1.- (BOOL)isDescendantOfView:(UIView *)view; // returns YES for self.
使用isDescendantOfView方法來驗證，是不是子類關系，不一定是直接子類。
// 彈框bgView
? ? [self.view addSubview:self.showView];
? ? // 創建一個輕拍手勢 同時綁定了一個事件
? ? UITapGestureRecognizer *aTapGR = [[UITapGestureRecognizer alloc] initWithTarget:self action:@selector(tapGRAction:)];
? ? aTapGR.delegate = self;
? ? [self.view addGestureRecognizer:aTapGR];
代理方法，只是陰影背景響應這個手勢，中間視圖不響應
- (BOOL)gestureRecognizer:(UIGestureRecognizer *)gestureRecognizer shouldReceiveTouch:(UITouch *)touch{
? ?if ([touch.view isDescendantOfView:self.showView]) {
? ? ? ? return NO;
? ? }
? ? return YES;
}
