacterElement(pos)以获得该位置的character元素，然后调用Element.getAttributes()以获得其属性集。
在AttributeSet包含风格，你可以检索使用所提供的方法StyleConstants。
C/C++ 结构体成员偏移量获取
分析代码节选自 muduo.
以下代码通过 offsetof 获取 sin_family 在 sockaddr_in6 中的字段偏移量.
static_assert(offsetof(sockaddr_in6, sin6_family) == 0, "sin6_family offset 0");
需要注意：
offsetof 并非 C/C++ 标准，需要编译器内置支持.
以及针对的数据类型，尽量使 POD 类型数据 (可参考下面链接中的提示).
具体详情可参考：https://en.cppreference.com/w/cpp/types/offsetof
补充：检查 sin_family6 字段时发现其是通过宏拼接而成，颇为有趣，代码如下所示：
1 //拼接宏
2 #define __SOCKADDR_COMMON(sa_prefix) \
3 sa_family_t sa_prefix##family
4
5 //结构体定义
6 #if !__USE_KERNEL_IPV6_DEFS
7 /* Ditto, for IPv6. */
8 struct sockaddr_in6
9 {
10 __SOCKADDR_COMMON (sin6_);
11 in_port_t sin6_port; /* Transport layer port # */
12 uint32_t sin6_flowinfo; /* IPv6 flow information */
13 struct in6_addr sin6_addr; /* IPv6 address */
14 uint32_t sin6_scope_id; /* IPv6 scope-id */
15 };
16 #endif /* !__USE_KERNEL_IPV6_DEFS */
PS:
如果您觉得我的文章对您有帮助，可以扫码领取下红包，谢谢！
HTML页面没有出现在Java Swing JTextPane中
我正在尝试使用非JTextArea Swing文本组件,并在此代码中尝试在JTextPane中显示一个非常简单的网页.我能够阅读网页并能够将其放入JTextPane的文档中,如下所示,当我打印出在我的
HTMLDocument上调用getText时返回的String时,但JTextPane中没有显示任何内容.我觉得好像缺少一些基本的东西.提前致谢.
我的SSCCE：
import java.awt.*;
import java.io.IOException;
import java.net.*;
import javax.swing.*;
import javax.swing.text.*;
import javax.swing.text.html.*;
@SuppressWarnings("serial")
public class TestStyledDoc2 extends JPanel {
public static final String GETTY_FILE = "http://www.d.umn.edu/~rmaclin/" +
"gettysburg-address.html";
private HTMLEditorKit htmlKit = new HTMLEditorKit();
private HTMLDocument htmlDocument = (HTMLDocument) htmlKit.createDefaultDocument();
private JTextPane htmlPane = new JTextPane(htmlDocument);
public TestStyledDoc2() {
JScrollPane scrollPane1 = new JScrollPane(htmlPane);
try {
htmlPane.setEditorKit(htmlKit);
URL gettyUrl = new URL(GETTY_FILE);
htmlKit.read(gettyUrl.openStream(),htmlDocument,0);
System.out.println(htmlDocument.getText(0,htmlDocument.getLength()));
} catch (MalformedURLException e) {
e.printstacktrace();
} catch (IOException e) {
e.printstacktrace();
} catch (BadLocationException e) {
e.printstacktrace();
}
scrollPane1.getViewport().setPreferredSize(new Dimension(400,400));
setLayout(new BorderLayout());
add(scrollPane1,BorderLayout.CENTER);
}
private static void createAndShowUI() {
JFrame frame = new JFrame("TestStyledDoc");
frame.getContentPane().add(new TestStyledDoc2());
frame.setDefaultCloSEOperation(JFrame.EXIT_ON_CLOSE);
frame.pack();
frame.setLocationRelativeto(null);
frame.setVisible(true);
}
public static void main(String[] args) {
java.awt.EventQueue.invokelater(new Runnable() {
public void run() {
createAndShowUI();
}
});
}
}
解决方法
setEditorKit()的调用将删除最初分配的文档,并将其替换为新文档.只需在其后添加另一行即可恢复正确的文档.
