VoIP: use UserListFragment to select someone for call transfer (+ clean some code)

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

@@ -17,10 +17,18 @@
 package im.vector.app.core.extensions
 
 // Create a new Set including the provided element if not already present, or removing the element if already present
-fun <T> Set<T>.toggle(element: T): Set<T> {
+fun <T> Set<T>.toggle(element: T, singleElement: Boolean = false): Set<T> {
     return if (contains(element)) {
-        minus(element)
+        if (singleElement) {
+            emptySet()
+        } else {
+            minus(element)
+        }
     } else {
-        plus(element)
+        if (singleElement) {
+            setOf(element)
+        } else {
+            plus(element)
+        }
     }
 }

vector/src/main/java/im/vector/app/core/platform/VectorBaseActivity.kt

@@ -42,6 +42,7 @@ import androidx.lifecycle.ViewModelProvider
 import androidx.viewbinding.ViewBinding
 import com.bumptech.glide.util.Util
 import com.google.android.material.snackbar.Snackbar
+import com.jakewharton.rxbinding3.view.clicks
 import im.vector.app.BuildConfig
 import im.vector.app.R
 import im.vector.app.core.di.ActiveSessionHolder
@@ -84,6 +85,7 @@ import io.reactivex.disposables.Disposable
 import org.matrix.android.sdk.api.extensions.tryOrNull
 import org.matrix.android.sdk.api.failure.GlobalError
 import timber.log.Timber
+import java.util.concurrent.TimeUnit
 import kotlin.system.measureTimeMillis
 
 abstract class VectorBaseActivity<VB: ViewBinding> : AppCompatActivity(), HasScreenInjector {
@@ -113,6 +115,19 @@ abstract class VectorBaseActivity<VB: ViewBinding> : AppCompatActivity(), HasScr
                 .disposeOnDestroy()
     }
 
+    /* ==========================================================================================
+     * Views
+     * ========================================================================================== */
+
+    protected fun View.debouncedClicks(onClicked: () -> Unit) {
+        clicks()
+                .throttleFirst(300, TimeUnit.MILLISECONDS)
+                .observeOn(AndroidSchedulers.mainThread())
+                .subscribe { onClicked() }
+                .disposeOnDestroy()
+    }
+
+
     /* ==========================================================================================
      * DATA
      * ========================================================================================== */

vector/src/main/java/im/vector/app/features/call/CallControlsBottomSheet.kt

@@ -63,6 +63,11 @@ class CallControlsBottomSheet : VectorBaseBottomSheetDialogFragment<BottomSheetC
             dismiss()
         }
 
+        views.callControlsTransfer.views.itemVerificationClickableZone.debouncedClicks {
+            callViewModel.handle(VectorCallViewActions.InitiateCallTransfer)
+            dismiss()
+        }
+
         callViewModel.observeViewEvents {
             when (it) {
                 is VectorCallViewEvents.ShowSoundDeviceChooser -> {
@@ -153,5 +158,6 @@ class CallControlsBottomSheet : VectorBaseBottomSheetDialogFragment<BottomSheetC
             views.callControlsToggleHoldResume.subTitle = null
             views.callControlsToggleHoldResume.leftIcon = ContextCompat.getDrawable(requireContext(), R.drawable.ic_call_hold_action)
         }
+        views.callControlsTransfer.isVisible = state.canOpponentBeTransferred
     }
 }

vector/src/main/java/im/vector/app/features/call/VectorCallActivity.kt

@@ -187,7 +187,7 @@ class VectorCallActivity : VectorBaseActivity<ActivityCallBinding>(), CallContro
                 views.callConnectingProgress.isVisible = true
                 configureCallInfo(state)
             }
-            is CallState.Connected    -> {
+            is CallState.Connected -> {
                 if (callState.iceConnectionState == MxPeerConnectionState.CONNECTED) {
                     if (state.isLocalOnHold || state.isRemoteOnHold) {
                         views.smallIsHeldIcon.isVisible = true
@@ -227,10 +227,10 @@ class VectorCallActivity : VectorBaseActivity<ActivityCallBinding>(), CallContro
                     views.callConnectingProgress.isVisible = true
                 }
             }
-            is CallState.Terminated   -> {
+            is CallState.Terminated -> {
                 finish()
             }
-            null                      -> {
+            null -> {
             }
         }
     }
@@ -320,6 +320,9 @@ class VectorCallActivity : VectorBaseActivity<ActivityCallBinding>(), CallContro
             is VectorCallViewEvents.ConnectionTimeout -> {
                 onErrorTimoutConnect(event.turn)
             }
+            is VectorCallViewEvents.ShowCallTransferScreen -> {
+                navigator.openCallTransfer(this, callArgs.callId)
+            }
             null -> {
             }
         }

