//控件 属性
@property (nonatomic, strong) UIButton *cancelBtn;
@property (nonatomic, strong) UIButton *sendBtn;
@property (nonatomic, strong) CircleProgressView *progressView;
@property (nonatomic, strong) VedioDetailModel *model;
@property(nonatomic,strong)NSURLSessionDownloadTask *downloadTask;

/** 下载视频 */

• (void)startDownLoadVedioWithModel:(VedioDetailModel *)model {
  _model = model;
  NSURLSessionConfiguration *config = [NSURLSessionConfiguration defaultSessionConfiguration];
  NSURLSession *session = [NSURLSession sessionWithConfiguration:config delegate:self delegateQueue:[NSOperationQueue mainQueue]];

  self.downloadTask = [session downloadTaskWithURL:[NSURL URLWithString:model.vedioUrl]];
  [self.downloadTask resume];
  }

pragma mark NSSessionUrlDelegate

• (void)URLSession:(NSURLSession *)session downloadTask:(NSURLSessionDownloadTask *)downloadTask
  didWriteData:(int64_t)bytesWritten
  totalBytesWritten:(int64_t)totalBytesWritten
  totalBytesExpectedToWrite:(int64_t)totalBytesExpectedToWrite
  {
  //下载进度
  CGFloat progress = totalBytesWritten / (double)totalBytesExpectedToWrite;
  dispatch_async(dispatch_get_main_queue(), ^{
  //进行UI操作 设置进度条
  [self.progressView roundProgressView:progress];
  });
  }
  //下载完成 保存到本地相册

• (void)URLSession:(NSURLSession *)session downloadTask:(NSURLSessionDownloadTask *)downloadTask
  didFinishDownloadingToURL:(NSURL *)location
  {
  //1.拿到cache文件夹的路径
  NSString *cache=[NSSearchPathForDirectoriesInDomains(NSCachesDirectory, NSUserDomainMask, YES)lastObject];
  //2,拿到cache文件夹和文件名
  NSString *file=[cache stringByAppendingPathComponent:downloadTask.response.suggestedFilename];

  [[NSFileManager defaultManager] moveItemAtURL:location toURL:[NSURL fileURLWithPath:file] error:nil];
  //3，保存视频到相册
  if (UIVideoAtPathIsCompatibleWithSavedPhotosAlbum(file)) {
  //保存相册核心代码
  UISaveVideoAtPathToSavedPhotosAlbum(file, self, nil, nil);
  }
  }

//控件本身的代理方法 更新控件样子

• (void)progressOverAndChangeViewContents {
  MyLog(@"下载完成");
  self.sendBtn.enabled = YES;

  self.titleBtn.enabled = NO;
  [self.titleBtn setTitle:@"视频已下载到本地" forState:UIControlStateNormal];
  self.contentBtn.enabled = NO;
  [self.contentBtn setTitle:@"商品简介已复制" forState:UIControlStateNormal];

}