弹出动画

//弹出蒙版及动画

- (void)selectedCategory:(UIButton *)btn
{
    btn.selected = !btn.selected;
    if (btn.selected) {

        [self.tableView addSubview:self.blurView];
        //设置blurView的约束
        [self.blurView mas_makeConstraints:^(MASConstraintMaker *make) {
            make.left.equalTo(self.tableView);

            make.top.equalTo(self.view.mas_top);

            make.size.mas_equalTo(CGSizeMake(MY_WIHTE, MY_HEIGHT-49-64));
        }];
        // 设置transform
        self.blurView.transform = CGAffineTransformMakeTranslation(0, -MY_HEIGHT);
        
    }
    
    
    [UIView animateWithDuration:0.5 animations:^{
      if (btn.selected) {
            //旋转
            btn.transform = CGAffineTransformMakeRotation((CGFloat)M_PI_2);
            //复原
            self.blurView.transform = CGAffineTransformIdentity;

            self.tableView.scrollEnabled = NO;
      }else
      {
          //复原
          btn.transform = CGAffineTransformIdentity;
          self.blurView.transform = CGAffineTransformMakeTranslation(0, -MY_HEIGHT);
          self.tableView.scrollEnabled = YES;
      }
        
    } completion:^(BOOL finished) {
        if (!btn.selected) {
            [self.blurView removeFromSuperview];
        }
    }];
}