根据字体和字符串来计算大小

iOS

+ (CGSize)actStringSizeFlexibleWithFont:(UIFont*)iFont text:(NSString*)text

{

UIFont *font = nil;

iFont == nil ? (font=[UIFont systemFontOfSize:13.0f]) : (font=iFont);

CGSize size = [text sizeWithFont:font constrainedToSize:CGSizeMake(MAXFLOAT, MAXFLOAT) lineBreakMode:NSLineBreakByWordWrapping];

return size;

}