/*

 Copyright (C) 2015 Apple Inc. All Rights Reserved.

 See LICENSE.txt for this sample’s licensing information

 Abstract:

 Subclass of UINavigationBar that displays a button above the

  navigation bar's contents.

 */

#import "CustomNavigationBar.h"

@implementation CustomNavigationBar

//| ----------------------------------------------------------------------------

//  A navigation bar subclass should override -sizeThatFits: to pad the fitting

//  height for the navigation bar, creating space for the extra elements that

//  will be added.  UINavigationController calls this method to retrieve the

//  size of the navigation bar, which it then uses when computing the bar's

//  frame.

//

- (CGSize)sizeThatFits:(CGSize)size

{

    CGSize navigationBarSize = [super sizeThatFits:size];

    // Pad the base navigation bar height by the fitting height of our button.

    CGSize buttonSize = [self.customButton sizeThatFits:CGSizeMake(size.width, 0)];

    navigationBarSize.height += buttonSize.height;

    return navigationBarSize;

}

//| ----------------------------------------------------------------------------

- (void)layoutSubviews

{

    // UINavigationBar positions its elements along the bottom edge of the

    // bar's bounds.  This allows our subclass to position our custom elements

    // at the top of the navigation bar, in the extra space we created by

    // padding the height returned from -sizeThatFits:

    [super layoutSubviews];

    // NOTE: You do not need to account for the status bar height in your

    //       layout.  The navigation bar is positioned just below the

    //       status bar by the navigation controller.

    // Retrieve the button's fitting height and position the button along the

    // top edge of the navigation bar.  The button is sized to the full

    // width of the navigation bar as it will automatically center its contents.

    CGSize buttonSize = [self.customButton sizeThatFits:CGSizeMake(self.bounds.size.width, 0)];

    self.customButton.frame = CGRectMake(0, 0, self.bounds.size.width, buttonSize.height);

}

//| ----------------------------------------------------------------------------

//  Custom implementation of the setter for the customButton property.

//

- (void)setCustomButton:(UIButton *)customButton

{

    // Remove the previous button

    [_customButton removeFromSuperview];

    _customButton = customButton;

    [self addSubview:customButton];

    // Force our -sizeThatFits: method to be called again and flag the

    // navigation bar as needing layout.

    [self invalidateIntrinsicContentSize];

    [self setNeedsLayout];

}

@end