Theme.swift

28 Oct 2015

I’ve been using (well I think, what is) an interesting pattern in some Swift projects recently. Rather than littering the code with random UIFont, UIColor initializers/magic variables we can define a struct that we’ll use as a container for all of our brand styles.

Defining common app wide constants such as view padding also allows us to remove magic numbers from our autolayout code (I am using SnapKit here)

self.loginButton.snp_makeConstraints { (make) -> Void in
    make.bottom.equalTo(self).offset(-Theme.Padding)
    make.left.equalTo(self).offset(Theme.Padding)
    make.right.equalTo(self).offset(-Theme.Padding)
    make.height.equalTo(60)
}

I also usually let the Theme struct contain my UIAppearance Proxy configuration too. In my applicationDidFinishLaunching I can now add a call to Theme.applyAppearance()

The Template

The standard Theme.swift file I usually start out with:

It’s a simple yet effective way to manage all things theme related in one place.

Reading through this I realise that I suck at writing! I’ll get better, eventually.