Change Spacing Between UIBarButtonItems in iOS 8

Thanks to @Fogmeister's help, I figured out that the width of the view1 and view2 objects, which are UIButtons, was too large. That was why there was abnormal spacing between them. Here is my final code:

    // Get the first button's image
    let view1Img = UIImage(named: "Image1")!
    
    // Create the first button
    let view1 = UIButton(frame: CGRect(x: 0, y: 0, width: view1Img.size.width, height: view1Img.size.height))
    
    // Get the second button's image
    let view2Img = UIImage(named: "Image2")!
    
    // Create the second button
    let view2 = UIButton(frame: CGRect(x: 0, y: 0, width: view2Img.size.width, height: view2Img.size.height))
    
    // Create two UIBarButtonItems
    let item1 = UIBarButtonItem(customView: view1)
    let item2 = UIBarButtonItem(customView: view2)
    
    // Set 26px of fixed space between the two UIBarButtonItems
    let fixedSpace = UIBarButtonItem(barButtonSystemItem: .fixedSpace, target: nil, action: nil)
    fixedSpace.width = 26.0
    
    // Set -7px of fixed space before the two UIBarButtonItems so that they are aligned to the edge
    let negativeSpace = UIBarButtonItem(barButtonSystemItem: .fixedSpace, target: nil, action: nil)
    negativeSpace.width = -7.0
    
    // Add the rightBarButtonItems on the navigation bar
    viewController.navigationItem.rightBarButtonItems = [negativeSpace, item2, fixedSpace, item1]

I create the background image for the first UIButton and then use its size to create the frame for that UIButton. I perform the same actions for the second UIButton. Then, I create UIBarButtonItems from the two UIButtons. After that, I create 26px of fixed space and then -7.0px of fixed space. The purpose of the former is to create a certain amount of space between the two buttons. The purpose of the latter is to move all UIBarButtonItems over to the right. Then, I add all of the UIBarButtonItems as rightBarButtonItems in a particular order so I get the look that I want.

It works great now! Thanks for all of the help, Fogmeister!

Another way is just by changing the Left and Right Image Inset in IB.