NSCache的主要方法.png
@interface AutoPurgeCache : NSCache
@end
// 自动清除缓存的Cache类
@implementation AutoPurgeCache
- (id)init
{
self = [super init];
if (self) {
[[NSNotificationCenter defaultCenter] addObserver:self selector:@selector(removeAllObjects) name:UIApplicationDidReceiveMemoryWarningNotification object:nil];
}
return self;
}
- (void)dealloc
{
[[NSNotificationCenter defaultCenter] removeObserver:self name:UIApplicationDidReceiveMemoryWarningNotification object:nil];
}
@end
@interface NSCache <KeyType, ObjectType> : NSObject {
@private
id _delegate;
void *_private[5];
void *_reserved;
}
@property (copy) NSString *name;
@property (nullable, assign) id<NSCacheDelegate> delegate;
- (nullable ObjectType)objectForKey:(KeyType)key;
- (void)setObject:(ObjectType)obj forKey:(KeyType)key; // 0 cost
- (void)setObject:(ObjectType)obj forKey:(KeyType)key cost:(NSUInteger)g;
- (void)removeObjectForKey:(KeyType)key;
- (void)removeAllObjects;
@property NSUInteger totalCostLimit; // limits are imprecise/not strict
// eg: countLimit = 10; 队列先进先出移除缓存 add 10 remove 0， add 11 remove 1 ......
@property NSUInteger countLimit; // limits are imprecise/not strict
@property BOOL evictsObjectsWithDiscardedContent;
@end
@protocol NSCacheDelegate <NSObject>
@optional
- (void)cache:(NSCache *)cache willEvictObject:(id)obj;
@end
