title: Programmatically adding constraints breaks auto layout constraints
body: <p><strong>Edit 1</strong></p>
  
  <p>Hello, This is my first time using code to add constraints. I normally just use interface builder. I am trying to add a vertical UISlider, before I thought that mixing visually added constraints was interfering with coded constraints. I have now updated my code and therefore this question to create constrains using ONLY code in this particular view container.</p>
  
  <p>What I have done is I created a view directly underneath another view. I created 3  small views inside that that match the width of the textfields in the view above and then spaced them out the same as how the textfields are spaced out. </p>
  
  <p>For testing purposes only I gave these 3 small views a color to see if it worked, and it does. 
  <a href="https://i.stack.imgur.com/lMT4r.png" rel="nofollow noreferrer"><img src="https://i.stack.imgur.com/lMT4r.png" alt="Good Screenshot"></a></p>
  
  <p>When I actually finish the app those red, green, and blue views will be clear. The only reason I wanted them was so when I create the sliders I can constrain each one of them to the center of the view...which is how the labels above the textfields are constrained.</p>
  
  <p>Here is the code for this
  which works</p>
  
  <pre><code>    // Mark: Hidden View
  
      let leftHiddenView = UIView()
      let centerHiddenView = UIView()
      let rightHiddenView = UIView()
  
      let hiddenViews = [leftHiddenView, centerHiddenView, rightHiddenView]
  
      for views in hiddenViews {
  
          views.translatesAutoresizingMaskIntoConstraints = false
          sliderContainer.addSubview(views)
          views.backgroundColor = .white
  
          let widthConstraint = views.widthAnchor.constraint(equalToConstant: 35)
          let heightConstraint = views.heightAnchor.constraint(equalToConstant: 5)
  
          NSLayoutConstraint.activate([widthConstraint, heightConstraint])
      }
  
      let centerViewHorizontalConstraint = centerHiddenView.centerXAnchor.constraint(equalTo: sliderContainer.centerXAnchor)
      let centerViewTopConstraint = centerHiddenView.topAnchor.constraint(equalTo: sliderContainer.topAnchor, constant: 50)
  
      NSLayoutConstraint.activate([centerViewHorizontalConstraint, centerViewTopConstraint])
  
      let leftViewVerticalCenterConstraint = leftHiddenView.centerYAnchor.constraint(equalTo: centerHiddenView.centerYAnchor, constant: 0)
      let leftViewTrailingConstraint = leftHiddenView.trailingAnchor.constraint(equalTo: centerHiddenView.leadingAnchor, constant: -60)
  
  
      NSLayoutConstraint.activate([leftViewVerticalCenterConstraint, leftViewTrailingConstraint])
  
      let rightViewVerticalCenterConstraint = rightHiddenView.centerYAnchor.constraint(equalTo: centerHiddenView.centerYAnchor, constant: 0)
      let rightViewTrailingConstraint = rightHiddenView.leadingAnchor.constraint(equalTo: centerHiddenView.trailingAnchor, constant: 60)
  
      NSLayoutConstraint.activate([rightViewVerticalCenterConstraint, rightViewTrailingConstraint])
  </code></pre>
  
  <p>Now, I started to add a UISlider as vertical. And the exact same thing that happened before happened now. </p>
  
  <p><a href="https://i.stack.imgur.com/uAMso.png" rel="nofollow noreferrer"><img src="https://i.stack.imgur.com/uAMso.png" alt="bad screenshot"></a></p>
  
  <p>As you can see everything breaks.</p>
  
  <p>Here is the code thus far on that </p>
  
  <pre><code>    // Mark: Slider View
  
      let leftSlider = UISlider()
      let centerSlider = UISlider()
      let rightSlider = UISlider()
  
      let colorSliders = [leftSlider, centerSlider, rightSlider]
  
      for slider in colorSliders {
  
          slider.translatesAutoresizingMaskIntoConstraints = false
          sliderContainer.addSubview(slider)
  
          let w = sliderContainer.bounds.width
          slider.bounds.size.width = w
          slider.center = CGPoint(x: w/2, y: w/2)
          slider.transform = CGAffineTransform(rotationAngle: CGFloat(M_PI_2))
  
          slider.value = 0
          slider.minimumValue = 0
          slider.maximumValue = 255
  
          let sliderTopConstraint = slider.topAnchor.constraint(equalTo: centerHiddenView.bottomAnchor, constant: 5)
          let sliderBottomConstraint = slider.bottomAnchor.constraint(equalTo: sliderContainer.bottomAnchor, constant: 5)
  
          NSLayoutConstraint.activate([sliderTopConstraint, sliderBottomConstraint])
          slider.backgroundColor = .purple
  
      }
  
      let centerSliderHorizontalConstraints = centerSlider.centerXAnchor.constraint(equalTo: sliderContainer.centerXAnchor)
      NSLayoutConstraint.activate([centerSliderHorizontalConstraints])
  </code></pre>