UIView+adjustText.m

//
//  UIView+adjustText.m
//
//  Created by J_ogawa on 2014/04/04.
//  Copyright (c) 2014年 J_ogawa. All rights reserved.
//

#import "UIView+adjustTextLabel.h"

@implementation UIView (adjustTextLabel)

- (id)initWithFrame:(CGRect)frame
               text:(id)text
            padding:(CGFloat)padding
          maxHeight:(CGFloat)maxHeight
      templateLabel:(UILabel *)templateLabel
{
    BOOL isAttributed;
    if ([text isKindOfClass:[NSString class]]) {
        isAttributed = NO;
    } else if ([text isKindOfClass:[NSAttributedString class]]) {
        isAttributed = YES;
    } else {
        return nil;
    }
    
    CGSize constraint = CGSizeMake(frame.size.width - (2 * padding), (maxHeight) ? MIN(maxHeight, 20000.0f) : 20000.0f);
    UILabel *label = (templateLabel) ? templateLabel : [UILabel new];
    
    CGSize size = isAttributed ? [self sizeOfAttrStr:text constraint:constraint] : [self sizeOfStr:text constraint:constraint font:label.font];
    
    label.frame = CGRectMake(padding, padding, size.width, size.height);
    [label setLineBreakMode:NSLineBreakByWordWrapping];
    [label setNumberOfLines:0];
    if (isAttributed) {
         label.attributedText = text;
    } else {
        label.text = text;
    }
   
    CGRect viewFrame = CGRectMake(frame.origin.x, frame.origin.y, frame.size.width, size.height + padding * 2);
    
    self = [self initWithFrame:viewFrame];
    if (self) {
        [self addSubview:label];
    }
    return self;
}

- (CGSize)sizeOfStr:(NSString *)str constraint:(CGSize)constraint font:(UIFont *)font
{
    CGSize size = [str boundingRectWithSize:constraint options:NSStringDrawingUsesLineFragmentOrigin attributes:@{NSFontAttributeName:font} context:nil].size;
    return (CGSize){ ceil(size.width), ceil(size.height) };
}

- (CGSize)sizeOfAttrStr:(NSAttributedString *)attrStr constraint:(CGSize)constraint
{
    CGSize size = [attrStr boundingRectWithSize:constraint options:NSStringDrawingUsesLineFragmentOrigin context:nil].size;
    return (CGSize){ ceil(size.width), ceil(size.height) };
}

@end

create view which have flexible height label with text length (attribute).