以编程方式设置UIButton标题UILabel字体大小
我需要以编程方式设置UIButton
的标题UILabel
的字体大小。
button.titleLabel.font = [UIFont systemFontOfSize:size];
应该有帮助
[button setFont:...]
已被弃用。
使用[button.titleLabel setFont:...]
代替,例如:
[myButton.titleLabel setFont:[UIFont systemFontOfSize:10]];
你也可以使用像这样的东西来设置字体大小和字体样式。 这比你要求的要多一点,但是,嘿,这是什么…
[myButton.titleLabel setFont:[UIFont fontWithName:@"Helvetica-Bold" size:13.0]];
而且…如果你感觉活跃,可以通过实现这个代码find可用字体列表,然后在xCodedebugging器中检查输出。
码:
NSArray *familyNames = [[NSArray alloc] initWithArray:[UIFont familyNames]]; NSArray *fontNames; NSInteger indFamily, indFont; for (indFamily=0; indFamily<[familyNames count]; ++indFamily) { NSLog(@"Family name: %@", [familyNames objectAtIndex:indFamily]); fontNames = [[NSArray alloc] initWithArray: [UIFont fontNamesForFamilyName: [familyNames objectAtIndex:indFamily]]]; for (indFont=0; indFont<[fontNames count]; ++indFont) { NSLog(@" Font name: %@", [fontNames objectAtIndex:indFont]); } }
例:
2012-04-02 11:36:34.395 MyApp[3579:707] Family name: Thonburi 2012-04-02 11:36:34.398 MyApp[3579:707] Font name: Thonburi-Bold 2012-04-02 11:36:34.402 MyApp[3579:707] Font name: Thonburi 2012-04-02 11:36:34.405 MyApp[3579:707] Family name: Snell Roundhand 2012-04-02 11:36:34.408 MyApp[3579:707] Font name: SnellRoundhand-Bold 2012-04-02 11:36:34.411 MyApp[3579:707] Font name: SnellRoundhand-Black 2012-04-02 11:36:34.415 MyApp[3579:707] Font name: SnellRoundhand 2012-04-02 11:36:34.418 MyApp[3579:707] Family name: Academy Engraved LET 2012-04-02 11:36:34.421 MyApp[3579:707] Font name: AcademyEngravedLetPlain 2012-04-02 11:36:34.424 MyApp[3579:707] Family name: Marker Felt 2012-04-02 11:36:34.427 MyApp[3579:707] Font name: MarkerFelt-Wide 2012-04-02 11:36:34.430 MyApp[3579:707] Font name: MarkerFelt-Thin 2012-04-02 11:36:34.434 MyApp[3579:707] Family name: Geeza Pro 2012-04-02 11:36:34.437 MyApp[3579:707] Font name: GeezaPro-Bold 2012-04-02 11:36:34.441 MyApp[3579:707] Font name: GeezaPro 2012-04-02 11:36:34.445 MyApp[3579:707] Family name: Arial Rounded MT Bold 2012-04-02 11:36:34.448 MyApp[3579:707] Font name: ArialRoundedMTBold 2012-04-02 11:36:34.451 MyApp[3579:707] Family name: Trebuchet MS 2012-04-02 11:36:34.455 MyApp[3579:707] Font name: TrebuchetMS 2012-04-02 11:36:34.458 MyApp[3579:707] Font name: TrebuchetMS-Bold 2012-04-02 11:36:34.461 MyApp[3579:707] Font name: TrebuchetMS-Italic 2012-04-02 11:36:34.464 MyApp[3579:707] Font name: Trebuchet-BoldItalic 2012-04-02 11:36:34.467 MyApp[3579:707] Family name: Arial 2012-04-02 11:36:34.471 MyApp[3579:707] Font name: Arial-BoldMT 2012-04-02 11:36:34.474 MyApp[3579:707] Font name: ArialMT 2012-04-02 11:36:34.477 MyApp[3579:707] Font name: Arial-ItalicMT 2012-04-02 11:36:34.480 MyApp[3579:707] Font name: Arial-BoldItalicMT 2012-04-02 11:36:34.483 MyApp[3579:707] Family name: Marion 2012-04-02 11:36:34.487 MyApp[3579:707] Font name: Marion-Regular 2012-04-02 11:36:34.491 MyApp[3579:707] Font name: Marion-Bold 2012-04-02 