Extend UITabBarController to achieve circular scrolling and sliding effect

Extend UITabBarController to achieve circular sliding effect

//Add gestures on
TabBar-(void)setOpenGestury
{
    //If the gestures on the tabbar are empty, create
    if ([self.view.gestureRecognizers count] == ​​0)
    {
        //Add left and right sliding gesture
        UISwipeGestureRecognizer* recognizer = nil;
        recognizer = [[UISwipeGestureRecognizer alloc] initWithTarget:selfaction:@selector(selectNextPage:)];
        [recognizer setDirection:(UISwipeGestureRecognizerDirectionLeft)];
        [self.view addGestureRecognizer:recognizer];
        [recognizer release];
       
        recognizer = [[UISwipeGestureRecognizer alloc] initWithTarget:selfaction:@selector(selectNextPage:)];
        [recognizer setDirection:(UISwipeGestureRecognizerDirectionRight)];
        [self.view addGestureRecognizer:recognizer];
        [recognizer release];
    }
   
}
//手势触发
-(void)selectNextPage:(UISwipeGestureRecognizer*)recognizer
{
    UIViewController* curViewC = self.selectedViewController;
    if ([curViewC isKindOfClass:[UINavigationController class]])
    {
        int subCount = [((UINavigationController*)curViewC).viewControllers count];
        if (subCount > 1)
        {
            //pop
            if (recognizer.direction==UISwipeGestureRecognizerDirectionRight)
            {
                [((UINavigationController*)curViewC) popViewControllerAnimated:YES];
            }
           
            return;
        }
    }
    NSArray* ary = self.viewControllers;
    if (recognizer.direction==UISwipeGestureRecognizerDirectionLeft)
    {
       
        for (int iIndex = 1 ;iIndex < ary.count ;iIndex++)
        {
            int nextIndex = (self.selectedIndex + iIndex)%ary.count;
           
            UIViewController* c = [ary objectAtIndex:nextIndex];
            BOOL couldClick = YES;
            if([self.delegaterespondsToSelector:@selector(tabBarController:shouldSelectViewController:)])
            {
                couldClick = [self.delegate tabBarController:self shouldSelectViewController:c];
            }
           
            if (!couldClick)
            {
                continue;
            }
            else
            {
               
                [self achieveAnimation:self.selectedIndex toIndex:nextIndexrecognizerDirection:UISwipeGestureRecognizerDirectionLeft];
                self.selectedIndex = nextIndex;
                break;
            }
           
        }
       
       
    }
    else if(recognizer.direction == UISwipeGestureRecognizerDirectionRight)
    {
       
        for (int searchCount = 1; searchCount < ary.count; searchCount++)
        {
           int nextIndex = (self.selectedIndex - searchCount + ary.count)%ary.count;           
            UIViewController* c = [ary objectAtIndex:nextIndex];
            BOOL couldClick = YES;
            if([self.delegaterespondsToSelector:@selector(tabBarController:shouldSelectViewController:)])
            {
                couldClick = [self.delegate tabBarController:self shouldSelectViewController:c];
            }
            if (!couldClick)
            {
                continue;
            }
            else
            {
                [self achieveAnimation:self.selectedIndex toIndex:nextIndexrecognizerDirection:UISwipeGestureRecognizerDirectionRight];
                self.selectedIndex = nextIndex;
               
                break;
            }
        }
              
    }
   
}


//截图方法，图片用来做动画
-(UIImage*)imageByCropping:(UIView*)imageToCrop toRect:(CGRect)rect
{
    CGFloat scale = [[UIScreen mainScreen] scale];
    CGSize pageSize = CGSizeMake(scale*rect.size.width, scale*rect.size.height) ;
    UIGraphicsBeginImageContext(pageSize);
    CGContextScaleCTM(UIGraphicsGetCurrentContext(), scale, scale);
   
    CGContextRef resizedContext =UIGraphicsGetCurrentContext();
    CGContextTranslateCTM(resizedContext,-1*rect.origin.x,-1*rect.origin.y);
    [imageToCrop.layer renderInContext:resizedContext];
    UIImage*imageOriginBackground =UIGraphicsGetImageFromCurrentImageContext();
    UIGraphicsEndImageContext();
    imageOriginBackground = [UIImage imageWithCGImage:imageOriginBackground.CGImage scale:scaleorientation:UIImageOrientationUp];
   
    return imageOriginBackground;
}
//实现动画效果
-(void)achieveAnimation:(int)originIndex toIndex:(int)toIndex recognizerDirection:(UISwipeGestureRecognizerDirection)direction
{
    if (originIndex < 0 || originIndex >= self.viewControllers.count)
    {
        EZGAssert(0);
        return;
    }
    if (toIndex < 0 || toIndex >= self.viewControllers.count)
    {
        EZGAssert(0);
        return;
    }
   
   
    UIViewController* v1 = [self.viewControllers objectAtIndex:originIndex];
    UIViewController* v2 = [self.viewControllers objectAtIndex:toIndex];
   
    UIImage* image1 = [self imageByCropping:v1.view toRect:v1.view.bounds];
    UIImage* image2 = [self imageByCropping:v2.view toRect:v1.view.bounds];
   
    if (image1 == nil || image2 == nil)
    {
        EZGAssert(0);
        return;
    }
   
    UIImageView* imageview1 = [[UIImageView alloc] initWithImage:image1];
    UIImageView* imageview2 = [[UIImageView alloc] initWithImage:image2];
   
    UIWindow* window = [UIApplication sharedApplication].keyWindow;
   
    CGRect rectV1 = [v1.view convertRect:v1.view.bounds toView:window];
    //    CGRect rectV2 = [v2.view convertRect:v1.view.bounds toView:window];
   
    //set possion
    imageview1.frame = rectV1;
    imageview2.frame = rectV1;
   
    [window addSubview:imageview1];
    [window addSubview:imageview2];
   
    window.userInteractionEnabled = NO;
   
    float screenWidth = [UIScreen mainScreen].bounds.size.width;
    if (direction == UISwipeGestureRecognizerDirectionLeft)
    {
        //to left
        imageview2.center = CGPointMake(imageview1.center.x + screenWidth, imageview1.center.y);
    }
    else
    {
        //to right
        imageview2.center = CGPointMake(imageview1.center.x - screenWidth, imageview1.center.y);
    }
   
    [UIView animateWithDuration:0.3 animations:^{
        if (direction == UISwipeGestureRecognizerDirectionLeft)
        {
            //to left
            imageview1.center = CGPointMake(imageview1.center.x - screenWidth, imageview1.center.y);
            imageview2.center = CGPointMake(imageview2.center.x - screenWidth, imageview1.center.y);
        }
        else
        {
            //to right
            imageview1.center = CGPointMake(imageview1.center.x + screenWidth, imageview1.center.y);
            imageview2.center = CGPointMake(imageview2.center.x + screenWidth, imageview1.center.y);
        }
       
       
    } completion:^(BOOL finished)
     {
         [imageview1 removeFromSuperview];
         [imageview2 removeFromSuperview];
         window.userInteractionEnabled = YES;
     }];
   
   
}