From 57cc2119dd9dbdad2c9e2c5c3108ebc3d60d90e1 Mon Sep 17 00:00:00 2001
From: Lonami Exo <totufals@hotmail.com>
Date: Tue, 11 Oct 2022 21:34:18 +0200
Subject: [PATCH] Scroll to the bottom on sending a message

---
 .../java/dev/lonami/talaria/ui/ChatScreen.kt   | 18 +++++++++++++++---
 1 file changed, 15 insertions(+), 3 deletions(-)

diff --git a/app/src/main/java/dev/lonami/talaria/ui/ChatScreen.kt b/app/src/main/java/dev/lonami/talaria/ui/ChatScreen.kt
index ff564d3..ea213d2 100644
--- a/app/src/main/java/dev/lonami/talaria/ui/ChatScreen.kt
+++ b/app/src/main/java/dev/lonami/talaria/ui/ChatScreen.kt
@@ -2,6 +2,8 @@ package dev.lonami.talaria.ui
 
 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.text.KeyboardActions
 import androidx.compose.foundation.text.KeyboardOptions
 import androidx.compose.material.Button
@@ -19,6 +21,7 @@ import androidx.lifecycle.viewmodel.compose.viewModel
 import dev.lonami.talaria.R
 import dev.lonami.talaria.model.Message
 import dev.lonami.talaria.ui.theme.TalariaTheme
+import kotlinx.coroutines.launch
 
 @Composable
 fun MessageCard(message: Message) {
@@ -40,8 +43,8 @@ fun MessageCard(message: Message) {
 }
 
 @Composable
-fun MessageList(messages: List<Message>, modifier: Modifier) {
-    LazyColumn(modifier) {
+fun MessageList(messages: List<Message>, modifier: Modifier, listState: LazyListState) {
+    LazyColumn(modifier, state = listState) {
         items(messages.size) { MessageCard(messages[it]) }
     }
 }
@@ -77,14 +80,23 @@ fun MessageInputField(
 fun ChatScreen(chatViewModel: ChatViewModel = viewModel()) {
     val chatUiState by chatViewModel.uiState.collectAsState()
     var messageText by remember { mutableStateOf("") }
+    val messageListState = rememberLazyListState()
+    val coroutineScope = rememberCoroutineScope()
 
     Column(modifier = Modifier.fillMaxSize()) {
-        MessageList(chatUiState.messages, modifier = Modifier.weight(1.0f))
+        MessageList(
+            chatUiState.messages,
+            modifier = Modifier.weight(1.0f),
+            listState = messageListState
+        )
         MessageInputField(messageText, onMessageChanged = {
             messageText = it
         }, onSendMessage = {
             chatViewModel.sendMessage(messageText)
             messageText = ""
+            coroutineScope.launch {
+                messageListState.animateScrollToItem(chatUiState.messages.size - 1)
+            }
         })
     }
 }