11:36:34.494 MyApp[3579:707] Font name: Marion-Italic 2012-04-02 11:36:34.503 MyApp[3579:707] Family name: Gurmukhi MN 2012-04-02 11:36:34.507 MyApp[3579:707] Font name: GurmukhiMN 2012-04-02 11:36:34.511 MyApp[3579:707] Font name: GurmukhiMN-Bold 2012-04-02 11:36:34.514 MyApp[3579:707] Family name: Malayalam Sangam MN 2012-04-02 11:36:34.518 MyApp[3579:707] Font name: MalayalamSangamMN-Bold 2012-04-02 11:36:34.522 MyApp[3579:707] Font name: MalayalamSangamMN 2012-04-02 11:36:34.525 MyApp[3579:707] Family name: Bradley Hand 2012-04-02 11:36:34.529 MyApp[3579:707] Font name: BradleyHandITCTT-Bold 2012-04-02 11:36:34.532 MyApp[3579:707] Family name: Kannada Sangam MN 2012-04-02 11:36:34.536 MyApp[3579:707] Font name: KannadaSangamMN 2012-04-02 11:36:34.540 MyApp[3579:707] Font name: KannadaSangamMN-Bold 2012-04-02 11:36:34.544 MyApp[3579:707] Family name: Bodoni 72 Oldstyle 2012-04-02 11:36:34.548 MyApp[3579:707] Font name: BodoniSvtyTwoOSITCTT-Book 2012-04-02 11:36:34.552 MyApp[3579:707] Font name: BodoniSvtyTwoOSITCTT-Bold 2012-04-02 11:36:34.555 MyApp[3579:707] Font name: BodoniSvtyTwoOSITCTT-BookIt 2012-04-02 11:36:34.559 MyApp[3579:707] Family name: Cochin 2012-04-02 11:36:34.562 MyApp[3579:707] Font name: Cochin 2012-04-02 11:36:34.566 MyApp[3579:707] Font name: Cochin-BoldItalic 2012-04-02 11:36:34.570 MyApp[3579:707] Font name: Cochin-Italic 2012-04-02 11:36:34.573 MyApp[3579:707] Font name: Cochin-Bold 2012-04-02 11:36:34.577 MyApp[3579:707] Family name: Sinhala Sangam MN 2012-04-02 11:36:34.581 MyApp[3579:707] Font name: SinhalaSangamMN 2012-04-02 11:36:34.584 MyApp[3579:707] Font name: SinhalaSangamMN-Bold 2012-04-02 11:36:34.588 MyApp[3579:707] Family name: Hiragino Kaku Gothic ProN 2012-04-02 11:36:34.592 MyApp[3579:707] Font name: HiraKakuProN-W6 2012-04-02 11:36:34.596 MyApp[3579:707] Font name: HiraKakuProN-W3 2012-04-02 11:36:34.599 MyApp[3579:707] Family name: Papyrus 2012-04-02 11:36:34.603 MyApp[3579:707] Font name: Papyrus-Condensed 2012-04-02 11:36:34.607 MyApp[3579:707] Font name: Papyrus 2012-04-02 11:36:34.614 MyApp[3579:707] Family name: Verdana 2012-04-02 11:36:34.620 MyApp[3579:707] Font name: Verdana 2012-04-02 11:36:34.626 MyApp[3579:707] Font name: Verdana-Bold 2012-04-02 11:36:34.674 MyApp[3579:707] Font name: Verdana-BoldItalic 2012-04-02 11:36:34.690 MyApp[3579:707] Font name: Verdana-Italic 2012-04-02 11:36:34.730 MyApp[3579:707] Family name: Zapf Dingbats 2012-04-02 11:36:34.748 MyApp[3579:707] Font name: ZapfDingbatsITC 2012-04-02 11:36:34.752 MyApp[3579:707] Family name: Courier 2012-04-02 11:36:34.757 MyApp[3579:707] Font name: Courier-Bold 2012-04-02 11:36:34.762 MyApp[3579:707] Font name: Courier 2012-04-02 11:36:34.769 MyApp[3579:707] Font name: Courier-BoldOblique 2012-04-02 11:36:34.778 MyApp[3579:707] Font name: Courier-Oblique 2012-04-02 11:36:34.786 MyApp[3579:707] Family name: Hoefler Text 2012-04-02 11:36:34.793 MyApp[3579:707] Font name: