在tableview

Question

我有一个用一个名为json的数组填充的tableview。如果json的长度为0，我想在tableview中返回1行。

 -(UITableViewCell *)tableView:(UITableView *)tableView cellForRowAtIndexPath:(NSIndexPath *)indexPath{
  TableViewCell *cell = [self->tableView dequeueReusableCellWithIdentifier:@"CustomCell"];
  NSDictionary *info = [json objectAtIndex:indexPath.row];
  //content is the name of label in the custom cell
  if ([json count]>0) {
    cell.content.text = [info objectForKey:@"message_text"];
  }
  else
    cell.content.text = @"There are currently no messages. Please pull down to refresh";

  return cell;
}

- (NSInteger)tableView:(UITableView *)tableView numberOfRowsInSection:(NSInteger)section{
if([json count]>0)
    return [json count];
else
    return 1;

}

上面的代码导致我的应用程序崩溃，我不确定为什么。为什么这不起作用，我该如何解决这个问题。 我收到以下错误：

*由于未捕获的异常'NSRangeException'而终止应用程序，原因：'* - [__ NSArray0 objectAtIndex：]：索引0超出空NSArray的边界'

Answer 1

更改此代码：

NSDictionary *info = [json objectAtIndex:indexPath.row];
//content is the name of label in the custom cell
if ([json count]>0) {
  cell.content.text = [info objectForKey:@"message_text"];
}
else
   cell.content.text = @"There are currently no messages. Please pull down to refresh";

要：

//content is the name of label in the custom cell
if ([json count]>0) {
  NSDictionary *info = [json objectAtIndex:indexPath.row];
  cell.content.text = [info objectForKey:@"message_text"];
}
else
   cell.content.text = @"There are currently no messages. Please pull down to refresh";

希望这有帮助！