问题
I was wondering if there is a straightforward way to display line numbers with StyledText
text field - even if lines are wrapped. I'm using it in my application and if content gets to big, some line numbers would be nice.
Thank you.
回答1:
The key is org.eclipse.swt.custom.Bullet. It's basically a symbol (or in our case a number) you can add to the beginning of a line.
//text is your StyledText
text.addLineStyleListener(new LineStyleListener()
{
public void lineGetStyle(LineStyleEvent e)
{
//Set the line number
e.bulletIndex = text.getLineAtOffset(e.lineOffset);
//Set the style, 12 pixles wide for each digit
StyleRange style = new StyleRange();
style.metrics = new GlyphMetrics(0, 0, Integer.toString(text.getLineCount()+1).length()*12);
//Create and set the bullet
e.bullet = new Bullet(ST.BULLET_NUMBER,style);
}
});
回答2:
This is my working implementation.
styledText.addLineStyleListener(new LineStyleListener() {
@Override
public void lineGetStyle(LineStyleEvent event) {
// Using ST.BULLET_NUMBER sometimes results in weird alignment.
//event.bulletIndex = styledText.getLineAtOffset(event.lineOffset);
StyleRange styleRange = new StyleRange();
styleRange.foreground = Display.getCurrent().getSystemColor(SWT.COLOR_GRAY);
int maxLine = styledText.getLineCount();
int bulletLength = Integer.toString(maxLine).length();
// Width of number character is half the height in monospaced font, add 1 character width for right padding.
int bulletWidth = (bulletLength + 1) * styledText.getLineHeight() / 2;
styleRange.metrics = new GlyphMetrics(0, 0, bulletWidth);
event.bullet = new Bullet(ST.BULLET_TEXT, styleRange);
// getLineAtOffset() returns a zero-based line index.
int bulletLine = styledText.getLineAtOffset(event.lineOffset) + 1;
event.bullet.text = String.format("%" + bulletLength + "s", bulletLine);
}
});
styledText.addModifyListener(new ModifyListener() {
@Override
public void modifyText(ModifyEvent e) {
// For line number redrawing.
styledText.redraw();
}
});
Note that the possible overhead of syntax highlighting recalculation when calling redraw() is likely to be acceptable, because lineGetStyle() are only called with lines currently on screen.
回答3:
I believe that using a LineStyleListener should work. Something along the lines of:
styledText.addLineStyleListener(
new LineStyleListener() {
@Override
public void lineGetStyle(LineStyleEvent event) {
String line = event.lineText;
int lineNumber = event.lineOffset;
// Do stuff to add line numbers
}
}
);
回答4:
This is a way to use bullets that updates the numbers when the content changes:
text.addModifyListener(new ModifyListener() {
public void modifyText(ModifyEvent event) {
int maxLine = text.getLineCount();
int lineCountWidth = Math.max(String.valueOf(maxLine).length(), 3);
StyleRange style = new StyleRange();
style.metrics = new GlyphMetrics(0, 0, lineCountWidth * 8 + 5);
Bullet bullet = new Bullet(ST.BULLET_NUMBER, style);
text.setLineBullet(0, text.getLineCount(), null);
text.setLineBullet(0, text.getLineCount(), bullet);
}
});
回答5:
As a side-note for colouring the line numbers:
Device device = Display.getCurrent();
style.background = new Color(device, LINE_NUMBER_BG);
style.foreground = new Color(device, LINE_NUMBER_FG);
where LINE_NUMBER_BG
and LINE_NUMBER_FG
might be a RGB object such as:
final RGB LINE_NUMBER_BG = new RBG(160, 80, 0); // brown
final RGB LINE_NUMBER_FG = new RGB(255, 255, 255); // white
来源:https://stackoverflow.com/questions/11057442/java-swt-show-line-numbers-for-styledtext