The Flutter & Dart tracker

Flutter 3.50 and Dart 3.14 shipped on November 11, 2026. On the web, Safari 26.2+ and Firefox 147+ can now run the Wasm build behind an opt-in wasmAllowList, and flutter build web gets built-in content hashing for long-lived caching.

flutter test never runs the Dart plugin registrant, so getTemporaryDirectory() hits the MethodChannel default and throws MissingPluginException. On a macOS, Windows or Linux host you can register the host implementation (PathProviderFoundation 2.6.0+ is FFI, not a channel), use a temp-dir PathProviderPlatform fake, or run integration_test on desktop. Checked on Flutter 3.44.8 with path_provider 2.1.6.

In Dart, identical(a, b) asks whether two references point to the same object, while a == b calls the left operand's operator == method, which falls back to Object.== (identity) unless the class overrides it. Null checks, const canonicalization, numbers, NaN, records, hashCode, and the places where the VM and dart2js disagree, verified on Dart 3.12.2.

A Dart Timer is a promise never to fire early, not a promise to fire on time. The VM truncates the Duration to whole milliseconds, adds one millisecond on purpose, and delivers the timer as an event that waits behind running code and every pending microtask. Measured lateness on Dart 3.12.2, periodic tick skipping, drift in chained delays, the 4 ms browser clamp, and the 30-day delay that fires instantly on the web.

pubspec_overrides.yaml is a file next to pubspec.yaml that pub reads on top of it, limited to dependency_overrides, resolution and workspace. It replaces the whole dependency_overrides section, applies workspace-wide, and is left out of published archives. What it does, when to use it in a monorepo, and every edge case, verified on Dart 3.12.2.

Replace the deprecated textScaleFactor on MediaQueryData, Text, RichText and TextPainter with TextScaler. What dart fix rewrites (3 of 9 call sites in our sample), why its output can quietly undo Android 14 nonlinear font scaling, how to cap text size with clamp and withClampedTextScaling, and the equality and test gotchas. Measured on Flutter 3.44.8 with Dart 3.12.2.

A tested, file-by-file conversion of a Flutter app's settings.gradle, build.gradle and app/build.gradle to Kotlin DSL on Flutter 3.44.8, AGP 9.0.1 and Gradle 9.1.0, with the real compiler errors each naive rename produces and the exact fix for signing configs, flavors, minifyEnabled and kotlinOptions.

Use shared_preferences (SharedPreferencesWithCache) for a handful of flat flags and a JSON file in getApplicationSupportDirectory for a structured settings object. Covers the atomic-write pattern, the concurrent-save race, the Documents-folder trap on Windows and Linux, web support, and measured write costs on Flutter 3.44.8.

flutter upgrade aborts if git status in the SDK folder prints anything. Inspect it, restore pubspec.lock or git stash -u, and use --force only as a last resort.

Anything you compile into a Flutter web build, including --dart-define values, ships to the browser in plain text. The only safe pattern is a small backend proxy that holds the key, authenticates the user, pins the model, and streams the Responses API SSE back. Full Dart shelf proxy and Flutter client, tested with Flutter 3.44, Dart 3.12, and http 1.6.

Lock one Flutter route to landscape or portrait with SystemChrome.setPreferredOrientations without breaking the rest of the app: a stack-based lock that survives pushReplacement and restores on pop, why the empty list is the wrong reset, why iPad multitasking and Android 16 large screens ignore the lock, and what UIRequiresFullScreen means after iPadOS 26 and the iOS 27 SDK. Tested on Flutter 3.47.8 with Dart 3.13.7 and Xcode 27.1.

Calling remove inside a for-in loop or forEach throws ConcurrentModificationError. Use removeWhere for in-place filtering, build a new list with where or a collection-for, or loop backwards by index. Verified on Dart 3.13.7, with a benchmark of why removeAt in a loop is the slow option.

Put a discriminator field in the JSON, switch on it in a factory on the sealed base, and switch on the subtype to write it back. Three working versions on Dart 3.13.7: hand-written pattern matching, json_serializable 6.15.2, and Freezed 4.0.3 with unionKey and fallbackUnion, plus the gotchas each one hides.

depend_on_referenced_packages fires when a file imports or exports a package that is not listed in your own pubspec.yaml, even if it resolves through another dependency. Here is exactly what the rule checks on Dart 3.12.2 and Flutter 3.44.8, why transitive imports are a real bug, and how to fix each variant.

Replace the deprecated Color.withOpacity, opacity, value, red, green, blue and alpha with withValues, .a/.r/.g/.b and toARGB32. What dart fix rewrites for you, the four getters it leaves behind, why exact color assertions and Map<Color, T> lookups break after the swap, and how withOpacity silently drops Display P3. Measured on Flutter 3.44.8 with Dart 3.12.2.

