Avoid adding twice the same server

vector/src/main/java/im/vector/app/core/extensions/Activity.kt

@@ -94,6 +94,10 @@ fun <T : Fragment> AppCompatActivity.addFragmentToBackstack(
     }
 }
 
+fun AppCompatActivity.popBackstack() {
+    supportFragmentManager.popBackStack()
+}
+
 fun AppCompatActivity.resetBackstack() {
     repeat(supportFragmentManager.backStackEntryCount) {
         supportFragmentManager.popBackStack()

vector/src/main/java/im/vector/app/features/roomdirectory/RoomDirectoryActivity.kt

@@ -25,6 +25,7 @@ import im.vector.app.R
 import im.vector.app.core.di.ScreenComponent
 import im.vector.app.core.extensions.addFragment
 import im.vector.app.core.extensions.addFragmentToBackstack
+import im.vector.app.core.extensions.popBackstack
 import im.vector.app.core.platform.VectorBaseActivity
 import im.vector.app.databinding.ActivitySimpleBinding
 import im.vector.app.features.roomdirectory.createroom.CreateRoomFragment
@@ -58,7 +59,7 @@ class RoomDirectoryActivity : VectorBaseActivity<ActivitySimpleBinding>() {
                 .observe()
                 .subscribe { sharedAction ->
                     when (sharedAction) {
-                        is RoomDirectorySharedAction.Back           -> onBackPressed()
+                        is RoomDirectorySharedAction.Back           -> popBackstack()
                         is RoomDirectorySharedAction.CreateRoom     -> {
                             // Transmit the filter to the CreateRoomFragment
                             withState(roomDirectoryViewModel) {

vector/src/main/java/im/vector/app/features/roomdirectory/picker/RoomDirectoryPickerViewModel.kt

@@ -27,9 +27,11 @@ import com.airbnb.mvrx.ViewModelContext
 import dagger.assisted.Assisted
 import dagger.assisted.AssistedFactory
 import dagger.assisted.AssistedInject
+import im.vector.app.R
 import im.vector.app.core.extensions.exhaustive
 import im.vector.app.core.platform.EmptyViewEvents
 import im.vector.app.core.platform.VectorViewModel
+import im.vector.app.core.resources.StringProvider
 import im.vector.app.features.ui.UiStateRepository
 import kotlinx.coroutines.launch
 import org.matrix.android.sdk.api.session.Session
@@ -39,6 +41,7 @@ class RoomDirectoryPickerViewModel @AssistedInject constructor(
         @Assisted initialState: RoomDirectoryPickerViewState,
         private val session: Session,
         private val uiStateRepository: UiStateRepository,
+        private val stringProvider: StringProvider,
         private val roomDirectoryListCreator: RoomDirectoryListCreator
 ) : VectorViewModel<RoomDirectoryPickerViewState, RoomDirectoryPickerAction, EmptyViewEvents>(initialState) {
 
@@ -141,17 +144,29 @@ class RoomDirectoryPickerViewModel @AssistedInject constructor(
     }
 
     private fun handleSubmit() = withState { state ->
+        // First avoid duplicate
+        val enteredServer = state.enteredServer
+
+        val existingServerList = state.directories.map { it.serverName }
+
+        if (enteredServer in existingServerList) {
+            setState {
+                copy(addServerAsync = Fail(Throwable(stringProvider.getString(R.string.directory_add_a_new_server_error_already_added))))
+            }
+            return@withState
+        }
+
         viewModelScope.launch {
             setState {
                 copy(addServerAsync = Loading())
             }
             try {
                 session.getPublicRooms(
-                        server = state.enteredServer,
+                        server = enteredServer,
                         publicRoomsParams = PublicRoomsParams(limit = 1)
                 )
                 // Success, let add the server to our local repository, and update the state
-                val newSet = uiStateRepository.getCustomRoomDirectoryHomeservers(session.sessionId) + state.enteredServer
+                val newSet = uiStateRepository.getCustomRoomDirectoryHomeservers(session.sessionId) + enteredServer
                 uiStateRepository.setCustomRoomDirectoryHomeservers(session.sessionId, newSet)
                 setState {
                     copy(

vector/src/main/res/values/strings.xml

@@ -1591,6 +1591,7 @@
     <string name="directory_add_a_new_server">Add a new server</string>
     <string name="directory_add_a_new_server_prompt">Enter the name of a new server you want to explore.</string>
     <string name="directory_add_a_new_server_error">"Can't find this server or its room list"</string>
+    <string name="directory_add_a_new_server_error_already_added">This server is already present in the list</string>
 
     <!-- Lock screen-->
     <string name="lock_screen_hint">Type here…</string>