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Add a scrollbar to the article screen (#63)

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Co-authored-by: Matt Vaughn <matt.vaughn@willowtreeapps.com>
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Matt Vaughn 2022-05-11 11:26:37 -04:00 committed by GitHub
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commit b7813d45f4
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4 changed files with 370 additions and 72 deletions
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1
app/build.gradle
View File

@ -149,6 +149,7 @@ dependencies {
implementation "androidx.compose.animation:animation-graphics:$compose"
// https://developer.android.com/jetpack/androidx/releases/compose-ui
implementation "androidx.compose.ui:ui:$compose"
implementation "androidx.compose.ui:ui-util:$compose"
// https://developer.android.com/jetpack/androidx/releases/compose-material
implementation "androidx.compose.material:material:$compose"
implementation "androidx.compose.material:material-icons-extended:$compose"

320
app/src/main/java/me/ash/reader/ui/ext/ScrollbarsExt.kt Normal file
View File

@ -0,0 +1,320 @@
package me.ash.reader.ui.ext
// From gist: https://gist.github.com/mxalbert1996/33a360fcab2105a31e5355af98216f5a/
/*
* MIT License
*
* Copyright (c) 2022 Albert Chang
*
* 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.
*/
import android.view.ViewConfiguration
import androidx.compose.animation.core.Animatable
import androidx.compose.animation.core.tween
import androidx.compose.foundation.ScrollState
import androidx.compose.foundation.gestures.Orientation
import androidx.compose.foundation.horizontalScroll
import androidx.compose.foundation.layout.Column
import androidx.compose.foundation.layout.Row
import androidx.compose.foundation.layout.fillMaxWidth
import androidx.compose.foundation.layout.padding
import androidx.compose.foundation.lazy.LazyColumn
import androidx.compose.foundation.lazy.LazyListState
import androidx.compose.foundation.lazy.LazyRow
import androidx.compose.foundation.lazy.rememberLazyListState
import androidx.compose.foundation.rememberScrollState
import androidx.compose.foundation.verticalScroll
import androidx.compose.material3.MaterialTheme
import androidx.compose.material3.Text
import androidx.compose.runtime.Composable
import androidx.compose.runtime.LaunchedEffect
import androidx.compose.runtime.remember
import androidx.compose.ui.Modifier
import androidx.compose.ui.composed
import androidx.compose.ui.draw.CacheDrawScope
import androidx.compose.ui.draw.DrawResult
import androidx.compose.ui.draw.drawWithCache
import androidx.compose.ui.geometry.Offset
import androidx.compose.ui.geometry.Size
import androidx.compose.ui.graphics.Color
import androidx.compose.ui.graphics.drawscope.DrawScope
import androidx.compose.ui.input.nestedscroll.NestedScrollConnection
import androidx.compose.ui.input.nestedscroll.NestedScrollSource
import androidx.compose.ui.input.nestedscroll.nestedScroll
import androidx.compose.ui.platform.LocalDensity
import androidx.compose.ui.platform.LocalLayoutDirection
import androidx.compose.ui.tooling.preview.Preview
import androidx.compose.ui.unit.LayoutDirection
import androidx.compose.ui.unit.dp
import androidx.compose.ui.util.fastSumBy
import kotlinx.coroutines.channels.BufferOverflow
import kotlinx.coroutines.delay
import kotlinx.coroutines.flow.MutableSharedFlow
import kotlinx.coroutines.flow.collectLatest
fun Modifier.drawHorizontalScrollbar(
state: ScrollState,
reverseScrolling: Boolean = false
): Modifier = drawScrollbar(state, Orientation.Horizontal, reverseScrolling)
fun Modifier.drawVerticalScrollbar(
state: ScrollState,
reverseScrolling: Boolean = false
): Modifier = drawScrollbar(state, Orientation.Vertical, reverseScrolling)
fun Modifier.drawHorizontalScrollbar(
state: LazyListState,
reverseScrolling: Boolean = false
): Modifier = drawScrollbar(state, Orientation.Horizontal, reverseScrolling)
fun Modifier.drawVerticalScrollbar(
state: LazyListState,
reverseScrolling: Boolean = false
): Modifier = drawScrollbar(state, Orientation.Vertical, reverseScrolling)
private fun Modifier.drawScrollbar(
state: ScrollState,
orientation: Orientation,
reverseScrolling: Boolean
): Modifier = drawScrollbar(
orientation, reverseScrolling
) { reverseDirection, atEnd, thickness, color, alpha ->
val showScrollbar = state.maxValue > 0
val canvasSize = if (orientation == Orientation.Horizontal) size.width else size.height
val totalSize = canvasSize + state.maxValue
val thumbSize = canvasSize / totalSize * canvasSize
val startOffset = state.value / totalSize * canvasSize
val drawScrollbar = onDrawScrollbar(
orientation, reverseDirection, atEnd, showScrollbar,
thickness, color, alpha, thumbSize, startOffset
)
onDrawWithContent {
drawContent()
drawScrollbar()
}
}
private fun Modifier.drawScrollbar(
state: LazyListState,
orientation: Orientation,
