amethyst/app/src/main/java/androidx/compose/material3/pullrefresh/PullRefreshIndicator.kt

232 wiersze
8.6 KiB
Kotlin

/**
* Copyright (c) 2024 Vitor Pamplona
*
* Permission is hereby granted, free of charge, to any person obtaining a copy of
* this software and associated documentation files (the "Software"), to deal in
* the Software without restriction, including without limitation the rights to use,
* copy, modify, merge, publish, distribute, sublicense, and/or sell copies of the
* Software, and to permit persons to whom the Software is furnished to do so,
* subject to the following conditions:
*
* The above copyright notice and this permission notice shall be included in all
* copies or substantial portions of the Software.
*
* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
* IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS
* FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR
* COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN
* AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION
* WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
*/
package androidx.compose.material3.pullrefresh
import androidx.compose.animation.Crossfade
import androidx.compose.animation.core.LinearEasing
import androidx.compose.animation.core.animateFloatAsState
import androidx.compose.animation.core.tween
import androidx.compose.foundation.Canvas
import androidx.compose.foundation.layout.Box
import androidx.compose.foundation.layout.fillMaxSize
import androidx.compose.foundation.layout.size
import androidx.compose.foundation.shape.CircleShape
import androidx.compose.material3.CircularProgressIndicator
import androidx.compose.material3.MaterialTheme
import androidx.compose.material3.Surface
import androidx.compose.material3.contentColorFor
import androidx.compose.runtime.Composable
import androidx.compose.runtime.Immutable
import androidx.compose.runtime.derivedStateOf
import androidx.compose.runtime.getValue
import androidx.compose.runtime.remember
import androidx.compose.ui.Alignment
import androidx.compose.ui.Modifier
import androidx.compose.ui.geometry.Offset
import androidx.compose.ui.geometry.Rect
import androidx.compose.ui.geometry.center
import androidx.compose.ui.graphics.Color
import androidx.compose.ui.graphics.Path
import androidx.compose.ui.graphics.PathFillType
import androidx.compose.ui.graphics.StrokeCap
import androidx.compose.ui.graphics.drawscope.DrawScope
import androidx.compose.ui.graphics.drawscope.Stroke
import androidx.compose.ui.graphics.drawscope.rotate
import androidx.compose.ui.semantics.semantics
import androidx.compose.ui.unit.dp
import kotlin.math.abs
import kotlin.math.max
import kotlin.math.min
import kotlin.math.pow
/**
* The default indicator for Compose pull-to-refresh, based on Android's SwipeRefreshLayout.
*
* @param refreshing A boolean representing whether a refresh is occurring.
* @param state The [PullRefreshState] which controls where and how the indicator will be drawn.
* @param modifier Modifiers for the indicator.
* @param backgroundColor The color of the indicator's background.
* @param contentColor The color of the indicator's arc and arrow.
* @param scale A boolean controlling whether the indicator's size scales with pull progress or not.
