OC链式封装进阶/终结篇：属性转为链式编程工具化实现

iOS 中习惯了 Swift 编程之后, 再修改老代码（OC）感觉调用特别不方便，想链式化一些内层属性，使代码调用更加简单；最终封装为一个链式属性生成器，普通属性一键转链式属性；

需要添加前缀以便和官方默认名称区分开[ 兼容 Swift ]；

🌰🌰：将 UICollectionViewFlowLayout 属性链式化

@interface UICollectionViewFlowLayout : UICollectionViewLayout

@property (nonatomic) CGSize itemSize;
@property (nonatomic) UICollectionViewScrollDirection scrollDirection;

@property (nonatomic) UIEdgeInsets sectionInset;

@property (nonatomic) BOOL sectionHeadersPinToVisibleBounds;

@end

工具生成如下：

//
//  UICollectionViewFlowLayout+Chain.h
//  MacTemplet
//
//  Created by Bin Shang on 2021/01/01 19:29
//  Copyright © 2021 Bin Shang. All rights reserved.
//
![WechatIMG423.jpeg](https://upload-images.jianshu.io/upload_images/281882-c01d05f7dfb3895a.jpeg?imageMogr2/auto-orient/strip%7CimageView2/2/w/1240)

#import <UIKit/UIKit.h>

NS_ASSUME_NONNULL_BEGIN

@interface UICollectionViewFlowLayout (Chain)

@property(nonatomic, copy, readonly) UICollectionViewFlowLayout *(^itemSizeChain)(CGSize);

@property(nonatomic, copy, readonly) UICollectionViewFlowLayout *(^scrollDirectionChain)(UICollectionViewScrollDirection);

@property(nonatomic, copy, readonly) UICollectionViewFlowLayout *(^sectionInsetChain)(UIEdgeInsets);

@property(nonatomic, copy, readonly) UICollectionViewFlowLayout *(^sectionHeadersPinToVisibleBoundsChain)(BOOL);

@end

NS_ASSUME_NONNULL_END

#import "UICollectionViewFlowLayout+Chain.h"

@implementation UICollectionViewFlowLayout (Chain)

- (UICollectionViewFlowLayout * (^)(CGSize))itemSizeChain{
    return ^(CGSize value) {
        self.itemSize = value;
        return self;
    };
}

- (UICollectionViewFlowLayout * (^)(UICollectionViewScrollDirection))scrollDirectionChain{
    return ^(UICollectionViewScrollDirection value) {
        self.scrollDirection = value;
        return self;
    };
}

- (UICollectionViewFlowLayout * (^)(UIEdgeInsets))sectionInsetChain{
    return ^(UIEdgeInsets value) {
        self.sectionInset = value;
        return self;
    };
}

- (UICollectionViewFlowLayout * (^)(BOOL))sectionHeadersPinToVisibleBoundsChain{
    return ^(BOOL value) {
        self.sectionHeadersPinToVisibleBounds = value;
        return self;
    };
}

@end

CodeHelper.dmg

附：NSString

#import <Foundation/Foundation.h>

NS_ASSUME_NONNULL_BEGIN

@interface NSString (Chain)
///过滤前后空格
@property (nonatomic, strong, readonly) NSString *trimmed;
/// 过滤字符集
@property(nonatomic, copy, readonly) NSString *(^trimmedBy)(NSString *);
@property(nonatomic, copy, readonly) NSString *(^trimmedBySet)(NSCharacterSet *);

@property(nonatomic, copy, readonly) NSString *(^subStringBy)(NSUInteger loc, NSUInteger len);
@property(nonatomic, copy, readonly) NSString *(^subStringFrom)(NSUInteger from);
@property(nonatomic, copy, readonly) NSString *(^subStringTo)(NSUInteger to);

@property(nonatomic, copy, readonly) NSString *(^appending)(NSString *);

@property(nonatomic, copy, readonly) NSString *(^appendingFormat)(NSString *format, ...);

@property(nonatomic, copy, readonly) NSString *(^replacingOccurrences)(NSString *, NSString *, NSStringCompareOptions);
@property(nonatomic, copy, readonly) NSString *(^replacingCharacters)(NSRange, NSString *);

@property(nonatomic, copy, readonly) NSComparisonResult (^compareBy)(NSString *, NSStringCompareOptions);

@property(nonatomic, copy, readonly) BOOL (^equalTo)(NSString *);

@property(nonatomic, copy, readonly) BOOL (^hasPrefix)(NSString *);
@property(nonatomic, copy, readonly) BOOL (^hasSuffix)(NSString *);
@property(nonatomic, copy, readonly) BOOL (^contains)(NSString *);
@property(nonatomic, copy, readonly) NSRange (^rangeBy)(NSString *, NSStringCompareOptions);
@property(nonatomic, copy, readonly, nullable) NSData *(^encoding)(NSStringEncoding);

