iOS 6+ Method for Hiding the Tab Bar

UITabBarController+HideTabBar.h

//
//  UITabBarController+HideTabBar.h
//
//  Created by Joshua Greene on 9/26/13.
//
// 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.

@interface UITabBarController (Additions)
- (void)setTabBarHidden:(BOOL)hidden;
- (void)setTabBarHidden:(BOOL)hidden animated:(BOOL)animated;
@end

UITabBarController+HideTabBar.m

//
//  UITabBarController+HideTabBar.m
//
//  Created by Joshua Greene on 9/26/13.
//
// 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.

#import "UITabBarController+HideTabBar.h"

@implementation UITabBarController (HideTabBar)

- (void)setTabBarHidden:(BOOL)hidden
{
    [self setTabBarHidden:hidden animated:YES];
}

- (void)setTabBarHidden:(BOOL)hidden animated:(BOOL)animated
{
    if (self.tabBar.hidden == hidden)
        return;
    
    CGSize screenSize = [[UIScreen mainScreen] bounds].size;
    BOOL isLandscape = UIDeviceOrientationIsLandscape([UIApplication sharedApplication].statusBarOrientation);
    float height =  isLandscape ? screenSize.width : screenSize.height;
    
    if (!hidden)
        height -= CGRectGetHeight(self.tabBar.frame);
    
    void (^animations)();
    
    // Check if running iOS 7
        if ([self.tabBar respondsToSelector:@selector(barTintColor)])
    {
        UIView *view = self.selectedViewController.view;
        
        animations = ^{
          
            CGRect frame = self.tabBar.frame;
            frame.origin.y = height;
            self.tabBar.frame = frame;
            
            frame = view.frame;
            frame.size.height += (hidden ? 1.0f : -1.0f) * CGRectGetHeight(self.tabBar.frame);
            view.frame = frame;
        };
    }
    else
    {
        animations = ^{
            for (UIView *subview in self.view.subviews)
            {
                CGRect frame = subview.frame;
                
                if (subview == self.tabBar)
                {
                    frame.origin.y = height;
                }
                else
                {
                    frame.size.height = height;
                }
                
                subview.frame = frame;
            }
        };
    }
    
    [UIView animateWithDuration:(animated ? 0.25f : 0) animations:animations completion:^(BOOL finished) {
        self.tabBar.hidden = hidden;
    }];
}

@end

I found a problem with this code where if I hide the tab bar and then send the app to the background, upon reopening it one of the layout containers gets resized to fit a blank tab bar at the bottom of the screen. Then when I show the tab bar again the tab bar slides up but there is a box above it with enough room for another tab bar.

I do have the exact same problem. There is a black box with the same size of the tabbar.

One workaround for this (which a friend found out) is you can set the attribute extendedLayoutIncludesOpaqueBars on the view controller to YES. Either programmatically (e.g. in viewDidLoad) or in interface builder.

Change

if (!hidden)
    height -= CGRectGetHeight(self.tabBar.frame);

To

if (!hidden) {
    height -= CGRectGetHeight(self.tabBar.frame);
    self.tabBar.hidden = NO;
}

You must set self.tabBar's hidden property to NO prior to any animation (therefore left only frame to be animated). Otherwise nothing will be visible during the animation because the tab bar is hidden all the time.

.h is missing @import UIKit;.