Rename MaterialState, MaterialStateProperty, MaterialStateColor and the rest of the family to their WidgetState equivalents. What dart fix rewrites, the input border subclasses it cannot touch, why a fromMap with & or | keys cannot be const, and how fromMap throws where resolveWith quietly fell back. Measured on Flutter 3.44.8 with Dart 3.12.2.

Replace hand-rolled WidgetsBindingObserver lifecycle code with AppLifecycleListener: the callback mapping, the state machine it enforces, the new hidden state that breaks exhaustive switches, desktop exit requests, and the test that suddenly asserts. Tested on Flutter 3.44.8 with Dart 3.12.2.

Use Expanded when a child must fill its share of a Row or Column, and Flexible when it may be smaller than its share. Measured layouts on Flutter 3.44 show where the leftover space goes, why loose children never donate it to siblings, and when only Flexible survives unbounded constraints.

unawaited_futures only looks inside async bodies, discarded_futures only inside sync bodies, and both miss arrow functions, tear-offs, and collection literals. Measured case by case on Dart 3.12.2 and Flutter 3.44.8, with the analysis_options.yaml I recommend.

A dependency was built with a Kotlin at least two minor versions newer than your build's compiler. Raise the org.jetbrains.kotlin.android version in settings.gradle.kts to X minus one or later, or pin the dependency back.

A single-subscription stream accepts exactly one listen() for its whole life. Create the stream once and give it to one listener, or share it with asBroadcastStream or Stream.multi.

ApiException: 10 is DEVELOPER_ERROR: Google does not recognize the package name plus signing certificate SHA-1 of the installed APK. Register the SHA-1 of the key that actually signed the build, and pass the Web client ID as serverClientId.

Subclass ThemeExtension, register one instance per ThemeData through the extensions list, read it with Theme.of(context).extension<T>(), and write a real lerp so MaterialApp's AnimatedTheme interpolates your tokens during a light/dark switch. Covers colors, radii, shadows, text styles and booleans, the missing-extension crash, the copyWith trap that drops every other extension, and why you need == and hashCode, all verified with widget tests on Flutter 3.44.8.

AnimatedSwitcher only transitions when Widget.canUpdate says the new child is a different widget, so Text to Text with no key just updates in place. Here is the one-line fix, where the key has to sit, why UniqueKey is a trap, the slide-direction bug caused by a static transitionBuilder, and the layout jump from the default Stack, all verified with widget tests on Flutter 3.44.8.

Android kills backgrounded Flutter apps to reclaim memory, and when the user comes back every StatefulWidget starts from scratch. Here is how to opt in with restorationScopeId, RestorationMixin and Restorable properties, restore text fields, scroll offsets and pushed routes, write a custom RestorableValue, and test it all with restartAndRestore and adb, verified on Flutter 3.44.8 and an Android 16 emulator.

FlutterError.onError only sees errors thrown inside framework callbacks. Unawaited futures, timers, streams, and code after an await go somewhere else. Here is which handler catches which error, measured on Flutter 3.44.8, and the main() setup that catches all of them, including on web.

A broadcast StreamController drops every event that fired before you subscribed. Here is a dependency-free BehaviorSubject replacement built on Stream.multi, a replayLatest() extension for existing streams, the async* shortcut that silently loses events, and the StreamBuilder initialData detail, all verified on Dart 3.12.2.

A one-time, crash-safe import of existing Hive boxes into a drift SQLite database on the user's device: schema design, the import function, idempotency, deleting the boxes, and the two gotchas that silently corrupt data (DateTime precision and class-name collisions). Tested on Flutter 3.44.8 with hive_ce 2.22.0 and drift 2.35.2.

WillPopScope and onPopInvoked are deprecated, and predictive back on Android 14+ ignores them. How to move each onWillPop pattern to PopScope.canPop and onPopInvokedWithResult, the confirm-dialog loop you have to guard against, the PopScope<T> type crash, and what dart fix will not do for you. Tested on Flutter 3.44.8.

The Flutter SDK pins versions of meta, vector_math, test_api and matcher, so every SDK change re-resolves your lockfile, and flutter upgrade runs pub upgrade on the project you stand in. Pin one Flutter version per repo and enforce the lockfile in CI.

A provisioning profile passed to xcodebuild on the command line applies to every SwiftPM resource bundle target. Set manual signing on the Runner target instead.

Drive NavigationBar.selectedIndex from StatefulNavigationShell.currentIndex, never from a setState field or a copy made in initState. Measured on Flutter 3.44.8 and go_router 18.0.2: which patterns drift on deep links, context.go and cross-branch pushes, why location-based indexes lie, and how to react to tab changes with didUpdateWidget.

Genkit Dart 1.0.0 freezes the API, moves HTTP serving into core with GenkitRouter, and changes the streamed error frame. Shipped Flutter apps on a 0.17 client need sendLegacyErrorFrame.

A build mode (debug, profile, release) decides how Flutter compiles your Dart code. A flavor (dev, staging, prod) is a native build variant you define in Gradle and Xcode that decides which app you ship. They are independent axes: 2 flavors times 3 modes is 6 builds. Verified on Flutter 3.44.8 with AGP 9.0.1, source checked against 3.47.7.

