Once I began out growing iOS apps, 11 years in the past I put a number of apps on the App Retailer. Since they grew to become fewer and fewer because the revenue from them didn’t warrant updating them. Amongst these my most profitable one was iWoman, which I offered in 2015. My second-most-valuable (when it comes to income) remained my beloved SpeakerClock, the final app standing.
I had left SpeakerClock on-line for the primary cause that it stored producing like a median of $100 per 30 days, even with out me doing something on it. For that cause, I didn’t wish to make it free, however fairly put it to a comparatively excessive price ticket of $5. There may be additionally an In-App-Buy of one other $5. I figured “why kill the cow whereas it nonetheless produces some tasty milk”.
The opposite aspect impact of those value tags was that – I consider – solely individuals who actually needed what the app was providing would really buy it. My philosophy with this talking timer was to have the most important LED digits potential, with the performance that helps the talking model of TED Talks, which traditionally have defaulted to a most size of 18 minutes.
Some crashes launched by new iOS variations brought about me to do small bug fixing releases (for iOS 3 in 2010, iOS 5 in 2011, and 2017 for iOS 10). Additionally, wanting again on the launch notes of these variations, I had made this actual promise:
“We’ve got completely modernised the code base in order that we will carry you some thrilling new options within the subsequent main launch”
However I didn’t lie with this assertion, a “subsequent main” launch would have been model 2.0. However I didn’t ever dare to show the model quantity up that top. I solely elevated the third digit of the model quantity.
Apple did pressure me to do a brand new construct finally, once they cracked down on apps which weren’t up to date in too lengthy a time. And the newest replace they did themselves, when the Apple certificates had expired they usually re-signed my app on their servers with out me doing something.
Enter SwiftUI
Over the previous couple of months, I’ve grown very keen on SwiftUI. Being a developer on Apple platforms for greater than a decade made me fairly bored with having to maintain writing the identical MVC code numerous instances. And that might solely get you want commonplace performance, nothing actually thrilling. So I jumped on the probability when one among my shoppers requested me to implement a brand new iOS Widget in SwiftUI, within the fall of 2020. Apple had turned to SwiftUI as the one manner you might create such widgets due to SwiftUIs means to provide and protect a static view hierarchy which the system may present to the person at sure factors in a timeline with out substantial energy utilization.
My consumer was joyful concerning the consequence and so I used to be tasked with the subsequent degree of SwiftUI growth. I wanted to implement a watchOS app, additionally totally in SwiftUI. Improvement was fairly much like the widget, however this time I additionally wanted to take care of person interplay and communication with the iOS counterpart app. That each one took some a number of months greater than the widget, however once more elevated my SwiftUI expertise tremendously.
After having delivered the watch app, I had a little bit additional time obtainable to do one thing for myself. I do have another concepts for apps, however my ideas turned to SpeakerClock. I figured that this extremely customized UI would lend itself properly to be applied in SwiftUI.
Paths in Shapes
Crucial asset within the legacy code was the drawing of the massive pink LED digits and the way they organize themselves in portrait versus panorama, in a pleasant animation. So my first SwiftUI view was one which had a Path aspect with the SwiftUI instructions including the trail parts to make up the person bars of the LED. My first error right here involved utilizing a GeometryReader to find out the scale of the trail. The LED digits have a hard and fast facet ratio and the drawing coordinates are based mostly on these.
struct LEDDigit: View
{
var digit: Int? = nil
var physique: some View
{
GeometryReader { proxy in
let (w, h) = proxy.unitSize
// high horizontal line
Path { path in
path.transfer(to: CGPoint(x: 24 * w, y: 7 * h))
path.addLine(to: CGPoint(x: 60 * w, y: 7 * h))
path.addLine(to: CGPoint(x: 62 * w, y: 10 * h))
path.addLine(to: CGPoint(x: 57 * w, y: 15 * h))
path.addLine(to: CGPoint(x: 24 * w, y: 15 * h))
path.addLine(to: CGPoint(x: 21 * w, y: 10 * h))
path.closeSubpath()
}
.activeLEDEffect(when: [0, 2, 3, 5, 7, 8, 9].accommodates(digit))
...
