The online home of John Pollard

Swift and Build Odds and Sods

Lots more tweaks of the UI, in particular making a better Settings page.

Settings Page

It’s a pretty straightforward static table view, but there were a few things I learnt/remembered along the way that are worth sharing here.

Selectors in Swift

Installing the app on my iPad exposed a bug I’d introduced in a selector - just shows you can’t always believe everything you read on StackOverflow!

Setting up the handler for incoming notifications, you need to add a colon to the end of the method name in the selector e.g.

NSNotificationCenter.defaultCenter().addObserver(self, selector: "updateKVStoreItems:", name: NSUbiquitousKeyValueStoreDidChangeExternallyNotification, object: store)

Also on the function being selected, you need to annotate the function with @objc so it can correctly interact with the Objective-C library code calling it

Custom data entry for text

I wanted a simple way of entering dates, as I stated in an earlier post simply adding a DatePicker to the page is pretty ugly and takes up a lot of screen.

The solution is to show the dates in a textbox, but then setting the inputView of the text box to be a DatePicker.

// Setup the date pickers as editors for text fields
self.textStart.inputView = self.startDatePicker

Text Date Picker

Obviously you have to take care in calling self.view.endEditing(true) as appropriate when other elements are selected, but it’s a neat solution that works well.

Setting the build version automatically

I can’t remember where I found this originally, but I’ve used it in projects before. Basically I want to set the build number automatically based on the Github revision number, so I can call it in the code.

The trick is to add this script as part of the “Run Script” you can set in a target’s Build Phases

git=`sh /etc/profile; which git`
appBuild=`$git rev-list --all |wc -l`
/usr/libexec/PlistBuddy -c "Set :CFBundleVersion $appBuild" "${TARGET_BUILD_DIR}/${INFOPLIST_PATH}"

You can then use this to add a version number to your display:

// Add version number
let infoDictionary = NSBundle.mainBundle();
let version = infoDictionary.objectForInfoDictionaryKey("CFBundleShortVersionString") as! String;
let build = infoDictionary.objectForInfoDictionaryKey("CFBundleVersion") as! String;
self.labelVersion.text = String(format: "v%@.%@", version, build);

Having a version number in the settings can be invaluable when trying to debug customer issues.

Next steps

Add some quality and animations to the counter control

Previous posts in the series

The code for the project is also available on GitHub