- (void)tabBarController:(UITabBarController *)tabBarController didSelectViewController:(UIViewController *)viewController
{
//    viewController.tabBarItem.gs_imageView.transform = CGAffineTransformMakeScale(0.1,0.1);
//    // 弹簧动画，参数分别为：时长，延时，弹性（越小弹性越大），初始速度
//    [UIView animateWithDuration: 0.7 delay:0.1 usingSpringWithDamping:0.25 initialSpringVelocity:0.3 options:0 animations:^{
//        // 放大
//        viewController.tabBarItem.gs_imageView.transform = CGAffineTransformMakeScale(1,1);
//    } completion:nil];
//    NSString *str = [[NSBundle mainBundle]pathForResource:@"home" ofType:@"gif"];
//
//    NSData *data = [NSData dataWithContentsOfFile:str];
//
//    viewController.tabBarItem.gs_imageView.image =  [UIImage sd_animatedGIFWithData:data];//[UIImage sd_animatedGIFWithData:data];
    NSString *gifName = @"";
    if (self.selectedIndex == 0) {
        gifName = @"home";
    }
    else if (self.selectedIndex == 1) {
        gifName = @"epluse";
    }
    else if (self.selectedIndex == 4) {
        gifName = @"Mine";
    }
    if (gifName.length>0) {
        VDGifPlayerTool *addGif =  [[VDGifPlayerTool alloc]init];
        [addGif startAnimateGifMethod:gifName toView:viewController.tabBarItem.gs_imageView];

    }
   
}

其中gs_imageView是为了使中间的tabbar凸出的修改图片位置的其他文件

#import "UITabBarItem+XKTabBarItem.h"
#import "UIBarItem+XKBarItem.h"

@implementation UITabBarItem (XKTabBarItem)

- (UIImageView *)gs_imageView {
    return [self.class gs_imageViewInTabBarButton:self.gs_view];
}

+ (UIImageView *)gs_imageViewInTabBarButton:(UIView *)tabBarButton {
    
    if (!tabBarButton) {
        return nil;
    }
    
    for (UIView *subview in tabBarButton.subviews) {
        // iOS10及以后，imageView都是用UITabBarSwappableImageView实现的，所以遇到这个class就直接拿
        if ([NSStringFromClass([subview class]) isEqualToString:@"UITabBarSwappableImageView"]) {
            return (UIImageView *)subview;
        }
        
//        if (IOS_VERSION < 10) {
//            // iOS10以前，选中的item的高亮是用UITabBarSelectionIndicatorView实现的，所以要屏蔽掉
//            if ([subview isKindOfClass:[UIImageView class]] && ![NSStringFromClass([subview class]) isEqualToString:@"UITabBarSelectionIndicatorView"]) {
//                return (UIImageView *)subview;
//            }
//        }
    }
    return nil;
}

//gif名字  加载在tabbaritem上
-(void)startAnimateGifMethod:(NSString *)name toView:(UIImageView *)imgView{
     NSDictionary *gifLoopCount = [NSDictionary dictionaryWithObject:[NSNumber numberWithInt:0] forKey:(NSString *)kCGImagePropertyGIFLoopCount];
      NSDictionary *gifCountDic = [NSDictionary dictionaryWithObject:gifLoopCount forKey:(NSString *)kCGImagePropertyGIFDictionary];
     NSData *gifData = [NSData dataWithContentsOfFile: [[NSBundle mainBundle] pathForResource:name ofType:@"gif"]];
     CGImageSourceRef imageSource = CGImageSourceCreateWithData((CFDataRef)gifData, (CFDictionaryRef)gifCountDic);
     size_t count = CGImageSourceGetCount(imageSource);
    NSTimeInterval duration = 0;
    NSMutableArray *imageArr = [NSMutableArray arrayWithCapacity:0];
    for (int i = 0; i<count; i++) {
        CGImageRef cgImage = CGImageSourceCreateImageAtIndex(imageSource, i, (CFDictionaryRef)gifCountDic);
        NSTimeInterval frameDuration = [self gifImageDeleyTime:imageSource index:i];
        duration += frameDuration;
            // 3.2.获取时长
//        guard let properties = CGImageSourceCopyPropertiesAtIndex(imageSource, i, nil) , let gifInfo = (properties as NSDictionary)[kCGImagePropertyGIFDictionary as String] as? NSDictionary,
//        (gifInfo[kCGImagePropertyGIFDelayTime as String] as? NSNumber) else { continue }
        UIImage *imageName =  [UIImage imageWithCGImage:cgImage];
        [imageArr addObject:imageName];
        if (i == count-1) {
//            imgView.image = imageName;这句话会使得tabbar点击加载GIF完后，点击其他项之前项变成灰色正方框的bug。（原因大概是tabbar上的图片本质上不是一个图片，而是一个形状图片。系统对我们使用的图片也只是把其中的形状“扣”出来，其余的背景什么的都不要。因为我们可能给背景加了颜色，所以系统扣的时候只是把背景扣出来了，只看到一个方块，而且还是系统处理过成灰色。
）
          
        }
        CGImageRelease(cgImage);
    }
    imgView.animationImages = imageArr;
    imgView.animationDuration = duration;
    imgView.animationRepeatCount = 1;
    [imgView startAnimating];
}
    //获取GIF图片每帧的时长
- (NSTimeInterval)gifImageDeleyTime:(CGImageSourceRef)imageSource index:(NSInteger)index {
    NSTimeInterval duration = 0;
    CFDictionaryRef imageProperties = CGImageSourceCopyPropertiesAtIndex(imageSource, index, NULL);
    if (imageProperties) {
        CFDictionaryRef gifProperties;
        BOOL result = CFDictionaryGetValueIfPresent(imageProperties, kCGImagePropertyGIFDictionary, (const void **)&gifProperties);
        if (result) {
            const void *durationValue;
            if (CFDictionaryGetValueIfPresent(gifProperties, kCGImagePropertyGIFUnclampedDelayTime, &durationValue)) {
                duration = [(__bridge NSNumber *)durationValue doubleValue];
                if (duration < 0) {
                    if (CFDictionaryGetValueIfPresent(gifProperties, kCGImagePropertyGIFDelayTime, &durationValue)) {
                        duration = [(__bridge NSNumber *)durationValue doubleValue];
                    }
                }
            }
        }
    }
    
    return duration;
}