React Native Academy · 课时

使用 useNativeDriver 实现 60fps 动画

在时序动画和弹簧动画中启用 useNativeDriver: true，将工作转移到原生线程，了解哪些属性支持该功能，并衡量性能提升。

使用 useNativeDriver 实现 60fps 动画 是 CoddyKit 上的免费 React Native Academy 课时。这是第 4 节课，共 4 节。你可以在下方免费阅读本课时的完整内容 — 然后在浏览器中使用内置代码编辑器和全天候 AI 导师进行实践。这是 React Native Academy 学习路径的一部分，你的进度在网页和 CoddyKit 应用中同步。 React Native Academy 课程共包含 4 节课。

本课时的部分内容尚未翻译，以英文显示。

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.

常见问题解答

「使用 useNativeDriver 实现 60fps 动画」课时是免费的吗？

是的 — 「使用 useNativeDriver 实现 60fps 动画」的完整文本可在网页上免费阅读。要进行交互式练习（内置代码编辑器和全天候 AI 导师）并解锁 React Native Academy 课程的其余内容，请升级到 CoddyKit PRO。 React Native Academy 课程共包含 4 节课。

「使用 useNativeDriver 实现 60fps 动画」这节课中我会学到什么？

在时序动画和弹簧动画中启用 useNativeDriver: true，将工作转移到原生线程，了解哪些属性支持该功能，并衡量性能提升。你通过在浏览器中直接运行的动手代码来练习 React Native Academy，全天候 AI 导师会在你学习这节课的过程中回答你的问题。

学习 React Native Academy 需要有经验吗？

无需任何先前经验。CoddyKit 上的 React Native Academy 课程适合初学者到高级学习者，你可以从这里开始或从头开始，按照自己的节奏学习。这是第 4 节课，共 4 节。

「使用 useNativeDriver 实现 60fps 动画」课时需要多长时间？

大多数 CoddyKit 课程大约需要 5–10 分钟。每节课都很精短且互动，所以你能稳步进步，并在网页和应用中从离开的地方继续。

我能在这节 React Native Academy 课中编写并运行代码吗？

能。每节 React Native Academy 课都包含内置代码编辑器，你可以在浏览器中直接编写并运行真实代码，并获得即时 AI 反馈 — 无需本地设置。

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