htmlPane.setEditorKit(htmlKit); htmlPane.setDocument(htmlDocument);
或者从您的textpane中重新获取文档
htmlPane.setEditorKit(htmlKit); htmlDocument = (HTMLDocument) htmlPane.getDocument();
Java JTextPane JScrollPane显示问题
以下类实现了chatGUI。正常运行时，屏幕如下所示：
精美的ChatGUI
http://img21.imageshack.us/img21/7177/rightchat.jpg
当我输入较大长度的文本时，问题经常出现。50到100个字符的gui变得疯狂。聊天记录框如下所示缩小
图片http://img99.imageshack.us/img99/6962/errorgui.jpg。
关于什么原因的任何想法？
谢谢。
PS：下面的附加类是完整的代码。您可以复制它并在计算机上进行编译，以确切地了解我的意思。
注意：一旦GUI变得疯狂，那么如果我单击“清除”按钮，历史记录窗口将清除，并且GUI返回到再次正确显示。
package Sartre.Connect4;
import javax.swing.*;
import java.net.*;
import java.awt.*;
import java.awt.event.*;
import javax.swing.text.StyledDocument;
import javax.swing.text.Style;
import javax.swing.text.StyleConstants;
import javax.swing.text.BadLocationException;
import java.io.BufferedOutputStream;
import javax.swing.text.html.HTMLEditorKit;
import java.io.FileOutputStream;
import java.io.IOException;
import java.io.FileNotFoundException;
import javax.swing.filechooser.FileNameExtensionFilter;
import javax.swing.JFileChooser;
/**
* Chat form class
* @author iAmjad
*/
public class ChatGUI extends JDialog implements ActionListener {
/**
* Used to hold chat history data
*/
private JTextPane textPaneHistory = new JTextPane();
/**
* provides scrolling to chat history pane
*/
private JScrollPane scrollPaneHistory = new JScrollPane(textPaneHistory);
/**
* used to input local message to chat history
*/
private JTextPane textPaneHome = new JTextPane();
/**
* Provides scrolling to local chat pane
*/
private JScrollPane scrollPaneHomeText = new JScrollPane(textPaneHome);
/**
* JLabel acting as a statusbar
*/
private JLabel statusBar = new JLabel("Ready");
/**
* Button to clear chat history pane
*/
private JButton JBClear = new JButton("Clear");
/**
* Button to save chat history pane
*/
private JButton JBSave = new JButton("Save");
/**
* Holds contentPane
*/
private Container containerPane;
/**
* Layout GridBagLayout manager
*/
private GridBagLayout gridBagLayout = new GridBagLayout();
/**
* GridBagConstraints
*/
private GridBagConstraints constraints = new GridBagConstraints();
/**
* Constructor for ChatGUI
*/
public ChatGUI(){
setTitle("Chat");
// set up dialog icon
URL url = getClass().getResource("Resources/SartreIcon.jpg");
ImageIcon imageIcon = new ImageIcon(url);
Image image = imageIcon.getImage();
this.setIconImage(image);
this.setAlwaysOnTop(true);
setLocationRelativeTo(this.getParent());
//////////////// End icon and placement /////////////////////////
// Get pane and set layout manager
containerPane = getContentPane();
containerPane.setLayout(gridBagLayout);
/////////////////////////////////////////////////////////////
//////////////// Begin Chat History //////////////////////////////
textPaneHistory.setToolTipText("Chat History Window");
textPaneHistory.setEditable(false);
textPaneHistory.setPreferredSize(new Dimension(350,250));
scrollPaneHistory.setVerticalScrollBarPolicy(ScrollPaneConstants.VERTICAL_SCROLLBAR_ALWAYS);
scrollPaneHistory.setHorizontalScrollBarPolicy(ScrollPaneConstants.HORIZONTAL_SCROLLBAR_NEVER);
// fill Chat History GridBagConstraints
constraints.gridx = 0;
constraints.gridy = 0;
constraints.gridwidth = 10;
constraints.gridheight = 10;
constraints.weightx = 100;
constraints.weighty = 100;
constraints.fill = GridBagConstraints.BOTH;
constraints.anchor = GridBagConstraints.CENTER;
constraints.insets = new Insets(10,10,10);
constraints.ipadx = 0;
constraints.ipady = 0;
gridBagLayout.setConstraints(scrollPaneHistory,constraints);
// add to the pane
containerPane.add(scrollPaneHistory);
/////////////////////////////// End Chat History ///////////////////////
///////////////////////// Begin Home Chat //////////////////////////////
textPaneHome.setToolTipText("Home Chat Message Window");
textPaneHome.setPreferredSize(new Dimension(200,50));
textPaneHome.addKeyListener(new MyKeyAdapter());
scrollPaneHomeText.setVerticalScrollBarPolicy(ScrollPaneConstants.VERTICAL_SCROLLBAR_ALWAYS);
