事件拦截

#import "ContentView.h"

@implementation ContentView

- (instancetype)initWithFrame:(CGRect)frame
{
    if (self = [super initWithFrame:frame])
    {
        UIButton *b1 = [UIButton buttonWithType: UIButtonTypeCustom];
        b1.backgroundColor = [UIColor redColor];
        b1.frame = CGRectMake(20, 40, 300, 300);
        [b1 addTarget:self action:@selector(buttonClick:) forControlEvents:UIControlEventTouchUpInside];
        b1.tag = 1;
        [self addSubview:b1];
        
        UIButton *b2 = [UIButton buttonWithType: UIButtonTypeCustom];
        b2.backgroundColor = [UIColor yellowColor];
        b2.frame = CGRectMake(20, 40, 260, 200);
        [b2 addTarget:self action:@selector(buttonClick:) forControlEvents:UIControlEventTouchUpInside];
        b2.tag = 2;
        [b1 addSubview:b2];
        
        UIButton *b3 = [UIButton buttonWithType:UIButtonTypeCustom];
        b3.frame = CGRectMake(40, 400, 200, 200);
        [b3 addTarget:self action:@selector(buttonClick:) forControlEvents:UIControlEventTouchUpInside];
        b3.tag = 3;
        b3.backgroundColor = [UIColor purpleColor];
        b3.layer.cornerRadius = b3.frame.size.width/2;
        [self addSubview:b3];
    }
    
    return self;
}

- (void)buttonClick:(UIButton *)btn
{
    NSLog(@"---%ld",btn.tag);
}

//触摸开始
//- (void)touchesBegan:(NSSet *)touches withEvent:(UIEvent *)event
//{
//    NSLog(@"contentView");
//}

//触摸事件交给哪个视图处理
- (UIView *)hitTest:(CGPoint)point withEvent:(UIEvent *)event
{
    UIButton *btn1 = (UIButton *)[self viewWithTag:1];
    UIButton *btn3 = (UIButton *)[self viewWithTag:3];
    
    //按钮3的中心
    CGPoint center = btn3.center;
    
    //触摸点到btn3的中心的距离
    CGFloat distance = sqrtf((center.x - point.x)*(center.x - point.x) + (center.y - point.y)*(center.y - point.y));
    
    //CGRectContainsPoint(frame, point)表示point点是否在frame范围内。
    if (CGRectContainsPoint(btn1.frame, point))
    {
        //如果点击的坐标在按钮的范围内，事件交给btn1处理
        return btn1;
    }
    //在圆形范围内
    else if (distance <= btn3.frame.size.width/2)
    {
        return btn3;
    }
    
    return self;
}

/*
// Only override drawRect: if you perform custom drawing.
// An empty implementation adversely affects performance during animation.
- (void)drawRect:(CGRect)rect {
    // Drawing code
}

#import "ViewController.h"
#import "ContentView.h"

@interface ViewController ()

@end

@implementation ViewController

- (void)viewDidLoad {
    [super viewDidLoad];
    // Do any additional setup after loading the view, typically from a nib.
    
    
    
    ContentView *contentView = [[ContentView alloc] initWithFrame:self.view.bounds];
    [self.view addSubview:contentView];
    
    
    
}

- (void)didReceiveMemoryWarning {
    [super didReceiveMemoryWarning];
    // Dispose of any resources that can be recreated.
}

@end