kurko/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