iOS 监听可变容器数量变化 笔记

直接上代码

// 可变数组
@property (nonatomic, strong) NSMutableArray *dataArray;

// 监听
 _dataArray = [NSMutableArray new];
 [self addObserver:self forKeyPath:@"dataArray" options:NSKeyValueObservingOptionNew | NSKeyValueObservingOptionOld context:nil];

// 代理
-(void)observeValueForKeyPath:(NSString *)keyPath ofObject:(id)object change:(NSDictionary<NSString *,id> *)change context:(void *)context{
    NSLog(@"%@",change);
}

// 记得移除
-(void)dealloc{
    [self removeObserver:self forKeyPath:@"dataArray"]; 
}

// 添加数据
- (void)addItemObserver{
    [[self mutableArrayValueForKey:@"dataArray"] addObject:@"foo"];
}
// 删除数据
- (void)removeItemObserver{
    [[self mutableArrayValueForKey:@"dataArray"] removeLastObject];
}

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创建一个安全的定时器

​​https://github.com/xjh093/JHSafeTimer​​

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