title: UITableView does not display cell immediately after reloading data
body: <p>In viewDidload, tableview load data from server</p>
  
  <pre><code>success:^(NSArray *array) {
      if (!_dataSource) {
          _dataSource = [@[] mutableCopy];
      }
      if (array) {
          [_dataSource addObjectsFromArray:array];
          [_tableView reloadData];
      }
  }
  </code></pre>
  
  <p>then every time I pull up from bottom, get new data from server and appended it to the <strong>_dataSource</strong>(the same way like first time)</p>
  
  <pre><code>success:^(NSArray *array) {
      if (!_dataSource) {
          _dataSource = [@[] mutableCopy];
      }
      if (array) {
          [_dataSource addObjectsFromArray:array];
          [_tableView reloadData];
      }
  }
  </code></pre>
  
  <p>now the problem is coming: sometime pull up from bottom, and <strong>get new data successly,but the tableview does not display new cell immediately,when I sweep the tableview a bit(even just touch the screen) the new cell displayed</strong>.
   What problem it could be?</p>
  
  <h2>Edit</h2>
  
  <p>Because every cell is not the same height, so I do not <em>reuse</em> cell, and init a new cell every time,is this reason?</p>
  
  <pre><code>//    TopicCell *cell = [tableView dequeueReusableCellWithIdentifier:TopicCellIdentifier];
  //    if(!cell){    
  //        cell = [[TopicCell alloc] initWithStyle:UITableViewCellStyleDefault reuseIdentifier:TopicCellIdentifier];
  //    }
  TopicCell *cell = [[TopicCell alloc] initWithStyle:UITableViewCellStyleDefault reuseIdentifier:TopicCellIdentifier];
  </code></pre>
  
  <p>@Jeffery Thomas, <strong>success</strong> is just a <strong>AFNetworking block</strong> like this</p>
  
  <pre><code> AFHTTPRequestOperationManager *manager = [AFHTTPRequestOperationManager manager];
   [manager GET:path
            parameters:parameters
               success:^(AFHTTPRequestOperation *operation1, id responseObject) {
  
               }
               failure:^(AFHTTPRequestOperation *operation2, NSError *error) {
  
               }];
  </code></pre>