iOS 支持超出父视图范围的子视图点击

事件传递的逻辑伪代码

- (UIView *)hitTest:(CGPoint)point withEvent:(UIEvent *)event {
    
    
    // Determine whether you can receive touch events
    if (self.userInteractionEnabled == NO || self.hidden == YES || self.alpha <= 0.01) return nil;
    // Determine if the touch point is out of reach
    if (![self pointInside:point withEvent:event]) return nil;
    NSInteger count = self.subviews.count;
    for (NSInteger i = count - 1; i >= 0; i--) {
    
    
        UIView *childView = self.subviews[i];
        CGPoint childPoint = [self convertPoint:point toView:childView];
        UIView *fitView = [childView hitTest:childPoint withEvent:event];
        if (fitView) {
    
    
            return fitView;
        }
    }
    return self;
}

有以上伪代码 “ if (![self pointInside:point withEvent:event]) return nil; ”可知，当点击点不在父视图中的时候，返回nil。

思路

重写父视图的 - (UIView *)hitTest:(CGPoint)point withEvent:(UIEvent *)event 方法，判断点击点是否在子视图范围内，如果在，就返回子视图

实现代码

- (UIView *)hitTest:(CGPoint)point withEvent:(UIEvent *)event {
    
    
    UIView *view = [super hitTest:point withEvent:event];
    if (view == nil) {
    
    
        //将坐标由当前视图发送到 指定视图 fromView是无法响应的范围小父视图
        CGPoint stationPoint = [_headImageView convertPoint:point fromView:self];
        if (CGRectContainsPoint(_headImageView.bounds, stationPoint))
        {
    
    
            view = _headImageView;
        }
    }
    return view;
}