Compose 动画效果

var visible by remember { mutableStateOf(true) }
val alpha by animateFloatAsState(if (visible) 1f else 0f)
 
Box(
    modifier = Modifier
        .alpha(alpha)
        .clickable { visible = !visible }
) {
    Text("点击切换透明度")
}

var visible by remember { mutableStateOf(true) }
 
AnimatedVisibility(
    visible = visible,
    enter = fadeIn() + slideInHorizontally(),
    exit = fadeOut() + slideOutHorizontally()
) {
    Text("动画显示/隐藏")
}

val color = remember { Animatable(Color.Red) }
 
LaunchedEffect(Unit) {
    color.animateTo(
        targetValue = Color.Green,
        animationSpec = tween(2000)
    )
}
 
Box(
    modifier = Modifier
        .size(100.dp)
        .background(color.value)
)

enum class BoxState { SMALL, LARGE }
 
var boxState by remember { mutableStateOf(BoxState.SMALL) }
val transition = updateTransition(boxState)
 
val size by transition.animateDp { state ->
    when (state) {
        BoxState.SMALL -> 50.dp
        BoxState.LARGE -> 100.dp
    }
}
 
Box(
    modifier = Modifier
        .size(size)
        .background(Color.Blue)
        .clickable { 
            boxState = when (boxState) {
                BoxState.SMALL -> BoxState.LARGE
                BoxState.LARGE -> BoxState.SMALL
            }
        }
)

var offsetX by remember { mutableStateOf(0f) }
val offsetXAnim by animateFloatAsState(offsetX)
 
Box(
    modifier = Modifier
        .offset { IntOffset(offsetXAnim.roundToInt(), 0) }
        .draggable(
            orientation = Orientation.Horizontal,
            state = rememberDraggableState { delta ->
                offsetX += delta
            }
        )
)

val customSpec = spring<Float>(
    dampingRatio = Spring.DampingRatioMediumBouncy,
    stiffness = Spring.StiffnessLow
)
 
var value by remember { mutableStateOf(0f) }
val animatedValue by animateFloatAsState(
    targetValue = value,
    animationSpec = customSpec
)

var state by remember { mutableStateOf(false) }
val transition = updateTransition(state)
 
val scale by transition.animateFloat(
    transitionSpec = { spring(stiffness = Spring.StiffnessLow) }
) { if (it) 1.5f else 1f }
 
val color by transition.animateColor(
    transitionSpec = { tween(1000) }
) { if (it) Color.Red else Color.Blue }
 
Box(
    modifier = Modifier
        .scale(scale)
        .background(color)
        .size(100.dp)
        .clickable { state = !state }
)

// 使用remember避免重复创建动画规范
val animSpec = remember {
    spring<Float>(
        dampingRatio = Spring.DampingRatioMediumBouncy,
        stiffness = Spring.StiffnessLow
    )
}
 
// 使用crossfade实现平滑过渡
Crossfade(
    targetState = currentScreen,
    animationSpec = tween(500)
) { screen ->
    when (screen) {
        Screen.Home -> HomeScreen()
        Screen.Profile -> ProfileScreen()
    }
}

// 使用AnimationDebugLogger跟踪动画状态
val transition = updateTransition(state, label = "StateTransition")
 
// 使用remember缓存动画值
val offset by remember(key1) {
    Animatable(0f)
}