Flutter 3.44 made Swift Package Manager the default for iOS and macOS, but an existing app keeps CocoaPods until you remove it. How to check which plugins are SwiftPM-ready, let the tool migrate the Xcode project, delete the Podfile safely, handle pods-only plugins and custom Podfile logic, and roll back if you need to.

Flutter 3.47 makes Impeller the default renderer on Windows and Linux. What actually changes underneath (it is still OpenGL ES, not Vulkan), how to A/B test against Skia on a built binary, a per-machine kill switch for release builds, and why your golden tests will not notice.

Flutter moved PageTransitionsBuilder and two built-in builders into the widgets layer and CupertinoPageTransitionsBuilder out of Material. What actually breaks (one import, with a misleading 'Not a constant expression' error), what dart fix does and gets wrong for material_ui projects, and how to rewrite custom builders and routes so they no longer depend on Material at all.

The android_libcpp_shared build hook (0.2.0 and older) cannot find your NDK, or your minSdk is above the NDK's newest API. Upgrade to 0.2.1+, or install an NDK that covers your minSdk.

A widget asked for height: double.infinity inside a parent with no height limit, like a Column or ListView. Use Expanded, a finite height, LimitedBox, or SliverFillRemaining instead.

The manifest's .MainActivity resolves against the Gradle namespace, and no class with that name is in the APK. Make namespace, the Kotlin package line, and the manifest agree.

Another Gradle process holds ~/.gradle/caches/journal-1 and cannot hand it over. Find the Owner PID, kill that daemon, and stop deleting .lock files: that only moves the error.

The official google_mobile_ads sample renders nothing until onAdLoaded, so your content jumps by 150 dp seconds after the screen appears. Ask for the anchored adaptive size first, reserve it with a SizedBox, persist the height across launches, and only then load the ad. Measured on Flutter 3.44.8 with google_mobile_ads 9.1.0.

material_ui 1.3.0 and cupertino_ui 1.1.0 use an annotation Flutter 3.44 does not export. Both are retracted, but a lockfile keeps them. Downgrade, then upgrade, to land on 1.2.0 and 1.0.2.

Dart 3.13 removed the VM's built-in fallback root certificates. Put a CA bundle in the runtime image: COPY /runtime/ from dart:stable or install ca-certificates.

Dart 3.13 reserves final and var in parameter lists for primary constructors. Run dart fix --apply --code=extraneous_modifier to strip them, and use parameter_assignments instead.

A monorepo with dozens of pubspec.yaml files makes the Dart analysis server build one analysis context per package, which is where the memory and the minute-long startup go. Convert to a pub workspace, exclude generated code in analysis_options.yaml, drop legacy analyzer plugins, and use the Insights page to prove it. Measured on Dart 3.12.2: 2.3x less peak memory and half the cold analysis time.

A dwds bug in Flutter 3.35 web sent a fake pause on every hot reload. Upgrade to Flutter 3.38+, or switch VS Code back to 'Debug my code' so package frames are skipped.

Error 153 means YouTube got no Referer; 152 means the page claims to be youtube.com. Upgrade youtube_player_iframe to 6.0.2 and set origin to https://<your app id>, or use youtube-nocookie on 5.x.

On Windows, Kotlin incremental compilation fails when the Flutter project and the pub cache sit on different drives. Move PUB_CACHE to the project's drive or turn off IC for pub-cache plugins.

The advisories warning in pub get is harmless: pub get exits 0. pub.dev fixed the bad response on 2026-05-04. If you still see it, the cause is a mirror or proxy.

Keep a Flutter WebView on your own domain with webview_flutter 4.14.1: parse the URL, compare Uri.host instead of startsWith, hand mailto: and tel: to url_launcher, and know what Android and iOS actually send to onNavigationRequest.

Run a Flutter location tracker that survives the Home button, a swipe from recents and a reboot on Android 15 and 16: a location-typed foreground service in its own Flutter engine, the exact permissions, and the SecurityException you get when the while-in-use rules bite. Tested with geolocator 14.0.3 and flutter_foreground_task 11.0.3.

The full path from an AGP 8 Flutter app that applies kotlin-android to AGP 9.1 with android.builtInKotlin=true on Flutter 3.47. Every step was built and measured, including the two edits that look optional and are not: kotlinOptions is a compile error under KGP 2.2+, and the KGP line in settings.gradle.kts has to stay.

describeEnum has been deprecated since Flutter 3.16 and its removal PR is approved. How to replace every call with Enum.name (Flutter 3.47.4, Dart 3.13), handle enum-like classes and diagnostics, find the calls hiding in dependencies like flutter_svg 1.x, and what the build error looks like once it is gone.