vector/src/main/java/im/vector/app/features/call/VectorCallViewActions.kt

@@ -30,4 +30,5 @@ sealed class VectorCallViewActions : VectorViewModelAction {
     object HeadSetButtonPressed : VectorCallViewActions()
     object ToggleCamera : VectorCallViewActions()
     object ToggleHDSD : VectorCallViewActions()
+    object InitiateCallTransfer : VectorCallViewActions()
 }

vector/src/main/java/im/vector/app/features/call/VectorCallViewEvents.kt

@@ -27,6 +27,7 @@ sealed class VectorCallViewEvents : VectorViewEvents {
             val available: List<CallAudioManager.SoundDevice>,
             val current: CallAudioManager.SoundDevice
     ) : VectorCallViewEvents()
+    object ShowCallTransferScreen: VectorCallViewEvents()
 //    data class CallAnswered(val content: CallAnswerContent) : VectorCallViewEvents()
 //    data class CallHangup(val content: CallHangupContent) : VectorCallViewEvents()
 //    object CallAccepted : VectorCallViewEvents()

vector/src/main/java/im/vector/app/features/call/VectorCallViewModel.kt

@@ -33,6 +33,7 @@ import org.matrix.android.sdk.api.session.call.CallState
 import org.matrix.android.sdk.api.session.call.MxCall
 import org.matrix.android.sdk.api.session.call.MxPeerConnectionState
 import org.matrix.android.sdk.api.session.call.TurnServerResponse
+import org.matrix.android.sdk.api.session.room.model.call.supportCallTransfer
 import org.matrix.android.sdk.api.util.MatrixItem
 import org.matrix.android.sdk.api.util.toMatrixItem
 import java.util.Timer
@@ -114,7 +115,8 @@ class VectorCallViewModel @AssistedInject constructor(
             }
             setState {
                 copy(
-                        callState = Success(callState)
+                        callState = Success(callState),
+                        canOpponentBeTransferred = call.capabilities.supportCallTransfer()
                 )
             }
         }
@@ -188,7 +190,8 @@ class VectorCallViewModel @AssistedInject constructor(
                         isFrontCamera = webRtcCall.currentCameraType() == CameraType.FRONT,
                         canSwitchCamera = webRtcCall.canSwitchCamera(),
                         formattedDuration = webRtcCall.formattedDuration(),
-                        isHD = webRtcCall.mxCall.isVideoCall && webRtcCall.currentCaptureFormat() is CaptureFormat.HD
+                        isHD = webRtcCall.mxCall.isVideoCall && webRtcCall.currentCaptureFormat() is CaptureFormat.HD,
+                        canOpponentBeTransferred = webRtcCall.mxCall.capabilities.supportCallTransfer()
                 )
             }
             updateOtherKnownCall(webRtcCall)
@@ -269,6 +272,11 @@ class VectorCallViewModel @AssistedInject constructor(
                 if (!state.isVideoCall) return@withState
                 call?.setCaptureFormat(if (state.isHD) CaptureFormat.SD else CaptureFormat.HD)
             }
+            VectorCallViewActions.InitiateCallTransfer -> {
+                _viewEvents.post(
+                        VectorCallViewEvents.ShowCallTransferScreen
+                )
+            }
         }.exhaustive
     }
 

vector/src/main/java/im/vector/app/features/call/VectorCallViewState.kt

@@ -39,7 +39,8 @@ data class VectorCallViewState(
         val callState: Async<CallState> = Uninitialized,
         val otherKnownCallInfo: CallInfo? = null,
         val callInfo: CallInfo = CallInfo(callId),
-        val formattedDuration: String = ""
+        val formattedDuration: String = "",
+        val canOpponentBeTransferred: Boolean = false
 ) : MvRxState {
 
