📱 Mobile Dev

OkHttp Caching: Beyond Simple Hits and Misses

OkHttp's cache acts like a browser's, saving network trips by storing responses on disk. It handles not just full hits and misses, but also validates stale data with the server. Use it for repeatable requests.

Using Device Motion Sensors in React Native

Treat device sensors as a data stream. Instead of polling, subscribe to an observable that emits readings for acceleration or rotation. This is for building compasses, shake detection, or AR views.

CAReplicatorLayer: A 'For Loop' for Layers

CAReplicatorLayer is a 'for loop' for layers, creating complex patterns from a single source layer. Use it for loading spinners or radial bursts. The footgun: transformations are cumulative, so each copy is transformed relative to the previous one, not the…

React Native Push Notifications: Permissions First

Think of push notifications as your app's mailbox. Your server sends a message, but your React Native app must ask the user for permission to show it. This is key for sending alerts via Firebase, but on iOS, silent failures occur if you don't request.

Core Location: Your App's Sense of Place

Core Location gives your app its sense of place, from a precise coordinate to a general region. It powers maps, ride-sharing, and location-based reminders. Use it for one-time fixes, continuous tracking, or geofencing.

Dependency Injection: Your Objects Shouldn't Create Their Own Helpers

Instead of creating its own helpers (like a network client), an object receives them from an outside source. This is crucial for building testable Android apps, as it lets you swap a real UserRepository with a fake one during tests.

Local Notifications: Your App's On-Device Messenger

Local notifications are messages your app sends to itself on the user's device, no server needed. Use them for timers, reminders, or download progress. The footgun: forgetting to create Android Notification Channels will cause your alerts to fail silently.

MapKit: Putting Apple Maps in Your iOS App

MapKit is the toolkit for embedding Apple's interactive maps directly into your app. Use it to show user location, display points of interest, or provide directions. The footgun is rendering too many pins at once; use clustering to keep the UI responsive.

dio Interceptors: Middleware for Network Requests

dio Interceptors are middleware for network requests, letting you inspect and modify them before they're sent or after a response is received. Use them to globally add auth tokens, log activity, or handle token refreshes.

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@HiltAndroidApp: The Entry Point for Hilt DI

@HiltAndroidApp is the main power switch for Hilt dependency injection. You place it on your Application class to trigger code generation and create the top-level dependency container.

UserNotifications Framework: iOS Alert Gatekeeper

UserNotifications is the gatekeeper between your app and the lock screen. You use it to request permission and schedule local or push alerts on iOS. Send a notification before authorization and the system silently drops it.

Connect React Native Apps to BLE Hardware

react-native-ble-plx is the bridge from your RN app to physical BLE hardware. Use it to scan for, connect to, and exchange data with peripherals like sensors or smart locks, without writing native code.

graphql_flutter: Client Setup and Querying

graphql_flutter connects your app to a GraphQL API via a client-provider-widget pattern. You provide a configured GraphQLClient to a GraphQLProvider, then use Query widgets to fetch data declaratively.

React Native's Performance Monitor Overlay

Think of it as a quick, in-app speedometer for your app's performance. Toggle it from the Dev Menu for a live overview on your screen. The footgun: it's only a guide, not a precise tool for deep performance analysis.

AVFoundation: Apple's Toolkit for Audio and Video

AVFoundation is Apple's low-level toolbox for audio and video. Use it for custom camera UIs, video editing, or complex audio playback. The main footgun is its complexity; managing sessions, inputs, and outputs on the correct threads is notoriously difficult.

Cross-Platform WebSockets with `web_socket_channel`

The web_socket_channel package abstracts away platform differences for WebSockets, giving you a single API for web, mobile, and server. Use it for real-time features like chat or live data feeds. The footgun: always await channel.ready before sending data.

Flipper: A Desktop Debugger for React Native

Flipper is a desktop debugging platform for React Native, acting like Chrome DevTools for your mobile app. It connects to your local Metro server, letting you inspect component trees, view logs, and trigger reloads. The main footgun: the project is archived.

Core ML: On-Device Machine Learning for Apple Apps

Core ML runs pre-trained machine learning models directly on Apple devices, enabling fast, private, and offline AI. It's used for features like real-time image recognition or text analysis. The footgun: Core ML only runs models; it doesn't train them.

shared_preferences for Simple On-Device Storage

shared_preferences is Flutter's go-to for simple on-device key-value storage, like a persistent dictionary for user settings. Use it to save a dark mode toggle or high score. Crucially, writes are not guaranteed, so don't use it for critical data.