JTextPane + Getting a row count..

Question

Hi,
I've been looking for a solution to this, but can't find one already in the forum. there are some close .. but this is my problem..
I'm looking to get the current row count of a JTextPane... I'm not looking to get the count of '\n'.... I want to take the wrapping into account .. so if I resize the JTextPane, the row counts will change accordingly.
The reason I'm looking for this information is so I can set the size on the JTextPane so that it always shows the data.. but when it only has one line, I only want it to take up space for one line (the reason for this is I don't want vertical scrollbars appearing where they're not needed)
I hope I have given enough information for someone to help me out..
Thanks :)
/Balmark

Answer 1

Unfortunately WrappedPlainView's methods and inner classes are private so we can't access it normal way.
This is an example of hack access to WrappedPlainView. In some cases it can throw access violation exception.
best regards
Stas
import javax.swing.*;
import java.awt.*;
import java.awt.event.*;
import javax.swing.text.*;
import java.lang.reflect.*;
public class Test {
JScrollPane scroll;
JTextArea textArea=new JTextArea();
public Test() throws Exception {
JFrame frame=new JFrame();
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
textArea.setLineWrap(true);
textArea.setText("12345 67890 12345 67890 12345 67890\n 12345 67890 12345 67890 12345 67890");
scroll=new JScrollPane(textArea);
frame.getContentPane().add(scroll);
JButton b=new JButton("print line count");
frame.getContentPane().add(b,BorderLayout.SOUTH);
b.addActionListener(new ActionListener() {
public void actionPerformed(ActionEvent e) {
System.err.println(textArea.getUI().getRootView(textArea).getView(0).getViewCount());
WrappedPlainView pv=(WrappedPlainView)textArea.getUI().getRootView(textArea).getView(0);
int lineCount=0;
for(int i=0; i<pv.getViewCount(); i++) {
View pvLine=pv.getView(i);
try {
Class cl=pvLine.getClass();
Field f=cl.getDeclaredField("nlines");
f.setAccessible(true);
lineCount+=f.getInt(pvLine);
/* Method methodLineCount=cl.getDeclaredMethod("calculateLineCount",null);
methodLineCount.setAccessible(true);
Object result=methodLineCount.invoke(pvLine,null);
System.err.println("Line count="+result.toString());*/
catch (Exception ex) {
ex.printStackTrace();
System.err.println("Line count="+lineCount);
frame.setSize(200,200);
frame.setLocationRelativeTo(null);
frame.show();
public static void main(String[] args) throws Exception {
new Test();
}