scrollPaneHomeText.setHorizontalScrollBarPolicy(ScrollPaneConstants.HORIZONTAL_SCROLLBAR_NEVER);
// fill Chat History GridBagConstraints
constraints.gridx = 0;
constraints.gridy = 10;
constraints.gridwidth = 6;
constraints.gridheight = 1;
constraints.weightx = 100;
constraints.weighty = 100;
constraints.fill = GridBagConstraints.BOTH;
constraints.anchor = GridBagConstraints.CENTER;
constraints.insets = new Insets(10,10);
constraints.ipadx = 0;
constraints.ipady = 0;
gridBagLayout.setConstraints(scrollPaneHomeText,constraints);
// add to the pane
containerPane.add(scrollPaneHomeText);
////////////////////////// End Home Chat /////////////////////////
///////////////////////Begin Clear Chat History ////////////////////////
JBClear.setToolTipText("Clear Chat History");
// fill Chat History GridBagConstraints
constraints.gridx = 6;
constraints.gridy = 10;
constraints.gridwidth = 2;
constraints.gridheight = 1;
constraints.weightx = 100;
constraints.weighty = 100;
constraints.fill = GridBagConstraints.BOTH;
constraints.anchor = GridBagConstraints.CENTER;
constraints.insets = new Insets(10,10);
constraints.ipadx = 0;
constraints.ipady = 0;
gridBagLayout.setConstraints(JBClear,constraints);
JBClear.addActionListener(this);
// add to the pane
containerPane.add(JBClear);
///////////////// End Clear Chat History ////////////////////////
/////////////// Begin Save Chat History //////////////////////////
JBSave.setToolTipText("Save Chat History");
constraints.gridx = 8;
constraints.gridy = 10;
constraints.gridwidth = 2;
constraints.gridheight = 1;
constraints.weightx = 100;
constraints.weighty = 100;
constraints.fill = GridBagConstraints.BOTH;
constraints.anchor = GridBagConstraints.CENTER;
constraints.insets = new Insets(10,10);
constraints.ipadx = 0;
constraints.ipady = 0;
gridBagLayout.setConstraints(JBSave,constraints);
JBSave.addActionListener(this);
// add to the pane
containerPane.add(JBSave);
///////////////////// End Save Chat History /////////////////////
/////////////////// Begin Status Bar /////////////////////////////
constraints.gridx = 0;
constraints.gridy = 11;
constraints.gridwidth = 10;
constraints.gridheight = 1;
constraints.weightx = 100;
constraints.weighty = 50;
constraints.fill = GridBagConstraints.BOTH;
constraints.anchor = GridBagConstraints.CENTER;
constraints.insets = new Insets(0,5,0);
constraints.ipadx = 0;
constraints.ipady = 0;
gridBagLayout.setConstraints(statusBar,constraints);
// add to the pane
containerPane.add(statusBar);
////////////// End Status Bar ////////////////////////////
// set resizable to false
this.setResizable(false);
// pack the GUI
pack();
}
/**
* Deals with necessary menu click events
* @param event
*/
public void actionPerformed(ActionEvent event) {
Object source = event.getSource();
// Process Clear button event
if (source == JBClear){
textPaneHistory.setText(null);
statusBar.setText("Chat History Cleared");
}
// Process Save button event
if (source == JBSave){
// process only if there is data in history pane
if (textPaneHistory.getText().length() > 0){
// process location where to save the chat history file
JFileChooser chooser = new JFileChooser();
chooser.setMultiSelectionEnabled(false);
chooser.setAcceptAllFileFilterUsed(false);
FileNameExtensionFilter filter = new FileNameExtensionFilter("HTML Documents","htm","html");
chooser.setFileFilter(filter);
int option = chooser.showSaveDialog(ChatGUI.this);
if (option == JFileChooser.APPROVE_OPTION) {
// Set up document to be parsed as HTML
StyledDocument doc = (StyledDocument)textPaneHistory.getDocument();
HTMLEditorKit kit = new HTMLEditorKit();
BufferedOutputStream out;
try {
// add final file name and extension
String filePath = chooser.getSelectedFile().getAbsoluteFile() + ".html";
out = new BufferedOutputStream(new FileOutputStream(filePath));
// write out the HTML document
kit.write(out,doc,doc.getStartPosition().getOffset(),doc.getLength());
} catch (FileNotFoundException e) {
