software-mariodiana
1/25/2017 - 10:09 PM

Subclass a UITextField to create a border only on the bottom. Note: Both the header (*.h) and the implementation (*.m) files are combined he

Subclass a UITextField to create a border only on the bottom. Note: Both the header (.h) and the implementation (.m) files are combined here, just to make this example a single file. Adapted from: http://stackoverflow.com/a/29428428/155167.

BottomBorderTextField.m
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// Makes sense to break this out into its own header file.
#import <UIKit/UIKit.h>

@interface BottomBorderTextField : UITextField
@end


// Here would begin the implementation file.

//#import "BottomBorderTextField.h"

@interface BottomBorderTextField ()
@property (weak, nonatomic) CALayer* bottomBorder;
@end

@implementation BottomBorderTextField

- (id)initWithFrame:(CGRect)frame
{
    self = [super initWithFrame:frame];
    
    if (self)
    {
        _bottomBorder = [self initializeBottomBorder];
    }
    
    return self;
}


- (id)initWithCoder:(NSCoder *)aDecoder
{
    self = [super initWithCoder:aDecoder];
    
    if (self)
    {
        _bottomBorder = [self initializeBottomBorder];
    }
    
    return self;
}


- (CALayer *)initializeBottomBorder
{
    CALayer* border = [CALayer layer];
    
    CGFloat borderWidth = 0.5;
    border.borderColor = [UIColor lightGrayColor].CGColor;
    border.borderWidth = borderWidth;
    
    [[self layer] addSublayer:border];
    [[self layer] setMasksToBounds:YES];
    
    return border;
}


- (void)layoutSubviews
{
    [super layoutSubviews];
    
    self.bottomBorder.frame = CGRectMake(0,
                              self.frame.size.height - self.bottomBorder.borderWidth,
                              self.frame.size.width,
                              self.frame.size.height);
}

@end