¿Cómo agregar números de línea a una UITextView?

Question

Quiero agregar números de línea a mi UITextView.
¿Tengo que escribir mi propio elemento UI o hay alguna otra solución?

Answer 1

lo logré subclasificando UIView y reemplazando el método drawRect: así:

#define TXT_VIEW_INSETS 8.0 // The default insets for a UITextView is 8.0 on all sides 

@implementation NumberedTextView 

@synthesize lineNumbers; 
@synthesize delegate; 

- (id)initWithFrame:(CGRect)frame { 
    if ((self = [super initWithFrame:frame])) { 
     [self setContentMode:UIViewContentModeRedraw]; 

     internalScrollView = [[UIScrollView alloc] initWithFrame:self.bounds]; 
     [internalScrollView  setAutoresizingMask:UIViewAutoresizingFlexibleWidth | UIViewAutoresizingFlexibleHeight]; 
     [internalScrollView  setBackgroundColor:[UIColor clearColor]]; 
     [internalScrollView   setClipsToBounds:YES]; 
     [internalScrollView   setScrollsToTop:YES]; 
     [internalScrollView   setContentSize:self.bounds.size]; 
     [internalScrollView   setContentMode:UIViewContentModeLeft]; 
     [internalScrollView    setDelegate:self]; 
     [internalScrollView    setBounces:NO]; 

     internalTextView = [[UITextView alloc] initWithFrame:self.bounds]; 
     [internalTextView setAutocapitalizationType:UITextAutocapitalizationTypeNone]; 
     [internalTextView  setAutocorrectionType:UITextAutocorrectionTypeNo]; 
     [internalTextView  setSpellCheckingType:UITextSpellCheckingTypeNo]; 
     [internalTextView  setAutoresizingMask:UIViewAutoresizingFlexibleWidth | UIViewAutoresizingFlexibleHeight]; 
     [internalTextView   setBackgroundColor:[UIColor clearColor]]; 
     [internalTextView   setClipsToBounds:YES]; 
     [internalTextView   setScrollsToTop:NO]; 
     [internalTextView    setContentMode:UIViewContentModeLeft]; 
     [internalTextView    setDelegate:self]; 
     [internalTextView     setBounces:NO]; 

     [internalScrollView addSubview:internalTextView]; 
     [self addSubview:internalScrollView]; 
    } 
    return self; 
} 

- (void)drawRect:(CGRect)rect { 
    if (self.lineNumbers) { 
     [[internalTextView textColor] set]; 
     CGFloat xOrigin, yOrigin, width/*, height*/; 
     uint numberOfLines = (internalTextView.contentSize.height + internalScrollView.contentSize.height)/internalTextView.font.lineHeight; 
     for (uint x = 0; x < numberOfLines; ++x) { 
      NSString *lineNum = [NSString stringWithFormat:@"%d:", x]; 

      xOrigin = CGRectGetMinX(self.bounds); 

      yOrigin = ((internalTextView.font.pointSize + abs(internalTextView.font.descender)) * x) + TXT_VIEW_INSETS - internalScrollView.contentOffset.y; 

      width = [lineNum sizeWithFont:internalTextView.font].width; 
//   height = internalTextView.font.lineHeight; 

      [lineNum drawAtPoint:CGPointMake(xOrigin, yOrigin) withFont:internalTextView.font]; 
     } 

     CGRect tvFrame = [internalTextView frame]; 
     tvFrame.size.width = CGRectGetWidth(internalScrollView.bounds) - width; 
     tvFrame.size.height = MAX(internalTextView.contentSize.height, CGRectGetHeight(internalScrollView.bounds)); 
     tvFrame.origin.x = width; 
     [internalTextView setFrame:tvFrame]; 
     tvFrame.size.height -= TXT_VIEW_INSETS; // This fixed a weird content size problem that I've forgotten the specifics of. 
     [internalScrollView setContentSize:tvFrame.size]; 
    } 
} 

#pragma mark - UITextView Delegate 

- (BOOL)textView:(UITextView *)textView shouldChangeTextInRange:(NSRange)range replacementText:(NSString *)text { 
    [self setNeedsDisplay]; 
    return YES; 
} 

- (void)textViewDidChange:(UITextView *)textView { 
    [self setNeedsDisplay]; 
} 

- (void)textViewDidChangeSelection:(UITextView *)textView { 
    [self setNeedsDisplay]; 
} 

#pragma mark - UIScrollView Delegate 

- (void)scrollViewDidScroll:(UIScrollView *)scrollView { 
    [self setNeedsDisplay]; 
} 

Answer 2

No hay nada incorporado para esto. Tendrás que hacerlo tú mismo.