     data class CallInfo(

vector/src/main/java/im/vector/app/features/call/transfer/CallTransferAction.kt

@@ -0,0 +1,23 @@
+/*
+ * Copyright (c) 2020 New Vector Ltd
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package im.vector.app.features.call.transfer
+
+import im.vector.app.core.platform.VectorViewModelAction
+
+sealed class CallTransferAction : VectorViewModelAction {
+    data class Connect(val consultFirst: Boolean, val selectedUserId: String) : CallTransferAction()
+}

vector/src/main/java/im/vector/app/features/call/transfer/CallTransferActivity.kt

@@ -20,19 +20,20 @@ import android.content.Context
 import android.content.Intent
 import android.os.Bundle
 import android.os.Parcelable
-import android.view.View
 import android.widget.Toast
 import com.airbnb.mvrx.MvRx
+import com.airbnb.mvrx.viewModel
 import im.vector.app.R
 import im.vector.app.core.di.ScreenComponent
 import im.vector.app.core.error.ErrorFormatter
 import im.vector.app.core.extensions.addFragment
 import im.vector.app.core.extensions.addFragmentToBackstack
-import im.vector.app.core.platform.SimpleFragmentActivity
+import im.vector.app.core.platform.VectorBaseActivity
 import im.vector.app.core.utils.PERMISSIONS_FOR_MEMBERS_SEARCH
 import im.vector.app.core.utils.PERMISSION_REQUEST_CODE_READ_CONTACTS
 import im.vector.app.core.utils.allGranted
 import im.vector.app.core.utils.checkPermissions
+import im.vector.app.databinding.ActivityCallTransferBinding
 import im.vector.app.features.contactsbook.ContactsBookFragment
 import im.vector.app.features.contactsbook.ContactsBookViewModel
 import im.vector.app.features.contactsbook.ContactsBookViewState
@@ -48,7 +49,9 @@ import javax.inject.Inject
 @Parcelize
 data class CallTransferArgs(val callId: String) : Parcelable
 
-class CallTransferActivity : SimpleFragmentActivity(), CallTransferViewModel.Factory, UserListViewModel.Factory, ContactsBookViewModel.Factory {
+private const val USER_LIST_FRAGMENT_TAG = "USER_LIST_FRAGMENT_TAG"
+
+class CallTransferActivity : VectorBaseActivity<ActivityCallTransferBinding>(), CallTransferViewModel.Factory, UserListViewModel.Factory, ContactsBookViewModel.Factory {
 
     private lateinit var sharedActionViewModel: UserListSharedActionViewModel
     @Inject lateinit var userListViewModelFactory: UserListViewModel.Factory
@@ -56,6 +59,10 @@ class CallTransferActivity : SimpleFragmentActivity(), CallTransferViewModel.Fac
     @Inject lateinit var contactsBookViewModelFactory: ContactsBookViewModel.Factory
     @Inject lateinit var errorFormatter: ErrorFormatter
 
+    private val callTransferViewModel: CallTransferViewModel by viewModel()
+
+    override fun getBinding() = ActivityCallTransferBinding.inflate(layoutInflater)
+
     override fun injectWith(injector: ScreenComponent) {
         super.injectWith(injector)
         injector.inject(this)
@@ -75,33 +82,50 @@ class CallTransferActivity : SimpleFragmentActivity(), CallTransferViewModel.Fac
 
