@property (nonatomic,strong) UIActivityIndicatorView *activityIndicatorView; //旋转菊花view
@property (nonatomic,strong) UIView *forwardView; //刷新是蒙版view

#pragma mark 添加动画效果 -- 点击事件
- (IBAction)click:(UIButton *)sender {
    
    [self.view addSubview:self.forwardView];
    self.activityIndicatorView.center = CGPointMake(self.view.bounds.size.width/2, self.view.bounds.size.height/2); //UIActivityIndicatorView大小不能改变，只能设置其center
    [self.activityIndicatorView startAnimating]; //开始动画
    [self.view addSubview:self.activityIndicatorView];
    //1.5秒后执行下面方法
    dispatch_after(dispatch_time(DISPATCH_TIME_NOW, (int64_t)(1.5 * NSEC_PER_SEC)), dispatch_get_main_queue(), ^{
        [self.activityIndicatorView stopAnimating]; //结束动画
        [self.activityIndicatorView removeFromSuperview]; //移除圆圈view
        [self.forwardView removeFromSuperview]; //移除蒙版view
    });
}

#pragma mark 创建蒙版view
- (UIView *)forwardView {
    if (!_forwardView) {
        _forwardView = [[UIView alloc] init];
        _forwardView.frame = [[UIScreen mainScreen] bounds];
        _forwardView.alpha = 0.5;
        _forwardView.backgroundColor = [UIColor grayColor];
    }
    return _forwardView;
}

#pragma mark 创建圆圈view
- (UIActivityIndicatorView *)activityIndicatorView {
    if (!_activityIndicatorView) {
        _activityIndicatorView = [[UIActivityIndicatorView alloc] initWithActivityIndicatorStyle:UIActivityIndicatorViewStyleWhiteLarge];
        _activityIndicatorView.hidesWhenStopped = YES;
    }
    return _activityIndicatorView;
}