Developer Documentation

This document provides a technical overview of the Android Camera Parameters application, its architecture, and development guidelines.

Project Overview

The application is a diagnostic tool for inspecting Android Camera2 CameraCharacteristics. It provides a modern, user-friendly interface to explore hardware levels, capabilities, and raw parameter values for all camera lenses on a device.

Architecture

The project follows the MVVM (Model-View-ViewModel) architectural pattern and is built using Jetpack Compose for the UI layer.

Core Components

CameraParamsActivity

The single entry point of the application.

• Handles runtime permissions (CAMERA).
• Initializes the Compose UI via setContent.
• Hosts the CameraParamsTheme.

CameraViewModel

The central state manager for the UI.

• Maintains UiState which includes the list of cameras, selected index, categorized parameters, and search query.
• Feature Detection: Contains logic in detectFeatureFlags() to dynamically determine hardware capabilities like RAW support, OIS, and Manual Exposure.
• Categorization: Groups hundreds of Camera2 keys into logical sections (Sensor, Lens, etc.) for better readability.

CameraParamsHelper

A utility wrapper around the Android CameraManager.

• Retrieves CameraCharacteristics for specific IDs.
• Provides specialized formatting for complex camera types (e.g., converting IntArray modes into human-readable strings).

UI Layer (Jetpack Compose)

The UI is built using Material 3 with a strictly enforced dark theme.

Navigation Structure

The app uses androidx.navigation.compose managed in MainScreen.kt.

Screen	Responsibility
Overview	High-level dashboard showing Summary Card, Hardware Level, and Key Feature chips.
Categories	Expandable list of all parameters grouped by section with search filtering.
Raw (JSON)	Syntax-highlighted JSON representation of all camera properties.
Detail	Focused view for a single parameter, showing formatted value and raw data.

Styling

• Theme: Defined in Theme.kt.
• Colors: Primary color #7B61FF (Violet) used for highlights and primary actions.
• Surface: Dark background #121417 with #1E1F23 variants for cards.

Key Logic

Dynamic Feature Detection

The "Key Features" chips on the dashboard are not static. They are computed in CameraViewModel.detectFeatureFlags():

• RAW: Checked via REQUEST_AVAILABLE_CAPABILITIES_RAW.
• OIS: Detected if LENS_INFO_AVAILABLE_OPTICAL_STABILIZATION contains ON.
• Manual Exp: Available if CONTROL_AE_MODE_OFF is supported.
• Manual Focus: Enabled if LENS_INFO_MINIMUM_FOCUS_DISTANCE is greater than 0.

Development Guide

Prerequisites

• Android Studio Ladybug (or newer).
• Kotlin 2.0+ (The project uses the new Compose Compiler Gradle plugin).
• Minimum SDK: 21 (Android 5.0).

Adding a New Category

To add or modify parameter grouping, update the getCategoryForKey() method in CameraViewModel.kt. It uses string matching on the camera key names to assign them to categories.

Updating the Theme

Colors can be adjusted in Color.kt. The app is designed to look best in dark mode; any changes to the light palette should be tested carefully.