!UITableView+Header

UITableView convenience classes for resizing header and footer with autolayout.

LICENSE

The MIT License (MIT)

Copyright (c) 2014, Alessio Anesa

Permission is hereby granted, free of charge, to any person obtaining a copy
of this software and associated documentation files (the "Software"), to deal
in the Software without restriction, including without limitation the rights
to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
copies of the Software, and to permit persons to whom the Software is
furnished to do so, subject to the following conditions:

The above copyright notice and this permission notice shall be included in all
copies or substantial portions of the Software.

THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
SOFTWARE.

UITableView+Header.podspec

Pod::Spec.new do |s|

  s.name         = "UITableView+Header"
  s.version      = "0.0.2"
  s.summary      = "UITableView convenience classes for resizing header and footer with autolayout."

  s.description  = <<-DESC
			
                   DESC

  s.homepage     = "https://gist.github.com/andreacremaschi/833829c80367d751cb83"
  
  # s.license      = "MIT"
  s.license      = { :type => "MIT", :file => "LICENSE" }
  
  s.author             = { "Andrea Cremaschi" => "andrea.cremaschi@midainformatica.it" }
  s.platform     = :ios, "6.0"
  s.source       = { :git => "https://gist.github.com/833829c80367d751cb83.git", :tag => "0.0.1" }

  s.source_files  = "*.{h,m}"
  s.exclude_files = "Classes/Exclude"

  s.public_header_files = "*.h"

  s.requires_arc = true

end

UITableView+HeaderView.h

#import <UIKit/UIKit.h>

@interface UITableView (HeaderView)

- (void) sizeHeaderToFit;
- (void) sizeFooterToFit;

@end

@interface UIView (FittingSize)

- (BOOL)sizeToFitVertically;

@end

UITableView+HeaderView.m

#import "UITableView+HeaderView.h"

static NSString *ConstraintIdentifier = @"WidthConstraintIdentifier";

@implementation UITableView (HeaderView)

- (void) sizeHeaderToFit
{
    UIView *headerView = self.tableHeaderView;
    
    [self updateWidthConstraintForView:headerView];
    if ([headerView sizeToFitVertically])
        self.tableHeaderView = headerView;
}

- (void) sizeFooterToFit
{
    UIView *footerView = self.tableFooterView;
    
    [self updateWidthConstraintForView:footerView];
    if ([footerView sizeToFitVertically])
        self.tableFooterView = footerView;
}

- (void)updateWidthConstraintForView:(UIView *)view
{
    NSLayoutConstraint *constraint;
    for (constraint in view.constraints)
    {
        if (constraint.identifier && [constraint.identifier isEqualToString:ConstraintIdentifier])
        {
            break;
        }
        else
            constraint = nil;
    }
    
    if (!constraint)
    {
        constraint = [NSLayoutConstraint constraintWithItem:view
                                                  attribute:NSLayoutAttributeWidth
                                                  relatedBy:NSLayoutRelationEqual
                                                     toItem:nil
                                                  attribute:NSLayoutAttributeNotAnAttribute
                                                 multiplier:1.0
                                                   constant:self.bounds.size.width];
        constraint.identifier = ConstraintIdentifier;
        [view addConstraint:constraint];
    }
    else
    {
        constraint.constant = self.bounds.size.width;
    }
}

@end

@implementation UIView (FittingSize)

- (BOOL)sizeToFitVertically
{
    CGSize size = [self systemLayoutSizeFittingSize:UILayoutFittingCompressedSize];
    
    if (CGSizeEqualToSize(self.frame.size, size))
        return NO;
    
    self.frame = ({
        CGRect headerFrame = self.frame;
        headerFrame.size = size;
        headerFrame;
    });
    return YES;
}

@end