From d2d4179ab6c4e3efc494b29093ba8f135b78c966 Mon Sep 17 00:00:00 2001 From: FuelBoard Contributor Date: Fri, 16 Oct 2026 20:33:10 +0100 Subject: [PATCH] Settings sliders: commit on release instead of writing on every step MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Both sliders now move a local draft (mpgDraft / fillUpDraft) and write once, when the drag ends, via Slider's onEditingChanged. While the thumb is down only this screen redraws: no store write, no fuelSavingsSettings mutation, and so no app-wide recompute — ContentView re-ran its body, rebuilt the savings lookup, and passed all 8,130 stations through the alert monitor on every step. The drafts are Double?, where nil means "not dragging" and the stored setting is shown. That falls back naturally after a commit, so the control shows what was actually saved (the clamps can lower it) and anything changing the setting from outside — a unit switch, the in-list control, a QA hook — is reflected without any re-seeding. The MPG and fill-up read-outs follow the draft, so the figure still tracks the thumb. The keychain write deliberately stays on the main thread: it is the authoritative mirror on read, so an async write could hand a relaunch or a widget a stale value. One write per gesture is cheap enough not to need it. --- FuelBoard/SettingsView.swift | 94 +++++++++++++++++++++++++++--------- 1 file changed, 70 insertions(+), 24 deletions(-) diff --git a/FuelBoard/SettingsView.swift b/FuelBoard/SettingsView.swift index b8b6804..1dc53cd 100644 --- a/FuelBoard/SettingsView.swift +++ b/FuelBoard/SettingsView.swift @@ -73,6 +73,13 @@ struct SettingsView: View { /// "Accurate distances" — read once on appear and written straight through to /// the shared store, which is what every display surface actually consults. @State private var accurateDistances: Bool = FuelStore.accurateDistancesEnabled + /// Slider drafts — the value under the thumb while it is down. `nil` means + /// "not dragging", in which case the stored setting is shown, so an external + /// change (a unit switch, the in-list control, a QA hook) is picked up with + /// no re-seeding. Dragging writes only the draft; the setting is saved once, + /// when the drag ends — see `commitMPG` / `commitFillUp`. + @State private var mpgDraft: Double? + @State private var fillUpDraft: Double? @State private var versionTapCount = 0 @State private var lastVersionTap = Date.distantPast /// Widget diagnostics: the extension's last makeEntry beacon PER intent @@ -132,9 +139,15 @@ struct SettingsView: View { .monospacedDigit() .foregroundStyle(.secondary) } - Slider(value: fuelSavingsMPGBinding, + // Draft-bound: the thumb moves a local value and the + // setting is written once, when the drag ends. Writing + // durable app-wide state on every step is what made this + // slider stutter. + Slider(value: mpgSliderValue, in: FuelSavingsCalculator.mpgSliderRange, - step: FuelSavingsCalculator.mpgSliderStep) + step: FuelSavingsCalculator.mpgSliderStep) { editing in + if !editing { commitMPG() } + } .accessibilityLabel("Average fuel economy") .accessibilityValue(mpgText) Picker("Fill-up unit", selection: fuelSavingsUnitBinding) { @@ -150,9 +163,11 @@ struct SettingsView: View { .monospacedDigit() .foregroundStyle(.secondary) } - Slider(value: fuelSavingsAmountBinding, + Slider(value: fillUpSliderValue, in: FuelSavingsCalculator.fillAmountSliderRange(for: fuelSavingsSettings.preferredAmount.unit), - step: FuelSavingsCalculator.fillAmountSliderStep(for: fuelSavingsSettings.preferredAmount.unit)) + step: FuelSavingsCalculator.fillAmountSliderStep(for: fuelSavingsSettings.preferredAmount.unit)) { editing in + if !editing { commitFillUp() } + } .accessibilityLabel("Typical fill-up") .accessibilityValue(fillUpText) Picker("Minimum saving", selection: $bestValueThresholdGBP) { @@ -710,27 +725,56 @@ struct SettingsView: View { private var fuelSavingsEnabledBinding: Binding { Binding( get: { fuelSavingsSettings.enabled }, - set: { fuelSavingsSettings.enabled = $0; persistFuelSavingsSettings() } + set: { fuelSavingsSettings.enabled = $0; saveFuelSavingsField(.enabled) } ) } - private var fuelSavingsMPGBinding: Binding { + /// Slider