方法1.协议和代理
在UIView中设置协议和代理属性

#import <UIKit/UIKit.h>
@protocol RootViewDelegate<NSObject>
- (void)changeColor:(UIView *)view;
@end
@interface RootView : UIView
@property (nonatomic, assign) id<RootViewDelegate> delegate;
@end

让UIViewController遵守协议并实现协议中的中的方法

#import "RootViewController.h"
#import "RootView.h"
@interface RootViewController ()<RootViewDelegate>
@end
@implementation RootViewController
- (void)changeColor:(UIView *)view{
    view.backgroundColor = [UIColor redColor];
}
- (void)viewDidLoad {
    [super viewDidLoad];
    RootView *rootView = [[RootView alloc] initWithFrame:CGRectMake(100,100,100,100)];
    rootView.background = [UIColor whiteColor];
    rootView.delegate = self;
    [self.view addSubview:rootView];
    [rootView release];
@end

在UIView中调用协议方法

@implementation RootView
- (void)touchesBegin:(NSSet <NSTouch *> *)touches withEvent:(UIEvent *)event{
    if ([self.delegate respondsToSelector:@selector(changeColor)]) {
        [self.delegate changeColor:self];
    }
}
@end

方法2.模拟UIControl的addTarget方法
在UIView的.h文件中设置声明addTarget方法，并在.m中实现和调用方法

@interface RootView : NSObject
{
    id _target;
    SEL _action;
}
- (void)addTarget:(id)target action:(SEL)action;
@end


@implementation RootView
- (void)addTarget:(id)target action:(SEL)action{
    _target = target;
    _action = action;
}
- (void)touchesBegin:(NSSet <NSTouch *> *)touches withEvent:(UIEvent *)event{
    [_target performSelector:_action withObject:self];
}
@end

在UIViewController中调用addTarget方法

#import "RootView.h"
@implementation RootViewController
- (void)viewDidLoad{
    [super viewDidLoad];
    RootView *rootVC = [[RootView alloc] initWithFrame:CGRectMake(100,200,300,400)];
    [rootVC addTarget:self action:@selector(rootVCAction:)];
    [self.view addSubview:rootVC];
    [rootVC release];
}
- (void)rootVCAction:(UIView *)view{
    view.backgroundColor = [UIColor redColor];
}
@end