iOS开发之功能模块--计算高度Demo探究手稿

本篇记录关于计算文本高度和Label高度的代码，以备后期再探究：

首先是YouXianMing老师的工具类别：

NSString+LabelWidthAndHeight.h

 //
 //  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)oneLineOfTextHeightWithStringAttribute:(NSDictionary <NSString *, id> *)attribute;

 - (CGSize)getSizeWithFont:(UIFont *)font constrainedToSize:(CGSize)size;

 @end

NSString+LabelWidthAndHeight.m

 //
 //  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 = ;

     if (self.length) {

         CGRect rect = [self boundingRectWithSize:CGSizeMake(width, MAXFLOAT)
                                          options:NSStringDrawingTruncatesLastVisibleLine |NSStringDrawingUsesLineFragmentOrigin |
                        NSStringDrawingUsesFontLeading
                                       attributes:attribute
                                          context:nil];

         height = rect.size.height;
     }

     return height;
 }

 - (CGFloat)widthWithStringAttribute:(NSDictionary <NSString *, id> *)attribute {

     NSParameterAssert(attribute);

     CGFloat width = ;

     if (self.length) {

         CGRect rect = [self boundingRectWithSize:CGSizeMake(MAXFLOAT, )
                                          options:NSStringDrawingTruncatesLastVisibleLine |NSStringDrawingUsesLineFragmentOrigin |
                        NSStringDrawingUsesFontLeading
                                       attributes:attribute
                                          context:nil];
         width = rect.size.width;
     }

     return width;
 }

 + (CGFloat)oneLineOfTextHeightWithStringAttribute:(NSDictionary <NSString *, id> *)attribute {

     CGFloat height = ;
     CGRect rect    = [@"One" boundingRectWithSize:CGSizeMake(, MAXFLOAT)
                                           options:NSStringDrawingTruncatesLastVisibleLine |NSStringDrawingUsesLineFragmentOrigin |
                       NSStringDrawingUsesFontLeading
                                        attributes:attribute
                                           context:nil];
     height = rect.size.height;
     return height;
 }

 - (CGSize)getSizeWithFont:(UIFont *)font constrainedToSize:(CGSize)size{
     NSParameterAssert(font);
     CGSize resultSize = CGSizeZero;
     if (self.length <= ) {
         return resultSize;
     }
     resultSize = [self boundingRectWithSize:size
                                     options:(NSStringDrawingUsesFontLeading | NSStringDrawingUsesLineFragmentOrigin)
                                  attributes:@{NSFontAttributeName: font}
                                     context:nil].size;
     resultSize = CGSizeMake(MIN(size.width, ceilf(resultSize.width)), MIN(size.height, ceilf(resultSize.height)));
     return resultSize;
 }

 @end

然后是我的探究代码，见笑：

 #import "ViewController.h"
 #import "NSString+LabelWidthAndHeight.h"

 #define Content @"字体ad大家\n好，我叫帅哥，你们\n\n\n\n\n\n字体ad大家\n好，我叫帅哥，你们都是好人你们都是好人你们都是好人你们都是好人\n都是不哦联赛结案件\n发；个；案发金额了\n国家；姐夫都\n\n\n\n\n\n是不哦联赛结案件\n发；个；案发金额了\n国家；姐夫"

 #define LabelFont [UIFont systemFontOfSize:14]
 @interface ViewController ()

 @end

 @implementation ViewController

 - (void)viewDidLoad {
     [super viewDidLoad];

     //    CGFloat labelHeigh = [Content heightWithStringAttribute:attDic fixedWidth:labelWidth];
 //    NSDictionary *attDic = @{NSFontAttributeName : [UIFont systemFontOfSize:14]};
     CGFloat labelWidth = ;
     CGSize maxSize = CGSizeMake(labelWidth, MAXFLOAT);
     CGFloat labelHeigh = [Content getSizeWithFont:LabelFont constrainedToSize:maxSize].height;
     CGFloat aHeigh = labelHeigh;

 //    NSLog(@"计算出来的高度是：%lf",labelHeigh);
     UILabel *label = [UILabel new];
     label.font = LabelFont;
     label.frame = CGRectMake(, , labelWidth , );
     label.numberOfLines = ;
     label.lineBreakMode = NSLineBreakByCharWrapping;
     label.text = Content;
     label.backgroundColor = [UIColor cyanColor];

     [label sizeToFit];
 //    NSLog(@"计算出来Label的高度是：%lf",label.frame.size.height);
 //    NSLog(@"计算出来Label的宽度是：%lf",label.frame.size.width);

     label.frame = CGRectMake(, , label.frame.size.width, label.frame.size.height);
     [self.view addSubview:label];

     NSLog(@"计算高度的差值：%lf",label.frame.size.height - aHeigh);

 //    CGSize size = CGSizeMake(200, 3);
 //    UILabel *label = [UILabel new];
 //    label.font = [UIFont systemFontOfSize:18];
 //    label.numberOfLines = 0;
 //    label.lineBreakMode = NSLineBreakByCharWrapping;
 //    label.text = Content;
 //    CGRect labelFrame = label.frame;
 //    labelFrame.size = size;
 //    label.frame = labelFrame;
 //    [label sizeToFit];
 //    labelFrame = label.frame;
 //    label.backgroundColor = [UIColor cyanColor];
 ////    resultSize = labelFrame.size;
 //    NSLog(@"计算出来Label的高度是：%lf",label.frame.size.height);
 //    NSLog(@"计算出来Label的宽度是：%lf",label.frame.size.width);
 //    [self.view addSubview:label];

     UILabel *label2 = [UILabel new];
     label2.frame = CGRectMake(, , labelWidth, aHeigh);
     label2.font = LabelFont;
     label2.text = Content;
     label2.lineBreakMode = NSLineBreakByCharWrapping;
     label2.numberOfLines = ;
     label2.backgroundColor = [UIColor redColor];
     [self.view addSubview:label2];

     NSLog(@"屏幕的宽度%lf",[UIScreen mainScreen].bounds.size.width);

 }

 @end