iOS - 数组,字典打印以及防止数组取值越界字典插入nil

数组打印类

NSArray+Log.h

descriptionWithLocale:

- (NSString *)descriptionWithLocale:(id)locale
{
NSMutableString *string = [NSMutableString string];

// 开头有个[
[string appendString:@"[\n"];

// 遍历所有的元素
[self enumerateObjectsUsingBlock:^(id obj, NSUInteger idx, BOOL *stop) {
[string appendFormat:@"\t%@,\n", obj];
}];

// 结尾有个]
[string appendString:@"]"];

// 查找最后一个逗号
NSRange range = [string rangeOfString:@"," options:NSBackwardsSearch];
if (range.location != NSNotFound)
[string deleteCharactersInRange:range];

return string;
}

字典打印类

NSDictionary+Log.h

descriptionWithLocale

-(NSString *)descriptionWithLocale:(id)locale{

NSMutableString *string = [NSMutableString string];
// 开头有个{
[string appendString:@"{\n"];

// 遍历所有的键值对
[self enumerateKeysAndObjectsUsingBlock:^(id key, id obj, BOOL *stop) {
[string appendFormat:@"\t%@", key];
[string appendString:@" : "];
[string appendFormat:@"%@,\n", obj];
}];
// 结尾有个}
[string appendString:@"}"];
// 查找最后一个逗号
NSRange range = [string rangeOfString:@"," options:NSBackwardsSearch];
if (range.location != NSNotFound)
[string deleteCharactersInRange:range];

return string;
}

防止数组取值越界

NSArray+EM

runtime

em_objectAtIndex

#import "NSArray+EM.h"
#import <objc/runtime.h>
@implementation NSArray (EM)
+(void)load {
Method fromMethod = class_getInstanceMethod(objc_getClass("__NSArrayI"), @selector(objectAtIndex:));
Method toMethod = class_getInstanceMethod(objc_getClass("__NSArrayI"), @selector(em_objectAtIndex:));
method_exchangeImplementations(fromMethod, toMethod);
}

- (id)em_objectAtIndex:(NSUInteger)index {
if (self.count - 1 < index) {
return @"越界";
}else {
return [self em_objectAtIndex:index];
}
}
@end

NSMutableArray+EM

#import "NSMutableArray+EM.h"
#import <objc/runtime.h>
@implementation NSMutableArray (EM)
+(void)load {
Method fromMethod = class_getInstanceMethod(objc_getClass("__NSArrayM"), @selector(objectAtIndex:));
Method toMethod = class_getInstanceMethod(objc_getClass("__NSArrayM"), @selector(em_objectAtIndex:));
method_exchangeImplementations(fromMethod, toMethod);
}

- (id)em_objectAtIndex:(NSUInteger)index {
if (self.count - 1 < index) {
return @"越界";
}else {
return [self em_objectAtIndex:index];
}
}
@end

可变字典防止插入空nil

NSMutableDictionary+EM

#import "NSMutableDictionary+EM.h"
#import <objc/runtime.h>
@implementation NSMutableDictionary (EM)
+ (void)load {

Method fromMethod = class_getInstanceMethod(objc_getClass("__NSDictionaryM"), @selector(setObject:forKey:));
Method toMethod = class_getInstanceMethod(objc_getClass("__NSDictionaryM"), @selector(em_setObject:forKey:));
method_exchangeImplementations(fromMethod, toMethod);
}

- (void)em_setObject:(id)emObject forKey:(NSString *)key {
if (emObject == nil) {

[self em_setObject:@"字典插入了nil" forKey:key];
}else {
[self em_setObject:emObject forKey:key];
}
}
@end

hello

hello

NSMutableDictionary+EM.m

越界

tableView