HoeflerText-Black 2012-04-02 11:36:34.802 MyApp[3579:707] Font name: HoeflerText-Italic 2012-04-02 11:36:34.810 MyApp[3579:707] Font name: HoeflerText-Regular 2012-04-02 11:36:34.819 MyApp[3579:707] Font name: HoeflerText-BlackItalic 2012-04-02 11:36:34.827 MyApp[3579:707] Family name: Euphemia UCAS 2012-04-02 11:36:34.836 MyApp[3579:707] Font name: EuphemiaUCAS-Bold 2012-04-02 11:36:34.843 MyApp[3579:707] Font name: EuphemiaUCAS 2012-04-02 11:36:34.848 MyApp[3579:707] Font name: EuphemiaUCAS-Italic 2012-04-02 11:36:34.853 MyApp[3579:707] Family name: Helvetica 2012-04-02 11:36:34.857 MyApp[3579:707] Font name: Helvetica-LightOblique 2012-04-02 11:36:34.863 MyApp[3579:707] Font name: Helvetica 2012-04-02 11:36:34.873 MyApp[3579:707] Font name: Helvetica-Oblique 2012-04-02 11:36:34.876 MyApp[3579:707] Font name: Helvetica-BoldOblique 2012-04-02 11:36:34.880 MyApp[3579:707] Font name: Helvetica-Bold 2012-04-02 11:36:34.884 MyApp[3579:707] Font name: Helvetica-Light 2012-04-02 11:36:34.887 MyApp[3579:707] Family name: Hiragino Mincho ProN 2012-04-02 11:36:34.892 MyApp[3579:707] Font name: HiraMinProN-W3 2012-04-02 11:36:34.898 MyApp[3579:707] Font name: HiraMinProN-W6 2012-04-02 11:36:34.902 MyApp[3579:707] Family name: Bodoni Ornaments 2012-04-02 11:36:34.905 MyApp[3579:707] Font name: BodoniOrnamentsITCTT 2012-04-02 11:36:34.923 MyApp[3579:707] Family name: Apple Color Emoji 2012-04-02 11:36:34.938 MyApp[3579:707] Font name: AppleColorEmoji 2012-04-02 11:36:34.942 MyApp[3579:707] Family name: Optima 2012-04-02 11:36:34.946 MyApp[3579:707] Font name: Optima-ExtraBlack 2012-04-02 11:36:34.950 MyApp[3579:707] Font name: Optima-Italic 2012-04-02 11:36:34.954 MyApp[3579:707] Font name: Optima-Regular 2012-04-02 11:36:34.965 MyApp[3579:707] Font name: Optima-BoldItalic 2012-04-02 11:36:34.969 MyApp[3579:707] Font name: Optima-Bold 2012-04-02 11:36:34.972 MyApp[3579:707] Family name: Gujarati Sangam MN 2012-04-02 11:36:34.985 MyApp[3579:707] Font name: GujaratiSangamMN 2012-04-02 11:36:34.989 MyApp[3579:707] Font name: GujaratiSangamMN-Bold 2012-04-02 11:36:34.993 MyApp[3579:707] Family name: Devanagari Sangam MN 2012-04-02 11:36:34.998 MyApp[3579:707] Font name: DevanagariSangamMN 2012-04-02 11:36:35.002 MyApp[3579:707] Font name: DevanagariSangamMN-Bold 2012-04-02 11:36:35.006 MyApp[3579:707] Family name: Times New Roman 2012-04-02 11:36:35.017 MyApp[3579:707] Font name: TimesNewRomanPS-ItalicMT 2012-04-02 11:36:35.021 MyApp[3579:707] Font name: TimesNewRomanPS-BoldMT 2012-04-02 11:36:35.032 MyApp[3579:707] Font name: TimesNewRomanPSMT 2012-04-02 11:36:35.037 MyApp[3579:707] Font name: TimesNewRomanPS-BoldItalicMT 2012-04-02 11:36:35.041 MyApp[3579:707] Family name: Kailasa 2012-04-02 11:36:35.045 MyApp[3579:707] Font name: Kailasa 2012-04-02 11:36:35.050 MyApp[3579:707] Font name: Kailasa-Bold 2012-04-02 11:36:35.053 MyApp[3579:707] Family name: Telugu Sangam MN 2012-04-02 11:36:35.064 MyApp[3579:707] Font