Jetpack Compose實(shí)現(xiàn)動(dòng)畫(huà)效果的方法詳解

更新時(shí)間：2022年02月26日 16:08:12 作者：安安安安卓

compose為支持動(dòng)畫(huà)提供了大量的 api，通過(guò)這些 api 我們可以輕松實(shí)現(xiàn)動(dòng)畫(huà)效果。本文將為大家介紹利用compose實(shí)現(xiàn)的多種動(dòng)畫(huà)效果的示例代碼，需要的可以參考一下

概述

compose 為支持動(dòng)畫(huà)提供了大量的 api，通過(guò)這些 api 我們可以輕松實(shí)現(xiàn)動(dòng)畫(huà)效果

ps：這些 api 的原理與 Flutter 很接近，與原生的 api 相去甚遠(yuǎn)

你可以提前看看用 compose 實(shí)現(xiàn)的一個(gè)放大縮小動(dòng)畫(huà)，總的來(lái)說(shuō)還是比較流暢：

低級(jí)別動(dòng)畫(huà) API

animate*AsState

所能處理屬性的種類：Float、Color、Dp、Size、Bounds、Offset、Rect、Int、IntOffset 和 IntSize

通過(guò) animate*AsState 我們可以實(shí)現(xiàn)單一屬性的動(dòng)畫(huà)效果,我們只需要提供目標(biāo)值就可以自動(dòng)從當(dāng)前進(jìn)度動(dòng)畫(huà)過(guò)渡到目標(biāo)值

實(shí)現(xiàn)放大動(dòng)畫(huà)

1.代碼

@Composable
fun animSize() {
    val enable = remember {
        mutableStateOf(true)
    }
    val size =
        animateSizeAsState(targetValue = if (enable.value) Size(50f, 50f) else Size(300f, 300f))
    Column(
        modifier = Modifier.fillMaxSize(1f),
        horizontalAlignment = Alignment.CenterHorizontally,
        verticalArrangement = Arrangement.Center
    ) {
        Image(
            modifier = Modifier
                .size(size.value.width.dp, size.value.height.dp)
                .clickable {
                    enable.value = !enable.value
                },
            painter = painterResource(id = R.drawable.apple),
            contentDescription = ""
        )
    }
}

2.實(shí)現(xiàn)效果

實(shí)現(xiàn)顏色變化動(dòng)畫(huà)

1.代碼

@Composable
fun animColor() {
    val enable = remember {
        mutableStateOf(true)
    }
    val colors = animateColorAsState(targetValue = if (enable.value) Color.Green else Color.Red)
    val size = animateIntSizeAsState(
        targetValue = if (enable.value) IntSize(100, 100) else IntSize(
            300,
            300
        )
    )
    Column(
        modifier = Modifier.fillMaxWidth(1f),
        horizontalAlignment = Alignment.CenterHorizontally,
        verticalArrangement = Arrangement.Center
    ) {
        Box(
            modifier = Modifier
                .size(size.value.width.dp, size.value.height.dp)
                .height(400.dp)
                .background(
                    color = colors.value,
                    shape = if (enable.value) RectangleShape else CircleShape
                )
        ) {

        }
    }
}

2.效果

使用 Animatable 實(shí)現(xiàn)顏色變化效果

Animatable 是一個(gè)值容器，我們可以通過(guò)調(diào)用 animateTo 實(shí)現(xiàn)動(dòng)畫(huà)效果。動(dòng)畫(huà)執(zhí)行過(guò)程中如果再次開(kāi)啟動(dòng)畫(huà)會(huì)中斷當(dāng)前動(dòng)畫(huà)。

Animatable 動(dòng)畫(huà)執(zhí)行過(guò)程中值的變化是在協(xié)程中執(zhí)行的，所以 animateTo 是一個(gè)掛起操作

1.代碼

@Composable
fun animChangeColor() {
    val color = remember {
        Animatable(Color.Red)
    }
    val state = remember {
        mutableStateOf(true)
    }
    LaunchedEffect(state.value) {
        color.animateTo(if (state.value) Color.Red else Color.Magenta)
    }
    Box(Modifier.fillMaxSize(1f), contentAlignment = Alignment.Center) {
        Box(
            modifier = Modifier
                .background(color.value, shape = RoundedCornerShape(30.dp))
                .size(200.dp)
                .clickable {
                    state.value = !state.value
                }, contentAlignment = Alignment.Center
        ) {
            Text(
                text = "顏色動(dòng)畫(huà)",
                style = TextStyle(color = Color.White, fontSize = 40.sp)
            )
        }
    }
}