reverseScrolling: Boolean
): Modifier = drawScrollbar(
orientation, reverseScrolling
) { reverseDirection, atEnd, thickness, color, alpha ->
val layoutInfo = state.layoutInfo
val viewportSize = layoutInfo.viewportEndOffset - layoutInfo.viewportStartOffset
val items = layoutInfo.visibleItemsInfo
val itemsSize = items.fastSumBy { it.size }
val showScrollbar = items.size < layoutInfo.totalItemsCount || itemsSize > viewportSize
val estimatedItemSize = if (items.isEmpty()) 0f else itemsSize.toFloat() / items.size
val totalSize = estimatedItemSize * layoutInfo.totalItemsCount
val canvasSize = if (orientation == Orientation.Horizontal) size.width else size.height
val thumbSize = viewportSize / totalSize * canvasSize
val startOffset = if (items.isEmpty()) 0f else items
.first()
.run {
(estimatedItemSize * index - offset) / totalSize * canvasSize
}
val drawScrollbar = onDrawScrollbar(
orientation, reverseDirection, atEnd, showScrollbar,
thickness, color, alpha, thumbSize, startOffset
)
onDrawWithContent {
drawContent()
drawScrollbar()
}
}
private fun CacheDrawScope.onDrawScrollbar(
orientation: Orientation,
reverseDirection: Boolean,
atEnd: Boolean,
showScrollbar: Boolean,
thickness: Float,
color: Color,
alpha: () -> Float,
thumbSize: Float,
startOffset: Float
): DrawScope.() -> Unit {
val topLeft = if (orientation == Orientation.Horizontal) {
Offset(
if (reverseDirection) size.width - startOffset - thumbSize else startOffset,
if (atEnd) size.height - thickness else 0f
)
} else {
Offset(
if (atEnd) size.width - thickness else 0f,
if (reverseDirection) size.height - startOffset - thumbSize else startOffset
)
}
val size = if (orientation == Orientation.Horizontal) {
Size(thumbSize, thickness)
} else {
Size(thickness, thumbSize)
}
return {
if (showScrollbar) {
drawRect(
color = color,
topLeft = topLeft,
size = size,
alpha = alpha()
)
}
}
}
private fun Modifier.drawScrollbar(
orientation: Orientation,
reverseScrolling: Boolean,
onBuildDrawCache: CacheDrawScope.(
reverseDirection: Boolean,
atEnd: Boolean,
thickness: Float,
color: Color,
alpha: () -> Float
) -> DrawResult
): Modifier = composed {
val scrolled = remember {
MutableSharedFlow<Unit>(
extraBufferCapacity = 1,
onBufferOverflow = BufferOverflow.DROP_OLDEST
)
}
val nestedScrollConnection = remember(orientation, scrolled) {
object : NestedScrollConnection {
override fun onPostScroll(
consumed: Offset,
available: Offset,
source: NestedScrollSource
): Offset {
val delta = if (orientation == Orientation.Horizontal) consumed.x else consumed.y
if (delta != 0f) scrolled.tryEmit(Unit)
return Offset.Zero
}
}
}
val alpha = remember { Animatable(0f) }
LaunchedEffect(scrolled, alpha) {
scrolled.collectLatest {
alpha.snapTo(1f)
delay(ViewConfiguration.getScrollDefaultDelay().toLong())
alpha.animateTo(0f, animationSpec = FadeOutAnimationSpec)
}
}
val isLtr = LocalLayoutDirection.current == LayoutDirection.Ltr
val reverseDirection = if (orientation == Orientation.Horizontal) {
if (isLtr) reverseScrolling else !reverseScrolling
} else reverseScrolling
val atEnd = if (orientation == Orientation.Vertical) isLtr else true
// Calculate thickness here to workaround https://issuetracker.google.com/issues/206972664
val thickness = with(LocalDensity.current) { Thickness.toPx() }
val color = MaterialTheme.colorScheme.onSurfaceVariant.copy(alpha = 0.5f)
Modifier
.nestedScroll(nestedScrollConnection)
.drawWithCache {
onBuildDrawCache(reverseDirection, atEnd, thickness, color, alpha::value)
}
}
private val Thickness = 4.dp
private val FadeOutAnimationSpec =
tween<Float>(durationMillis = ViewConfiguration.getScrollBarFadeDuration())
@Preview(widthDp = 400, heightDp = 400, showBackground = true)
@Composable
fun ScrollbarPreview() {
val state = rememberScrollState()
Column(
modifier = Modifier
.drawVerticalScrollbar(state)
.verticalScroll(state),
) {
repeat(50) {
Text(
text = "Item ${it + 1}",
modifier = Modifier
.fillMaxWidth()
.padding(16.dp)
)
}
}
}
@Preview(widthDp = 400, heightDp = 400, showBackground = true)
@Composable
fun LazyListScrollbarPreview() {
val state = rememberLazyListState()
LazyColumn(
modifier = Modifier.drawVerticalScrollbar(state),
state = state
) {
items(50) {
Text(
text = "Item ${it + 1}",
modifier = Modifier
.fillMaxWidth()
.padding(16.dp)
)
}
}
}
@Preview(widthDp = 400, showBackground = true)
@Composable
fun HorizontalScrollbarPreview() {
val state = rememberScrollState()
Row(
modifier = Modifier
.drawHorizontalScrollbar(state)
.horizontalScroll(state)
) {
repeat(50) {
Text(
text = (it + 1).toString(),
modifier = Modifier
.padding(horizontal = 8.dp, vertical = 16.dp)
)
}
}
}
@Preview(widthDp = 400, showBackground = true)
@Composable
fun LazyListHorizontalScrollbarPreview() {
val state = rememberLazyListState()
LazyRow(
modifier = Modifier.drawHorizontalScrollbar(state),
state = state
) {
items(50) {
Text(
text = (it + 1).toString(),
modifier = Modifier
.padding(horizontal = 8.dp, vertical = 16.dp)
)
}
}
}

