直接上代码

//
//  NSArray+OOBKit.h
//  UITableViewBlockDemo
//
//  Created by LT on 16/11/15.
//  Copyright © 2016年 LT. All rights reserved.
//

#import <Foundation/Foundation.h>

@interface  NSArray (OOBKit)
/**
 检查数组是否越界

 @param index 角标

 @return 检查是否越界和NSNull如果是返回nil
 */
- (id)objectAtIndexCheck:(NSUInteger)index;
@end
@interface NSMutableArray (OOBKit)
/**
 检查可变数组是否越界
 
 @param index 角标
 
 @return 检查是否越界和NSNull如果是返回nil
 */
- (id)objectAtIndexCheck:(NSUInteger)index;
@end

//
//  NSArray+OOBKit.m
//  UITableViewBlockDemo
//
//  Created by LT on 16/11/15.
//  Copyright © 2016年 LT. All rights reserved.
//

#import "NSArray+OOBKit.h"

@implementation NSArray (OOBKit)
- (id)objectAtIndexCheck:(NSUInteger)index
{
    if (index >= [self count]) {
        return nil;
    }
    
    id value = [self objectAtIndex:index];
    if (value == [NSNull null]) {
        return nil;
    }
    return value;
}
@end
@implementation NSMutableArray (OOBKit)
- (id)objectAtIndexCheck:(NSUInteger)index
{
    if (index >= [self count]) {
        return nil;
    }
    
    id value = [self objectAtIndex:index];
    if (value == [NSNull null]) {
        return nil;
    }
    return value;
}
@end

使用示例

#import "NSArray+OOBKit.h"

    NSArray *arr=@[@"1",@"2",@"3"];
    NSLog(@"item=%@",[arr objectAtIndexCheck:3]);
    
    NSMutableArray *arr2=[NSMutableArray arrayWithObjects:@"1",@"2",@"3", nil];
    NSLog(@"item2=%@",[arr2 objectAtIndexCheck:3]);

访问越界数据是不会崩溃并返回nil

Paste_Image.png