feat: Hide BottomAppBar when scrollable list is not scrollable #256

This commit introduces the ability to hide the BottomAppBar when a scrollable list (like in LogScreen and ListManagerScreen) is not scrollable. It also refactors the code to achieve this:

-   Adds `LocalBottomBarBehavior` to provide the `BottomAppBarScrollBehavior` for child composables.
-   Adds a check in `LogScreen` and `ListManagerScreen` to monitor the list's scroll state.
-   When the list is not scrollable (neither can scroll backward nor forward), the BottomAppBar's height offset is reset to zero, effectively hiding it.
-   The code related to `LazyListState` has been refactored to use the `listState` variable consistently.

Author: jing332

app/src/main/java/com/github/jing332/tts_server_android/compose/MainPager.kt

@@ -9,12 +9,15 @@ import androidx.compose.foundation.pager.HorizontalPager
 import androidx.compose.foundation.pager.rememberPagerState
 import androidx.compose.material3.BottomAppBar
 import androidx.compose.material3.BottomAppBarDefaults
+import androidx.compose.material3.BottomAppBarScrollBehavior
 import androidx.compose.material3.ExperimentalMaterial3Api
 import androidx.compose.material3.NavigationBarDefaults
 import androidx.compose.material3.NavigationBarItem
 import androidx.compose.material3.Scaffold
 import androidx.compose.material3.Text
 import androidx.compose.runtime.Composable
+import androidx.compose.runtime.CompositionLocalProvider
+import androidx.compose.runtime.compositionLocalOf
 import androidx.compose.runtime.rememberCoroutineScope
 import androidx.compose.ui.Modifier
 import androidx.compose.ui.input.nestedscroll.nestedScroll
@@ -28,6 +31,11 @@ import com.github.jing332.tts_server_android.compose.systts.TtsLogScreen
 import com.github.jing332.tts_server_android.compose.systts.list.ListManagerScreen
 import kotlinx.coroutines.launch
 
+
+@OptIn(ExperimentalMaterial3Api::class)
+val LocalBottomBarBehavior =
+    compositionLocalOf<BottomAppBarScrollBehavior>() { error("LocalBottomBarBehavior not initialized") }
+
 @OptIn(
     ExperimentalFoundationApi::class, ExperimentalLayoutApi::class,
     ExperimentalMaterial3Api::class
@@ -83,11 +91,13 @@ fun MainPager(sharedVM: SharedViewModel) {
             state = pagerState,
             userScrollEnabled = false
         ) { index ->
-            when (index) {
-                PagerDestination.SystemTts.index -> ListManagerScreen(sharedVM)
-                PagerDestination.SystemTtsLog.index -> TtsLogScreen()
-                PagerDestination.Settings.index -> SettingsScreen()
-                PagerDestination.SystemTtsForwarder.index -> SystemTtsForwarderScreen()
+            CompositionLocalProvider(LocalBottomBarBehavior provides scrollBehavior) {
+                when (index) {
+                    PagerDestination.SystemTts.index -> ListManagerScreen(sharedVM)
+                    PagerDestination.SystemTtsLog.index -> TtsLogScreen()
+                    PagerDestination.Settings.index -> SettingsScreen()
+                    PagerDestination.SystemTtsForwarder.index -> SystemTtsForwarderScreen()
+                }
             }
         }
     }

app/src/main/java/com/github/jing332/tts_server_android/compose/systts/LogScreen.kt

@@ -20,6 +20,7 @@ import androidx.compose.foundation.shape.CircleShape
 import androidx.compose.foundation.text.selection.SelectionContainer
 import androidx.compose.material.icons.Icons
 import androidx.compose.material.icons.filled.KeyboardDoubleArrowDown
+import androidx.compose.material3.ExperimentalMaterial3Api
 import androidx.compose.material3.FloatingActionButton
 import androidx.compose.material3.HorizontalDivider
 import androidx.compose.material3.Icon
@@ -44,22 +45,30 @@ import com.github.jing332.common.toArgb
 import com.github.jing332.common.toLogLevelChar
 import com.github.jing332.compose.ComposeExtensions.toAnnotatedString
 import com.github.jing332.tts_server_android.R
+import com.github.jing332.tts_server_android.compose.LocalBottomBarBehavior
 import kotlinx.coroutines.launch
 