2.效果

使用 updateTransition 實(shí)現(xiàn)顏色和圓角動(dòng)畫(huà)

使用 updateTransition 可以實(shí)現(xiàn)多個(gè)動(dòng)畫(huà)組合的效果。

例如：我們可以在動(dòng)畫(huà)執(zhí)行過(guò)程中同時(shí)執(zhí)行大小和顏色變化效果

本例中我們定義了一個(gè)枚舉用來(lái)控制動(dòng)畫(huà)，枚舉可以定義多個(gè)，分別用來(lái)對(duì)應(yīng)動(dòng)畫(huà)的多個(gè)狀態(tài)

1.代碼

@Composable
fun animupdateTransition() {
    var state by remember {
        mutableStateOf(BoxState.Collapsed)
    }
    val transition = updateTransition(targetState = state, label = "")

    val round = transition.animateDp(label = "") {
        when (it) {
            BoxState.Collapsed -> 40.dp
            BoxState.Expanded -> 100.dp
        }
    }
    val color = transition.animateColor(label = "") {
        when (it) {
            BoxState.Collapsed -> Color.Red
            BoxState.Expanded -> Color.Green
        }
    }
    Box(Modifier.fillMaxSize(1f),contentAlignment = Alignment.Center) {
        Box(
            modifier = Modifier
                .size(300.dp)
                .background(
                    color.value,
                    shape = RoundedCornerShape(corner = CornerSize(round.value))
                )
                .clickable {
                    state =
                        if (state == BoxState.Collapsed) BoxState.Expanded else BoxState.Collapsed
                },contentAlignment = Alignment.Center
        ) {
            Text(text = "點(diǎn)擊開(kāi)始動(dòng)畫(huà)",style = TextStyle(color = Color.White,fontSize = 20.sp))
        }
    }
}
private enum class BoxState {
    Collapsed,
    Expanded
}

2.效果

rememberInfiniteTransition

rememberInfiniteTransition 的使用和 updateTransition 基本一樣，不同的是 rememberInfiniteTransition 的動(dòng)畫(huà)一旦開(kāi)始便會(huì)一直反復(fù)運(yùn)行下去，只有被移除動(dòng)畫(huà)才能結(jié)束

1.代碼

@Composable
fun rememberInfiniteTransition1() {
    val infiniteTransition = rememberInfiniteTransition()
    val color by infiniteTransition.animateColor(
        initialValue = Color.Red,
        targetValue = Color.Green,
        animationSpec = infiniteRepeatable(
            animation = tween(1000, easing = LinearEasing),
            repeatMode = RepeatMode.Reverse
        )
    )

    Box(Modifier.fillMaxSize(1f), contentAlignment = Alignment.Center) {
        Box(
            Modifier
                .fillMaxSize(0.8f)
                .background(color),
            contentAlignment = Alignment.Center
        ) {
            Text(
                text = "公眾號(hào)：安安安安卓 原創(chuàng)，禁抄襲",
                style = TextStyle(color = Color.White, fontSize = 30.sp)
            )
        }
    }
}

2.效果 ???????

TargetBasedAnimation

TargetBasedAnimation 可以控制動(dòng)畫(huà)的執(zhí)行時(shí)間，還可以延遲一段時(shí)間再開(kāi)啟動(dòng)畫(huà)。

1.代碼

@Composable
fun animTargetBasedAnimation() {
    var state by remember {
        mutableStateOf(0)
    }
    val anim = remember {
        TargetBasedAnimation(
            animationSpec = tween(2000),
            typeConverter = Float.VectorConverter,
            initialValue = 100f,
            targetValue = 300f
        )
    }
    var playTime by remember { mutableStateOf(0L) }
    var animationValue by remember {
        mutableStateOf(0)
    }

