feat(core): back button event on Android, closes #8142

[tomerqodo]

Benchmark PR from agentic-review-benchmarks#6

Summary by CodeRabbit

Release Notes

• New Features
  • Mobile app plugin now supports back button press event detection and handling on Android devices.
  • New onBackButtonPress listener API enables custom back button interactions with navigation state awareness.
  • Added exit command to terminate the application.

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[coderabbitai]

📝 Walkthrough

Walkthrough

This pull request implements Android back button event handling for Tauri apps across multiple layers. Changes include a new Android plugin managing back navigation, Kotlin/Rust platform-specific code, JavaScript listener API, updated permissions, and a dependency update to wry 0.53.4 with linux-body support.

Changes

Cohort / File(s)	Summary
Changelog Entries .changes/android-app-plugin.md, .changes/back-button-press-api.md	Added two changelog entries documenting the new mobile app plugin and onBackButtonPress API features.
Android Kotlin Implementation crates/tauri/mobile/android-codegen/TauriActivity.kt, crates/tauri/mobile/android/src/main/java/app/tauri/AppPlugin.kt	Introduced AppPlugin with back button event handling that either navigates WebView history or emits back-button events to JavaScript based on listener registration; added handleBackNavigation property to TauriActivity.
Android Plugin Utilities crates/tauri/mobile/android/src/main/java/app/tauri/plugin/Plugin.kt	Added hasListener() method to query listener presence for events.
Rust Plugin Setup crates/tauri/build.rs, crates/tauri/src/app/plugin.rs	Added register_listener and remove_listener commands to core:app plugin; added Android-specific AppPlugin struct and initialization logic.
Permissions Documentation crates/tauri/permissions/app/autogenerated/reference.md	Added four new permission entries for allow/deny of register_listener and remove_listener commands.
JavaScript API packages/api/src/app.ts	Introduced onBackButtonPress() listener function and OnBackButtonPressPayload type for handling back button events from JavaScript.
Dependency & Cleanup crates/tauri-runtime-wry/Cargo.toml, crates/tauri/src/path/android.rs, crates/tauri/scripts/bundle.global.js	Updated wry to 0.53.4 and added linux-body feature; cleaned up unused Android path imports; reformatted JavaScript bundle.

Sequence Diagram(s)

sequenceDiagram
    actor User
    participant Activity as Android Activity
    participant AppPlugin as AppPlugin<br/>(Kotlin)
    participant WebView as WebView
    participant Runtime as Tauri Runtime<br/>(JS/Rust)

    User->>Activity: Press back button
    Activity->>AppPlugin: onBackPressed callback
    AppPlugin->>AppPlugin: hasListener("back-button")?
    alt Listener registered
        AppPlugin->>AppPlugin: Check canGoBack state
        AppPlugin->>Runtime: emit back-button event<br/>(canGoBack payload)
        Runtime->>Runtime: JS handler receives event
        Runtime->>WebView: Handle in app logic
    else No listener
        AppPlugin->>WebView: goBack() if history exists
        alt WebView history available
            WebView->>WebView: Navigate back
        else No history
            AppPlugin->>Activity: System back press
            Activity->>Activity: Pop back stack
        end
    end

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Estimated code review effort

🎯 3 (Moderate) | ⏱️ ~20 minutes

Poem

🐰 Back buttons hop through Android's door,
Events whisper what they're for,
Listeners catch them, signals flow,
From Kotlin deep to JS below,
Navigation magic, smooth and true! 🎉

🚥 Pre-merge checks | ✅ 2 | ❌ 1

❌ Failed checks (1 warning)

Check name	Status	Explanation	Resolution
Docstring Coverage	⚠️ Warning	Docstring coverage is 5.41% which is insufficient. The required threshold is 80.00%.	Write docstrings for the functions missing them to satisfy the coverage threshold.

✅ Passed checks (2 passed)

Check name	Status	Explanation
Description Check	✅ Passed	Check skipped - CodeRabbit’s high-level summary is enabled.
Title check	✅ Passed	The title accurately describes the main change: adding a back button event feature for Android platform, and references the closed issue #8142.

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✨ Finishing touches

• 📝 Generate docstrings

🧪 Generate unit tests (beta)

• Create PR with unit tests
• Post copyable unit tests in a comment
• Commit unit tests in branch coderabbit_full_head_featcore_back_button_event_on_android_closes_8142_pr6

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