title: Dropbox sync api
body: <p>I am adding a observer to filesystem and Dbfile, but I am getting error that file already open. Please tell me where to close my file.
  Below is my code:</p>
  
  <pre><code>[filesystem addObserver:self forPathAndChildren:pathDB block:^(DBObserver complete){////observer to folder
                  DBError *error= nil;
                  NSLog(@"File(s) %@ changed!",pathDB);
  
                   DBFile *file=[filesystem openFile:pathDB error:&amp;error];
                  [file addObserver:self block:^() { ///observer to file
  
  
                      DBFileStatus *newerStatus = file.newerStatus;
                      if (newerStatus)
                      {
                          if (!newerStatus.cached)
                          {
                              NSLog(@"newerStatus.cached == NO; this means the file downloading");
  
                          }
                          else
                          {
                              // Update to the newly available version and print it out
                              [file update:nil];
  
                              NSData *fileData = [file readData:nil];
                              [fileData writeToFile:[[appDelegate.directoryPath stringByAppendingPathComponent:@"Projects"]  stringByAppendingFormat:@"/%@",path] atomically:YES];
  
                              [file close];
  
                      }
  
                  }];
  
              }];
  </code></pre>