iOS 显示与隐藏TabBar

3种方法
第一种

#pragma mark -隐藏TabBar
- (void)hideTabBar {
    if (self.tabBarController.tabBar.hidden == YES) {
        return;
    }
    UIView *contentView;
    if ( [[self.tabBarController.view.subviews objectAtIndex:0] isKindOfClass:[UITabBar class]] )
        contentView = [self.tabBarController.view.subviews objectAtIndex:1];
    else
        contentView = [self.tabBarController.view.subviews objectAtIndex:0];
    contentView.frame = CGRectMake(contentView.bounds.origin.x,  contentView.bounds.origin.y,  contentView.bounds.size.width, contentView.bounds.size.height + self.tabBarController.tabBar.frame.size.height);
    self.tabBarController.tabBar.hidden = YES;
    
}

#pragma mark -显示TabBar
- (void)showTabBar {
    if (self.tabBarController.tabBar.hidden == NO)
    {
        return;
    }
    UIView *contentView;
    if ([[self.tabBarController.view.subviews objectAtIndex:0] isKindOfClass:[UITabBar class]])
        contentView = [self.tabBarController.view.subviews objectAtIndex:1];
    
    else
        
        contentView = [self.tabBarController.view.subviews objectAtIndex:0];
    contentView.frame = CGRectMake(contentView.bounds.origin.x, contentView.bounds.origin.y,  contentView.bounds.size.width, contentView.bounds.size.height - self.tabBarController.tabBar.frame.size.height);
    self.tabBarController.tabBar.hidden = NO;
    
}

第二种

//隐藏
self.hidesBottomBarWhenPushed = YES;
//显示
self.hidesBottomBarWhenPushed = NO;

第三种

vc.hidesBottomBarWhenPushed = YES;
[self.navigationController pushViewController:vc animated:YES];