How to programmatically add bullet list to NSTextView

Question

The question may sound strange but I\'ve been struggling with it for a few days.

I have a NSTextView that can display some text with a few formatting options. One of the

Answer 1

Two methods of programmatically adding a bulleted list to an NSTextView:

Method 1:

The following links led me to this first method, but it’s unnecessarily roundabout unless you want to use some special non-Unicode glyph for the bullet:

• Display hidden characters in NSTextView
• How to draw one NSGlyph, that hasn't unicode representation?
• appendBezierPathWithGlyph fails in [NSBezierPath currentPoint]

This requires: (1) a subclassed layout manager that substitutes the bullet glyph for some arbitrary character; and (2) a paragraph style with a firstLineHeadIndent, a tab stop slightly bigger than that indent, and a headIndent for wrapped lines that combines the two.

The layout manager looks like this:

#import <Foundation/Foundation.h>

@interface TickerLayoutManager : NSLayoutManager {

// Might as well let this class hold all the fonts used by the progress ticker.
// That way they're all defined in one place, the init method.
NSFont *fontNormal;
NSFont *fontIndent; // smaller, for indented lines
NSFont *fontBold;

NSGlyph glyphBullet;
CGFloat fWidthGlyphPlusSpace;

}

@property (nonatomic, retain) NSFont *fontNormal;
@property (nonatomic, retain) NSFont *fontIndent; 
@property (nonatomic, retain) NSFont *fontBold;
@property NSGlyph glyphBullet;
@property CGFloat fWidthGlyphPlusSpace;

@end

#import "TickerLayoutManager.h"

@implementation TickerLayoutManager

@synthesize fontNormal;
@synthesize fontIndent; 
@synthesize fontBold;
@synthesize glyphBullet;
@synthesize fWidthGlyphPlusSpace;

- (id)init {
    self = [super init];
    if (self) {
        self.fontNormal = [NSFont fontWithName:@"Baskerville" size:14.0f];
        self.fontIndent = [NSFont fontWithName:@"Baskerville" size:12.0f];
        self.fontBold = [NSFont fontWithName:@"Baskerville Bold" size:14.0f];
        // Get the bullet glyph.
        self.glyphBullet = [self.fontIndent glyphWithName:@"bullet"];
        // To determine its point size, put it in a Bezier path and take its bounds.
        NSBezierPath *bezierPath = [NSBezierPath bezierPath];
        [bezierPath moveToPoint:NSMakePoint(0.0f, 0.0f)]; // prevents "No current point for line" exception
        [bezierPath appendBezierPathWithGlyph:self.glyphBullet inFont:self.fontIndent];
        NSRect rectGlyphOutline = [bezierPath bounds];
        // The bullet should be followed with a space, so get the combined size...
        NSSize sizeSpace = [@" " sizeWithAttributes:[NSDictionary dictionaryWithObject:self.fontIndent forKey:NSFontAttributeName]];
        self.fWidthGlyphPlusSpace = rectGlyphOutline.size.width + sizeSpace.width;
        // ...which is for some reason inexact. If this number is too low, your bulleted text will be thrown to the line below, so add some boost.
        self.fWidthGlyphPlusSpace *= 1.5; // 
    }

    return self;
}

- (void)drawGlyphsForGlyphRange:(NSRange)range 
                        atPoint:(NSPoint)origin {

    // The following prints only once, even though the textview's string is set 4 times, so this implementation is not too expensive.
    printf("\nCalling TickerLayoutManager's drawGlyphs method.");

    NSString *string = [[self textStorage] string];
    for (int i = range.location; i < range.length; i++) {
        // Replace all occurrences of the ">" char with the bullet glyph.
        if ([string characterAtIndex:i] == '>')
            [self replaceGlyphAtIndex:i withGlyph:self.glyphBullet];
    }

    [super drawGlyphsForGlyphRange:range atPoint:origin];
}

@end

Assign the layout manager to the textview in your window/view controller’s awakeFromNib, like this:

- (void) awakeFromNib {

    // regular setup...

    // Give the ticker display NSTextView its subclassed layout manager.
    TickerLayoutManager *newLayoutMgr = [[TickerLayoutManager alloc] init];
    NSTextContainer *textContainer = [self.txvProgressTicker textContainer];
    // Use "replaceLM" rather than "setLM," in order to keep shared relnshps intact. 
    [textContainer replaceLayoutManager:newLayoutMgr];
    [newLayoutMgr release];
    // (Note: It is possible that all text-displaying controls in this class’s window will share this text container, as they would a field editor (a textview), although the fact that the ticker display is itself a textview might isolate it. Apple's "Text System Overview" is not clear on this point.)