106
app/src/main/java/me/ash/reader/ui/page/home/read/ReadPage.kt
View File

@ -2,10 +2,10 @@ package me.ash.reader.ui.page.home.read
import android.util.Log
import androidx.compose.animation.*
import androidx.compose.foundation.ScrollState
import androidx.compose.foundation.layout.*
import androidx.compose.foundation.lazy.LazyColumn
import androidx.compose.foundation.lazy.LazyListState
import androidx.compose.foundation.lazy.rememberLazyListState
import androidx.compose.foundation.rememberScrollState
import androidx.compose.foundation.verticalScroll
import androidx.compose.material.icons.Icons
import androidx.compose.material.icons.outlined.Headphones
import androidx.compose.material.icons.outlined.MoreVert
@ -25,6 +25,7 @@ import me.ash.reader.data.entity.ArticleWithFeed
import me.ash.reader.ui.component.FeedbackIconButton
import me.ash.reader.ui.component.WebView
import me.ash.reader.ui.ext.collectAsStateValue
import me.ash.reader.ui.ext.drawVerticalScrollbar
@OptIn(ExperimentalMaterial3Api::class)
@Composable
@ -43,21 +44,14 @@ fun ReadPage(
}
}
if (viewState.listState.isScrollInProgress) {
if (viewState.scrollState.isScrollInProgress) {
LaunchedEffect(Unit) {
Log.i("RLog", "scroll: start")
}
val preItemIndex by remember { mutableStateOf(viewState.listState.firstVisibleItemIndex) }
val preScrollStartOffset by remember { mutableStateOf(viewState.listState.firstVisibleItemScrollOffset) }
val currentItemIndex = viewState.listState.firstVisibleItemIndex
val currentScrollStartOffset = viewState.listState.firstVisibleItemScrollOffset
isScrollDown = when {
currentItemIndex > preItemIndex -> true
currentItemIndex < preItemIndex -> false
else -> currentScrollStartOffset > preScrollStartOffset
}
val preScrollOffset by remember { mutableStateOf(viewState.scrollState.value) }
val currentOffset = viewState.scrollState.value
isScrollDown = currentOffset > preScrollOffset
DisposableEffect(Unit) {
onDispose {
@ -98,7 +92,7 @@ fun ReadPage(
content = viewState.content ?: "",
articleWithFeed = viewState.articleWithFeed,
viewState = viewState,
LazyListState = viewState.listState,
scrollState = viewState.scrollState,
)
Box(
modifier = Modifier
@ -182,10 +176,14 @@ private fun Content(
content: String,
articleWithFeed: ArticleWithFeed?,
viewState: ReadViewState,
LazyListState: LazyListState = rememberLazyListState(),
scrollState: ScrollState = rememberScrollState(),
) {
Column(
modifier = Modifier.statusBarsPadding(),
modifier = Modifier
.statusBarsPadding()
.navigationBarsPadding()
.drawVerticalScrollbar(scrollState)
.verticalScroll(scrollState),
) {
if (articleWithFeed == null) {
Spacer(modifier = Modifier.height(64.dp))
@ -196,54 +194,44 @@ private fun Content(
// url = "https://assets8.lottiefiles.com/packages/lf20_jm7mv1ib.json",
// )
} else {
LazyColumn(
state = LazyListState,
) {
item {
Spacer(modifier = Modifier.height(64.dp))
Column {
Spacer(modifier = Modifier.height(64.dp))
Spacer(modifier = Modifier.height(2.dp))
Column(
modifier = Modifier
.padding(horizontal = 12.dp)
) {