}
Whereas this produces the right output, it causes the person Path
s to animate individually when rotating the machine. I solved this downside by transferring the person path’s code right into a Form the place I’m including the bars solely based mostly on whether or not I’m searching for the energetic or inactive LED parts. The trail(in rect: CGRect) operate palms us the required dimension, so we don’t a GeometryReader any extra.
struct LEDDigitShape: Form
{
var digit: Int? = nil
var isActive: Bool
func path(in rect: CGRect) -> Path
{
let w = rect.dimension.width / 73
let h = rect.dimension.peak / 110
var path = Path()
// high horizontal line
if [0, 2, 3, 5, 7, 8, 9].accommodates(digit) == isActive
{
path.transfer(to: CGPoint(x: 24 * w, y: 7 * h))
path.addLine(to: CGPoint(x: 60 * w, y: 7 * h))
path.addLine(to: CGPoint(x: 62 * w, y: 10 * h))
path.addLine(to: CGPoint(x: 57 * w, y: 15 * h))
path.addLine(to: CGPoint(x: 24 * w, y: 15 * h))
path.addLine(to: CGPoint(x: 21 * w, y: 10 * h))
path.closeSubpath()
}
...
}
That is used such:
struct LEDDigit: View
{
var digit: Int? = nil
var physique: some View
{
ZStack
{
LEDDigitShape(digit: digit, dot: dot, isActive: false)
.activeLEDEffect(isActive: false)
LEDDigitShape(digit: digit, dot: dot, isActive: true)
.activeLEDEffect(isActive: true)
}
}
The 2 members of the ZStack
draw all of the inactive LED parts behind the energetic LED parts. It nonetheless wanted to be two Shapes as a result of one form can solely have a single drawing model. The inactive parts are merely crammed in a grey. The energetic parts are stuffed with pink and have a pink glow round them simulating some radiance.
With this strategy a digit is at all times drawn in its entirety which lends itself to easy resizing.
Structure and Orientation Woes
The subsequent step was to combination a number of LED digits and lay them out over the display screen with totally different positions for panorama and portrait orientations, with a easy animation while you rotate the machine.
I’ve mainly two layouts:
- Hour digits, Colon, Minute digits (in a
HStack
)- in horizontal format with the outer sides touching the secure space insets - A
VStack
of Hour digits and Minute digits – in vertical format
Sounds simple, however my makes an attempt with HStacks and VStacks failed miserably. Firstly of the rotation animation the digits would at all times get a really small body increasing into the ultimate one.
I can solely think about that by some means the SwiftUI format system doesn’t do not forget that these are the identical views. So I attempted giving them static identifiers and I additionally tried geometry matching. However I couldn’t shake these animation artefacts. There should be some piece lacking in my understanding about view identification.
Ultimately I got here again to doing my very own format inside a GeometryReader, setting body’s width/peak and acceptable offsets (i.e. translation) for particular person parts. This works very properly and likewise lets me have a separate animation for the opacity of the colon.
The colon sticks to the best aspect of the hour digits and disappears in portrait format. By sorting view modifiers in a sure manner I used to be in a position to get this impact that the colon fades in with a slight delay.
