iPhone获取字符串高度和宽度 …

通常我们使用UILabel只是显示较短的字符串，下面是一种获取字符串的换行高度，显示

 代码如下所示:

[cpp] view plain copy print ?
NSString* str = @"test testImplement viewDidLoad to do additional setup after loading the view, typically from a nib";  
  
//CGSize labelSize =  [str sizeWithFont:[UIFont systemFontOfSize:14]];      
  
//可以精确计算字符串的换行，高宽等   
CGSize labelSize = [str sizeWithFont:[UIFont boldSystemFontOfSize:17.0f]  
                        constrainedToSize:CGSizeMake(280, 100)   
                        lineBreakMode:UILineBreakModeCharacterWrap];  
  
UILabel* label = [[UILabel alloc] init];  
label.frame = CGRectMake(50, 20, labelSize.width, labelSize.height);  
label.backgroundColor = [UIColor whiteColor];  
label.text = str;  
label.font = [UIFont systemFontOfSize:17.0f];  
label.numberOfLines = 0;  
label.lineBreakMode = UILineBreakModeCharacterWrap;  
  
[self.view addSubview:label];  
[label release];