How to add underline below text of UIButton in iPhone? [duplicate] - iphone

Question

Can anyone suggest how to underline the title of a UIButton ? I have a UIButton of Custom type, and I want the Title to be underlined, but the Interface Builder does not provide any option to do so.
In Interface Builder when you select the Font Option for a Button, it provides option to select None, Single, Double, Color but none of these provide any changes to the Title on the Button.
Any help appreciated.

Answer 1

To use interface builder to underline, one has to:
Change it to attributed
Highlight the text in the Attributes inspector
Right click, choose Font and then Underline
Video someone else made
https://www.youtube.com/watch?v=5-ZnV3jQd9I

Answer 2

From iOS6 it is now possible to use an NSAttributedString to perform underlining (and anything else attributed strings support) in a much more flexible way:
NSMutableAttributedString *commentString = [[NSMutableAttributedString alloc] initWithString:#"The Quick Brown Fox"];
[commentString addAttribute:NSUnderlineStyleAttributeName value:[NSNumber numberWithInteger:NSUnderlineStyleSingle] range:NSMakeRange(0, [commentString length])];
[button setAttributedTitle:commentString forState:UIControlStateNormal];
Note: added this as another answer - as its a totally different solution to my previous one.
Edit:
oddly (in iOS8 at least) you have to underline the first character otherwise it doesn't work!
so as a workaround, set the first char underlined with clear colour!
// underline Terms and condidtions
NSMutableAttributedString* tncString = [[NSMutableAttributedString alloc] initWithString:#"View Terms and Conditions"];
// workaround for bug in UIButton - first char needs to be underlined for some reason!
[tncString addAttribute:NSUnderlineStyleAttributeName
value:#(NSUnderlineStyleSingle)
range:(NSRange){0,1}];
[tncString addAttribute:NSUnderlineColorAttributeName value:[UIColor clearColor] range:NSMakeRange(0, 1)];
[tncString addAttribute:NSUnderlineStyleAttributeName
value:#(NSUnderlineStyleSingle)
range:(NSRange){5,[tncString length] - 5}];
[tncBtn setAttributedTitle:tncString forState:UIControlStateNormal];

Answer 3

UIUnderlinedButton.h
#interface UIUnderlinedButton : UIButton {
}
+ (UIUnderlinedButton*) underlinedButton;
#end
UIUnderlinedButton.m
#implementation UIUnderlinedButton
+ (UIUnderlinedButton*) underlinedButton {
UIUnderlinedButton* button = [[UIUnderlinedButton alloc] init];
return [button autorelease];
}
- (void) drawRect:(CGRect)rect {
CGRect textRect = self.titleLabel.frame;
// need to put the line at top of descenders (negative value)
CGFloat descender = self.titleLabel.font.descender;
CGContextRef contextRef = UIGraphicsGetCurrentContext();
// set to same colour as text
CGContextSetStrokeColorWithColor(contextRef, self.titleLabel.textColor.CGColor);
CGContextMoveToPoint(contextRef, textRect.origin.x, textRect.origin.y + textRect.size.height + descender);
CGContextAddLineToPoint(contextRef, textRect.origin.x + textRect.size.width, textRect.origin.y + textRect.size.height + descender);
CGContextClosePath(contextRef);
CGContextDrawPath(contextRef, kCGPathStroke);
}
#end

Answer 4

You can do it in the interface builder itself.
Select the attribute inspector
Change the title type from plain to attributed
Set appropriate font size and text alignment
Then select the title text and set the font as underlined

Answer 5

It is very simple with attributed string
Creates a dictionary with set attributes and apply to the attributed string. Then you can set the attributed string as attibutedtitle in uibutton or attributedtext in uilabel.
NSDictionary *attrDict = #{NSFontAttributeName : [UIFont
systemFontOfSize:14.0],NSForegroundColorAttributeName : [UIColor
whiteColor]};
NSMutableAttributedString *title =[[NSMutableAttributedString alloc] initWithString:#"mybutton" attributes: attrDict];
[title addAttribute:NSUnderlineStyleAttributeName value:[NSNumber numberWithInteger:NSUnderlineStyleSingle] range:NSMakeRange(0,[commentString length])]; [btnRegLater setAttributedTitle:title forState:UIControlStateNormal];

Answer 6

Here is my function, works in Swift 1.2.
func underlineButton(button : UIButton, text: String) {
var titleString : NSMutableAttributedString = NSMutableAttributedString(string: text)
titleString.addAttribute(NSUnderlineStyleAttributeName, value: NSUnderlineStyle.StyleSingle.rawValue, range: NSMakeRange(0, count(text.utf8)))
button.setAttributedTitle(titleString, forState: .Normal)
}
UPDATE Swift 3.0 extension:
extension UIButton {
func underlineButton(text: String) {
let titleString = NSMutableAttributedString(string: text)
titleString.addAttribute(NSUnderlineStyleAttributeName, value: NSUnderlineStyle.styleSingle.rawValue, range: NSMakeRange(0, text.characters.count))
self.setAttributedTitle(titleString, for: .normal)
}
}