* @sample androidx.compose.material.samples.PullRefreshSample
*/
@Composable
fun PullRefreshIndicator(
refreshing: Boolean,
state: PullRefreshState,
modifier: Modifier = Modifier,
backgroundColor: Color = MaterialTheme.colorScheme.surface,
contentColor: Color = contentColorFor(backgroundColor),
scale: Boolean = false,
) {
val showElevation by
remember(refreshing, state) { derivedStateOf { refreshing || state.position > 0.5f } }
Surface(
modifier = modifier.size(IndicatorSize).pullRefreshIndicatorTransform(state, scale),
shape = SpinnerShape,
color = backgroundColor,
shadowElevation = if (showElevation) Elevation else 0.dp,
) {
Crossfade(
targetState = refreshing,
animationSpec = tween(durationMillis = CROSSFADE_DURATION_MS),
) { refreshing ->
Box(
modifier = Modifier.fillMaxSize(),
contentAlignment = Alignment.Center,
) {
val spinnerSize = (ArcRadius + StrokeWidth).times(2)
if (refreshing) {
CircularProgressIndicator(
color = contentColor,
strokeWidth = StrokeWidth,
modifier = Modifier.size(spinnerSize),
)
} else {
CircularArrowIndicator(state, contentColor, Modifier.size(spinnerSize))
}
}
}
}
}
/** Modifier.size MUST be specified. */
@Composable
private fun CircularArrowIndicator(
state: PullRefreshState,
color: Color,
modifier: Modifier,
) {
val path = remember { Path().apply { fillType = PathFillType.EvenOdd } }
val targetAlpha by
remember(state) { derivedStateOf { if (state.progress >= 1f) MAX_ALPHA else MIN_ALPHA } }
val alphaState = animateFloatAsState(targetValue = targetAlpha, animationSpec = AlphaTween)
// Empty semantics for tests
Canvas(modifier.semantics {}) {
val values = ArrowValues(state.progress)
val alpha = alphaState.value
rotate(degrees = values.rotation) {
val arcRadius = ArcRadius.toPx() + StrokeWidth.toPx() / 2f
val arcBounds =
Rect(
size.center.x - arcRadius,
size.center.y - arcRadius,
size.center.x + arcRadius,
size.center.y + arcRadius,
)
drawArc(
color = color,
alpha = alpha,
startAngle = values.startAngle,
sweepAngle = values.endAngle - values.startAngle,
useCenter = false,
topLeft = arcBounds.topLeft,
size = arcBounds.size,
style =
Stroke(
width = StrokeWidth.toPx(),
cap = StrokeCap.Square,
),
)
drawArrow(path, arcBounds, color, alpha, values)
}
}
}
@Immutable
private class ArrowValues(
val rotation: Float,
val startAngle: Float,
val endAngle: Float,
val scale: Float,
)
private fun ArrowValues(progress: Float): ArrowValues {
// Discard first 40% of progress. Scale remaining progress to full range between 0 and 100%.
val adjustedPercent = max(min(1f, progress) - 0.4f, 0f) * 5 / 3
// How far beyond the threshold pull has gone, as a percentage of the threshold.
val overshootPercent = abs(progress) - 1.0f
// Limit the overshoot to 200%. Linear between 0 and 200.
val linearTension = overshootPercent.coerceIn(0f, 2f)
// Non-linear tension. Increases with linearTension, but at a decreasing rate.
val tensionPercent = linearTension - linearTension.pow(2) / 4
// Calculations based on SwipeRefreshLayout specification.
val endTrim = adjustedPercent * MAX_PROGRESS_ARC
val rotation = (-0.25f + 0.4f * adjustedPercent + tensionPercent) * 0.5f
val startAngle = rotation * 360
val endAngle = (rotation + endTrim) * 360
val scale = min(1f, adjustedPercent)
return ArrowValues(rotation, startAngle, endAngle, scale)
}
private fun DrawScope.drawArrow(
arrow: Path,
bounds: Rect,
color: Color,
alpha: Float,
values: ArrowValues,
) {
arrow.reset()
arrow.moveTo(0f, 0f) // Move to left corner
arrow.lineTo(x = ArrowWidth.toPx() * values.scale, y = 0f) // Line to right corner
// Line to tip of arrow
arrow.lineTo(
x = ArrowWidth.toPx() * values.scale / 2,
y = ArrowHeight.toPx() * values.scale,
)
val radius = min(bounds.width, bounds.height) / 2f
val inset = ArrowWidth.toPx() * values.scale / 2f
arrow.translate(
Offset(
x = radius + bounds.center.x - inset,
y = bounds.center.y + StrokeWidth.toPx() / 2f,
),
)
arrow.close()
rotate(degrees = values.endAngle) { drawPath(path = arrow, color = color, alpha = alpha) }
}
private const val CROSSFADE_DURATION_MS = 100
private const val MAX_PROGRESS_ARC = 0.8f
private val IndicatorSize = 40.dp
private val SpinnerShape = CircleShape
private val ArcRadius = 7.5.dp
private val StrokeWidth = 2.5.dp
private val ArrowWidth = 10.dp
private val ArrowHeight = 5.dp
private val Elevation = 6.dp
// Values taken from SwipeRefreshLayout
private const val MIN_ALPHA = 0.3f
private const val MAX_ALPHA = 1f
private val AlphaTween = tween<Float>(300, easing = LinearEasing)