多个自动布局动画问题

Question

所以我有一个动画，从左到右移动一个视图，然后在.2秒后反弹。我为第二个视图启动相同的动画。问题是第一个动画中的layoutIfNeeded影响第二个动画，我没有得到0.2秒的延迟。有什么方法吗？ （我想我可以通过添加他们自己的超级视图中的每一行并在其上运行layoutIfNeeded来解决它，但我希望将视图数量保持在最低限度） 所以这是我的代码：

[self removeConstraint:_thirdRowConstraint];
    _thirdRowConstraint = [NSLayoutConstraint constraintWithItem:row3 attribute:NSLayoutAttributeCenterX relatedBy:NSLayoutRelationEqual toItem:self attribute:NSLayoutAttributeCenterX multiplier:1 constant:0];
    [self addConstraint:_thirdRowConstraint];
[UIView animateWithDuration:0.2 delay: 0 options: 0 animations:^{
    [self layoutIfNeeded];
} completion:^(BOOL finished) {
    [self removeConstraint:_thirdRowConstraint];
    _thirdRowConstraint = [NSLayoutConstraint constraintWithItem:row3 attribute:NSLayoutAttributeCenterX relatedBy:NSLayoutRelationEqual toItem:self attribute:NSLayoutAttributeCenterX multiplier:1 constant:20];
    [self addConstraint:_thirdRowConstraint];
    [UIView animateWithDuration:0.2 animations:^{
        [self layoutIfNeeded];
    } completion:^(BOOL finished) {
        [self removeConstraint:_thirdRowConstraint];
        _thirdRowConstraint = [NSLayoutConstraint constraintWithItem:row3 attribute:NSLayoutAttributeCenterX relatedBy:NSLayoutRelationEqual toItem:self attribute:NSLayoutAttributeCenterX multiplier:1 constant:0];
        [self addConstraint:_thirdRowConstraint];
        [UIView animateWithDuration:0.2 animations:^{
            [self layoutIfNeeded];
        }completion:^(BOOL finished) {

        }];
    }];
}];

[self removeConstraint:_forthRowConstraint];
    _forthRowConstraint = [NSLayoutConstraint constraintWithItem:row4 attribute:NSLayoutAttributeCenterX relatedBy:NSLayoutRelationEqual toItem:self attribute:NSLayoutAttributeCenterX multiplier:1 constant:0];
    [self addConstraint:_forthRowConstraint];
[UIView animateWithDuration:0.2 delay: 0.2 options: 0 animations:^{
    [self layoutIfNeeded];
} completion:^(BOOL finished) {
    [self removeConstraint:_forthRowConstraint];
    _forthRowConstraint = [NSLayoutConstraint constraintWithItem:row4 attribute:NSLayoutAttributeCenterX relatedBy:NSLayoutRelationEqual toItem:self attribute:NSLayoutAttributeCenterX multiplier:1 constant:20];
    [self addConstraint:_forthRowConstraint];
    [UIView animateWithDuration:0.2 animations:^{
        [self layoutIfNeeded];
    } completion:^(BOOL finished) {
        [self removeConstraint:_forthRowConstraint];
        _forthRowConstraint = [NSLayoutConstraint constraintWithItem:row4 attribute:NSLayoutAttributeCenterX relatedBy:NSLayoutRelationEqual toItem:self attribute:NSLayoutAttributeCenterX multiplier:1 constant:0];
        [self addConstraint:_forthRowConstraint];
        [UIView animateWithDuration:0.2 animations:^{
            [self layoutIfNeeded];
        }completion:^(BOOL finished) {

        }];
    }];
}];