}

And then add a method something like this:

- (void) addProgressTickerLine:(NSString *)string 
                   inStyle:(uint8_t)uiStyle {

    // Null check.
    if (!string)
        return;

    // Prepare the font.
    // (As noted above, TickerLayoutManager holds all 3 ticker display fonts.)
    NSFont *font = nil;
    TickerLayoutManager *tickerLayoutMgr = (TickerLayoutManager *)[self.txvProgressTicker layoutManager];
    switch (uiStyle) {
        case kTickerStyleNormal:
            font = tickerLayoutMgr.fontNormal;
            break;
        case kTickerStyleIndent:
            font = tickerLayoutMgr.fontIndent;
            break;
        case kTickerStyleBold:
            font = tickerLayoutMgr.fontBold;
            break;
        default:
            font = tickerLayoutMgr.fontNormal;
            break;
    }


    // Prepare the paragraph style, to govern indentation.    
    // CAUTION: If you propertize it for re-use, make sure you don't mutate it once it has been assigned to an attributed string. (See warning in class ref.)
    // At the same time, add the initial line break and, if indented, the tab.
    NSMutableParagraphStyle *paragStyle = [[NSParagraphStyle defaultParagraphStyle] mutableCopy]; // ALLOC
    [paragStyle setAlignment:NSLeftTextAlignment]; // default, but just in case
    if (uiStyle == kTickerStyleIndent) {
        // (The custom layout mgr will replace ‘>’ char with a bullet, so it should be followed with an extra space.)
        string = [@"\n>\t" stringByAppendingString:string];
        // Indent the first line up to where the bullet should appear.
        [paragStyle setFirstLineHeadIndent:15.0f];
        // Define a tab stop to the right of the bullet glyph.
        NSTextTab *textTabFllwgBullet = [[NSTextTab alloc] initWithType:NSLeftTabStopType location:15.0f + tickerLayoutMgr.fWidthGlyphPlusSpace];
        [paragStyle setTabStops:[NSArray arrayWithObject:textTabFllwgBullet]];  
        [textTabFllwgBullet release];
        // Set the indentation for the wrapped lines to the same place as the tab stop.
        [paragStyle setHeadIndent:15.0f + tickerLayoutMgr.fWidthGlyphPlusSpace];
    }
    else {
        string = [@"\n" stringByAppendingString:string];
    }


    // PUT IT ALL TOGETHER.
    // Combine the above into a dictionary of attributes.
    NSDictionary *dict = [NSDictionary dictionaryWithObjectsAndKeys:
                            font, NSFontAttributeName, 
                            paragStyle, NSParagraphStyleAttributeName, 
                            nil];
    // Use the attributes dictionary to make an attributed string out of the plain string.
    NSAttributedString *attrs = [[NSAttributedString alloc] initWithString:string attributes:dict]; // ALLOC
    // Append the attributed string to the ticker display.
    [[self.txvProgressTicker textStorage] appendAttributedString:attrs];

    // RELEASE
    [attrs release];
    [paragStyle release];

}

Test it out:

NSString *sTicker = NSLocalizedString(@"First normal line of ticker should wrap to left margin", @"First normal line of ticker should wrap to left margin");
[self addProgressTickerLine:sTicker inStyle:kTickerStyleNormal];
sTicker = NSLocalizedString(@"Indented ticker line should have bullet point and should wrap farther to right.", @"Indented ticker line should have bullet point and should wrap farther to right.");
[self addProgressTickerLine:sTicker inStyle:kTickerStyleIndent];
sTicker = NSLocalizedString(@"Try a second indented line, to make sure both line up.", @"Try a second indented line, to make sure both line up.");
[self addProgressTickerLine:sTicker inStyle:kTickerStyleIndent];
sTicker = NSLocalizedString(@"Final bold line", @"Final bold line");
[self addProgressTickerLine:sTicker inStyle:kTickerStyleBold];

You get this:

Method 2:

But the bullet is a regular Unicode char, at hex 2022. So you can put it in the string directly, and get an exact measurement, like this:

    NSString *stringWithGlyph = [NSString stringWithUTF8String:"\u2022"];
    NSString *stringWithGlyphPlusSpace = [stringWithGlyph stringByAppendingString:@" "];
    NSSize sizeGlyphPlusSpace = [stringWithGlyphPlusSpace sizeWithAttributes:[NSDictionary dictionaryWithObject:self.fontIndent forKey:NSFontAttributeName]];
    self.fWidthGlyphPlusSpace = sizeGlyphPlusSpace.width;

So there is no need for the custom layout manager. Just set the paragStyle indentations as above, and append your text string to a string holding the line return + bullet char + space (or + tab, in which case you’ll still want that tab stop).

Using a space, this produced a tighter result:

Want to use a character other than the bullet? Here’s a nice Unicode chart: http://www.danshort.com/unicode/