我有一个已存在的应用程序,我在其中使用XML中的Objectanimator实现了以下FlipCard动画。如果我点击卡片,它会水平翻转。但现在我想将其迁移到Jetpack Compose。所以在Jetpack Compose中是否可以制作FlipCard动画?
更新:
最终,我得到了这个结果。虽然我不知道它是否正确,但我得到了我想要的结果。如果你有更好的替代方案可以建议一下。谢谢。
方法1:使用animate*AsState
@Composable
fun FlipCard() {
var rotated by remember { mutableStateOf(false) }
val rotation by animateFloatAsState(
targetValue = if (rotated) 180f else 0f,
animationSpec = tween(500)
)
val animateFront by animateFloatAsState(
targetValue = if (!rotated) 1f else 0f,
animationSpec = tween(500)
)
val animateBack by animateFloatAsState(
targetValue = if (rotated) 1f else 0f,
animationSpec = tween(500)
)
val animateColor by animateColorAsState(
targetValue = if (rotated) Color.Red else Color.Blue,
animationSpec = tween(500)
)
Box(
Modifier.fillMaxSize(),
contentAlignment = Alignment.Center
) {
Card(
Modifier
.fillMaxSize(.5f)
.graphicsLayer {
rotationY = rotation
cameraDistance = 8 * density
}
.clickable {
rotated = !rotated
},
backgroundColor = animateColor
)
{
Column(
Modifier.fillMaxSize(),
horizontalAlignment = Alignment.CenterHorizontally,
verticalArrangement = Arrangement.Center
) {
Text(text = if (rotated) "Back" else "Front",
modifier = Modifier
.graphicsLayer {
alpha = if (rotated) animateBack else animateFront
rotationY = rotation
})
}
}
}
}
方法2:封装一个过渡并使其可重用。 您将获得与方法1相同的输出。但它是可重复使用的,适用于复杂情况。
enum class BoxState { Front, Back }
@Composable
fun AnimatingBox(
rotated: Boolean,
onRotate: (Boolean) -> Unit
) {
val transitionData = updateTransitionData(
if (rotated) BoxState.Back else BoxState.Front
)
Card(
Modifier
.fillMaxSize(.5f)
.graphicsLayer {
rotationY = transitionData.rotation
cameraDistance = 8 * density
}
.clickable { onRotate(!rotated) },
backgroundColor = transitionData.color
)
{
Column(
Modifier.fillMaxSize(),
horizontalAlignment = Alignment.CenterHorizontally,
verticalArrangement = Arrangement.Center
) {
Text(text = if (rotated) "Back" else "Front",
modifier = Modifier
.graphicsLayer {
alpha =
if (rotated) transitionData.animateBack else transitionData.animateFront
rotationY = transitionData.rotation
})
}
}
}
private class TransitionData(
color: State<Color>,
rotation: State<Float>,
animateFront: State<Float>,
animateBack: State<Float>
) {
val color by color
val rotation by rotation
val animateFront by animateFront
val animateBack by animateBack
}
@Composable
private fun updateTransitionData(boxState: BoxState): TransitionData {
val transition = updateTransition(boxState, label = "")
val color = transition.animateColor(
transitionSpec = {
tween(500)
},
label = ""
) { state ->
when (state) {
BoxState.Front -> Color.Blue
BoxState.Back -> Color.Red
}
}
val rotation = transition.animateFloat(
transitionSpec = {
tween(500)
},
label = ""
) { state ->
when (state) {
BoxState.Front -> 0f
BoxState.Back -> 180f
}
}
val animateFront = transition.animateFloat(
transitionSpec = {
tween(500)
},
label = ""
) { state ->
when (state) {
BoxState.Front -> 1f
BoxState.Back -> 0f
}
}
val animateBack = transition.animateFloat(
transitionSpec = {
tween(500)
},
label = ""
) { state ->
when (state) {
BoxState.Front -> 0f
BoxState.Back -> 1f
}
}
return remember(transition) { TransitionData(color, rotation, animateFront, animateBack) }
}
输出
.graphicsLayer
很好用。我只是在 90 度时切换颜色,而不是连续动画改变它,以避免紫色阴影。为什么const val DefaultCameraDistance = 8.0f
不够好呢? - pommy