有没有办法在Xcode 4.4中获得整洁的Objective-C文字索引功能？

好吧,有办法做到这一点！将索引方法作为类别添加到NSArray和NSDictionary中,您可以获得您希望它的大多数类的功能.您可以阅读ObjectiveC文字 here.感谢James Webster的@YES和@NO解决方案,您现在也可以在项目中正确使用它们！ (the technique)

1)创建接口文件

// NSArray+Indexing.h
#if !defined(__IPHONE_6_0) || __IPHONE_OS_VERSION_MIN_required < __IPHONE_6_0
@interface NSArray (Indexing)
- (id)objectAtIndexedSubscript:(NSUInteger)idx;
@end
@interface NSMutableArray (Indexing)
- (void)setobject:(id)obj atIndexedSubscript:(NSUInteger)idx;
@end
// NSDictionary+Indexing.h
@interface  NSDictionary (Indexing)
- (id)objectForKeyedSubscript:(id)key;
@end
@interface  NSMutableDictionary (Indexing)
- (void)setobject:(id)obj forKeyedSubscript:(id)key;
@end
#endif

2)创建实施文件//在执行此操作之前参见下面的编辑 – 您可以跳过此步骤

// NSArray+Indexing.m
#if !defined(__IPHONE_6_0) || __IPHONE_OS_VERSION_MIN_required < __IPHONE_6_0
#import "NSArray+Indexing.h"
@implementation NSArray (Indexing)
- (id)objectAtIndexedSubscript:(NSUInteger)idx
{
    return [self objectAtIndex:idx];
}
@end
@implementation NSMutableArray (Indexing)
- (void)setobject:(id)obj atIndexedSubscript:(NSUInteger)idx
{
    [self replaceObjectAtIndex:idx withObject:obj];
}
@end

// NSMutableDictionary+Indexing.m
@implementation  NSDictionary (Indexing)

- (id)objectForKeyedSubscript:(id)key
{
    return [self objectForKey:key];
}
@end
@implementation  NSMutableDictionary (Indexing)
- (void)setobject:(id)obj forKeyedSubscript:(id)key
{
    [self setobject:obj forKey:key];
}
@end
#endif

3)将接口文件添加到pch文件以供全局使用,或根据需要将它们添加到.m文件中

// Add to PCH file
#ifdef __OBJC__
    #import <UIKit/UIKit.h>
    #import <Foundation/Foundation.h>
...
#if !defined(__IPHONE_6_0) || __IPHONE_OS_VERSION_MIN_required < __IPHONE_6_0

// New Indexing
#import "NSDictionary+Indexing.h"
#import "NSArray+Indexing.h"

// Provided by James Webster on StackOverFlow
#if __has_feature(objc_bool) 
#undef YES 
#undef NO 
#define YES __objc_yes 
#define NO __objc_no 
#endif 

#endif
#endif

#endif

4)重建,然后添加以下文件以验证它是否全部有效

// Test Example
{

    NSMutableArray *a = [NSMutableArray arrayWithArray:@[ @"a",@"b",@"c" ]];
    NSLog(@"%@",a[1]);
    a[1] = @"foo";
    NSLog(@"a: %@",a);

    NSMutableDictionary *dict = [NSMutableDictionary dictionaryWithDictionary:@{ @"key" : @"object" }];
    NSLog(@"%@",dict[@"key"]);

    dict[@"key"] = @"New Object";
    dict[@"newKey"] = @"WOW a new object";

    NSLog(@"dict: %@",dict);

    NSLog(@" %@ %@",@YES,@NO );
}

编辑：嗯,根据一位关键的llvm / clang Apple工程师的说法,有一个库已经与实现相关联,所以你只需要接口文件：

日期：星期一,2012年8月20日15:16:43 -0700
来自：格雷格帕克
至： …
主题：Re：如何让iOS 5上的Obj-C集合下载工作？
…

As an experiment I added the category @interface for these methods,but not the @implementation — the app still ran fine (at least in the 5.1 simulator)

编译器发出相同的调用.神奇之处在于越来越不准确地命名为libarclite(“它不仅仅适用于ARC Anymore™”),它在运行时添加了下标方法的实现(如果它们尚不存在).

IIRC有一些可下标的类,libarclite不升级(可能是NSOrderedSet？)所以你仍需要对旧的部署目标进行彻底测试.