| /* |
| * Copyright 2019 The Android Open Source Project |
| * |
| * Licensed under the Apache License, Version 2.0 (the "License"); |
| * you may not use this file except in compliance with the License. |
| * You may obtain a copy of the License at |
| * |
| * http://www.apache.org/licenses/LICENSE-2.0 |
| * |
| * Unless required by applicable law or agreed to in writing, software |
| * distributed under the License is distributed on an "AS IS" BASIS, |
| * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. |
| * See the License for the specific language governing permissions and |
| * limitations under the License. |
| */ |
| |
| package androidx.compose.animation.demos |
| |
| import android.graphics.PointF |
| import androidx.compose.animation.core.FloatPropKey |
| import androidx.compose.animation.core.InterruptionHandling |
| import androidx.compose.animation.core.TransitionDefinition |
| import androidx.compose.animation.core.TransitionState |
| import androidx.compose.animation.core.keyframes |
| import androidx.compose.animation.core.transitionDefinition |
| import androidx.compose.animation.core.tween |
| import androidx.compose.Composable |
| import androidx.compose.remember |
| import androidx.compose.state |
| import androidx.compose.animation.transition |
| import androidx.ui.core.DensityAmbient |
| import androidx.ui.core.Modifier |
| import androidx.ui.core.gesture.pressIndicatorGestureFilter |
| import androidx.compose.foundation.Box |
| import androidx.compose.foundation.Canvas |
| import androidx.compose.ui.geometry.Offset |
| import androidx.compose.ui.graphics.Color |
| import androidx.compose.foundation.layout.fillMaxSize |
| import androidx.ui.unit.dp |
| |
| @Composable |
| fun StateBasedRippleDemo() { |
| Box(Modifier.fillMaxSize()) { |
| RippleRect() |
| } |
| } |
| |
| @Composable |
| private fun RippleRect() { |
| val radius = with(DensityAmbient.current) { TargetRadius.toPx() } |
| val toState = state { ButtonStatus.Initial } |
| val rippleTransDef = remember { createTransDef(radius) } |
| val onPress: (Offset) -> Unit = { position -> |
| down.x = position.x |
| down.y = position.y |
| toState.value = ButtonStatus.Pressed |
| } |
| |
| val onRelease: () -> Unit = { |
| toState.value = ButtonStatus.Released |
| } |
| val state = transition(definition = rippleTransDef, toState = toState.value) |
| RippleRectFromState( |
| Modifier.pressIndicatorGestureFilter(onStart = onPress, onStop = onRelease), state = state) |
| } |
| |
| @Composable |
| private fun RippleRectFromState(modifier: Modifier = Modifier, state: TransitionState) { |
| Canvas(modifier.fillMaxSize()) { |
| // TODO: file bug for when "down" is not a file level val, it's not memoized correctly |
| drawCircle( |
| Color( |
| alpha = (state[alpha] * 255).toInt(), |
| red = 0, |
| green = 235, |
| blue = 224 |
| ), |
| center = Offset(down.x, down.y), |
| radius = state[radius] |
| ) |
| } |
| } |
| |
| private enum class ButtonStatus { |
| Initial, |
| Pressed, |
| Released |
| } |
| |
| private val TargetRadius = 200.dp |
| |
| private val down = PointF(0f, 0f) |
| |
| private val alpha = FloatPropKey() |
| private val radius = FloatPropKey() |
| |
| private fun createTransDef(targetRadius: Float): TransitionDefinition<ButtonStatus> { |
| return transitionDefinition { |
| state(ButtonStatus.Initial) { |
| this[alpha] = 0f |
| this[radius] = targetRadius * 0.3f |
| } |
| state(ButtonStatus.Pressed) { |
| this[alpha] = 0.2f |
| this[radius] = targetRadius + 15f |
| } |
| state(ButtonStatus.Released) { |
| this[alpha] = 0f |
| this[radius] = targetRadius + 15f |
| } |
| |
| // Grow the ripple |
| transition(ButtonStatus.Initial to ButtonStatus.Pressed) { |
| alpha using keyframes { |
| durationMillis = 225 |
| 0f at 0 // optional |
| 0.2f at 75 |
| 0.2f at 225 // optional |
| } |
| radius using tween(durationMillis = 225) |
| interruptionHandling = InterruptionHandling.UNINTERRUPTIBLE |
| } |
| |
| // Fade out the ripple |
| transition(ButtonStatus.Pressed to ButtonStatus.Released) { |
| alpha using tween(durationMillis = 200) |
| interruptionHandling = InterruptionHandling.UNINTERRUPTIBLE |
| // switch back to Initial to prepare for the next ripple cycle |
| nextState = ButtonStatus.Initial |
| } |
| |
| // State switch without animation |
| snapTransition(ButtonStatus.Released to ButtonStatus.Initial) |
| } |
| } |