title: iOS slider to change a color changes wrong label
body: <p>Am using Xcode 4.5, targeting iOS5 and above.
  I am updating an app, using Storyboard for all scenes. Have a previous XIB and controller that I converted, but it is not functioning the same way.
  The controller allows changing the color of text and creating new colors.
  Creating new RGB colors relies on 3 Horizontal Sliders to change a swatch of color and the corresponding RGB values on 3 separate labels, before saving the new color. The sliders are Value Changed Sent Events and are hooked up to one action.
  The issue: when I change any of the sliders, ONLY the red label and red color value. 
  I've tried changing the individual cases for the sliders into separate actions, and moving the setPreviewImage into a method of its own, but then, it does not change the swatch.
  Any help would be greatly appreciated. Thanks in advance.</p>
  
  <pre><code>-(IBAction)RGBSliderChange:(UISlider *)sender {
     switch ([sender tag])
    {
        case 0: {
           self.rLabel.text = [NSString stringWithFormat:@"%d", (int)[sender value]];
           break;
        }
        case 1: {
           self.gLabel.text = [NSString stringWithFormat:@"%d", (int)[sender value]];
           break;
        }
        case 2: {
           self.bLabel.text = [NSString stringWithFormat:@"%d", (int)[sender value]];
           break;
        }
        default:
           break;
    }
        self.colorPreviewImage.backgroundColor = [UIColor colorWithRed:(CGFloat)[self.rLabel.text floatValue]/256
             green:(CGFloat)[self.gLabel.text floatValue]/256
             blue:(CGFloat)[self.bLabel.text floatValue]/256
             alpha:1.0];
  }
  </code></pre>