name: TeluguSangamMN-Bold 2012-04-02 11:36:35.068 MyApp[3579:707] Font name: TeluguSangamMN 2012-04-02 11:36:35.071 MyApp[3579:707] Family name: Heiti SC 2012-04-02 11:36:35.099 MyApp[3579:707] Font name: STHeitiSC-Medium 2012-04-02 11:36:35.107 MyApp[3579:707] Font name: STHeitiSC-Light 2012-04-02 11:36:35.111 MyApp[3579:707] Family name: Futura 2012-04-02 11:36:35.115 MyApp[3579:707] Font name: Futura-Medium 2012-04-02 11:36:35.119 MyApp[3579:707] Font name: Futura-CondensedExtraBold 2012-04-02 11:36:35.122 MyApp[3579:707] Font name: Futura-CondensedMedium 2012-04-02 11:36:35.135 MyApp[3579:707] Font name: Futura-MediumItalic 2012-04-02 11:36:35.155 MyApp[3579:707] Family name: Bodoni 72 2012-04-02 11:36:35.160 MyApp[3579:707] Font name: BodoniSvtyTwoITCTT-BookIta 2012-04-02 11:36:35.164 MyApp[3579:707] Font name: BodoniSvtyTwoITCTT-Book 2012-04-02 11:36:35.168 MyApp[3579:707] Font name: BodoniSvtyTwoITCTT-Bold 2012-04-02 11:36:35.171 MyApp[3579:707] Family name: Baskerville 2012-04-02 11:36:35.183 MyApp[3579:707] Font name: Baskerville-SemiBoldItalic 2012-04-02 11:36:35.187 MyApp[3579:707] Font name: Baskerville-Bold 2012-04-02 11:36:35.197 MyApp[3579:707] Font name: Baskerville-Italic 2012-04-02 11:36:35.245 MyApp[3579:707] Font name: Baskerville-BoldItalic 2012-04-02 11:36:35.253 MyApp[3579:707] Font name: Baskerville-SemiBold 2012-04-02 11:36:35.258 MyApp[3579:707] Font name: Baskerville 2012-04-02 11:36:35.262 MyApp[3579:707] Family name: Chalkboard SE 2012-04-02 11:36:35.266 MyApp[3579:707] Font name: ChalkboardSE-Regular 2012-04-02 11:36:35.269 MyApp[3579:707] Font name: ChalkboardSE-Bold 2012-04-02 11:36:35.279 MyApp[3579:707] Font name: ChalkboardSE-Light 2012-04-02 11:36:35.284 MyApp[3579:707] Family name: Heiti TC 2012-04-02 11:36:35.288 MyApp[3579:707] Font name: STHeitiTC-Medium 2012-04-02 11:36:35.299 MyApp[3579:707] Font name: STHeitiTC-Light 2012-04-02 11:36:35.305 MyApp[3579:707] Family name: Copperplate 2012-04-02 11:36:35.310 MyApp[3579:707] Font name: Copperplate 2012-04-02 11:36:35.313 MyApp[3579:707] Font name: Copperplate-Light 2012-04-02 11:36:35.317 MyApp[3579:707] Font name: Copperplate-Bold 2012-04-02 11:36:35.320 MyApp[3579:707] Family name: Party LET 2012-04-02 11:36:35.334 MyApp[3579:707] Font name: PartyLetPlain 2012-04-02 11:36:35.338 MyApp[3579:707] Family name: American Typewriter 2012-04-02 11:36:35.351 MyApp[3579:707] Font name: AmericanTypewriter-CondensedLight 2012-04-02 11:36:35.357 MyApp[3579:707] Font name: AmericanTypewriter-Light 2012-04-02 11:36:35.361 MyApp[3579:707] Font name: AmericanTypewriter-Bold 2012-04-02 11:36:35.364 MyApp[3579:707] Font name: AmericanTypewriter 2012-04-02 11:36:35.368 MyApp[3579:707] Font name: AmericanTypewriter-CondensedBold 2012-04-02 11:36:35.372 MyApp[3579:707] Font name: AmericanTypewriter-Condensed 2012-04-02 11:36:35.384 MyApp[3579:707] Family name: AppleGothic 2012-04-02 11:36:35.400 MyApp[3579:707] Font