I have a UIButton and I'm trying to set the title to have 2 lines and the second line should be a smaller font than the first. Here's my code:
self.startBtn.setTitle("First\nSecond Line", forState: .Normal)
let string = NSMutableAttributedString()
string.addAttribute(NSFontAttributeName, value: UIFont.systemFontOfSize(13), range: NSMakeRange(4, 5))
self.startBtn.titleLabel?.attributedText = string
When I run the app, I get the following error:
Terminating app due to uncaught exception 'NSRangeException', reason: 'NSMutableRLEArray objectAtIndex:effectiveRange:: Out of bounds'
*** First throw call stack:
(
0 CoreFoundation 0x0000000106fbbc65 __exceptionPreprocess + 165
1 libobjc.A.dylib 0x0000000106c54bb7 objc_exception_throw + 45
2 CoreFoundation 0x0000000106fbbb9d +[NSException raise:format:] + 205
3 Foundation 0x00000001067e26ae -[NSRLEArray objectAtIndex:effectiveRange:] + 142
4 Foundation 0x00000001067fa029 -[NSConcreteMutableAttributedString addAttribute:value:range:] + 209
5 myApp 0x00000001064e0a93 _TFC7myApp18MainViewController9startTimefS0_FCSo8UIButtonT_ + 1363
6 myApp 0x00000001064e0eaa _TToFC7myApp18MainViewController9startTimefS0_FCSo8UIButtonT_ + 58
7 UIKit 0x0000000107561da2 -[UIApplication sendAction:to:from:forEvent:] + 75
8 UIKit 0x000000010767354a -[UIControl _sendActionsForEvents:withEvent:] + 467
9 UIKit 0x0000000107672919 -[UIControl touchesEnded:withEvent:] + 522
10 UIKit 0x00000001075ae998 -[UIWindow _sendTouchesForEvent:] + 735
11 UIKit 0x00000001075af2c2 -[UIWindow sendEvent:] + 682
12 UIKit 0x0000000107575581 -[UIApplication sendEvent:] + 246
13 UIKit 0x0000000107582d1c _UIApplicationHandleEventFromQueueEvent + 18265
14 UIKit 0x000000010755d5dc _UIApplicationHandleEventQueue + 2066
15 CoreFoundation 0x0000000106eef431 __CFRUNLOOP_IS_CALLING_OUT_TO_A_SOURCE0_PERFORM_FUNCTION__ + 17
16 CoreFoundation 0x0000000106ee52fd __CFRunLoopDoSources0 + 269
17 CoreFoundation 0x0000000106ee4934 __CFRunLoopRun + 868
18 CoreFoundation 0x0000000106ee4366 CFRunLoopRunSpecific + 470
19 GraphicsServices 0x00000001096cca3e GSEventRunModal + 161
20 UIKit 0x0000000107560900 UIApplicationMain + 1282
21 myApp 0x00000001064da2c7 main + 135
22 libdyld.dylib 0x0000000109ab3145 start + 1
23 ??? 0x0000000000000001 0x0 + 1
)
libc++abi.dylib: terminating with uncaught exception of type NSException
The reason you get the exception is that your NSMutableAttributedString is empty at the time when you set the font for some of its characters. Making sure that the string has characters in the range {4, 5} will fix this problem:
let string = NSMutableAttributedString(string:"First\nSecond Line")
string.addAttribute(NSFontAttributeName, value: UIFont.systemFontOfSize(13), range: NSMakeRange(4, 5))
self.startBtn.titleLabel?.attributedText = string
Note: Characters in the range {4, 5} are "t\nSec". If you wand the second line to be in smaller font, the range should be {6, 11}.