Answer 7

The Swift 5.0 version that works as of September 2019 in Xcode 10.3:
extension UIButton {
func underlineText() {
guard let title = title(for: .normal) else { return }
let titleString = NSMutableAttributedString(string: title)
titleString.addAttribute(
.underlineStyle,
value: NSUnderlineStyle.single.rawValue,
range: NSRange(location: 0, length: title.count)
)
setAttributedTitle(titleString, for: .normal)
}
}
To use it, set your button title first with button.setTitle("Button Title", for: .normal) and then call button.underlineText() to make that title underlined.

Answer 8

Nick's answer is a great, quick way to do this.
I added support in drawRect for shadows.
Nick's answer doesn't take into account if your button title has a shadow below the text:
But you can move the underline down by the height of the shadow like so:
CGFloat descender = self.titleLabel.font.descender;
CGContextRef contextRef = UIGraphicsGetCurrentContext();
CGFloat shadowHeight = self.titleLabel.shadowOffset.height;
descender += shadowHeight;
Then you'll get something like this:

Answer 9

For Swift 3 the following extension can be used:
extension UIButton {
func underlineButton(text: String) {
let titleString = NSMutableAttributedString(string: text)
titleString.addAttribute(NSUnderlineStyleAttributeName, value: NSUnderlineStyle.styleSingle.rawValue, range: NSMakeRange(0, text.characters.count))
self.setAttributedTitle(titleString, for: .normal)
}
}

Answer 10

// Only override drawRect: if you perform custom drawing.
// An empty implementation adversely affects performance during animation.
- (void)drawRect:(CGRect)rect {
CGRect textRect = self.titleLabel.frame;
// need to put the line at top of descenders (negative value)
CGFloat descender = self.titleLabel.font.descender;
CGContextRef contextRef = UIGraphicsGetCurrentContext();
UIColor *colr;
// set to same colour as text
if (self.isHighlighted || self.isSelected) {
colr=self.titleLabel.highlightedTextColor;
}
else{
colr= self.titleLabel.textColor;
}
CGContextSetStrokeColorWithColor(contextRef, colr.CGColor);
CGContextMoveToPoint(contextRef, textRect.origin.x, textRect.origin.y + textRect.size.height + descender);
CGContextAddLineToPoint(contextRef, textRect.origin.x + textRect.size.width, textRect.origin.y + textRect.size.height + descender);
CGContextClosePath(contextRef);
CGContextDrawPath(contextRef, kCGPathStroke);
}
//Override this to change the underline color to highlighted color
-(void)setHighlighted:(BOOL)highlighted
{
[super setHighlighted:highlighted];
// [self setNeedsDisplay];
}

Answer 11

Expanding on the answer by #Nick H247, I experienced an issue where firstly the underline was not redrawing when the button resized on rotation; this can be solved by setting your button to redraw like so:
myButton.contentMode = UIViewContentModeRedraw;
This forces the button to redraw when the bounds change.
Secondly, the original code assumed you only had 1 line of text in the button (my button wraps to 2 lines on rotation) and the underline only appears on the last line of text. The drawRect code can be modified to first calculate the number of lines in the button, then put an underline on every line rather than just the bottom, like so:
- (void) drawRect:(CGRect)rect {
CGRect textRect = self.titleLabel.frame;
// need to put the line at top of descenders (negative value)
CGFloat descender = self.titleLabel.font.descender;
CGContextRef contextRef = UIGraphicsGetCurrentContext();
// set to same colour as text
CGContextSetStrokeColorWithColor(contextRef, self.titleLabel.textColor.CGColor);
CGSize labelSize = [self.titleLabel.text sizeWithFont:self.titleLabel.font
constrainedToSize:self.titleLabel.frame.size
lineBreakMode:UILineBreakModeWordWrap];
CGSize labelSizeNoWrap = [self.titleLabel.text sizeWithFont:self.titleLabel.font forWidth:self.titleLabel.frame.size.width lineBreakMode:UILineBreakModeMiddleTruncation ];
int numberOfLines = abs(labelSize.height/labelSizeNoWrap.height);
for(int i = 1; i<=numberOfLines;i++) {
// Original code
// CGContextMoveToPoint(contextRef, textRect.origin.x, textRect.origin.y + textRect.size.height + descender + PADDING);
//
// CGContextAddLineToPoint(contextRef, textRect.origin.x + textRect.size.width, textRect.origin.y + textRect.size.height + descender);
CGContextMoveToPoint(contextRef, textRect.origin.x, textRect.origin.y + (labelSizeNoWrap.height*i) + descender + PADDING);
CGContextAddLineToPoint(contextRef, textRect.origin.x + textRect.size.width, textRect.origin.y + (labelSizeNoWrap.height*i) + descender);
CGContextClosePath(contextRef);
CGContextDrawPath(contextRef, kCGPathStroke);
}
}
Hope this code helps someone else!