JOptionPane.showMessageDialog(ChatGUI.this,"Application will now close. \n A restart may cure the error!\n\n"
+ e.getMessage(),"Fatal Error",JOptionPane.WARNING_MESSAGE,null);
System.exit(2);
} catch (IOException e){
JOptionPane.showMessageDialog(ChatGUI.this,null);
System.exit(3);
} catch (BadLocationException e){
JOptionPane.showMessageDialog(ChatGUI.this,null);
System.exit(4);
}
statusBar.setText("Chat History Saved");
}
}
}
}
/**
* Process return key for sending the message
*/
private class MyKeyAdapter extends KeyAdapter {
@Override
@SuppressWarnings("static-access")
public void keyPressed(KeyEvent ke) {
//DateTime dateTime = new DateTime();
//String nowdateTime = dateTime.getDateTime();
int kc = ke.getKeyCode();
if (kc == ke.VK_ENTER) {
try {
// Process only if there is data
if (textPaneHome.getText().length() > 0){
// Add message origin formatting
StyledDocument doc = (StyledDocument)textPaneHistory.getDocument();
Style style = doc.addStyle("HomeStyle",null);
StyleConstants.setBold(style,true);
String home = "Home [" + nowdateTime + "]: ";
doc.insertString(doc.getLength(),home,style);
StyleConstants.setBold(style,false);
doc.insertString(doc.getLength(),textPaneHome.getText() + "\n",style);
// update caret location
textPaneHistory.setCaretPosition(doc.getLength());
textPaneHome.setText(null);
statusBar.setText("Message Sent");
}
} catch (BadLocationException e) {
JOptionPane.showMessageDialog(ChatGUI.this,"Application will now close. \n A restart may cure the error!\n\n"
+ e.getMessage(),null);
System.exit(1);
}
ke.consume();
}
}
}
}
java – JTextPane阻止在父JScrollPane中滚动
我有以下“树”的对象：
JPanel
JScrollPane
JPanel
JPanel
JScrollPane
JTextPane
当使用鼠标滚轮滚动外部JScrollPane我遇到一个恼人的问题.一旦鼠标光标触及内部JScrollPane,似乎滚动事件就会传递到JScrollPane中,并且第一个不再处理.这意味着滚动“父”JScrollPane停止.
是否可以仅禁用内部JScrollPane上的鼠标滚轮？或者更好的是,如果没有要滚动的内容(大多数情况下textpane只包含1-3行文本),则禁用滚动,但如果有更多内容则启用它？
解决方法
我也遇到了这个恼人的问题,而Sbodd的解决方案对我来说是不可接受的,因为我需要能够在表格和JTextAreas中滚动.我希望该行为与浏览器相同,其中鼠标悬停在可滚动控件上将滚动该控件直到控件达到最低点,然后继续滚动父滚动窗格,通常是整个页面的滚动窗格.
这个课就是这样做的.只需使用它代替常规的JScrollPane即可.我希望它对你有所帮助.
/**
* A JScrollPane that will bubble a mouse wheel scroll event to the parent
* JScrollPane if one exists when this scrollpane either tops out or bottoms out.
*/
public class PDControlScrollPane extends JScrollPane {
public PDControlScrollPane() {
super();
addMouseWheelListener(new PDMouseWheelListener());
}
class PDMouseWheelListener implements MouseWheelListener {
private JScrollBar bar;
private int prevIoUsValue = 0;
private JScrollPane parentScrollPane;
private JScrollPane getParentScrollPane() {
if (parentScrollPane == null) {
Component parent = getParent();
while (!(parent instanceof JScrollPane) && parent != null) {
parent = parent.getParent();
}
parentScrollPane = (JScrollPane)parent;
}
return parentScrollPane;
}
public PDMouseWheelListener() {
bar = PDControlScrollPane.this.getVerticalScrollBar();
}
public void mouseWheelMoved(MouseWheelEvent e) {
JScrollPane parent = getParentScrollPane();
if (parent != null) {
/*
* Only dispatch if we have reached top/bottom on prevIoUs scroll
*/
if (e.getWheelRotation() < 0) {
if (bar.getValue() == 0 && prevIoUsValue == 0) {
parent.dispatchEvent(cloneEvent(e));
}
} else {
if (bar.getValue() == getMax() && prevIoUsValue == getMax()) {
parent.dispatchEvent(cloneEvent(e));
}
}
prevIoUsValue = bar.getValue();
}
/*
* If parent scrollpane doesn't exist,remove this as a listener.
* We have to defer this till Now (vs doing it in constructor)
* because in the constructor this item has no parent yet.
*/
else {
PDControlScrollPane.this.removeMouseWheelListener(this);
}
}
private int getMax() {
return bar.getMaximum() - bar.getVisibleAmount();
}
private MouseWheelEvent cloneEvent(MouseWheelEvent e) {
return new MouseWheelEvent(getParentScrollPane(),e.getID(),e
.getWhen(),e.getModifiers(),1,e
.getClickCount(),false,e.getScrollType(),e
.getScrollAmount(),e.getWheelRotation());
}
}
}
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