iOS计算完整文字高度(适应iOS 10)

动态计算文字的高度:(切记LineSapcing>=2,不然会显示不全)

+(CGSize) boundingALLRectWithSize:(NSString*) txt Font:(UIFont*) font Size:(CGSize) size{    
    NSMutableAttributedString *attributedString = [[NSMutableAttributedString alloc] initWithString:txt];
    NSMutableParagraphStyle *style = [[NSMutableParagraphStyle alloc]init];
    [style setLineSpacing:2.0f];
    [attributedString addAttribute:NSParagraphStyleAttributeName value:style range:NSMakeRange(0, [txt length])];
    
    CGSize realSize = CGSizeZero;

#if __IPHONE_OS_VERSION_MAX_ALLOWED > __IPHONE_6_1
    CGRect textRect = [txt boundingRectWithSize:size options:NSStringDrawingUsesLineFragmentOrigin attributes:@{NSFontAttributeName:font,NSParagraphStyleAttributeName:style} context:nil];
    realSize = textRect.size;
#else
    realSize = [txt sizeWithFont:font constrainedToSize:size];
#endif
    
    realSize.width = ceilf(realSize.width);
    realSize.height = ceilf(realSize.height);
    return realSize;
}