Animate tabBarController custom

gistfile1.m

    NSInteger controllerIndex = 2;
    UIView *fromView = self.tabBarController.selectedViewController.view;
    UIView *toView = [[self.tabBarController.viewControllers objectAtIndex:controllerIndex] view];
    
    // Get the size of the view area.
    CGRect viewSize = fromView.frame;
    BOOL scrollRight = controllerIndex > self.tabBarController.selectedIndex;
    
    // Add the to view to the tab bar view.
    [fromView.superview addSubview:toView];
    
    // Position it off screen.
    toView.frame = CGRectMake((scrollRight ? 320 : -320), viewSize.origin.y, 320, viewSize.size.height);
    
    [UIView animateWithDuration:0.3
                     animations: ^{
                         
                         // Animate the views on and off the screen. This will appear to slide.
                         fromView.frame =CGRectMake((scrollRight ? -320 : 320), viewSize.origin.y, 320, viewSize.size.height);
                         toView.frame = CGRectMake(0, viewSize.origin.y, 320, viewSize.size.height);
                     }
     
                     completion:^(BOOL finished) {
                         if (finished) {
                             
                             // Remove the old view from the tabbar view.
                             [fromView removeFromSuperview];
                             self.tabBarController.selectedIndex = controllerIndex;
                         }
                     }];