Lottie — 是什么，移动应用中的矢量动画

<com.airbnb.lottie.LottieAnimationView
    android:id="@+id/animationView"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    app:lottie_rawRes="@raw/loading_animation"
    app:lottie_autoPlay="true"
    app:lottie_loop="true" />

import com.airbnb.lottie.LottieAnimationView
import com.airbnb.lottie.LottieListener

// 以编程方式配置 LottieAnimationView
val lottieView = LottieAnimationView(context).apply {
    setAnimation(R.raw.celebrate_animation)
    repeatCount = ValueAnimator.INFINITE
    speed = 1.5f
    addAnimatorUpdateListener { animator ->
        val progress = animator.animatedValue as Float
        progressBar.progress = (progress * 100).toInt()
    }
    playAnimation()
}

// 从 assets 加载和缓存
lottieView.setAnimation("animations/confetti.json")
lottieView.setCacheStrategy(LottieAnimationView.CacheStrategy.Strong)

// LottieDrawable — 无需视图的自定义绘制
val drawable = LottieDrawable().apply {
    setComposition(
        LottieCompositionFactory.fromRawRes(context, R.raw.star)
            .addListener { composition -> composition?.let { setComposition(it); play() } }
    )
}

import Lottie

// UIKit：带手动控制的 AnimationView
let animationView = AnimationView(name: "confetti")
animationView.frame = view.bounds
animationView.contentMode = .scaleAspectFit
animationView.loopMode = .loop
animationView.animationSpeed = 1.5
animationView.play(fromProgress: 0, toProgress: 0.5) { finished in
    print("动画段已完成：\(finished)")
}
view.addSubview(animationView)

// UIKit：带进度的动画（用于绑定到事件）
animationView.play(fromFrame: AnimationFrameTime(30),
                    toFrame: AnimationFrameTime(90))

// SwiftUI：LottieView 作为 UIViewRepresentable
import Lottie
import SwiftUI

struct LottieView: UIViewRepresentable {
    let name: String
    var loopMode: LottieLoopMode = .loop
    @Binding var progress: CGFloat

    func makeUIView(context: Context) -> AnimationView {
        let view = AnimationView(name: name)
        view.contentMode = .scaleAspectFit
        view.loopMode = loopMode
        return view
    }

    func updateUIView(_ uiView: AnimationView, context: Context) {
        uiView.currentProgress = progress
    }
}

// 在 SwiftUI 中使用
LottieView(name: "loading", progress: $animationProgress)
    .frame(width: 100, height: 100)

// 针对 RecyclerView 优化 Lottie
import com.airbnb.lottie.LottieAnimationView
import com.airbnb.lottie.LottieDrawable
import com.airbnb.lottie.LottieCompositionFactory

// 在内存中缓存合成
private val cache = LottieCompositionFactory.setCacheStrategy(CacheStrategy.Strong)

// LottieAnimationView 池用于重用
class LottiePool {
    private val pool = LinkedList<LottieAnimationView>()

    fun acquire(context: Context): LottieAnimationView {
        return pool.poll() ?: LottieAnimationView(context)
    }

    fun release(view: LottieAnimationView) {
        view.pauseAnimation()
        view.cancelAnimation()
        pool.add(view)
    }
}

// 禁用不必要的功能
lottieView.enableMergePathsForKitKatAndAbove(true)
lottieView.setHardwareAcceleration(true)
lottieView.setMaxFrame(60) // 限制帧数