name: AppleGothic 2012-04-02 11:36:35.406 MyApp[3579:707] Family name: Bangla Sangam MN 2012-04-02 11:36:35.411 MyApp[3579:707] Font name: BanglaSangamMN-Bold 2012-04-02 11:36:35.414 MyApp[3579:707] Font name: BanglaSangamMN 2012-04-02 11:36:35.418 MyApp[3579:707] Family name: Noteworthy 2012-04-02 11:36:35.422 MyApp[3579:707] Font name: Noteworthy-Light 2012-04-02 11:36:35.432 MyApp[3579:707] Font name: Noteworthy-Bold 2012-04-02 11:36:35.436 MyApp[3579:707] Family name: Zapfino 2012-04-02 11:36:35.443 MyApp[3579:707] Font name: Zapfino 2012-04-02 11:36:35.448 MyApp[3579:707] Family name: Tamil Sangam MN 2012-04-02 11:36:35.452 MyApp[3579:707] Font name: TamilSangamMN 2012-04-02 11:36:35.456 MyApp[3579:707] Font name: TamilSangamMN-Bold 2012-04-02 11:36:35.459 MyApp[3579:707] Family name: DB LCD Temp 2012-04-02 11:36:35.463 MyApp[3579:707] Font name: DBLCDTempBlack 2012-04-02 11:36:35.467 MyApp[3579:707] Family name: Arial Hebrew 2012-04-02 11:36:35.471 MyApp[3579:707] Font name: ArialHebrew 2012-04-02 11:36:35.475 MyApp[3579:707] Font name: ArialHebrew-Bold 2012-04-02 11:36:35.479 MyApp[3579:707] Family name: Chalkduster 2012-04-02 11:36:35.482 MyApp[3579:707] Font name: Chalkduster 2012-04-02 11:36:35.486 MyApp[3579:707] Family name: Georgia 2012-04-02 11:36:35.490 MyApp[3579:707] Font name: Georgia-Italic 2012-04-02 11:36:35.493 MyApp[3579:707] Font name: Georgia-BoldItalic 2012-04-02 11:36:35.497 MyApp[3579:707] Font name: Georgia-Bold 2012-04-02 11:36:35.501 MyApp[3579:707] Font name: Georgia 2012-04-02 11:36:35.504 MyApp[3579:707] Family name: Helvetica Neue 2012-04-02 11:36:35.508 MyApp[3579:707] Font name: HelveticaNeue-Bold 2012-04-02 11:36:35.511 MyApp[3579:707] Font name: HelveticaNeue-CondensedBlack 2012-04-02 11:36:35.515 MyApp[3579:707] Font name: HelveticaNeue-Medium 2012-04-02 11:36:35.518 MyApp[3579:707] Font name: HelveticaNeue 2012-04-02 11:36:35.522 MyApp[3579:707] Font name: HelveticaNeue-Light 2012-04-02 11:36:35.526 MyApp[3579:707] Font name: HelveticaNeue-CondensedBold 2012-04-02 11:36:35.529 MyApp[3579:707] Font name: HelveticaNeue-LightItalic 2012-04-02 11:36:35.532 MyApp[3579:707] Font name: HelveticaNeue-UltraLightItalic 2012-04-02 11:36:35.536 MyApp[3579:707] Font name: HelveticaNeue-UltraLight 2012-04-02 11:36:35.540 MyApp[3579:707] Font name: HelveticaNeue-BoldItalic 2012-04-02 11:36:35.543 MyApp[3579:707] Font name: HelveticaNeue-Italic 2012-04-02 11:36:35.547 MyApp[3579:707] Family name: Gill Sans 2012-04-02 11:36:35.551 MyApp[3579:707] Font name: GillSans-LightItalic 2012-04-02 11:36:35.555 MyApp[3579:707] Font name: GillSans-BoldItalic 2012-04-02 11:36:35.558 MyApp[3579:707] Font name: GillSans-Italic 2012-04-02 11:36:35.562 MyApp[3579:707] Font name: GillSans 2012-04-02 11:36:35.565 MyApp[3579:707] Font name: GillSans-Bold 2012-04-02 11:36:35.569 MyApp[3579:707] Font name: GillSans-Light 2012-04-02 11:36:35.572 MyApp[3579:707] Family name: Palatino 