-@OptIn(ExperimentalFoundationApi::class)
+@OptIn(ExperimentalFoundationApi::class, ExperimentalMaterial3Api::class)
 @Composable
 fun LogScreen(
     modifier: Modifier,
     list: List<LogEntry>,
-    lazyListState: LazyListState = rememberLazyListState(),
+    listState: LazyListState = rememberLazyListState(),
 ) {
+    val bottomBarBehavior = LocalBottomBarBehavior.current
+    LaunchedEffect(listState.canScrollBackward || listState.canScrollForward) {
+        if (!(listState.canScrollBackward || listState.canScrollForward)) {
+            bottomBarBehavior.state.heightOffset = 0f
+        }
+    }
+
     val scope = rememberCoroutineScope()
     val view = LocalView.current
     val context = LocalContext.current
     Box(modifier) {
         val isAtBottom by remember {
             derivedStateOf {
-                val layoutInfo = lazyListState.layoutInfo
+                val layoutInfo = listState.layoutInfo
                 val visibleItemsInfo = layoutInfo.visibleItemsInfo
                 if (layoutInfo.totalItemsCount <= 0) {
                     true
@@ -73,7 +82,7 @@ fun LogScreen(
         LaunchedEffect(list.size) {
             if (isAtBottom && list.isNotEmpty())
                 scope.launch {
-                    lazyListState.animateScrollToItem(list.size - 1)
+                    listState.animateScrollToItem(list.size - 1)
                 }
         }
 
@@ -87,7 +96,7 @@ fun LogScreen(
 
         val darkTheme = isSystemInDarkTheme()
         SelectionContainer {
-            LazyColumn(Modifier.fillMaxSize(), state = lazyListState) {
+            LazyColumn(Modifier.fillMaxSize(), state = listState) {
                 itemsIndexed(list, key = { index, _ -> index }) { index, log ->
                     val style = MaterialTheme.typography.bodyMedium
                     val spanned = remember {
@@ -130,7 +139,7 @@ fun LogScreen(
                 onClick = {
                     scope.launch {
                         kotlin.runCatching {
-                            lazyListState.scrollToItem(list.size - 1)
+                            listState.scrollToItem(list.size - 1)
                         }
                     }
                 }) {

app/src/main/java/com/github/jing332/tts_server_android/compose/systts/list/ListManagerScreen.kt

@@ -48,6 +48,7 @@ import com.github.jing332.database.entities.systts.source.LocalTtsSource
 import com.github.jing332.database.entities.systts.source.PluginTtsSource
 import com.github.jing332.tts_server_android.AppLocale
 import com.github.jing332.tts_server_android.R
+import com.github.jing332.tts_server_android.compose.LocalBottomBarBehavior
 import com.github.jing332.tts_server_android.compose.LocalDrawerState
 import com.github.jing332.tts_server_android.compose.LocalNavController
 import com.github.jing332.tts_server_android.compose.SharedViewModel
@@ -271,6 +272,13 @@ internal fun ListManagerScreen(
         },
     ) { paddingValues ->
         Box(Modifier.padding(top = paddingValues.calculateTopPadding())) {
+            val bottomBarBehavior = LocalBottomBarBehavior.current
+            LaunchedEffect(listState.canScrollBackward || listState.canScrollForward) {
+                if (!(listState.canScrollBackward || listState.canScrollForward)) {
+                    bottomBarBehavior.state.heightOffset = 0f
+                }
+            }
+
             LazyColumn(
                 Modifier
                     .fillMaxSize()