var physique: some View
{
GeometryReader { proxy in
let digitSize = self.digitSize(proxy: proxy)
let colonSize = self.colonSize(proxy: proxy)
let centeringOffset = self.centeringOffset(proxy: proxy)
let isLandscape = proxy.isLandscape
let timerSize = self.timerSize(proxy: proxy)
Group
{
LEDNumber(worth: mannequin.countdown.minutes)
.body(width: digitSize.width * 2, peak: digitSize.peak)
.animation(nil)
LEDColon()
.body(width: colonSize.width, peak: colonSize.peak)
.offset(x: digitSize.width * 2, y: 0)
.animation(nil)
.opacity(isLandscape ? 1 : 0)
.animation(isPadOrPhone ? (isLandscape ? .easeInOut.delay(0.2)
: .easeInOut) : nil)
LEDNumber(worth: mannequin.countdown.seconds)
.body(width: digitSize.width * 2, peak: digitSize.peak)
.offset(x: isLandscape ? digitSize.width * 2 + colonSize.width : 0,
y: isLandscape ? 0 : digitSize.peak)
.animation(nil)
}
.offset(x: centeringOffset.width,
y: centeringOffset.peak)
You possibly can see that I’m particularly disabling animation with .animation(nil)
for probably the most elements as a result of I discovered that the animation in any other case is at all times out of sync with the rotation resizing animation. The LED colon then again has its personal animation with a further delay of 0.2 seconds.
The second cause why I explicitly disabled animations is as a result of on the Mac model these animations would lag behind the resizing of the app’s window. This resizing additionally switches between each layouts relying on the way you drag the window nook, form of like “responsive design” as now we have seen on HTML net pages. Extra on Mac issues additional down beneath.
Multi-Modal Buttons
One other problem that had me strive a number of approaches involved the preset buttons (high left) and visitors mild buttons (middle backside). These buttons have a special operate for a single faucet (choose) versus a protracted press (set).
The principle downside is that you simply can’t have a easy .onLongPressGesture
as a result of this prevents the traditional faucets from being dealt with. One strategy is to have a .simultaneousGesture
for the lengthy press, however then the faucet motion is executed proper (i.e. “simultaneous”) after the lengthy press motion if you happen to carry the finger over the button. The opposite strategy is to make use of a .highPriorityGesture
which once more disables the built-in faucet.
I ended up with the next strategy which makes use of the gesture masks to selectively disable the lengthy press gesture if there isn’t any lengthy press motion and to disable the faucet gesture if a protracted press was detected.
struct LEDButton: View
{
var motion: ()->()
var longPressAction: (()->())?
@ViewBuilder var content material: ()->Content material
@State fileprivate var didLongPress = false
var physique: some View
{
Button(motion: {}, label: content material) // will need to have empty motion
.contentShape(Circle())
.buttonStyle(PlainButtonStyle()) // wanted for Mac
.simultaneousGesture(LongPressGesture().onEnded({ _ in
didLongPress = true
longPressAction!()
didLongPress = false
}), together with: longPressAction != nil ? .all : .subviews)
.highPriorityGesture(TapGesture().onEnded({ _ in
motion()
}), together with: didLongPress ? .subviews : .all)
}
}
This strategy makes use of a customized TapGesture
in tandem with the LongPressGesture
. A @State
variable retains observe of the lengthy press. We do must reset didLongPress
to false
or else all subsequent faucets would proceed to be ignored. I discovered that I don’t want a dispatch async for placing it again to false.
I consider that the rationale for that’s that the primary setting of the variable causes the physique to be up to date and thus the together with:
to disable the faucet gesture whereas in progress. Thus the faucet doesn’t fireplace upon releasing the lengthy press. Good to know: The .all
allows the gesture and the .subviews
disables a gesture.
Opposite to different approaches I’ve seen on the web this strategy preserves the usual habits of Button for highlighting, Whilst you press a customized button like this, it makes it barely clear.
A Mac Model – For Free?
The massive promise of SwiftUI is that you’d get a Mac model of your app for little additional work, successfully “totally free”. So I made a decision to place this to the check additionally produce a macOS model. I set the focused units to iPhone, iPad, Mac and selected the “Optimize Interface for Mac” as a result of that sounded to me like the higher consequence.

