update

app/src/main/java/io/nexilis/alpha/ui/main/Chat.kt

@@ -2,13 +2,20 @@ package io.nexilis.alpha.ui.main
 
 import androidx.compose.foundation.layout.*
 import androidx.compose.foundation.lazy.LazyColumn
+import androidx.compose.foundation.lazy.LazyListState
 import androidx.compose.foundation.lazy.items
 import androidx.compose.foundation.lazy.rememberLazyListState
+import androidx.compose.foundation.shape.CircleShape
+import androidx.compose.material.icons.Icons
+import androidx.compose.material.icons.filled.KeyboardArrowDown
 import androidx.compose.material3.*
 import androidx.compose.runtime.*
 import androidx.compose.runtime.livedata.observeAsState
 import androidx.compose.ui.Modifier
 import androidx.compose.ui.graphics.Color
+import androidx.compose.ui.unit.dp
+import androidx.constraintlayout.compose.ConstraintLayout
+import androidx.constraintlayout.compose.Dimension
 import androidx.hilt.navigation.compose.hiltViewModel
 import androidx.navigation.NavHostController
 import io.nexilis.alpha.ui.components.ContentChat
@@ -17,10 +24,12 @@ import io.nexilis.alpha.ui.components.LeftBubbleChat
 import io.nexilis.alpha.ui.components.RightBubbleChat
 import io.nexilis.service.data.entities.Buddy
 import io.nexilis.service.data.viewmodels.MessageViewModel
+import kotlinx.coroutines.launch
 
 @OptIn(ExperimentalLayoutApi::class)
 @Composable
 fun Chat(
+    modifier: Modifier = Modifier,
     navController: NavHostController,
     pin: String,
     me: Buddy
@@ -28,21 +37,24 @@ fun Chat(
     val messageModel: MessageViewModel = hiltViewModel()
     val messages by messageModel.getOpposite(pin).observeAsState()
     val listState = rememberLazyListState()
+    val scope = rememberCoroutineScope()
     messages?.let {
         LaunchedEffect(key1 = it.size) {
             if (it.isNotEmpty())
                 listState.scrollToItem(it.size - 1)
         }
     }
-    Column(
-        modifier = Modifier
-            .fillMaxSize()
-            .imePadding()
-//            .imeNestedScroll()
-    ) {
+    ConstraintLayout(modifier = modifier
+        .imePadding()
+        .imeNestedScroll()) {
+        val (list, fab, input) = createRefs()
         LazyColumn(
             modifier = Modifier
-                .weight(1f),
+                .constrainAs(list) {
+                    top.linkTo(parent.top)
+                    bottom.linkTo(input.top)
+                    height = Dimension.fillToConstraints
+                },
             state = listState,
             reverseLayout = false
         ) {
@@ -79,40 +91,42 @@ fun Chat(
                 }
             }
         }
-//        ConstraintLayout {
-//                    val (fab, input) = createRefs()
-//            val showButton by remember {
-//                derivedStateOf {
-//                    listState.firstVisibleItemIndex > 0
-//                }
-//            }
-//            if (showButton) {
-//                Button(
-//                    onClick = {
-//                        scope.launch { listState.scrollToItem(0) }
-//                    },
-//                    modifier = Modifier
-//                        .constrainAs(fab) {
-//                            end.linkTo(parent.end)
-//                            bottom.linkTo(input.top)
-//                        }
-//                        .padding(end = 6.dp, bottom = 6.dp)
-//                        .size(32.dp),
-//                    shape = CircleShape,
-//                    contentPadding = PaddingValues(0.dp)
-//                ) {
-//                    Icon(imageVector = Icons.Default.KeyboardArrowDown, contentDescription = "")
-//                }
-//            }
+        val showButton by remember {
+            derivedStateOf {
+                !listState.isScrolledToTheEnd()
+            }
+        }
+        if (showButton) {
+            Button(
+                onClick = {
+                    messages?.let {
+                        if (it.isNotEmpty())
+                            scope.launch { listState.scrollToItem(it.size - 1) }
+                    }
+                },
+                modifier = Modifier
+                    .constrainAs(fab) {
+                        end.linkTo(parent.end)
+                        bottom.linkTo(input.top)
+                    }
+                    .padding(end = 6.dp, bottom = 6.dp)
+                    .size(32.dp),
+                shape = CircleShape,
+                contentPadding = PaddingValues(0.dp)
+            ) {
+                Icon(imageVector = Icons.Default.KeyboardArrowDown, contentDescription = "")
+            }
+        }
         InputChat(
-//                modifier = Modifier.constrainAs(input) {
-//                    bottom.linkTo(parent.bottom)
-//                },
+            modifier = Modifier.constrainAs(input) {
+                bottom.linkTo(parent.bottom)
+            },
             navController = navController,
             pin = pin,
             me = me
         )
-//        }
     }
 }
 
+fun LazyListState.isScrolledToTheEnd() =
+    layoutInfo.visibleItemsInfo.lastOrNull()?.index == layoutInfo.totalItemsCount - 1

app/src/main/java/io/nexilis/alpha/ui/main/Main.kt

@@ -101,6 +101,7 @@ fun Main(navController: NavHostController, me: Buddy) {
                     it.arguments?.getString("pin")
                         ?.let { pin ->
                             Chat(
+                                modifier = Modifier.fillMaxSize(),
                                 navController = navMainController,
                                 pin = pin,
                                 me = me