详解iOS如何让Lottie使用网络资源做动画的实现

- (void)animationView:(LOTAnimationView *)animationView fetchResourceWithURL:(NSURL *)url completionHandler:(LOTResourceCompletionHandler)completionHandler {
    [CDNService requestLottieImageWithURL:url completion:^(UIImage * _Nullable image, NSError * _Nullable error) {
        if (completionHandler) {
            completionHandler(image, error);
        }
    }];

}

+ (void)requestLottieModelWithURL:(NSURL *)url completion:(void(^)(LOTComposition * _Nullable sceneModel,  NSError * _Nullable error))completion {
    dispatch_async(dispatch_get_global_queue(DISPATCH_QUEUE_PRIORITY_DEFAULT, 0), ^(void) {
        NSData *animationData = [NSData dataWithContentsOfURL:url];
        if (!animationData) {
            return;
        }
        NSError *error;
        NSDictionary *animationJSON = [NSJSONSerialization JSONObjectWithData:animationData options:0 error:&error];
        if (error || !animationJSON) {
            if (completion) {
                completion(nil, error);
            }
            return;
        }
        LOTComposition *model = [[LOTComposition alloc] initWithJSON:animationJSON withAssetBundle:[NSBundle mainBundle]];
        dispatch_async(dispatch_get_main_queue(), ^(void) {
            [[LOTAnimationCache sharedCache] addAnimation:model forKey:url.absoluteString];
            //注意，这里的baseURL是你的请求path，需要根据你的业务情况自行设置
            model.baseURL = @"https://os.xxx.cn/lottie/animation/";
            model.cacheKey = url.absoluteString;
            if (completion) {
                completion(model, nil);
            }
        });
    });
}

- animation
    - data.json
    - images
        - img_0.png
        - img_1.png

- (LOTAnimationView *)animationView {
    if (!_animationView) {
        //注意，如果想先初始化view再请求资源，不要使用new或者init来初始化
        _animationView = [[LOTAnimationView alloc] initWithFrame:CGRectZero];
        _animationView.animationDelegate = self;
        NSURL *url = [NSURL URLWithString:@"https://os.xxx.cn/lottie/animation/data.json"];
        //请求json配置，生成LOTComposition后传给view
        @weakify(self);
        [CCDNService requestLottieModelWithURL:url completion:^(LOTComposition * _Nullable sceneModel, NSError * _Nullable error) {
            @strongify(self);
            self.animationView.sceneModel = sceneModel;
        }];
    }
    return _animationView;
}