This optimized mode brought about some points for my customized buttons, as a result of they obtained changed with empty spherical rects destroying my customized look. You possibly can forestall this modification by including .buttonStyle(PlainButtonStyle())
.
Aside from this my code actually did run as a local Mac app fairly properly. Behind the scenes although it’s all Mac Catalyst. As I perceive it, meaning UIKit remains to be on the helm, on Mac only a macOS model of it.
I left the code signing settings alone as I needed to have customers be capable to set up the Mac and iOS variations with the identical buy. This “common buy” is enabled by having the identical bundle identifier for each variations.

Some very minor tweaks have been required for adjusting some minimal and most button sizes. There’s a bug on macOS that stumped me for some time. Solely on Mac I discovered that after I tapped in sure spots in my app this is able to trigger gestures to cease working. Then after I triggered a brand new format by resizing the window, the whole lot returned again to regular.
My workaround for this was to connect the Pan Gesture (for setting the timer) solely to the LED digits. This fashion there isn’t any interference and all buttons proceed to work usually. The system would possibly get confused by having too many conflicting gestures on high of one another.
A side-effect of the Mac model is that you simply begin to connect keyboard shortcuts to buttons. This was additionally a cause why I needed to get Button
to work with faucet and lengthy press versus making a customized view that’s not a button.
let title = "(index+1)"
PresetButton()
.keyboardShortcut(KeyEquivalent(title.first!), modifiers: [.command])
This fashion you’ll be able to set off the preset buttons additionally with COMMAND plus quantity. And never only for the Mac app, however that works for iPads with hooked up keyboard as properly.
That obtained me pondering, that perhaps it could be nice to permit the area bar to cease/begin the timer, like we’re used to from video gamers. For that function I’ve an empty utterly black button behind the LED digits:
Button(motion: { mannequin.isTimerActive.toggle() },
label: {
Rectangle()
.foregroundColor(.black)
.body(width: timerSize.width, peak: timerSize.peak)
.onTapGesture(rely: 2) { mannequin.restoreGreenTime() }
})
.keyboardShortcut(.area, modifiers: [])
.buttonStyle(PlainButtonStyle())
This button permits me so as to add a keyboard shortcut for area to behave the identical as a faucet. Curiously having a two-tap gesture hooked up to the Rectangle()
poses no downside.
I submitted the Mac construct proper after the one for iOS however initially obtained a surprising rejection:
The person interface of your app will not be in line with the macOS Human Interface Tips. Particularly:
We discovered that the app accommodates iOS contact management directions comparable to faucet and swipe.
The explanation for that was that I put again the assistance display screen with a textual content I had beforehand written with iOS in thoughts. I wanted to switch mentions of swiping with dragging and as a substitute of tapping you might be clicking. I’ve exhausting coded the textual content and formatting for now and with and #if
I can change the textual content between a model for Mac and one for iOS.
Group
{
Textual content("Setting the Timer")
.font(.headline)
.padding(.backside, 5)
#if targetEnvironment(macCatalyst)
Textual content("To regulate the timer, click on on the LED digits and drag horizontally.")
.font(.physique)
.padding(.backside, 5)
#else
Textual content("To regulate the timer swipe left and proper.")
.font(.physique)
.padding(.backside, 5)
#endif
}
As soon as I had made these modifications the Mac app was authorized in a short time.
Conclusion
I’ve skilled first hand how I can rewrite an app in SwiftUI and the good pleasure that may be had from deleting all of your crufty Goal-C code when doing so.
SwiftUI is my new love and this fashion my app is now not a “baby from one other mom”. This restores some enthusiasm in me to truly lastly actually add some long-promised “thrilling new options”. For starters I’m pondering of getting a watchOS companion app which exhibits the timer and lets you distant management it. One other thought could be to retailer my presets on iCloud in order that they’re the identical on all my units.
I’d love to listen to from you what you consider the method of re-implementing elements of apps and even complete apps in SwiftUI.
Additionally revealed on Medium.
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