Answer 12

In swift
func underlineButton(button : UIButton) {
var titleString : NSMutableAttributedString = NSMutableAttributedString(string: button.titleLabel!.text!)
titleString.addAttribute(NSUnderlineStyleAttributeName, value: NSUnderlineStyle.StyleSingle.rawValue, range: NSMakeRange(0, button.titleLabel!.text!.utf16Count))
button.setAttributedTitle(titleString, forState: .Normal)}

Answer 13

You can use this code to add underline with spacing in button.
When I tried to draw an underline from interface builder. It look like below image.
1 - Interface builder reference
And after using below code I achieved the result as I wanted.
2 - using described code
public func setTextUnderline()
{
let dummyButton: UIButton = UIButton.init()
dummyButton.setTitle(self.titleLabel?.text, for: .normal)
dummyButton.titleLabel?.font = self.titleLabel?.font
dummyButton.sizeToFit()
let dummyHeight = dummyButton.frame.size.height + 3
let bottomLine = CALayer()
bottomLine.frame = CGRect.init(x: (self.frame.size.width - dummyButton.frame.size.width)/2, y: -(self.frame.size.height - dummyHeight), width: dummyButton.frame.size.width, height: 1.0)
bottomLine.backgroundColor = self.titleLabel?.textColor.cgColor
self.layer.addSublayer(bottomLine)
}

Answer 14

How will one handle the case when we keep a button underlined pressed? In that case the button's textcolor changes according to highlighted color but line remains of original color. Let say if button text color in normal state is black then its underline will also have black color. The button's highlighted color is white. Keeping button pressed changes button text color from black to white but underline color remains black.

Answer 15

I believe it's some bug in font editor in XCode. If you using interface builder you have to change title from Plain to Attributed, open TextEdit create underlined text and copy-paste to textbox in XCode

Answer 16

Nick H247's answer but Swift approach:
import UIKit
class UnderlineUIButton: UIButton {
override func drawRect(rect: CGRect) {
super.drawRect(rect)
let textRect = self.titleLabel!.frame
var descender = self.titleLabel?.font.descender
var contextRef: CGContextRef = UIGraphicsGetCurrentContext();
CGContextSetStrokeColorWithColor(contextRef, self.titleLabel?.textColor.CGColor);
CGContextMoveToPoint(contextRef, textRect.origin.x, textRect.origin.y + textRect.size.height + descender!);
CGContextAddLineToPoint(contextRef, textRect.origin.x + textRect.size.width, textRect.origin.y + textRect.size.height + descender!);
CGContextClosePath(contextRef);
CGContextDrawPath(contextRef, kCGPathStroke);
}
}

Answer 17

func underline(text: String, state: UIControlState = .normal, color:UIColor? = nil) {
var titleString = NSMutableAttributedString(string: text)
if let color = color {
titleString = NSMutableAttributedString(string: text,
attributes: [NSForegroundColorAttributeName: color])
}
let stringRange = NSMakeRange(0, text.characters.count)
titleString.addAttribute(NSUnderlineStyleAttributeName,
value: NSUnderlineStyle.styleSingle.rawValue,
range: stringRange)
self.setAttributedTitle(titleString, for: state)
}

Answer 18

Swift 3 version for #NickH247's answer with custom underline color, linewidth and gap:
import Foundation
class UnderlinedButton: UIButton {
private let underlineColor: UIColor
private let thickness: CGFloat
private let gap: CGFloat
init(underlineColor: UIColor, thickness: CGFloat, gap: CGFloat, frame: CGRect? = nil) {
self.underlineColor = underlineColor
self.thickness = thickness
self.gap = gap
super.init(frame: frame ?? .zero)
}
override func draw(_ rect: CGRect) {
super.draw(rect)
guard let textRect = titleLabel?.frame,
let decender = titleLabel?.font.descender,
let context = UIGraphicsGetCurrentContext() else { return }
context.setStrokeColor(underlineColor.cgColor)
context.move(to: CGPoint(x: textRect.origin.x, y: textRect.origin.y + textRect.height + decender + gap))
context.setLineWidth(thickness)
context.addLine(to: CGPoint(x: textRect.origin.x + textRect.width, y: textRect.origin.y + textRect.height + decender + gap))
context.closePath()
context.drawPath(using: .stroke)
}
required init?(coder aDecoder: NSCoder) {
fatalError("init(coder:) has not been implemented")
}
}