///componentsSeparatedByString
@property(nonatomic, strong, readonly) NSArray<NSString *> *(^separatedBy)(NSString *);
///componentsSeparatedByString
@property(nonatomic, strong, readonly) NSArray<NSString *> *(^separatedBySet)(NSCharacterSet *);
@end



NS_ASSUME_NONNULL_END

#import "NSString+Chain.h"

@implementation NSString (Chain)

- (NSString *(^)(NSString *))trimmedBy{
    return ^(NSString *value) {
        NSCharacterSet *set = [NSCharacterSet characterSetWithCharactersInString:value];
        NSString *result = [self stringByTrimmingCharactersInSet:set];
        return result;
    };
}

- (NSString * (^)(NSCharacterSet * _Nonnull))trimmedBySet{
    return ^(NSCharacterSet *value) {
        return [self stringByTrimmingCharactersInSet:value];
    };
}

- (NSString * (^)(NSUInteger, NSUInteger))subStringBy{
    return ^(NSUInteger loc, NSUInteger len) {
        if (loc + len > self.length) {
            return self;
        }
        NSString *result = [self substringWithRange:NSMakeRange(loc, len)];
        return result;
    };
}

- (NSString * (^)(NSUInteger))subStringFrom{
    return ^(NSUInteger value) {
        return [self substringFromIndex:value];;
    };
}

- (NSString * (^)(NSUInteger))subStringTo{
    return ^(NSUInteger value) {
        return [self substringFromIndex:value];;
    };
}


- (NSString *(^)(NSString * _Nonnull))appending{
    return ^(NSString *value){
        return [self stringByAppendingString:value];
    };
}

- (NSString * _Nonnull (^)(NSString * _Nonnull, ...))appendingFormat{
    return ^(NSString *format, ...){
        va_list list;
        va_start(list, format);
        NSString *string = [[NSString alloc] initWithFormat:format arguments:list];
        va_end(list);
        NSString *result = [self stringByAppendingString:string];
        return result;
    };
}

- (NSString * (^)(NSString * _Nonnull, NSString * _Nonnull, NSStringCompareOptions))replacingOccurrences{
    return ^(NSString *target, NSString *replacement, NSStringCompareOptions options){
        return [self stringByReplacingOccurrencesOfString:target withString:replacement options:options range:NSMakeRange(0, self.length)];
    };
}


- (NSString * (^)(NSRange, NSString * _Nonnull))replacingCharacters{
    return ^(NSRange range, NSString *replacement){
        return [self stringByReplacingCharactersInRange:range withString:replacement];
    };
}

- (NSComparisonResult (^)(NSString * _Nonnull, NSStringCompareOptions))compareBy{
    return ^(NSString *value, NSStringCompareOptions options){
        return [self compare:value options:options];
    };
}

- (BOOL (^)(NSString * _Nonnull))equalTo{
    return ^(NSString *value){
        return [self isEqualToString:value];
    };
}

- (BOOL (^)(NSString * _Nonnull))hasPrefix{
    return ^(NSString *value){
        return [self hasPrefix:value];
    };
}

- (BOOL (^)(NSString * _Nonnull))hasSuffix{
    return ^(NSString *value){
        return [self hasSuffix:value];
    };
}

- (BOOL (^)(NSString * _Nonnull))contains{
    return ^(NSString *value){
        return [self containsString:value];
    };
}

- (NSRange (^)(NSString * _Nonnull, NSStringCompareOptions))rangeBy{
    return ^(NSString *value, NSStringCompareOptions options){
        return [self rangeOfString:value options:options];
    };
}

- (NSData * _Nonnull (^)(NSStringEncoding))encoding{
    return ^(NSStringEncoding value){
        return [self dataUsingEncoding:value];
    };
}

- (NSArray<NSString *> *(^)(NSString *))separatedBy{
    return ^(NSString *value) {
        return [self componentsSeparatedByString: value];
    };
}

- (NSArray<NSString *> * _Nonnull (^)(NSCharacterSet * _Nonnull))separatedBySet{
    return ^(NSCharacterSet *value) {
        return [self componentsSeparatedByCharactersInSet:value];
    };
}

@end

附：NSMutableString

@interface NSMutableString (Chain)

//- (void)appendString:(NSString *)aString;
@property(nonatomic, copy, readonly) NSMutableString * (^appending)(NSString *);

///- (void)appendFormat:(NSString *)format, ... NS_FORMAT_FUNCTION(1,2);
@property(nonatomic, copy, readonly) NSMutableString * (^appendingFormat)(NSString *format, ...);

///- (void)replaceCharactersInRange:(NSRange)range withString:(NSString *)aString;
@property(nonatomic, copy, readonly) NSMutableString * (^replacingCharacters)(NSRange, NSString *);

