title: Trying to use Slider to adjust color in Swift / iOS 8 - get "Extra Argument Saturation In Call" error
body: <p>I'm learning to use the controls in Swift for iOS. I'm trying to build a simple app that uses the Slider to adjust the background color of the screen using the UIColor class.</p>
  
  <pre><code>// function is called when slider is moved.
  @IBAction func sliderValueChanged(sender: UISlider) {
  
      // creates variable to hold new color
      var newBackgroundColor : UIColor
  
      // creates variable holding the value from slider
      var sliderValue = slider.value
  
      // changes the newBackgroundColor variable to new color values. 
      newBackgroundColor = UIColor(hue: sliderValue, saturation: 0.5, brightness: 0.5, alpha: 0.5)
  
      // changes the background color
      self.view.backgroundColor = newBackgroundColor
  </code></pre>
  
  <p>The slider seems to be connected correctly, and the code for adjusting the background works. I've created a variable to hold the value of the slider (between 0.0 and 1.0) but when I try to insert this variable into the UIColor code it comes up with an error "Extra Argument Saturation In Call".</p>
  
  <p>PS: Sorry if the code is scrappy. It's my first post (I can't post images yet).</p>