参考:简书-事件穿透<p>坐标转换

appDelegate.m

- (BOOL)application:(UIApplication *)application didFinishLaunchingWithOptions:(NSDictionary *)launchOptions {
    // Override point for customization after application launch.
    
    self.window = [[UIWindow alloc] initWithFrame:[UIScreen mainScreen].bounds];
    
    self.window.backgroundColor = [UIColor orangeColor];
    
    ViewController *vc = [[ViewController alloc] init];
    UINavigationController *nav = [[UINavigationController alloc] initWithRootViewController:vc];
    self.window.rootViewController = nav;
    
    return YES;
}

AboveButton.h

//
//  AboveButton.h
//  LuckyCoderCai_DemoTest
//
//  Created by luckyCoderCai on 16/9/21.
//  Copyright © 2016年 luckyCoderCai. All rights reserved.
//

#import <UIKit/UIKit.h>

@interface AboveButton : UIButton

@property (nonatomic, strong) UIButton *underBtn;

@end

AboveButton.m

//
//  AboveButton.m
//  LuckyCoderCai_DemoTest
//
//  Created by luckyCoderCai on 16/9/21.
//  Copyright © 2016年 luckyCoderCai. All rights reserved.
//

#import "AboveButton.h"

@implementation AboveButton

- (UIView *)hitTest:(CGPoint)point withEvent:(UIEvent *)event
{
    //将像素point由point所在视图转换到目标视图view中，返回在目标视图view中的像素值
    CGPoint underBtnPoint = [self convertPoint:point toView:_underBtn];
    
    if ([_underBtn pointInside:underBtnPoint withEvent:event]) {
        return _underBtn;
    }
    
    return [super hitTest:point withEvent:event];
}

@end

ViewController.m

//
//  ViewController.m
//  LuckyCoderCai_DemoTest
//
//  Created by luckyCoderCai on 16/9/14.
//  Copyright © 2016年 luckyCoderCai. All rights reserved.
//

#define NSLog(FORMAT, ...) fprintf(stderr, "[%s:%d行] %s\n",[[[NSString stringWithUTF8String:__FILE__] lastPathComponent] UTF8String], __LINE__, [[NSString stringWithFormat:FORMAT, ##__VA_ARGS__] UTF8String]);

#import "ViewController.h"
#import "AboveButton.h"

@interface ViewController ()

@property (nonatomic, strong) AboveButton *aboveBtn;

@end

@implementation ViewController

- (void)viewDidLoad {
    [super viewDidLoad];
    // Do any additional setup after loading the view, typically from a nib.
    
    self.title = @"DemoTest";
    self.view.backgroundColor = [UIColor orangeColor];
    
    [self hitTest];
    
}

- (void)hitTest
{
    UIButton *btn = [UIButton buttonWithType:UIButtonTypeCustom];
    btn.backgroundColor = [UIColor purpleColor];
    [btn setTitle:@"under" forState:UIControlStateNormal];
    btn.frame = CGRectMake(100, 100, 200, 100);
    [self.view addSubview:btn];
    [btn addTarget:self action:@selector(underBtnAction) forControlEvents:UIControlEventTouchUpInside];
    
    self.aboveBtn = [AboveButton buttonWithType:UIButtonTypeCustom];
    self.aboveBtn.frame = CGRectMake(220, 160, 200, 100);
    [self.aboveBtn setTitle:@"above" forState:UIControlStateNormal];
    self.aboveBtn.backgroundColor = [UIColor cyanColor];
    [self.view addSubview:self.aboveBtn];
    [self.aboveBtn addTarget:self action:@selector(aboveBtnAction) forControlEvents:UIControlEventTouchUpInside];
    
    self.aboveBtn.underBtn = btn;
}

- (void)aboveBtnAction
{
    NSLog(@"--aboveBtn");
}

- (void)underBtnAction
{
    NSLog(@"---underBtn");
}

@end

Gif:

hitTest.gif