    LaunchedEffect(state) {
        val startTime = withFrameNanos { it }
        println("進(jìn)入?yún)f(xié)程：")
        do {
            playTime = withFrameNanos { it } - startTime
            animationValue = anim.getValueFromNanos(playTime).toInt()
        } while (!anim.isFinishedFromNanos(playTime))

    }
    Box(modifier = Modifier.fillMaxSize(1f),contentAlignment = Alignment.Center) {
        Box(modifier = Modifier
            .size(animationValue.dp)
            .background(Color.Red,shape = RoundedCornerShape(animationValue/5))
            .clickable {
                state++
            },contentAlignment = Alignment.Center) {
            Text(text = animationValue.toString(),style = TextStyle(color = Color.White,fontSize = (animationValue/5).sp))
        }
    }
}

2.效果 ???????

自定義動(dòng)畫(huà)

AnimationSpec

AnimationSpec 可以自定義動(dòng)畫(huà)的行為，效果類似于原生動(dòng)畫(huà)中的估值器。

SpringSpec 彈簧效果

1.代碼

@Composable
fun animSpring() {
    val state = remember {
        mutableStateOf(true)
    }
    var value = animateIntAsState(
        targetValue = if (state.value) 300 else 100,
        animationSpec = spring(
            dampingRatio = Spring.DampingRatioHighBouncy,
            stiffness = Spring.StiffnessVeryLow
        )
    )

    Box(
        Modifier
            .fillMaxSize(1f)
            .padding(start = 30.dp), contentAlignment = Alignment.CenterStart
    ) {
        Box(
            Modifier
                .width(value.value.dp)
                .height(80.dp)
                .background(Color.Red, RoundedCornerShape(topEnd = 30.dp, bottomEnd = 30.dp))
                .clickable {
                    state.value = !state.value
                }, contentAlignment = Alignment.CenterStart
        ) {
            Text(text = "哈哈哈", style = TextStyle(color = Color.White, fontSize = 20.sp))
        }
    }
}

2.效果 ???????

TweenSpec 動(dòng)畫(huà)時(shí)間可控

1.代碼

@Composable
fun animTweenSpec() {
    val state = remember {
        mutableStateOf(true)
    }
    val value = animateIntAsState(
        targetValue = if (state.value) 300 else 100,
        animationSpec = tween(
            durationMillis = 1500,
            delayMillis = 200,
            easing = LinearEasing
        )
    )

    Box(
        Modifier
            .fillMaxSize(1f)
            .padding(start = 50.dp), contentAlignment = Alignment.CenterStart
    ) {
        Box(
            Modifier
                .width(value.value.dp)
                .height(100.dp)
                .background(Color.Red, RoundedCornerShape(topEnd = 30.dp, bottomEnd = 30.dp))
                .clickable {
                    state.value = !state.value
                }
        ) {

        }
    }

}

2.效果 ???????

FrameSpec

1.代碼

@Composable
fun animkeyframesSpec() {
    var state by remember {
        mutableStateOf(true)
    }
    val value by animateIntAsState(
        targetValue = if (state) 300 else 100,
        animationSpec = keyframes {
            durationMillis = 2000
            0 at 700 with LinearOutSlowInEasing
            700 at 1400 with FastOutLinearInEasing
            1400 at 2000
        })

    Box(Modifier.fillMaxSize(1f), contentAlignment = Alignment.CenterStart) {
        Box(
            Modifier
                .width(value.dp)
                .height(100.dp)
                .background(Color.Red, RoundedCornerShape(topEnd = 30.dp, bottomEnd = 30.dp))
                .clickable {
                    state = !state
                }
        ) {

        }
    }
}

2.效果

RepeatableSpec 實(shí)現(xiàn)有限次數(shù)的重復(fù)動(dòng)畫(huà)

執(zhí)行有限次數(shù)動(dòng)畫(huà)后自動(dòng)停止

1.代碼

@Composable
fun animrepeatableSpec() {
    var state by remember {
        mutableStateOf(true)
    }
    val value by animateIntAsState(
        targetValue = if (state) 300 else 100,
        animationSpec = repeatable(
            iterations = 5,//動(dòng)畫(huà)重復(fù)執(zhí)行的次數(shù)，設(shè)置多少就執(zhí)行多少次
            animation = tween(durationMillis = 1000),
            repeatMode = RepeatMode.Reverse
        )
    )
    Box(
        Modifier
            .fillMaxSize(1f)
            .padding(start = 30.dp), contentAlignment = Alignment.CenterStart) {
        Box(
            Modifier
                .width(value.dp)
                .height(100.dp)
                .background(Color.Red, RoundedCornerShape(topEnd = 30.dp, bottomEnd = 30.dp))
                .clickable {
                    state = !state
                }
        ) {

