adding shared prefs to save the users name

app/src/main/java/com/mattintech/lchat/ui/LobbyFragment.kt

@@ -1,6 +1,8 @@
 package com.mattintech.lchat.ui
 
 import android.os.Bundle
+import android.text.Editable
+import android.text.TextWatcher
 import android.util.Log
 import android.view.LayoutInflater
 import android.view.View
@@ -48,6 +50,18 @@ class LobbyFragment : Fragment() {
     }
     
     private fun setupUI() {
+        binding.nameInput.addTextChangedListener(object : TextWatcher {
+            override fun beforeTextChanged(s: CharSequence?, start: Int, count: Int, after: Int) {}
+            
+            override fun onTextChanged(s: CharSequence?, start: Int, before: Int, count: Int) {}
+            
+            override fun afterTextChanged(s: Editable?) {
+                s?.toString()?.trim()?.let { name ->
+                    viewModel.saveUserName(name)
+                }
+            }
+        })
+        
         binding.modeRadioGroup.setOnCheckedChangeListener { _, checkedId ->
             when (checkedId) {
                 R.id.hostRadio -> {
@@ -80,6 +94,12 @@ class LobbyFragment : Fragment() {
     }
     
     private fun observeViewModel() {
+        viewModel.savedUserName.observe(viewLifecycleOwner) { savedName ->
+            if (!savedName.isNullOrEmpty() && binding.nameInput.text.isNullOrEmpty()) {
+                binding.nameInput.setText(savedName)
+            }
+        }
+        
         viewModel.state.observe(viewLifecycleOwner) { state ->
             when (state) {
                 is LobbyState.Idle -> {

app/src/main/java/com/mattintech/lchat/utils/PreferencesManager.kt

@@ -0,0 +1,36 @@
+package com.mattintech.lchat.utils
+
+import android.content.Context
+import android.content.SharedPreferences
+import dagger.hilt.android.qualifiers.ApplicationContext
+import javax.inject.Inject
+import javax.inject.Singleton
+
+@Singleton
+class PreferencesManager @Inject constructor(
+    @ApplicationContext private val context: Context
+) {
+    private val sharedPreferences: SharedPreferences = 
+        context.getSharedPreferences(PREFS_NAME, Context.MODE_PRIVATE)
+
+    fun saveUserName(name: String) {
+        if (name.isBlank()) {
+            clearUserName()
+        } else {
+            sharedPreferences.edit().putString(KEY_USER_NAME, name).apply()
+        }
+    }
+
+    fun getUserName(): String? {
+        return sharedPreferences.getString(KEY_USER_NAME, null)
+    }
+
+    fun clearUserName() {
+        sharedPreferences.edit().remove(KEY_USER_NAME).apply()
+    }
+
+    companion object {
+        private const val PREFS_NAME = "lchat_preferences"
+        private const val KEY_USER_NAME = "user_name"
+    }
+}

app/src/main/java/com/mattintech/lchat/viewmodel/LobbyViewModel.kt

@@ -5,6 +5,7 @@ import androidx.lifecycle.MutableLiveData
 import androidx.lifecycle.ViewModel
 import androidx.lifecycle.viewModelScope
 import com.mattintech.lchat.repository.ChatRepository
+import com.mattintech.lchat.utils.PreferencesManager
 import dagger.hilt.android.lifecycle.HiltViewModel
 import kotlinx.coroutines.launch
 import javax.inject.Inject
@@ -27,7 +28,8 @@ sealed class LobbyEvent {
 
 @HiltViewModel
 class LobbyViewModel @Inject constructor(
-    private val chatRepository: ChatRepository
+    private val chatRepository: ChatRepository,
+    private val preferencesManager: PreferencesManager
 ) : ViewModel() {
     
     private val _state = MutableLiveData<LobbyState>(LobbyState.Idle)
@@ -36,8 +38,16 @@ class LobbyViewModel @Inject constructor(
     private val _events = MutableLiveData<LobbyEvent?>()
     val events: LiveData<LobbyEvent?> = _events
     
+    private val _savedUserName = MutableLiveData<String?>()
+    val savedUserName: LiveData<String?> = _savedUserName
+    
     init {
         setupConnectionCallback()
+        loadSavedUserName()
+    }
+    
+    private fun loadSavedUserName() {
+        _savedUserName.value = preferencesManager.getUserName()
     }
     
     private fun setupConnectionCallback() {
@@ -65,6 +75,7 @@ class LobbyViewModel @Inject constructor(
         
         viewModelScope.launch {
             _state.value = LobbyState.Connecting
+            preferencesManager.saveUserName(userName)
             chatRepository.startHostMode(roomName)
             _events.value = LobbyEvent.NavigateToChat(roomName, userName, true)
         }
@@ -78,11 +89,13 @@ class LobbyViewModel @Inject constructor(
         
         viewModelScope.launch {
             _state.value = LobbyState.Connecting
+            preferencesManager.saveUserName(userName)
             chatRepository.startClientMode()
         }
     }
     
     fun onConnectedToRoom(roomName: String, userName: String) {
+        preferencesManager.saveUserName(userName)
         _events.value = LobbyEvent.NavigateToChat(roomName, userName, false)
     }
     
@@ -90,6 +103,12 @@ class LobbyViewModel @Inject constructor(
         _events.value = null
     }
     
+    fun saveUserName(name: String) {
+        if (name.isNotBlank()) {
+            preferencesManager.saveUserName(name)
+        }
+    }
+    
     override fun onCleared() {
         super.onCleared()
         // Clean up resources if needed