Mobile Development Errors

Mobile dev errors come in two flavors: platform-specific (Xcode signing, Gradle build, AndroidManifest) and cross-platform (React Native bridge, Flutter widget tree, Expo runtime). The toolchain is the usual culprit — getting builds reproducible is half the battle.

Recommended starting points:

• Xcode build failed — provisioning and signing mysteries.
• Swift fatal error unwrapping nil — the iOS NPE.

All articles (18)

• Fix: Expo Router Not Working — Routes Not Matching, Layout Nesting Wrong, or Deep Links Failing

  How to fix Expo Router issues — file-based routing, layout routes, dynamic segments, tabs and stack navigation, modal routes, authentication flows, and deep linking configuration.

• Fix: NativeWind Not Working — Styles Not Applying, Dark Mode Broken, or Metro Bundler Errors

  How to fix NativeWind issues — Tailwind CSS for React Native setup, Metro bundler configuration, className prop, dark mode, responsive styles, and Expo integration.

• Fix: React Native Paper Not Working — Theme Not Applying, Icons Missing, or Components Unstyled

  How to fix React Native Paper issues — PaperProvider setup, Material Design 3 theming, custom color schemes, icon configuration, dark mode, and Expo integration.

• Fix: React Navigation Not Working — Screens Not Rendering, TypeScript Errors, or Gestures Broken

  How to fix React Navigation issues — stack and tab navigator setup, TypeScript typing, deep linking, screen options, nested navigators, authentication flow, and performance optimization.

• Fix: Tamagui Not Working — Styles Not Applying, Compiler Errors, or Web/Native Mismatch

  How to fix Tamagui UI kit issues — setup with Expo, theme tokens, styled components, animations, responsive props, media queries, and cross-platform rendering.

• Fix: Expo Not Working — Build Failing, Native Module Not Found, or EAS Build Error

  How to fix Expo issues — Expo Go vs development builds, native module installation with expo-modules-core, EAS Build configuration, bare workflow setup, and common SDK upgrade problems.

• Fix: React Native Reanimated Not Working — Worklet Error, useAnimatedStyle Not Updating, or Gesture Not Responding

  How to fix React Native Reanimated issues — worklet rules, shared values, useAnimatedStyle, Gesture Handler setup, web support, Babel plugin configuration, and Reanimated 3 migration.

• Fix: Swift async/await Not Working — Task Not Running, Actor Isolation Error, or MainActor Crash

  How to fix Swift concurrency issues — async/await in non-async context, Task creation, actor isolation violations, MainActor UI updates, structured concurrency, and Sendable errors.

• Fix: Kotlin Flow Not Working — Not Collecting, StateFlow Not Updating, or Flow Cancelled Unexpectedly

  How to fix Kotlin Flow issues — cold vs hot flows, collectLatest vs collect, StateFlow and SharedFlow setup, lifecycle-aware collection in Android, and common Flow cancellation problems.

• Fix: Kotlin Sealed Class Not Working — when Expression Not Exhaustive or Subclass Not Found

  How to fix Kotlin sealed class issues — when exhaustiveness, sealed interface vs class, subclass visibility, Result pattern, and sealed classes across modules.

• Fix: Kotlin Coroutine Not Executing — launch{} or async{} Blocks Not Running

  How to fix Kotlin coroutines not executing — CoroutineScope setup, dispatcher selection, structured concurrency, cancellation handling, blocking vs suspending calls, and exception propagation.

• Fix: Kotlin Coroutine Scope Cancelled — JobCancellationException or Coroutine Not Running

  How to fix Kotlin coroutine cancellation issues — scope lifecycle, SupervisorJob, CancellationException handling, structured concurrency, viewModelScope, and cooperative cancellation.

• Fix: React Native Android Build Failed

  How to fix React Native Android build failures — SDK version mismatches, Gradle errors, duplicate module issues, Metro bundler problems, and NDK configuration for common build errors.

• Fix: React Native Metro Bundler Failed to Start or Bundle

  How to fix React Native Metro bundler errors — unable to resolve module, EMFILE too many open files, port already in use, transform cache errors, and Metro failing to start on iOS or Android.

• Fix: Xcode Build Failed - Common Causes and Solutions

  How to fix Xcode build failed errors including clean build folder, derived data, provisioning profiles, code signing, Swift version mismatch, CocoaPods, SPM, architecture, and missing framework issues.

• Fix: Flutter Build Failed – Gradle, CocoaPods, or Dart Compilation Errors

  How to fix Flutter build failures including Gradle errors on Android, CocoaPods issues on iOS, Dart compilation errors, and version mismatch problems.

• Fix: Gradle Build Failed – Could Not Resolve Dependencies or Compilation Error

  How to fix Gradle build failures including dependency resolution errors, compilation failures, incompatible Java versions, and daemon issues.

• Fix: Swift Fatal Error – Unexpectedly Found Nil While Unwrapping an Optional Value

  How to fix the Swift fatal error 'unexpectedly found nil while unwrapping an Optional value' with safe unwrapping, guard let, nil coalescing, and debugging techniques.