axiom-now-playing-carplay

CarPlay Integration

Time cost: 15-20 minutes (if MPNowPlayingInfoCenter already working)

Key Insight

CarPlay uses the SAME MPNowPlayingInfoCenter and MPRemoteCommandCenter as Lock Screen and Control Center. If your Now Playing integration works on iOS, it automatically works in CarPlay with zero additional code.

What CarPlay Reads

iOS Component	CarPlay Display
MPNowPlayingInfoCenter.nowPlayingInfo	CPNowPlayingTemplate metadata (title, artist, artwork)
MPRemoteCommandCenter handlers	CPNowPlayingTemplate button responses
Artwork from nowPlayingInfo	Album art in CarPlay UI

No CarPlay-specific metadata needed. Your existing code works.

CPNowPlayingTemplate Customization (iOS 14+)

For custom playback controls beyond standard play/pause/skip:

import CarPlay

@MainActor
class SceneDelegate: UIResponder, UIWindowSceneDelegate, CPTemplateApplicationSceneDelegate {

    func templateApplicationScene(
        _ templateApplicationScene: CPTemplateApplicationScene,
        didConnect interfaceController: CPInterfaceController
    ) {
        // ✅ Configure CPNowPlayingTemplate at connection time (not when pushed)
        let nowPlayingTemplate = CPNowPlayingTemplate.shared

        // Enable Album/Artist browsing (shows button that navigates to album/artist view in your app)
        nowPlayingTemplate.isAlbumArtistButtonEnabled = true

        // Enable Up Next queue (shows button that displays upcoming tracks)
        nowPlayingTemplate.isUpNextButtonEnabled = true

        // Add custom buttons (iOS 14+)
        setupCustomButtons(for: nowPlayingTemplate)
    }

    private func setupCustomButtons(for template: CPNowPlayingTemplate) {
        var buttons: [CPNowPlayingButton] = []

        // Playback rate button
        let rateButton = CPNowPlayingPlaybackRateButton { [weak self] button in
            self?.cyclePlaybackRate()
        }
        buttons.append(rateButton)

        // Shuffle button
        let shuffleButton = CPNowPlayingShuffleButton { [weak self] button in
            self?.toggleShuffle()
        }
        buttons.append(shuffleButton)

        // Repeat button
        let repeatButton = CPNowPlayingRepeatButton { [weak self] button in
            self?.cycleRepeatMode()
        }
        buttons.append(repeatButton)

        // Update template with custom buttons
        template.updateNowPlayingButtons(buttons)
    }
}

Entitlement Requirement

CarPlay requires an entitlement in your Xcode project:

Info.plist:

<key>UIBackgroundModes</key>
<array>
    <string>audio</string>
</array>

Entitlements file:

<key>com.apple.developer.carplay-audio</key>
<true/>

Without the entitlement, CarPlay won't show your app at all.

CarPlay-Specific Gotchas

Issue	Cause	Fix	Time
CarPlay doesn't show app	Missing entitlement	Add com.apple.developer.carplay-audio	5 min
Now Playing blank in CarPlay	MPNowPlayingInfoCenter not set	Same fix as Lock Screen (Pattern 1)	10 min
Custom buttons don't appear	Configured after push	Configure at templateApplicationScene(_:didConnect:)	5 min
Buttons work on device, not CarPlay simulator	Debugger interference	Test without debugger attached	1 min
Album art missing	Same as iOS issue	Fix MPMediaItemArtwork (Pattern 3)	15 min

Testing CarPlay

Simulator (Xcode 12+):

1. I/O → External Displays → CarPlay
2. Tap CarPlay display
3. Find your app in Audio section
4. Important: Run without debugger for reliable testing (debugger can interfere with CarPlay audio session activation)

Real Vehicle: Requires entitlement approval from Apple (automatic for apps with UIBackgroundModes audio; no manual request needed).

Verification

• App appears in CarPlay Audio section
• Now Playing shows correct metadata
• Album artwork displays
• Play/pause/skip buttons respond
• Custom buttons (if any) appear and work
• Tested both with and without debugger

Resources

Skills: axiom-now-playing, axiom-now-playing-musickit