Xcode 27 refuses to build anything below macOS 12, and Flutter 3.47 moved its own floor from 10.15 to 12.0. What the automatic migration rewrites, the three places it silently skips (custom values, Podfile post_install overrides, plugin podspecs), and a Podfile fix for teams still on Flutter 3.44.

Ship skwasm with flutter build web --wasm when your dependencies compile to Wasm: it downloads less and rendered 36% more frames than CanvasKit on a heavy scene. On Flutter 3.47.x, keep it single-threaded until the multi-threaded text crash fix leaves beta.

Flutter 3.47.0 cannot parse adb rows whose serial is 22+ characters, so wireless and some USB Android devices vanish. Upgrade to 3.47.1 or later, or adb connect by IP.

cmdline-tools 23.0 retired sdkmanager --licenses, so Flutter before 3.47.3 reports license status unknown. Upgrade Flutter, or pin cmdline-tools 22.0.

A reload only revalidates index.html, so an unhashed main.dart.js keeps coming from the browser cache. Send Cache-Control: no-cache for the Flutter build output, stamp a build id where you cannot set headers, and let the self-cleaning service worker retire pre-3.41 caches.

Flutter web 3.41 to 3.44 reports a ~625x line-height override when an Android WebView's textZoom is not 100. Upgrade to 3.47, or clear the override in MaterialApp.builder.

Your app imports material_ui but google_fonts 8.2.1 still returns the SDK TextTheme. Build the TextTheme yourself from GoogleFonts.roboto tear-offs until google_fonts migrates.

The release APK shipped without libapp.so. Flutter 3.44.0 to 3.44.4 could drop it: upgrade to 3.44.5 or later and split the combined subprojects block.

dart fix takes one target directory and it can be the repo root: the analyzer opens a context per nested pubspec.yaml and migrates every package in one pass. Here is the full flag surface, the four things that silently suppress fixes and make a dirty repo report Nothing to fix, why the exit code is useless in CI, and a case where a Flutter transform emits code that does not compile.

ImageIcon flattens a multi-color PNG into a silhouette because it always applies ColorFilter.mode(iconThemeColor, BlendMode.srcIn). Flutter 3.47 adds useOriginalColors to switch that off. Here is why passing color: null never worked, what useOriginalColors silently drops, and the hand-rolled replacement for older SDKs.

flutter attach has no --flavor option, so the resident compiler it spawns never defines FLUTTER_APP_FLAVOR and the appFlavor const collapses to null on the first hot restart. Three fixes: default-flavor in pubspec.yaml, flutter run --use-application-binary, and a platform channel that reads the flavor natively. Verified on Flutter 3.47.2 / Dart 3.13.2.

onChanged never fires because no edit happens, and on iOS the engine's deleteBackward returns without touching anything when the field is empty. Two approaches that actually work on every platform: a zero-width sentinel that guarantees an edit, and a single EditableText behind painted cells. Verified on Flutter 3.47.2 / Dart 3.13.2.

ref.watch subscribes and rebuilds, ref.read reads once and never rebuilds. Use watch in every build method and read only inside event callbacks. Here is the decision matrix, the source of both methods in flutter_riverpod 3.4.3, and the four silent failure modes: watch in a callback, read in a provider body, read on an autoDispose provider, and read used as an optimization.

Flutter keys identify stateful rows through a reorder. See when ValueKey is enough, when a lazy builder needs an index callback, and how GlobalKey reparenting works.

A step-by-step migration off the deprecated dart:html, dart:js_util, and package:js onto package:web 1.1.1 and dart:js_interop: how to find every offending import with the dart2wasm compiler, what dart fix does and does not rename, the JSImmutableListWrapper and innerHTML traps, and how to verify with flutter build web --wasm.

The full migration off package:flutter/material.dart and package:flutter/cupertino.dart onto material_ui 1.1.1 and cupertino_ui 1.0.2: what dart fix --code=migrate_design_widgets rewrites, why third-party widgets start throwing ancestor-lookup errors, what MaterialUiCompatibilityBridge actually fixes, and how the flutter_localizations dependency changes.

Firebase Auth restores the Android session from a private SharedPreferences file with no network call, so a release-only sign-out is never broken persistence. It is a different google-services.json, a rejected token refresh, App Check, or your own catch block.

build_runner fails to compile because source_gen 3.1.0 or 4.0.0 calls an analyzer API removed in analyzer 8.4.0. Upgrade the generator that pins source_gen below 4.0.1.

A thread shares memory with every other thread in the process. A Dart isolate does not: it owns its heap, runs one event loop, and talks to other isolates only by messages. Here is what that means at the VM level, where isolate groups blur the line, and how it plays out in Flutter, FFI, and on the web.

Inside testWidgets the ambient clock from package:clock is already fake, but it starts at whatever wall time the test began. Pin it for a whole suite by overriding runTest on a custom AutomatedTestWidgetsFlutterBinding installed from flutter_test_config.dart. Verified on Flutter 3.44.2, clock 1.1.2, fake_async 1.3.3.

The JEP 472 warning on JDK 24+ is harmless and prints once. Fix it by matching your JDK to a Gradle version that supports it, not by pasting flags into gradle.properties.

getToken() runs before APNs hands iOS the device token. Poll getAPNSToken() until it returns non-null, then call getToken(). Check the Push Notifications capability if it never arrives.

Targeting Android SDK 35 puts your Flutter app in edge-to-edge mode, so the Scaffold body draws behind the navigation bar. Consume the insets with SafeArea and MediaQuery padding instead of opting out, because the opt-out is already dead on Android 16.

Gradle is compiling with a JRE. It is not searching your machine, it is using the exact JVM it was launched on. Point flutter config --jdk-dir at a real JDK, or clear org.gradle.java.home.

The 3.47.1 hotfix validates plugin class and package identifiers before they land in GeneratedPluginRegistrant. Here is the hole it closes, the regex that closes it, and the other 11 fixes in the release.

google_sign_in 7.0.0 made GoogleSignIn a singleton. Replace GoogleSignIn(scopes: ...) with GoogleSignIn.instance, await initialize() once, then call authenticate().

iOS 26 simulator runtimes are arm64-only, so a leftover EXCLUDED_ARCHS arm64 line builds an Intel-only Runner no simulator can execute. Drop the exclusion.

Flutter 3.47.0 stable flips desktop apps from Skia to Impeller without touching a line of your runner code. Here is what moves, how to opt out on each platform, and why that opt-out is temporary.

Pick by the return type of build(): T means Notifier, FutureOr<T> means AsyncNotifier, Stream<T> means StreamNotifier. Here is the decision matrix, the type hierarchy that explains why, and the == filtering and state-clobbering gotchas that bite each one. Verified against flutter_riverpod 3.4.2 on Flutter 3.44.2.

The SDK Manager is re-unpacking a corrupt archive it cached in .downloadIntermediates. Delete that folder and the half-extracted ndk/<version> directory, then re-run the build.

Play rejects the bundle because a 64-bit .so still has 4 KB ELF segments. Find the offending library, rebuild it with NDK r28+, and verify with zipalign -P 16.

iOS blocks the Dart VM from flipping memory pages to executable, so JIT dies at startup. Upgrade to Flutter 3.35.0 or later for iOS 26, 3.32.0 for iOS 18.4. There is no entitlement that fixes it.

Radio.groupValue and Radio.onChanged were deprecated after Flutter 3.32 and RadioGroup shipped in 3.35. A step-by-step migration for Radio, RadioListTile and CupertinoRadio, why dart fix cannot do it for you, and the generic type-inference trap that silently renders a migrated radio disabled. Verified on Flutter 3.44.2 stable.

Install the Android SDK Command-line Tools so the binaries land in <sdk>/cmdline-tools/latest/bin, point ANDROID_HOME at the SDK root, then re-run flutter doctor.

Wrap the subtree in Material(type: MaterialType.transparency) or put the screen in a Scaffold. MaterialApp alone does not provide a Material ancestor, which is why TextField and InkWell assert.

Attach a ScrollController to a ListView.builder, fire the next page when position.extentAfter drops below a prefetch threshold, and guard the fetch with isLoading, hasMore, and error flags. Full implementation plus the short-first-page trap.

Flutter 3.44.8 stable still ships no public multi-window API. Here is how to turn on the experimental windowing feature flag on the main channel, use RegularWindowController and WindowManager to open real top-level windows, and what to ship instead if you need stable today.

The keyboard shrinks your Scaffold body's max height, so a Column that just fit now overflows. Wrap the body in a scrollable instead of turning resizeToAvoidBottomInset off.

Read the second line of the error, not the first. It names the cause: a stale Podfile.lock snapshot, a deployment target that is too low, or two plugins pinning the same transitive pod.

That line is a wrapper, not the error. Re-run with flutter run --verbose or ./gradlew assembleDebug --stacktrace, read the real Gradle failure, then fix that.

The asset key is missing from the compiled bundle, not from your disk. Fix the pubspec indentation, add the trailing slash, match the key exactly, then full restart.

A complete guide to shipping a Flutter web app compiled to WebAssembly on Flutter 3.44: what the two emitted builds look like, why Firefox and Safari still get JavaScript because of the loader's wasmAllowList, migrating off dart:html for dart2wasm, the COOP/COEP headers that decide whether skwasm runs multi-threaded, and how to prove at runtime which build the browser actually loaded.

A step-by-step move from widget-local setState to a Riverpod 3.x Notifier: classify what actually leaves the widget, write the Notifier, convert to ConsumerWidget, and survive the == filtering, build() re-entry, and autoDispose defaults that bite setState refugees. Tested on Flutter 3.44, Dart 3.x, flutter_riverpod 3.3.2.

Install flutter_riverpod for almost every Flutter app. Use riverpod only for Dart-only code, and hooks_riverpod only if you already use flutter_hooks.

In Riverpod 3.0 every provider filters listener notifications with ==, not identity. A StreamProvider that re-emits the same mutable object stops rebuilding the UI after the first frame. Here is why it happens and three ways to fix it. Tested on flutter_riverpod 3.3.2, Flutter 3.44, Dart 3.x.

Riverpod 3.0 retries a failed provider up to 10 times by default. Pass a retry function that returns null on ProviderScope, ProviderContainer, or an individual provider to turn it off or bound it.

This error means the BuildContext you passed is above the Scaffold or ScaffoldMessenger, not below it. Wrap the caller in a Builder, extract it into its own widget, or use a GlobalKey.

This runtime error means a null reached a cast expecting a non-nullable type, almost always from JSON. Make the field nullable, or supply a default before the cast runs.

Wrap the same widget on both routes in a Hero with an identical tag and Flutter animates its position and size across the navigation. Full guide: images, flightShuttleBuilder, createRectTween, RectTween arcs, gesture transitions, and the tag collisions that break it. Tested on Flutter 3.44, Dart 3.12.

A stream keeps emitting after the user leaves the screen, its onData calls setState on a disposed State, and Flutter throws. Store the subscription, cancel it in dispose before super.dispose, and the callback can never fire on a dead widget. The full pattern for Flutter 3.44.

After an await, the widget may already be disposed, and calling setState throws. Guard the resume with if (!mounted) return; and, better, cancel the work that triggers it. The full pattern for Flutter 3.44.

A step-by-step upgrade from flutter_riverpod 2.x to 3.x: bump the packages, move StateProvider and friends to the legacy import, drop the AutoDispose and Family ref types, handle ProviderException wrapping and automatic retry, and fix the == notification filtering that silently drops StreamProvider events. Tested on Flutter 3.44, Dart 3.x, flutter_riverpod 3.3.2.

Flutter 3.44 exposes the device's rounded display corners through MediaQuery.displayCornerRadiiOf. Stop guessing a magic radius and clip your UI to the exact hardware curve on Android API 31+.

go_router and auto_route both sit on top of Navigator 2.0, so the real choice is declarative URL routing vs code-generated typed routes vs hand-rolling the Router API. A decision matrix with config for each, and when raw Navigator still wins.

For a long list, never use shrinkWrap. Use Expanded when the list is the only scrollable, and slivers (CustomScrollView) when it shares a scroll with other sections. Here is why, with a build-count benchmark.

Riverpod 3.0 wraps errors thrown while reading a provider in a ProviderException. Catch that type and read e.exception to get your original error back, or use AsyncValue.error which is unwrapped.

Dot shorthands went stable in Dart 3.12.2. Write .center or .new and let the compiler infer the type from context. Here is how they work across enums, static members, and constructors.

Move the color inside the decoration: use decoration: BoxDecoration(color: ...) instead of passing both color and decoration to the same Container.

This error means an Expanded or Flexible is not a direct child of a Row, Column, or Flex. Move it directly under the flex widget, or drop Expanded if the parent is not a flex.

The slivers list of a CustomScrollView only accepts slivers. Wrap box widgets in SliverToBoxAdapter, or swap ListView/Padding/Column for SliverList and SliverPadding.

In a Notifier, resolve dependencies before the await, then guard the state write with if (!ref.mounted) return. This is the Riverpod 3.0 replacement for the old onDispose mixin, and it stops UnmountedRefException when a provider is disposed mid-await. Tested on flutter_riverpod 3.x, Flutter 3.44, Dart 3.x.

Put a list and a grid in a single continuous scroll without nested scrollables. Use CustomScrollView with SliverList and SliverGrid, and skip the shrinkWrap trap that quietly kills performance.

Why a ListView in a Column throws 'Vertical viewport was given unbounded height', and the four fixes (Expanded, Flexible, shrinkWrap, SizedBox) with the performance trade-offs that decide which one you want.

Fix reads of uninitialized late fields in Flutter. Choose synchronous initialization or explicit loading/error/data state, with tested lifecycle-safe code.

The ! operator hit a null at runtime. Replace it with ?. and ?? for a safe default, or guard with an explicit null check, instead of asserting a value that was not there.

Build a persistent shell with nested routes using ShellRoute and StatefulShellRoute, then wire up path-based deep links that rebuild the full page stack. Full config for Android and iOS, plus the gotchas that break the back stack.

Capture what you need from the context before the await, then guard the resume with if (context.mounted) return. Here is the full pattern, the lint that enforces it, and the edge cases it misses.

Migrate FutureBuilder to Riverpod 3 AsyncNotifier with a verified manual family provider, explicit cache lifetime and retry behavior, and safe mutation handling.

A version-pinned guide to moving a legacy Flutter 2.x app to a current Flutter 3.x release, with the sound null safety migration as the hard gate: why you need a two-hop path through Dart 2.19, what dart migrate does, and what breaks along the way.

A step-by-step migration from the provider package to Riverpod 3.x in a real Flutter app: ChangeNotifierProvider to Notifier, MultiProvider to ProviderScope, context.watch to ref.watch, ProxyProvider to ref.watch composition, plus the equality and lifecycle gotchas that bite. Tested on Flutter 3.27.1, Dart 3.11, provider 6.1.5, flutter_riverpod 3.3.1.

Use FutureBuilder or StreamBuilder for a self-contained, throwaway async widget. Reach for Riverpod AsyncValue once the result is shared, cached, or mutated. Here is the decision, the gotchas, and runnable code for both. Tested on Flutter 3.44 and flutter_riverpod 3.3.1.

This crash means a WidgetRef was used after its widget left the tree, usually in an async callback. Read what you need before the await, then guard with a mounted check.

This crash means you called context.of() after the widget left the tree, usually in an async callback or dispose(). Capture the value before the await, or in didChangeDependencies().

FutureBuilder re-runs your async work every time the parent rebuilds because you created the Future inside build. Hoist it into State.initState (or memoize it), and FutureBuilder will reuse the same Future. Here is the why, the repro, and every variant that bites.

Dart 3.12 adds an experimental primary constructors syntax that declares fields and a constructor in the class header, collapsing the classic three-line data class to one.

Pick Riverpod for most new Flutter apps in 2026. Choose Bloc for large teams that want an enforced event-driven structure, and keep Provider only for legacy code.

RenderBox was not laid out is almost always a secondary error. Find the first layout assertion above it, usually a scrollable given unbounded constraints, and fix that.

This crash means code touched a controller after dispose() ran. Guard async callbacks with a mounted check, and never dispose a controller you do not own.

This error means you mutated state while Flutter was building. Move the setState out of build, or defer it with addPostFrameCallback. Here is why it happens and the right fix.

Render loading, data, and error UI from a single AsyncValue in Riverpod 3. Use AsyncNotifier and AsyncValue.guard for mutations, .when() and switch pattern matching for the UI, keep previous data on refresh, and migrate the legacy StateNotifier pattern. Tested on flutter_riverpod 3.x, Flutter 3.44, Dart 3.x.

AnimationController, TextEditingController, and ScrollController hold resources that Dart's GC cannot reclaim until you dispose them. Here is the correct pattern, the ordering rules, and how to catch leaks before they ship.

A request can fail with no connectivity, a timeout, a DNS failure, a 500, or malformed JSON, and each needs a different response. Here is how to catch the right exceptions, classify them, retry safely, and show a UI a user can act on.

Dart 3.12 ships dart mcp-server, the official MCP bridge into the Dart and Flutter toolchain. Register it once in Claude Code, Cursor, or Codex CLI and your agent gets hot reload, pub.dev search, and live widget introspection without copy-pasting a DTD URI.

Pick Dart 3.12 records for ephemeral, locally-shaped data with no methods, and Freezed 3.x classes for named domain models that need copyWith, sealed unions, JSON serialization, or any behaviour.

For a greenfield mobile app in 2026, pick Flutter 3.44 when pixel-identical UI and animation budget matter, React Native 0.82 when your team already lives in TypeScript and you need a real browser sibling, and .NET MAUI 11 when iOS and Android are part of a wider .NET product and you need first-party Microsoft support.

Dart 3.12 lets constructors initialize private fields directly with named parameters, killing one of the language's most persistent boilerplate patterns.

Firebase shipped experimental Dart support for Cloud Functions on May 6, 2026. HTTPS and callable triggers, AOT-compiled cold starts, and the Firebase CLI handles compilation.

The fix in 30 seconds: set android.useAndroidX=true and android.enableJetifier=true in android/gradle.properties, then find any plugin still on the old support library and upgrade or replace it.

The fix in 30 seconds: set minSdkVersion to 21 (or higher) in android/app/build.gradle. background_fetch is built on Android's JobScheduler, which only exists from API 21.

The fix in 60 seconds: upgrade Flutter to 3.24.4 or later, raise the Podfile platform to iOS 13, wipe Pods plus DerivedData, then pod install. The error rarely lives in your Dart code.

The fix in 30 seconds: your response body is not the JSON you think it is. Print the raw bytes, decode with utf8.decode(response.bodyBytes), and never feed an HTML error page or a BOM-prefixed string to jsonDecode.

The fix in 30 seconds: read the 'because' chain in the error, find the one constraint that boxes pub in, and either widen it or add a dependency_overrides entry. Do not start with flutter clean.

The fix in 30 seconds: wrap the offending child in Expanded or Flexible. Then read the rest to learn why Row and Column do not clip, what unbounded constraints actually mean, and which fix is right for each layout.

Flutter 3.44 stable freezes Material and Cupertino inside the SDK and points new work at the material_ui and cupertino_ui packages on pub.dev. SwiftPM also becomes the default for iOS and macOS, finally retiring CocoaPods.