Header(articleWithFeed)
}
item {
Spacer(modifier = Modifier.height(2.dp))
Column(
modifier = Modifier
.padding(horizontal = 12.dp)
Spacer(modifier = Modifier.height(22.dp))
AnimatedVisibility(
visible = viewState.isLoading,
enter = fadeIn() + expandVertically(),
exit = fadeOut() + shrinkVertically(),
) {
Box(
modifier = Modifier.fillMaxSize(),
contentAlignment = Alignment.Center,
) {
Header(articleWithFeed)
}
}
item {
Spacer(modifier = Modifier.height(22.dp))
AnimatedVisibility(
visible = viewState.isLoading,
enter = fadeIn() + expandVertically(),
exit = fadeOut() + shrinkVertically(),
) {
Box(
modifier = Modifier.fillMaxSize(),
contentAlignment = Alignment.Center,
) {
Column {
Spacer(modifier = Modifier.height(22.dp))
CircularProgressIndicator(
modifier = Modifier
.size(30.dp),
color = MaterialTheme.colorScheme.onSurface,
)
Spacer(modifier = Modifier.height(22.dp))
}
Column {
Spacer(modifier = Modifier.height(22.dp))
CircularProgressIndicator(
modifier = Modifier
.size(30.dp),
color = MaterialTheme.colorScheme.onSurface,
)
Spacer(modifier = Modifier.height(22.dp))
}
}
if (!viewState.isLoading) {
WebView(
content = content
)
Spacer(modifier = Modifier.height(50.dp))
}
}
item {
Spacer(modifier = Modifier.height(64.dp))
Spacer(modifier = Modifier.height(64.dp))
if (!viewState.isLoading) {
WebView(
content = content
)
Spacer(modifier = Modifier.height(50.dp))
}
Spacer(modifier = Modifier.height(64.dp))
Spacer(modifier = Modifier.height(64.dp))
}
}
}

15
app/src/main/java/me/ash/reader/ui/page/home/read/ReadViewModel.kt
View File

@ -1,7 +1,7 @@
package me.ash.reader.ui.page.home.read
import android.util.Log
import androidx.compose.foundation.lazy.LazyListState
import androidx.compose.foundation.ScrollState
import androidx.lifecycle.ViewModel
import androidx.lifecycle.viewModelScope
import dagger.hilt.android.lifecycle.HiltViewModel
@ -31,7 +31,6 @@ class ReadViewModel @Inject constructor(
is ReadViewAction.RenderFullContent -> renderFullContent()
is ReadViewAction.MarkUnread -> markUnread(action.isUnread)
is ReadViewAction.MarkStarred -> markStarred(action.isStarred)
is ReadViewAction.ScrollToItem -> scrollToItem(action.index)
is ReadViewAction.ClearArticle -> clearArticle()
is ReadViewAction.ChangeLoading -> changeLoading(action.isLoading)
}
@ -130,12 +129,6 @@ class ReadViewModel @Inject constructor(
}
}
private fun scrollToItem(index: Int) {
viewModelScope.launch {
_viewState.value.listState.scrollToItem(index)
}
}
private fun clearArticle() {
_viewState.update {
it.copy(articleWithFeed = null)
@ -153,7 +146,7 @@ data class ReadViewState(
val articleWithFeed: ArticleWithFeed? = null,
val content: String? = null,
val isLoading: Boolean = true,
val listState: LazyListState = LazyListState(),
val scrollState: ScrollState = ScrollState(0),
)
sealed class ReadViewAction {
@ -173,10 +166,6 @@ sealed class ReadViewAction {
val isStarred: Boolean,
) : ReadViewAction()
data class ScrollToItem(
val index: Int
) : ReadViewAction()
object ClearArticle : ReadViewAction()
data class ChangeLoading(