Iphone sizewithfont不起作用？

Question

我有以下代码:

- (CGFloat) tableView:(UITableView *)tableView heightForRowAtIndexPath:(NSIndexPath *)indexPath{
NSString *currentMessage = [FeedMessages objectAtIndex:indexPath.row];

NSLog(currentMessage);

UIFont *font = [UIFont systemFontOfSize:14];

NSLog([NSString stringWithFormat:@"Height: %@",[currentMessage sizeWithFont:font forWidth:270 lineBreakMode:UILineBreakModeWordWrap].height]);

return [currentMessage sizeWithFont:font forWidth:270 lineBreakMode:UILineBreakModeWordWrap].height;
}

任何人都可以告诉我为什么"[currentMessage sizeWithFont:font forWidth:270 lineBreakMode:UILineBreakModeWordWrap] .height"总是返回null或nil？

我检查过并正确填充了currentMessage.

有任何想法吗？

Answer 1

回答这个问题.它描述了 - 您必须使用CGFLOAT_MAX或查看以下代码(从那里抓取).

 NSString *text = @"A really long string in here"; 
 CGSize theSize = [text sizeWithFont:[UIFont boldSystemFontOfSize:18.0f] constrainedToSize:CGSizeMake(265.0f, CGFLOAT_MAX) lineBreakMode:UILineBreakModeWordWrap];
 NSString *stringHeight = [NSString stringWithFormat:@"%f", theSize.height];