values, draft-first: while the thumb is down the draft is what the + /// control and its read-out show; with no drag in progress the store's value + /// shows, so any external change (unit switch, in-list control, QA hook) is + /// reflected without re-seeding anything. + private var mpgSliderValue: Binding { Binding( - get: { fuelSavingsSettings.mpg }, - set: { fuelSavingsSettings.mpg = min(max($0, 0), FuelSavingsCalculator.maximumMPG); persistFuelSavingsSettings() } + get: { mpgDraft ?? fuelSavingsSettings.mpg }, + set: { mpgDraft = $0 } ) } - private var fuelSavingsAmountBinding: Binding { + private var fillUpSliderValue: Binding { Binding( - get: { fuelSavingsSettings.preferredAmount.value }, - set: { - fuelSavingsSettings.preferredAmount.value = min(max($0, 0), FuelSavingsCalculator.maximumFillAmount(for: fuelSavingsSettings.preferredAmount.unit)) - persistFuelSavingsSettings() - } + get: { fillUpDraft ?? fuelSavingsSettings.preferredAmount.value }, + set: { fillUpDraft = $0 } ) } + /// The drag has ended: write the value once, and only if it actually moved. + /// The draft is cleared either way, so the control falls back to the stored + /// setting and shows what was saved — the clamps can lower it. + private func commitMPG() { + defer { mpgDraft = nil } + guard let draft = mpgDraft else { return } + let mpg = min(max(draft, 0), FuelSavingsCalculator.maximumMPG) + guard mpg != fuelSavingsSettings.mpg else { return } + fuelSavingsSettings.mpg = mpg + saveFuelSavingsField(.mpg) + } + + private func commitFillUp() { + defer { fillUpDraft = nil } + guard let draft = fillUpDraft else { return } + let amount = min(max(draft, 0), + FuelSavingsCalculator.maximumFillAmount(for: fuelSavingsSettings.preferredAmount.unit)) + guard amount != fuelSavingsSettings.preferredAmount.value else { return } + fuelSavingsSettings.preferredAmount.value = amount + saveFuelSavingsField(.amount) + } + + /// Persists the one field that changed. Saving the whole settings object + /// rewrites all four keys, which is only right when more than one has moved. + private func saveFuelSavingsField(_ field: FuelStore.FuelSavingsField) { + FuelStore.saveFuelSavingsField(field, from: fuelSavingsSettings) + } + private var fuelSavingsUnitBinding: Binding { Binding( get: { fuelSavingsSettings.preferredAmount.unit }, @@ -739,30 +783,32 @@ struct SettingsView: View { fuelSavingsSettings.preferredAmount = FuelSavingsCalculator.newComparisonAmount( afterSwitching: fuelSavingsSettings.preferredAmount, to: newUnit) settingsUnitChangeNotice = "New comparison basis — adjust the \(newUnit.displayName) amount to your intended fill-up." - persistFuelSavingsSettings() + // The unit and the amount move together, so both keys are written. + saveFuelSavingsField(.unit) + saveFuelSavingsField(.amount) + // A drag in progress on the old scale no longer maps to this one. + fillUpDraft = nil } ) } /// "45 MPG" / "45.5 MPG". The slider is the only control, so this read-out - /// is the one place the figure is stated. + /// is the one place the figure is stated. It follows the draft while the + /// thumb is down. private var mpgText: String { - let mpg = fuelSavingsSettings.mpg + let mpg = mpgDraft ?? fuelSavingsSettings.mpg return mpg.rounded() == mpg ? String(format: "%.0f MPG", mpg) : String(format: "%.1f MPG", mpg) } - /// "£40" / "40 L" — the fill-up slider's read-out. + /// "£40" / "40 L" — the fill-up slider's read-out, draft-first like the MPG one. private var fillUpText: String { + let value = fillUpDraft ?? fuelSavingsSettings.preferredAmount.value switch fuelSavingsSettings.preferredAmount.unit { - case .pounds: return String(format: "£%.0f", fuelSavingsSettings.preferredAmount.value) - case .litres: return String(format: "%.0f L", fuelSavingsSettings.preferredAmount.value) + case .pounds: return String(format: "£%.0f", value) + case .litres: return String(format: "%.0f L", value) } } - private func persistFuelSavingsSettings() { - FuelStore.saveFuelSavingsSettings(fuelSavingsSettings) - } - /// "API" when the relay is serving the official Fuel Finder API, "CSV" /// when it fell back to the public mirror, "—" when unknown/never fetched. private var connectionText: String {