iOS7中Cell高度 Label高度自适应


- (float)tableView:(UITableView *)tableView heightForRowAtIndexPath:(NSIndexPath *)indexPath{

NSString *str = [_dataArray objectAtIndex:indexPath.row];
UIFont *tfont = [UIFont systemFontOfSize:14.0];
NSDictionary * dic = [NSDictionary dictionaryWithObjectsAndKeys:tfont,NSFontAttributeName,nil];
//   ios 7
CGSize sizeText = [str boundingRectWithSize:CGSizeMake(320, 1000) options:NSStringDrawingUsesLineFragmentOrigin attributes:dic context:nil].size;
//   ios 6
CGSize sizeText1 = [str sizeWithFont:[UIFont systemFontOfSize:16.0f] constrainedToSize:CGSizeMake(320, 1000) lineBreakMode:NSLineBreakByCharWrapping];
return sizeText1.height+50;

}