iOS 如何拿到相册中的视频文件

通过ALAsset的方式，无法获取系统相册中文件的具体路径，一般采取的方式是通过ALAssetRepresentation直接获取视频数据，如果还需要一个fileURL的话，可以将视频数据写入自定义fileURL的文件中，示例代码如下：

-(void)assetPickerController:(ZYQAssetPickerController )picker didFinishPickingAssets:(NSArray )assets{

    //TODO:
    for (ALAsset *asset in assets) {
        NSLog(@"HERE\n asset.defaultRepresentation.url = %@\n asset.defaultRepresentation.filename = %@",asset.defaultRepresentation.url, asset.defaultRepresentation.filename);
    
        [self saveVideoToApp:nil asset:asset];
        // 我想在这里拿到视频文件
        
        ALAssetRepresentation *representation = asset.defaultRepresentation;
        if ([mediaType isEqualToString:ALAssetTypeVideo]) {
            long long size = representation.size;
            NSMutableData* data = [[NSMutableData alloc] initWithCapacity:size];
            void* buffer = [data mutableBytes];
            [representation getBytes:buffer fromOffset:0 length:size error:nil];
            NSData *fileData = [[NSData alloc] initWithBytes:buffer length:size];
            
            //File URL
            NSString *savePath = [NSString stringWithFormat:@"%@%@", [NSHomeDirectory() stringByAppendingString:@"/tmp/"], representation.filename];
            [[NSFileManager defaultManager] removeItemAtPath:savePath error:nil];
        dispatch_async(dispatch_get_global_queue(DISPATCH_QUEUE_PRIORITY_DEFAULT, 0), ^(void)   {
        [fileData writeToFile:savePath atomically:NO];
        
        });

        }
    }
}