///- (NSUInteger)replaceOccurrencesOfString:(NSString *)target withString:(NSString *)replacement options:(NSStringCompareOptions)options range:(NSRange)searchRange;
@property(nonatomic, copy, readonly) NSMutableString * (^replacingOccurrences)(NSString *, NSString *, NSStringCompareOptions);

///- (void)insertString:(NSString *)aString atIndex:(NSUInteger)loc;
@property(nonatomic, copy, readonly) NSMutableString * (^insertAtIndex)(NSString *, NSUInteger);

///- (void)deleteCharactersInRange:(NSRange)range;
@property(nonatomic, copy, readonly) NSMutableString * (^deleteCharacters)(NSRange);

@end

@implementation NSMutableString (Chain)

- (NSMutableString * (^)(NSString * _Nonnull))appending{
    return ^(NSString *value) {
        [self appendString:value];
        return self;
    };
}

- (NSMutableString * (^)(NSString * _Nonnull, ...))appendingFormat{
    return ^(NSString *format, ...){
        va_list args;
        va_start(args, format);
        NSString *string = [[NSString alloc] initWithFormat:format arguments:args];
        va_end(args);
        [self appendString:string];
        return self;
    };
}

- (NSMutableString * (^)(NSRange, NSString * _Nonnull))replacingCharacters{
    return ^(NSRange range, NSString *value) {
        [self replaceCharactersInRange:range withString:value];
        return self;
    };
}
                                                                                                    
- (NSMutableString * (^)(NSString * _Nonnull, NSString * _Nonnull, NSStringCompareOptions))replacingOccurrences{
    return ^(NSString *target, NSString *replacement, NSStringCompareOptions options) {
        [self replaceOccurrencesOfString:target withString:replacement options:options range:NSMakeRange(0, self.length)];
        return self;
    };
}

- (NSMutableString * (^)(NSString * _Nonnull, NSUInteger))insertAtIndex{
    return ^(NSString *value, NSUInteger index) {
        [self insertString:value atIndex:index];
        return self;
    };
}

- (NSMutableString * _Nonnull (^)(NSRange))deleteCharacters{
    return ^(NSRange range) {
        [self deleteCharactersInRange:range];
        return self;
    };
}

@end

附：NSMutableArray

#import <Foundation/Foundation.h>

NS_ASSUME_NONNULL_BEGIN

@interface NSMutableArray<ObjectType> (Helper)

@property(nonatomic, copy, readonly) NSMutableArray *(^addObject)(ObjectType);
@property(nonatomic, copy, readonly) NSMutableArray *(^addObjects)(NSArray<ObjectType> *);

@property(nonatomic, copy, readonly) NSMutableArray *(^insertAtIndex)(ObjectType, NSUInteger);
@property(nonatomic, copy, readonly) NSMutableArray *(^removeAtIndex)(NSUInteger);
@property(nonatomic, copy, readonly) NSMutableArray *(^removeObjects)(NSArray<ObjectType> *);
@property(nonatomic, copy, readonly) NSMutableArray *(^removeAll)(void);

@property(nonatomic, copy, readonly) NSMutableArray *(^replaceAtIndex)(ObjectType, NSUInteger);

@property(nonatomic, copy, readonly) NSMutableArray *(^sort)(SEL);

@end

NS_ASSUME_NONNULL_END

#import "NSMutableArray+Helper.h"

@implementation NSMutableArray (Helper)

- (NSMutableArray * (^)(id _Nonnull))addObject{
    return ^(id obj) {
        if (obj) {
            [self addObject:obj];
        }
        return self;
    };
}

- (NSMutableArray * (^)(NSArray<id> *))addObjects{
    return ^(NSArray<id> * value) {
        if (value) {
            [self addObjectsFromArray:value];
        }
        return self;
    };
}

- (NSMutableArray * (^)(id, NSUInteger))insertAtIndex{
    return ^(id value, NSUInteger index) {
        if (value) {
            [self insertObject:value atIndex:index];
        }
        return self;
    };
}

- (NSMutableArray * (^)(NSUInteger))removeAtIndex{
    return ^(NSUInteger index) {
        if (index < self.count) {
            [self removeObjectAtIndex:index];
        }
        return self;
    };
}

- (NSMutableArray * (^)(NSArray<id> *))removeObjects{
    return ^(NSArray<id> * value) {
        [self removeObjectsInArray:value];
        return self;
    };
}

- (NSMutableArray * (^)(void))removeAll{
    return ^(void) {
        [self removeAllObjects];
        return self;
    };
}

- (NSMutableArray * (^)(id, NSUInteger))replaceAtIndex{
    return ^(id value, NSUInteger index) {
        if (index < self.count) {
            [self replaceObjectAtIndex:index withObject:value];
        }
        return self;
    };
}

- (NSMutableArray * (^)(SEL))sort{
    return ^(SEL aSel) {
        [self sortUsingSelector:aSel];
        return self;
    };
}

@end

Swift 链式编程库： SwiftChain
另类实现点语法：Then