Saurabh
我从我的工作代码里黏贴的这个。你可以调用这些方法来隐藏和显现UITabBarController。只要添加Tabbarcontroller实例到这些功能。

// Method call
[self hideTabBar:self.tabBarController];   

// Method implementations
- (void)hideTabBar:(UITabBarController *) tabbarcontroller
{
    [UIView beginAnimations:nil context:NULL];
    [UIView setAnimationDuration:0.5];

    for(UIView *view in tabbarcontroller.view.subviews)
    {
        if([view isKindOfClass:[UITabBar class]])
        {
            [view setFrame:CGRectMake(view.frame.origin.x, 480, view.frame.size.width, view.frame.size.height)];
        } 
        else
        {
            [view setFrame:CGRectMake(view.frame.origin.x, view.frame.origin.y, view.frame.size.width, 480)];
        }
    }

    [UIView commitAnimations];   
}

- (void)showTabBar:(UITabBarController *) tabbarcontroller
{       
    [UIView beginAnimations:nil context:NULL];
    [UIView setAnimationDuration:0.5];
    for(UIView *view in tabbarcontroller.view.subviews)
    {
        NSLog(@"%@", view);

        if([view isKindOfClass:[UITabBar class]])
        {
            [view setFrame:CGRectMake(view.frame.origin.x, 431, view.frame.size.width, view.frame.size.height)];

        } 
        else
        {
            [view setFrame:CGRectMake(view.frame.origin.x, view.frame.origin.y, view.frame.size.width, 431)];
        }
    }

    [UIView commitAnimations]; 
}

karlbecker_com
修改Setomidor的答案使其在两个情况下都能有效，portrait和ipad。320*480的值只能在iPhone上有效。

- (void) hideTabBar:(UITabBarController *) tabbarcontroller 
{
    CGRect screenRect = [[UIScreen mainScreen] bounds];

    [UIView beginAnimations:nil context:NULL];
    [UIView setAnimationDuration:0.5];
    float fHeight = screenRect.size.height;
    if(  UIDeviceOrientationIsLandscape([UIApplication sharedApplication].statusBarOrientation) )
    {
        fHeight = screenRect.size.width;
    }

    for(UIView *view in tabbarcontroller.view.subviews)
    {
        if([view isKindOfClass:[UITabBar class]])
        {
            [view setFrame:CGRectMake(view.frame.origin.x, fHeight, view.frame.size.width, view.frame.size.height)];
        } 
        else
        {
            [view setFrame:CGRectMake(view.frame.origin.x, view.frame.origin.y, view.frame.size.width, fHeight)];
            view.backgroundColor = [UIColor blackColor];
        }
    }
    [UIView commitAnimations];
}



- (void) showTabBar:(UITabBarController *) tabbarcontroller 
{   
    CGRect screenRect = [[UIScreen mainScreen] bounds];
    float fHeight = screenRect.size.height - tabbarcontroller.tabBar.frame.size.height;

    if(  UIDeviceOrientationIsLandscape([UIApplication sharedApplication].statusBarOrientation) )
    {
        fHeight = screenRect.size.width - tabbarcontroller.tabBar.frame.size.height;
    }

    [UIView beginAnimations:nil context:NULL];
    [UIView setAnimationDuration:0.5];
    for(UIView *view in tabbarcontroller.view.subviews)
    {   
        if([view isKindOfClass:[UITabBar class]])
        {
            [view setFrame:CGRectMake(view.frame.origin.x, fHeight, view.frame.size.width, view.frame.size.height)];            
        } 
        else
        {
            [view setFrame:CGRectMake(view.frame.origin.x, view.frame.origin.y, view.frame.size.width, fHeight)];
        }       
    }
    [UIView commitAnimations]; 
}

同时修改代码来处理了iOS 6 UIDevice方向的变化，确保其正常工作。

Setomidor
Saurabh的答案扩展一下就可以在横向也起作用。

+ (void) hideTabBar:(UITabBarController *) tabbarcontroller {

    [UIView beginAnimations:nil context:NULL];
    [UIView setAnimationDuration:0.5];

    //Support for landscape views
    int orientation = [[UIDevice currentDevice] orientation];
    int x_pos = 480;
    if (orientation == UIInterfaceOrientationLandscapeLeft || orientation == UIInterfaceOrientationLandscapeRight) {
        x_pos = 320;
    }

    for(UIView *view in tabbarcontroller.view.subviews)
    {
        if([view isKindOfClass:[UITabBar class]])
        {
            [view setFrame:CGRectMake(view.frame.origin.x, x_pos, view.frame.size.width, view.frame.size.height)];
        } 
        else
        {
            [view setFrame:CGRectMake(view.frame.origin.x, view.frame.origin.y, view.frame.size.width, x_pos)];
        }       
    }   
    [UIView commitAnimations]; 
}

showTabBar()相应的 x_pos 数值是431和271。

Sailesh
按钮的操作方法：

[self.tabBarController.tabBar setHidden:YES];

Thomas Verbeek
Saurahb和karlbecker_com的答案都非常棒, 虽然当视图包含tableview而标签栏动画备份时他们可能导致明显的弹跳效果。我做了一些修改使其结合成一个功能（作为UITabBarController上的一个类别）。这并不完美（延迟修正动画）但是可以给table非常好的效果。
如果你喜欢动画块和类别，可以试试这个，方向和设备友好：

UITabBarController+ShowHideBar.m:
#import "UITabBarController+ShowHideBar.h"

@implementation UITabBarController (ShowHideBar)

- (void) setHidden:(BOOL)hidden{

    CGRect screenRect = [[UIScreen mainScreen] bounds];
    float fHeight = screenRect.size.height;
    if(  UIDeviceOrientationIsLandscape([UIApplication sharedApplication].statusBarOrientation) ){
        fHeight = screenRect.size.width;
    }

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

    [UIView animateWithDuration:0.25 animations:^{
        for(UIView *view in self.view.subviews){
            if([view isKindOfClass:[UITabBar class]]){
                [view setFrame:CGRectMake(view.frame.origin.x, fHeight, view.frame.size.width, view.frame.size.height)];
            }else{
                if(hidden) [view setFrame:CGRectMake(view.frame.origin.x, view.frame.origin.y, view.frame.size.width, fHeight)];
            }
        }
    }completion:^(BOOL finished){
        if(!hidden){

            [UIView animateWithDuration:0.25 animations:^{

                for(UIView *view in self.view.subviews)
                {
                    if(![view isKindOfClass:[UITabBar class]])
                        [view setFrame:CGRectMake(view.frame.origin.x, view.frame.origin.y, view.frame.size.width, fHeight)];
                }

            }];
        }
    }];

}

@end

UITabBarController+ShowHideBar.h:

#import `<UIKit/UIKit.h>`

@interface UITabBarController (ShowHideBar)

- (void) setHidden:(BOOL)hidden;

@end

Usage:

[self.tabBarController setHidden:YES];
[self.tabBarController setHidden:NO];