为什么是我的sizeWithFont：constrainedToSize：lineBreakMode：总是返回零？

问题描述

我试图创建一个UITableViewCell，它会根据显示的字符串的长度调整其高度。我有：

  NSString * text = @这里真的很长的字符串; 
 CGSize theSize = [text sizeWithFont：[UIFont boldSystemFontOfSize：18.0f] constrainedToSize：CGSizeMake（265.0f，MAXFLOAT）lineBreakMode：UILineBreakModeWordWrap]; 
 NSString * stringHeight = [NSString stringWithFormat：@％d，theSize.height]; 
  

无论如何， stringHeight code> 0 。

谢谢！

解决方案

CGFloat 对应于C float 数据类型;它们的正确格式说明符是％f ：

  NSString * text = @这里真的很长的字符串; 
 CGSize theSize = [text sizeWithFont：[UIFont boldSystemFontOfSize：18.0f] constrainedToSize：CGSizeMake（265.0f，CGFLOAT_MAX）lineBreakMode：UILineBreakModeWordWrap]; 
 NSString * stringHeight = [NSString stringWithFormat：@％f，theSize.height]; 
  

此外，您应该使用 CGFLOAT_MAX MAXFLOAT

I'm trying to make a UITableViewCell that adjusts its height based on the length of a string it's displaying, but am getting hung up on this method.

Here's what I've got:

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

No matter what, stringHeight displays as 0. What am I missing?

Thanks!

解决方案

CGFloats correspond to the C float data type; the proper format specifier for them is %f:

 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];

Also, you should use CGFLOAT_MAX instead of MAXFLOAT

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