代码如下：[self layoutIfNeeded];必须加上，否则动画不生效

[UIView animateWithDuration:0.25 animations:^{
    [self.checkBoxBtn mas_updateConstraints:^(MASConstraintMaker *make) {
        make.top.mas_equalTo(100);
        make.left.mas_equalTo(50);
        make.width.mas_equalTo(25);
        make.height.mas_equalTo(25);
    }];
}];
[self layoutIfNeeded];// 需要在此处调用layoutIfNeeded方法才能产生动画