Question

我正在尝试根据内容的内容计算tableview中单元格的必要高度。这是- (CGFloat)tableView:(UITableView *)tableView heightForRowAtIndexPath:(NSIndexPath *)indexPath。

然而，有时sizeWithFont返回0.我无法弄清楚这是怎么可能的，因为所有参数都是硬编码的，除了一个，我可以看到该参数没有改变。

NSString *address = [properties objectAtIndex:1];

CGFloat calculatedSize = [address sizeWithFont:[[UIFont alloc] fontWithSize:15.f] constrainedToSize:CGSizeMake(207.f, 100.f) lineBreakMode:UILineBreakModeWordWrap].height;

NSLog(@"Calculated size for %@: %f", address, calculatedSize);

calculatedSize += 19.f;

return calculatedSize;

这是输出，如果我多次来回看几次尝试这个：

Calculated size for 1234 Fake St: 0.000000
Calculated size for 1234 Fake St: 0.000000
Calculated size for 1234 Fake St: 0.000000
Calculated size for 1234 Fake St: 38.000000
Calculated size for 1234 Fake St: 0.000000
Calculated size for 1234 Fake St: 38.000000

Answer 1

替换：

[[UIFont alloc] fontWithSize:15.0f]

使用：

[UIFont systemFontOfSize:15.f]

Answer 2

我对此进行了测试并且有效

NSString *address = @"Sample text Sample text Sample text Sample text Sample text Sample text Sample text";

CGFloat calculatedSize = [address sizeWithFont:[UIFont systemFontOfSize:15.0] 
                             constrainedToSize:CGSizeMake(207.f, 100.f) 
                                 lineBreakMode:UILineBreakModeWordWrap].height;    

NSLog(@"Calculated size for %@: %f", address, calculatedSize); //String... 76.000000

sizeWithFont返回随机值

2 个答案: