React Native Academy · レッスン

60fpsアニメーションのためのuseNativeDriver

timingおよびspringアニメーションでuseNativeDriver: trueを有効にし、処理をネイティブスレッドにオフロードします。対応するプロパティを確認し、パフォーマンスの向上を測定します。

「60fpsアニメーションのためのuseNativeDriver」はCoddyKit上の無料React Native Academyレッスンです。これはレッスン4/4です。下記で完全なレッスンを無料で読むことができます。その後、ブラウザ内の組み込みコードエディタと24時間対応のAIチューターでハンズオン演習できます。これはReact Native Academy学習パスの一部であり、ウェブとCoddyKitアプリ全体で進捗が同期されます。 React Native Academyコースには全4レッスンが含まれています。

このレッスンの一部はまだ翻訳されておらず、英語で表示されています。

The JavaScript Bridge Problem

React Native traditionally communicates between JavaScript and the native layer through a bridge — an asynchronous message channel. During animations, style updates must cross this bridge on every frame. If the JavaScript thread is busy (processing data, rendering, or garbage collecting), frames are dropped and animations stutter.

On a 60fps display, you have only ~16ms per frame to do all work. Any JavaScript overhead beyond that causes visible jank. For animations that update properties like opacity and transform, there is a better way: the native driver.

What useNativeDriver Does

When you set useNativeDriver: true, React Native serializes the animation configuration (start value, end value, duration, easing) and sends it to the native side once before the animation starts. The native layer then runs the animation entirely without touching JavaScript on each frame.

This means the animation continues smoothly even if JavaScript is blocked — loading data, parsing JSON, or running heavy logic. The result is consistently smooth 60fps animations on both iOS and Android.

Animated.timing(opacity, {
  toValue: 1,
  duration: 500,
  useNativeDriver: true, // offloads to native thread
}).start();
// JavaScript thread can now do other work
// without affecting animation smoothness

Which Properties Support Native Driver

Not all style properties can be animated with the native driver. The native driver supports transform (translateX, translateY, scale, rotate) and opacity — properties that can be applied on the GPU without a layout pass. Properties that affect layout like width, height, top, left, padding, margin, and backgroundColor are NOT supported.

If you try to animate an unsupported property with useNativeDriver: true, React Native will log a warning and silently fall back to the JS driver. Always check the property list when migrating animations.

// SUPPORTED with useNativeDriver: true
Animated.timing(opacity, { toValue: 1, useNativeDriver: true, duration: 300 })
Animated.timing(translateX, { toValue: 100, useNativeDriver: true, duration: 300 })
Animated.timing(scale, { toValue: 1.2, useNativeDriver: true, duration: 300 })

// NOT supported - must use useNativeDriver: false
Animated.timing(width, { toValue: 200, useNativeDriver: false, duration: 300 })
Animated.timing(backgroundColor, { toValue: '...', useNativeDriver: false, duration: 300 })

Mixing Native and Non-Native Animations

When you need to animate both native-driver-compatible and incompatible properties simultaneously, you must use two separate Animated.Values — one with useNativeDriver: true and one with useNativeDriver: false. You cannot use the same Animated.Value for both native and non-native driven animations.

A common pattern is running the transform and opacity (native) in a parallel group while running a color change (non-native) in a separate parallel group started at the same time.

// Two separate animations started together
Animated.timing(opacity, {
  toValue: 1,
  duration: 400,
  useNativeDriver: true,  // GPU
}).start();

Animated.timing(bgColor, {
  toValue: 1,
  duration: 400,
  useNativeDriver: false, // JS thread
}).start();

Measuring Animation Performance

React Native DevTools and Flipper can show you the frame rate of your app in real time. Look for the UI thread FPS (native rendering) and the JS thread FPS (JavaScript execution). With useNativeDriver, UI thread FPS should stay at 60 even when JS thread FPS drops.

In development mode, enable the performance monitor from the developer menu (shake device or press Cmd+D/Ctrl+D in simulator). The monitor shows both threads' frame rates overlaid on the app.

// Enable in development via developer menu:
// Shake device > Show Perf Monitor
// Or programmatically:
import { PerfMonitor } from 'react-native';
// Not an actual API - use the developer menu
// or Flipper performance plugin

Native Driver with Spring and Decay

The native driver works with all three animation types — Animated.timing, Animated.spring, and Animated.decay — as well as composition methods like Animated.parallel and Animated.sequence. Just add useNativeDriver: true to every leaf animation in the group.

The rule is: every animation in a composed group must have the same driver setting. Mixing native and non-native animated values inside a single Animated.parallel group will cause an error.

Animated.parallel([
  Animated.spring(scale, {
    toValue: 1,
    tension: 80,
    friction: 8,
    useNativeDriver: true,
  }),
  Animated.timing(opacity, {
    toValue: 1,
    duration: 300,
    useNativeDriver: true,
  }),
]).start();

Easing Functions and Native Driver

Easing functions are fully compatible with the native driver. React Native ships an Easing module with common curves: Easing.linear, Easing.ease, Easing.easeIn, Easing.easeOut, Easing.easeInOut, and configurable curves like Easing.bezier.

The easing curve is serialized and sent to the native side along with the animation config, so easing does not require JavaScript frame-by-frame computation. All the smoothness of custom easing with all the performance of native driving.

import { Animated, Easing } from 'react-native';

Animated.timing(translateY, {
  toValue: 0,
  duration: 500,
  easing: Easing.out(Easing.cubic), // decelerate into place
  useNativeDriver: true,
}).start();

// Custom bezier curve:
Animated.timing(scale, {
  toValue: 1,
  duration: 400,
  easing: Easing.bezier(0.25, 0.46, 0.45, 0.94),
  useNativeDriver: true,
}).start();

Interpolation with Native Driver

Interpolation also works with the native driver. When you call animatedValue.interpolate(), the interpolation config is serialized and evaluated natively alongside the animation. This means you can drive transforms and opacity through interpolation at 60fps without JavaScript involvement.

A common pattern is a single scroll position value (from ScrollView) interpolating into multiple header properties — opacity, scale, translateY — all natively driven for smooth parallax effects.

const scrollY = useRef(new Animated.Value(0)).current;

const headerOpacity = scrollY.interpolate({
  inputRange: [0, 100],
  outputRange: [1, 0],
  extrapolate: 'clamp',
});

const headerScale = scrollY.interpolate({
  inputRange: [0, 100],
  outputRange: [1, 0.8],
  extrapolate: 'clamp',
});

// Both driven natively by scroll position

Animated.event and Native ScrollView

Animated.event maps a native event's value directly to an Animated.Value without passing through JavaScript at all when useNativeDriver: true is set. The scroll offset from a ScrollView can feed directly into animated header effects completely on the native thread.

This is the foundation of native-thread parallax scroll effects — the most complex animation pattern in React Native — achieved without any JavaScript overhead per scroll event.

const scrollY = useRef(new Animated.Value(0)).current;

<Animated.ScrollView
  onScroll={Animated.event(
    [{ nativeEvent: { contentOffset: { y: scrollY } } }],
    { useNativeDriver: true }
  )}
  scrollEventThrottle={16}
>

Common Pitfalls with Native Driver

Common mistakes when adopting the native driver:

Animating unsupported properties — causes a silent fallback or error. Test with layout properties separately.
Calling setValue mid-animation — setValue works on both drivers but use it before starting, not while running.
Missing cleanup — always stop animations on unmount to prevent state updates on unmounted components.
Mixing drivers in one Value — one Animated.Value can only be driven by one driver type across its lifetime.

When to Skip Native Driver

You must set useNativeDriver: false for animations that affect layout (width, height, padding) or colors. These require the layout engine to recalculate positions and cannot be pre-serialized. Accept the JS-thread cost for these and ensure JS is not heavily loaded during layout animations.

A practical approach: use native driver for entrance/exit animations (transforms + opacity) and JS driver only for interactive layout changes like expanding accordion panels or resizing inputs. Keep layout animations short (under 300ms) to minimize the window of vulnerability.

// Layout animation: must use JS driver
Animated.timing(height, {
  toValue: 200,
  duration: 250,
  useNativeDriver: false, // required for height
}).start();

// But the card's entrance can still be native:
Animated.timing(opacity, {
  toValue: 1,
  duration: 250,
  useNativeDriver: true,
}).start();

Quick Check

Test your understanding of React Native Mobile Development concepts from this lesson.

Lesson Recap

In this lesson you learned: useNativeDriver: true serializes animation config to the native thread, enabling 60fps animations even when JavaScript is busy, only transform and opacity properties support the native driver, and Animated.event with useNativeDriver lets scroll position drive animations without any JS overhead per frame. Next up we explore React Native Reanimated 3 for even more powerful gesture-driven animations.

よくある質問

「60fpsアニメーションのためのuseNativeDriver」レッスンは無料ですか？

はい。「60fpsアニメーションのためのuseNativeDriver」の完全なテキストはこのウェブで無料で読めます。インタラクティブに演習し（組み込みコードエディタと24時間対応のAIチューター）、React Native Academyコースの残りをアンロックするには、CoddyKit PROにアップグレードしてください。 React Native Academyコースには全4レッスンが含まれています。

「60fpsアニメーションのためのuseNativeDriver」で何を学びますか？

timingおよびspringアニメーションでuseNativeDriver: trueを有効にし、処理をネイティブスレッドにオフロードします。対応するプロパティを確認し、パフォーマンスの向上を測定します。ブラウザで直接実行するハンズオンコードでReact Native Academyを演習し、24時間対応のAIチューターがレッスンを進める中での質問に答えます。

React Native Academyを始めるのに経験は必要ですか？

事前経験は必要ありません。CoddyKitのReact Native Academyは初級者から上級者向けに構成されているため、ここから始めるか最初から始めて、自分のペースで進むことができます。これはレッスン4/4です。

「60fpsアニメーションのためのuseNativeDriver」レッスンにはどのくらい時間がかかりますか？

ほとんどのCoddyKitレッスンは約5～10分かかります。各レッスンはコンパクトでインタラクティブなので、着実に進歩し、ウェブとアプリ全体で正確に前回の場所から再開できます。

このReact Native Academyレッスンでコードを書いて実行できますか？

はい。すべてのReact Native Academyレッスンに組み込みコードエディタが含まれているため、ブラウザでリアルコードを書いて実行し、即座のAIフィードバックを取得できます。ローカル設定は不要です。

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