iphone/ipad: How exactly use NSAttributedString?

Solution 1:

Starting from the iOS 6.0 you can do it like that:

NSMutableAttributedString *str = [[NSMutableAttributedString alloc] initWithString:@"Hello. That is a test attributed string."];
[str addAttribute:NSBackgroundColorAttributeName value:[UIColor yellowColor] range:NSMakeRange(3,5)];
[str addAttribute:NSForegroundColorAttributeName value:[UIColor greenColor] range:NSMakeRange(10,7)];
[str addAttribute:NSFontAttributeName value:[UIFont fontWithName:@"HelveticaNeue-Bold" size:20.0] range:NSMakeRange(20, 10)];
label.attributedText = str;

Solution 2:

You should take a look at AliSoftware's OHAttributedLabel. It is a subclass of UILabel that draws an NSAttributedString and also provides convenience methods for setting the attributes of an NSAttributedString from UIKit classes.

From the sample provided in the repo:

#import "NSAttributedString+Attributes.h"
#import "OHAttributedLabel.h"

/**(1)** Build the NSAttributedString *******/
NSMutableAttributedString* attrStr = [NSMutableAttributedString attributedStringWithString:@"Hello World!"];
// for those calls we don't specify a range so it affects the whole string
[attrStr setFont:[UIFont systemFontOfSize:12]];
[attrStr setTextColor:[UIColor grayColor]];
// now we only change the color of "Hello"
[attrStr setTextColor:[UIColor redColor] range:NSMakeRange(0,5)];


/**(2)** Affect the NSAttributedString to the OHAttributedLabel *******/
myAttributedLabel.attributedText = attrStr;
// Use the "Justified" alignment
myAttributedLabel.textAlignment = UITextAlignmentJustify;
// "Hello World!" will be displayed in the label, justified, "Hello" in red and " World!" in gray.

Note: In iOS 6+ you can render attributed strings using the attributedText property of UILabel.

Solution 3:

You should try TTTAttributedLabel. It's a drop-in replacement for UILabel that works with NSAttributedString and is performant enough for UITableViewCells.

Solution 4:

Is there any simple ways like

NSAttributedString *str;

UILabel *label;

label.attributedString = str;

Almost. Just use a CATextLayer. It has a string property that you can set to an NSAttributedString.

EDIT (November, 2012): Of course all this has changed in iOS 6. In iOS 6, you can do exactly what the OP asked for - assign an attributed string directly to a label's attributedText.

Solution 5:

Answer for UILabel attributed text alignment on iOS 6: Use NSMutableAttributedString and add NSMutableParagraphStyle to the attribute. Something like this:

NSString *str = @"Hello World!";
NSRange strRange = NSMakeRange(0, str.length);
NSMutableAttributedString *attributedStr = [[NSMutableAttributedString alloc] initWithString:str];

NSMutableParagraphStyle *paragrahStyle = [[NSMutableParagraphStyle alloc] init];
[paragrahStyle setAlignment:NSTextAlignmentCenter];
[attributedStr addAttribute:NSParagraphStyleAttributeName value:paragrahStyle range:strRange];

myUILabel.attributedText = attributedStr;