Step-by-step migration from GetX to Riverpod 3.x in a real Flutter app: GetxController to Notifier, .obs to derived providers, Get.find to ref.watch, Get.to to go_router, plus snackbars, theming, and tests. Tested on Flutter 3.27.1, Dart 3.11, flutter_riverpod 3.3.1.

Step-by-step guide to finding and fixing jank in Flutter 3.27 with DevTools: profile mode, the Performance overlay, the Frame Analysis tab, the CPU Profiler, raster vs UI thread, shader warm-up, and Impeller-specific gotchas. Tested on Flutter 3.27.1, Dart 3.11, DevTools 2.40.

The 2026 way to set an accent color in Flutter with Material 3: ColorScheme.fromSeed, the colorSchemeSeed shorthand, the seven DynamicSchemeVariant options, dark mode, dynamic_color on Android 12+, and harmonizing brand colors. Tested on Flutter 3.27.1 and Dart 3.11.

Call native Android (Kotlin) and iOS (Swift) code from a Flutter 3.x app without writing a plugin: MethodChannel, EventChannel, BasicMessageChannel, the StandardMessageCodec type table, threading rules, and the cases where a plugin still wins.

When async/await is not enough: spawn a Dart isolate to run CPU-bound work off the UI thread. Isolate.run, Flutter's compute, long-lived workers with SendPort/ReceivePort, what can cross the boundary, and the JS/web caveat. Tested on Dart 3.11 and Flutter 3.27.1.

Practical guide to running one Flutter project against multiple SDK versions in CI: a GitHub Actions matrix with subosito/flutter-action v2, FVM 3 .fvmrc as the source of truth, channel pinning, caching, and the gotchas that bite when the matrix grows past three versions.

Fluorite is an open-source 3D game engine that embeds Google Filament rendering inside Flutter widgets and lets you write game logic in Dart.

Droido 1.2.0 landed on Feb 8, 2026 as a debug-only network inspector for Flutter. The interesting part is not the UI. It is the packaging story: keep a modern inspector in debug builds while ensuring release builds remain clean, small, and unaffected.

biometric_signature 10.0.0 adds simplePrompt() and new BiometricError values. Here is how to handle the breaking change and future-proof your Flutter 3.x auth flows.

TrailBase is an open-source, single-executable backend built on Rust, SQLite, and Wasmtime. Version 0.23.7 ships UI fixes and improved error handling.

A pragmatic workflow for debugging Flutter iOS apps from Windows: offload the build to macOS in GitHub Actions, install the IPA on a real iPhone, and use flutter attach for hot reload and DevTools.

particles_flutter 2.0.2 adds particle shapes, rotation, boundary modes, and emitters. A quick tour of what changed and a tiny integration snippet for Flutter 3.x projects.

The leadingDistribution property in Flutter's TextHeightBehavior controls how extra leading is distributed above and below glyphs. Here is when it matters and how to fix text that looks vertically off.

TypeMonkey, a Flutter desktop typing app, shows why desktop projects need clean architecture from day one: sealed states, interface boundaries, and testable logic.

Dart 3.12 dev tags are landing fast. Here is how to read the version string, pin a dev SDK in CI, and triage failures so your Flutter 3.x migration is a small PR instead of a fire drill.

Flet lets you build Flutter UIs with Python logic. Here are the real trade-offs: latency from event chatter, ecosystem mismatch with Dart plugins, and split-brain debugging -- plus when it actually makes sense.

mobile_rag_engine brings on-device RAG to Flutter with a Rust core, ONNX embeddings, HNSW vector search, and SQLite storage. A practical look at the API, integration flow, and shipping constraints.

FlutterGuard CLI scans your Flutter 3.x build artifacts for leaked secrets, debug symbols, and metadata. A practical workflow for integrating it into CI and handling what it finds.

Flutter 3.38.6 bumped engine.version, and that matters for reproducible builds. Learn how to pin the SDK in CI, avoid engine drift, and diagnose 'what changed' when builds break with no code changes.

tp_router is a generator-driven Flutter router that eliminates manual route tables. Annotate your pages, run build_runner, and navigate with typed APIs instead of stringly-typed paths.

Fix Flutter `MissingPluginException` 'No implementation found for method getAll' on shared_preferences and similar plugins (package_info_plus, etc.) — ProGuard, plugin registration, minSdkVersion, hot restart fixes.

This Flutter error occurs when calling a method on a null object reference. Learn how to diagnose and fix the NoSuchMethod error using the call stack and breakpoints.

The most likely cause of this error is an update to Flutter (flutter upgrade) which led to some incompatibility with your existing code or your project's dependencies. The Theme.of(context).accentColor property has been deprecated since Flutter 1.17 and is entirely removed from the current version, thus the error you are seeing. What to use instead Or, if…

Fix the Flutter error 'Your project requires a newer version of the Kotlin Gradle plugin' by updating the ext.kotlin_version in your build.gradle file to the latest Kotlin release.