2012-04-02 11:36:35.576 MyApp[3579:707] Font name: Palatino-Roman 2012-04-02 11:36:35.580 MyApp[3579:707] Font name: Palatino-Bold 2012-04-02 11:36:35.583 MyApp[3579:707] Font name: Palatino-BoldItalic 2012-04-02 11:36:35.587 MyApp[3579:707] Font name: Palatino-Italic 2012-04-02 11:36:35.591 MyApp[3579:707] Family name: Courier New 2012-04-02 11:36:35.594 MyApp[3579:707] Font name: CourierNewPSMT 2012-04-02 11:36:35.598 MyApp[3579:707] Font name: CourierNewPS-BoldMT 2012-04-02 11:36:35.601 MyApp[3579:707] Font name: CourierNewPS-BoldItalicMT 2012-04-02 11:36:35.605 MyApp[3579:707] Font name: CourierNewPS-ItalicMT 2012-04-02 11:36:35.608 MyApp[3579:707] Family name: Oriya Sangam MN 2012-04-02 11:36:35.612 MyApp[3579:707] Font name: OriyaSangamMN-Bold 2012-04-02 11:36:35.616 MyApp[3579:707] Font name: OriyaSangamMN 2012-04-02 11:36:35.619 MyApp[3579:707] Family name: Didot 2012-04-02 11:36:35.623 MyApp[3579:707] Font name: Didot-Italic 2012-04-02 11:36:35.627 MyApp[3579:707] Font name: Didot 2012-04-02 11:36:35.630 MyApp[3579:707] Font name: Didot-Bold 2012-04-02 11:36:35.634 MyApp[3579:707] Family name: Bodoni 72 Smallcaps 2012-04-02 11:36:35.638 MyApp[3579:707] Font name: BodoniSvtyTwoSCITCTT-Book
Objective-C的:
[button.titleLabel setFont: [button.titleLabel.font fontWithSize: sizeYouWant]];
迅速:
button.titleLabel?.font = button.titleLabel?.font.fontWithSize(sizeYouWant)
只会改变字体大小。
这将是有益的
button.titleLabel.font = [UIFont fontWithName:@"YOUR FONTNAME" size:12.0f]
您可以使用:
button.titleLabel.font = [UIFont systemFontOfSize:14.0];
我希望这会对你有所帮助
[_button.titleLabel setFont:[UIFont systemFontOfSize:15]];
祝你好运
迅速:
shareButton.titleLabel?.font = UIFont.systemFontOfSize(size)
不重要的注意:被animuson删除♦14年5月5日在16:48
在我发布这个答案后的一个月里,我遇到了同样的问题。 我在Google上search,发现这个post不容易复制成一个快速的项目。 当我滚动看到我删除的答案,并复制它。 所以请不要删除实际有用的东西..
您还可以使用粗体,斜体自定义button字体。 这个例子用粗体系的字体大小。
[LoginButton.titleLabel setFont:[UIFont boldSystemFontOfSize:15.0f*Ratio]];
button.titleLabel.font = <whatever font you want>
对于那些想知道为什么他们的文本没有出现的人,如果你这样做的话
button.titleLabel.text = @"something";
它不会出现,你需要做的:
[button setTitle:@"My title" forState:UIControlStateNormal]; //or whatever you want the control state to be
这应该让你去
[btn_submit.titleLabel setFont:[UIFont systemFontOfSize:14.0f]];
这样你可以设置fontSize,并且可以在一个class
处理它。
1.创build了UIButton
的extension
并添加了以下代码:
- (void)awakeFromNib{ [super awakeFromNib]; [self setTitleColor:[UIColor whiteColor] forState:UIControlStateNormal]; [self.titleLabel setFont:[UIFont fontWithName:@"font" size:self.titleLabel.font.pointSize]]; [self setContentHorizontalAlignment:UIControlContentHorizontalAlignmentCenter]; }
2.1在代码中创buildUIButton
现在,如果您在代码中创build一个UIButton
,请#import
导入UIButton的extension of your
并创buildButton。
2.2在Interface Builder
创buildbutton
如果在Interface Builder
创buildUIButton
,请selectUIButton
,转到Identity Inspector
,并将创build的extension
添加为UIButton
class
。
Swift 3:
myButton.titleLabel?.font = myButton.titleLabel?.font.withSize(40)