objective-c – 如何以编程方式将项目符号列表添加到NSTextView

方法1：

以下链接引导我使用第一种方法,但除非您想为子弹使用一些特殊的非Unicode字形,否则它将不必要地转向：

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

这需要：(1)子类化布局管理器,用子弹字形替换某些任意字符; (2)带有firstLineHeadIndent的段落样式,比该缩进略大的制表位,以及用于组合两者的包裹线的headIndent.

布局管理器如下所示：

#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

将布局管理器分配给窗口/视图控制器的awakeFromNib中的textview,如下所示：

- (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.)

}

然后添加一个类似这样的方法：

- (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];

}

测试出来：

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];

你得到这个：

方法2：

但子弹是一个常规的Unicode字符,在十六进制2022.所以你可以直接把它放在字符串中,并得到一个精确的测量,如下所示：

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

因此不需要自定义布局管理器.只需像上面一样设置paragStyle缩进,并将文本字符串附加到一个字符串,该字符串包含行返回项目符号空格(或选项卡,在这种情况下,您仍然希望该制表符停止).

使用空格,这产生了更严格的结果：

想要使用子弹以外的角色吗？这是一个很好的Unicode图表：http://www.danshort.com/unicode/