iOS如何定义名为任意的变量详解

// MYScrollView.m

- (instancetype)init
{
 ...
 self.delegae = self;
 ...
}

- (void)scrollViewDidScroll:(UIScrollView *)scrollView
{
 NSLog(@"%s 我被执行", __func__);
 ...
}

// ViewController.m
- (void)viewDidLoad 
{
 ...
 scrollView.delegate = self;
 ...
}

- (void)scrollViewDidScroll:(UIScrollView *)scrollView
{
 NSLog(@"%s 执行了ViewController里的方法,就不执行MYScrollView的方法了", __func__);
 ...
}

// ViewController.m
- (void)scrollViewDidScroll:(UIScrollView *)scrollView
{
 [(MYScrollView *)scrollView scrollViewDidScroll:scrollView];
 ...
}
...

// MYScrollView.m
@synthesize delegate = _myDelegate;

- (instancetype)init
{
 ...
 [super setDelegate:self];
 ...
}

// 需要挂钩多少delegate方法就写多少
- (void)scrollViewDidScroll:(UIScrollView *)scrollView
{
 NSLog(@"%s 我先执行", __func__);
 [self.delegate scrollViewDidScroll:scrollView];
}


// ViewController.m
- (void)viewDidLoad 
{
 ...
 scrollView.delegate = self;
 ...
}

- (void)scrollViewDidScroll:(UIScrollView *)scrollView
{
 NSLog(@"%s 我接着被执行了", __func__);
 ...
}