ios - 内容已弃用 sizeWithFont :constrainedToSize to boundingRectWithSize:options:attributes:context:

Question

我怎样才能转换

 CGSize labelHeighSize = [text sizeWithFont: [UIFont systemFontOfSize:16] constrainedToSize:maximumSize lineBreakMode:NSLineBreakByTruncatingTail];

到

CGSize labelHeighSize = [text boundingRectWithSize:maximumSize options:  attributes:  context: 

Answer 1

首先是方法:

 - (CGRect)   boundingRectWithSize:(CGSize)size 
                           options:(NSStringDrawingOptions)options 
                        attributes:(NSDictionary *)attributes 
                           context:(NSStringDrawingContext *)context;

返回 CGRect 而不是 CGSize 所以你需要使用 CGRect。

编辑根据苹果文档，请参阅 here , 它说

This option is ignored if NSStringDrawingUsesLineFragmentOrigin is not also set. In addition, the line break mode must be either NSLineBreakByWordWrapping or NSLineBreakByCharWrapping for this option to take effect. The line break mode can be specified in a paragraph style passed in the attributes dictionary argument of the drawing methods.

下面是您可以使用的示例代码:

NSString *text = @"Some text to measure";
UIFont *labelFont = [UIFont systemFontOfSize:16];

NSMutableParagraphStyle *paragraphStyle = [[NSMutableParagraphStyle alloc]init];
//set the line break mode
paragraphStyle.lineBreakMode = NSLineBreakByWordWrapping; 

NSDictionary *attrDict = [NSDictionary dictionaryWithObjectsAndKeys:labelFont,
                                       NSFontAttributeName,
                                       paragraphStyle,
                                       NSParagraphStyleAttributeName,
                                       nil];


//assume your maximumSize contains {255, MAXFLOAT}     
CGRect lblRect = [text boundingRectWithSize:(CGSize){225, MAXFLOAT} 
                                    options:NSStringDrawingUsesLineFragmentOrigin
                                 attributes:attrDict 
                                    context:nil];
CGSize labelHeighSize = lblRect.size;