        }
    }
}

2.效果

代碼中設(shè)置了重復(fù) 5 次，所以反復(fù)執(zhí)行五次后動(dòng)畫(huà)結(jié)束

InfiniteRepeatableSpec 無(wú)限次數(shù)執(zhí)行動(dòng)畫(huà)

動(dòng)畫(huà)會(huì)無(wú)限次的執(zhí)行下去，直到視圖被移除

1.代碼

@Composable
fun animinfiniteRepeatableSpec() {
    var state by remember {
        mutableStateOf(true)
    }
    val value by animateIntAsState(
        targetValue = if (state) 300 else 100,
        animationSpec = infiniteRepeatable(
            animation = tween(durationMillis = 1000),
            repeatMode = RepeatMode.Reverse
        )
    )
    Box(
        Modifier
            .fillMaxSize(1f)
            .padding(start = 30.dp), contentAlignment = Alignment.CenterStart) {
        Box(
            Modifier
                .width(value.dp)
                .height(100.dp)
                .background(Color.Red, RoundedCornerShape(topEnd = 30.dp, bottomEnd = 30.dp))
                .clickable {
                    state = !state
                }
        ) {
            Text(text = "公眾號(hào)：安安安安卓 原創(chuàng)，禁轉(zhuǎn)載")
        }
    }
}

2.效果

Easing

Easing 類似于我們?cè)鷦?dòng)畫(huà)中的差值器

有以下幾種選擇：

FastOutSlowInEasing
LinearOutSlowInEasing
FastOutLinearInEasing
LinearEasing
CubicBezierEasing

這幾種實(shí)現(xiàn)的效果和 android 原生實(shí)現(xiàn)的動(dòng)畫(huà)差值器差距很大，甚至看不出有啥效果，所以代碼我就不放了。有清楚原因的讀者可以聯(lián)系我

實(shí)現(xiàn)效果：

AnimationVector

大多數(shù) Compose 動(dòng)畫(huà) API 都支持將 Float、Color、Dp 以及其他基本數(shù)據(jù)類型作為開(kāi)箱即用的動(dòng)畫(huà)值，但有時(shí)我們需要為其他數(shù)據(jù)類型（包括我們的自定義類型）添加動(dòng)畫(huà)效果

本例中實(shí)現(xiàn)顏色和大小的變換動(dòng)畫(huà)

代碼中我們定義了一個(gè) AnimSize 類，類中的第一個(gè)參數(shù)是顏色數(shù)據(jù)，第二個(gè)參數(shù)是尺寸數(shù)據(jù)。動(dòng)畫(huà)執(zhí)行過(guò)程中會(huì)同事改變顏色和控件尺寸效果。

1.代碼

@Composable
fun animAnimationVector() {
    var state by remember {
        mutableStateOf(true)
    }
    val value by animateValueAsState(
        targetValue = if (state) AnimSize(0xffff5500, 100f) else AnimSize(0xff00ff00, 300f),
        typeConverter = TwoWayConverter(
            convertToVector = {
//                AnimationVector2D(target.color.toFloat(), target.size)
                AnimationVector2D(it.color.toFloat(), it.size)
            },
            convertFromVector = {
                AnimSize(it.v1.toLong(), it.v2)
            }
        )
    )
    println("顏色:${value.color}")
    Box(modifier = Modifier.fillMaxSize(1f).padding(30.dp), contentAlignment = Alignment.Center) {
        Box(
            modifier = Modifier
                .size(value.size.dp)
//                .size(300.dp)
                .background(Color(value.color), RoundedCornerShape(30.dp))
                .clickable {
                    state = !state
                }
        ) {

        }
    }
}

data class AnimSize(val color: Long, val size: Float)

2.效果

缺點(diǎn)是執(zhí)行顏色變化過(guò)程中有閃爍