计算一行文本的高度

说明

有时候我们需要知道指定的几行文本的高度，此工具用于解决此种问题。

源码

//
//  NSString+LabelWidthAndHeight.h
//  ZiPeiYi
//
//  Created by YouXianMing on 15/12/9.
//  Copyright © 2015年 YouXianMing. All rights reserved.
//

#import <Foundation/Foundation.h>
#import <UIKit/UIKit.h>@interface NSString (LabelWidthAndHeight)/***  Get the string's height with the fixed width.**  @param attribute String's attribute, eg. attribute = @{NSFontAttributeName: [UIFont systemFontOfSize:18.f]}*  @param width     Fixed width.**  @return String's height.*/
- (CGFloat)heightWithStringAttribute:(NSDictionary <NSString *, id> *)attribute fixedWidth:(CGFloat)width;/***  Get the string's width.**  @param attribute String's attribute, eg. attribute = @{NSFontAttributeName: [UIFont systemFontOfSize:18.f]}**  @return String's width.*/
- (CGFloat)widthWithStringAttribute:(NSDictionary <NSString *, id> *)attribute;/***  Get a line of text height.**  @param attribute String's attribute, eg. attribute = @{NSFontAttributeName: [UIFont systemFontOfSize:18.f]}**  @return String's width.*/
+ (CGFloat)aLineOfTextHeightWithStringAttribute:(NSDictionary <NSString *, id> *)attribute;@end

//
//  NSString+LabelWidthAndHeight.m
//  ZiPeiYi
//
//  Created by YouXianMing on 15/12/9.
//  Copyright © 2015年 YouXianMing. All rights reserved.
//

#import "NSString+LabelWidthAndHeight.h"@implementation NSString (LabelWidthAndHeight)- (CGFloat)heightWithStringAttribute:(NSDictionary <NSString *, id> *)attribute fixedWidth:(CGFloat)width {NSParameterAssert(attribute);CGFloat height = 0;if (self.length) {CGRect rect = [self boundingRectWithSize:CGSizeMake(width, MAXFLOAT)options:NSStringDrawingTruncatesLastVisibleLine |NSStringDrawingUsesLineFragmentOrigin |NSStringDrawingUsesFontLeadingattributes:attributecontext:nil];height = rect.size.height;}return height;
}- (CGFloat)widthWithStringAttribute:(NSDictionary <NSString *, id> *)attribute {NSParameterAssert(attribute);CGFloat width = 0;if (self.length) {CGRect rect = [self boundingRectWithSize:CGSizeMake(MAXFLOAT, 0)options:NSStringDrawingTruncatesLastVisibleLine |NSStringDrawingUsesLineFragmentOrigin |NSStringDrawingUsesFontLeadingattributes:attributecontext:nil];width = rect.size.width;}return width;
}+ (CGFloat)aLineOfTextHeightWithStringAttribute:(NSDictionary <NSString *, id> *)attribute {CGFloat height = 0;CGRect rect    = [@"One" boundingRectWithSize:CGSizeMake(200, MAXFLOAT)options:NSStringDrawingTruncatesLastVisibleLine |NSStringDrawingUsesLineFragmentOrigin |NSStringDrawingUsesFontLeadingattributes:attributecontext:nil];height = rect.size.height;return height;
}@end