如何使用KVO对NSMutableArray进行监听

[NSObject mutableArrayValueForKey:<#(nonnull NSString *)#>]

通过上面的方法获取到mutableArray并进行操作则可以对数组进行监听

@property (nonatomic, strong) NSMutableArray *mtbArray;

    [[self mutableArrayValueForKey:@"mtbArray"] removeObjectAtIndex:0];
    [[self mutableArrayValueForKey:@"mtbArray"] insertObject:@"" atIndex:1];