@interface NSArray (Extend)

- (id)objectAtCheckedIndex:(int)index;

- (NSString *)stringAtCheckedIndex:(int)index;

@end

@interface NSDictionary (Extend)

- (id)objectForCheckedKey:(id)key;

- (NSString *)stringForCheckedKey:(id)key;

@end

//检查index是否超过总大小

- (id)objectAtCheckedIndex:(int)index

{

if ([self count] <= index) {

//        DLog(@"NSArray数据超过容量");

return nil;

}

else if (index <= -1) {

//        DLog(@"index 错误");

return nil;

}

else

{

return [self objectAtIndex:index];

}

}

- (NSString *)stringAtCheckedIndex:(int)index

{

if ([self count] <= index) {

//        DLog(@"NSArray数据超过容量");

return @"";

}

else if (index <= -1) {

//        DLog(@"index 错误");

return @"";

}

else

{

return (NSString *)[self objectAtIndex:index];

}

}

@end

@implementation NSDictionary (Extend)

- (id)objectForCheckedKey:(id)key

{

id object_ = [self objectForKey:key];

if ([object_ isKindOfClass:[NSNull class] ]) {

return nil;

}

return object_;

}

- (NSString *)stringForCheckedKey:(id)key

{

id object_ = [self objectForKey:key];

if ([object_ isKindOfClass:[NSString class] ]) {

return object_;

}

if([object_ isKindOfClass:[NSNumber class] ]) {

return [object_ stringValue];

}

else if ([object_ isKindOfClass:[NSString class] ]) {

return @"";

}

else

{

return @"";

}

}

@end

使用stringForCheckedKey，objectForCheckedKey来取字典便不会崩溃，使用objectAtCheckedIndex，stringAtCheckedIndex便不会越界