添加 NSLayoutConstraints 的代码放在什么位置？

- (void)loadView
{
    self.view = [UIView new];

    [self.view addSubview:self.blueView];
    [self.view addSubview:self.redView];
    [self.view addSubview:self.yellowView];
    [self.view addSubview:self.greenView];

    [self.view setNeedsUpdateConstraints]; // bootstrap Auto Layout
}

- (void)updateViewConstraints
{
    if (!self.didSetupConstraints) {
        // Apply a fixed height of 50 pt to two views at once, and a fixed height of 70 pt to another two views
        [@[self.redView, self.yellowView] autoSetViewsDimension:ALDimensionHeight toSize:50.0];
        [@[self.blueView, self.greenView] autoSetViewsDimension:ALDimensionHeight toSize:70.0];

        self.didSetupConstraints = YES;
    }

    [super updateViewConstraints];
}