     override fun onCreate(savedInstanceState: Bundle?) {
         super.onCreate(savedInstanceState)
-
-        views.toolbar.visibility = View.GONE
-
         sharedActionViewModel = viewModelProvider.get(UserListSharedActionViewModel::class.java)
         sharedActionViewModel
                 .observe()
                 .subscribe { sharedAction ->
                     when (sharedAction) {
-                        UserListSharedAction.Close                 -> finish()
+                        UserListSharedAction.OpenPhoneBook -> openPhoneBook()
-                        UserListSharedAction.GoBack                -> onBackPressed()
-                        UserListSharedAction.OpenPhoneBook         -> openPhoneBook()
                         // not exhaustive because it's a sharedAction
-                        else                                       -> {
+                        else                               -> {
                         }
                     }
                 }
                 .disposeOnDestroy()
         if (isFirstCreation()) {
             addFragment(
-                    R.id.container,
+                    R.id.callTransferFragmentContainer,
                     UserListFragment::class.java,
                     UserListFragmentArgs(
-                            title = "Call transfer",
+                            title = "",
-                            menuResId = -1
+                            menuResId = -1,
-                    )
+                            singleSelection = true,
+                            showInviteActions = false,
+                            showToolbar = false
+                    ),
+                    USER_LIST_FRAGMENT_TAG
             )
         }
+        callTransferViewModel.observeViewEvents {
+            when (it) {
+                is CallTransferViewEvents.Dismiss -> finish()
+            }
+        }
+        configureToolbar(views.callTransferToolbar)
+        setupConnectAction()
+    }
+
+    private fun setupConnectAction() {
+        views.callTransferConnectAction.debouncedClicks {
+            val userListFragment = supportFragmentManager.findFragmentByTag(USER_LIST_FRAGMENT_TAG) as? UserListFragment
+            val selectedUser = userListFragment?.getCurrentState()?.getSelectedMatrixId()?.firstOrNull()
+            if (selectedUser != null) {
+                val action = CallTransferAction.Connect(views.callTransferConsultCheckBox.isChecked, selectedUser)
+                callTransferViewModel.handle(action)
+            }
+        }
     }
 
     private fun openPhoneBook() {
@@ -110,7 +134,7 @@ class CallTransferActivity : SimpleFragmentActivity(), CallTransferViewModel.Fac
                         this,
                         PERMISSION_REQUEST_CODE_READ_CONTACTS,
                         0)) {
-            addFragmentToBackstack(R.id.container, ContactsBookFragment::class.java)
+            addFragmentToBackstack(R.id.callTransferFragmentContainer, ContactsBookFragment::class.java)
         }
     }
 
@@ -118,7 +142,7 @@ class CallTransferActivity : SimpleFragmentActivity(), CallTransferViewModel.Fac
         super.onRequestPermissionsResult(requestCode, permissions, grantResults)
         if (allGranted(grantResults)) {
             if (requestCode == PERMISSION_REQUEST_CODE_READ_CONTACTS) {
-                doOnPostResume { addFragmentToBackstack(R.id.container, ContactsBookFragment::class.java) }
+                doOnPostResume { addFragmentToBackstack(R.id.callTransferFragmentContainer, ContactsBookFragment::class.java) }
             }
         } else {
             Toast.makeText(baseContext, R.string.missing_permissions_error, Toast.LENGTH_SHORT).show()
@@ -126,7 +150,7 @@ class CallTransferActivity : SimpleFragmentActivity(), CallTransferViewModel.Fac
     }
 
     companion object {
-
+        
         fun newIntent(context: Context, callId: String): Intent {
             return Intent(context, CallTransferActivity::class.java).also {
                 it.putExtra(MvRx.KEY_ARG, CallTransferArgs(callId))

vector/src/main/java/im/vector/app/features/call/transfer/CallTransferViewEvents.kt

@@ -0,0 +1,23 @@
+/*
+ * Copyright (c) 2020 New Vector Ltd
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package im.vector.app.features.call.transfer
+
+import im.vector.app.core.platform.VectorViewEvents
+
+sealed class CallTransferViewEvents : VectorViewEvents {
+    object Dismiss : CallTransferViewEvents()
+}

vector/src/main/java/im/vector/app/features/call/transfer/CallTransferViewModel.kt

@@ -16,20 +16,23 @@
 
 package im.vector.app.features.call.transfer
 
+import androidx.lifecycle.viewModelScope
 import com.airbnb.mvrx.ActivityViewModelContext
 import com.airbnb.mvrx.MvRxViewModelFactory
 import com.airbnb.mvrx.ViewModelContext
 import com.squareup.inject.assisted.Assisted
 import com.squareup.inject.assisted.AssistedInject
-import im.vector.app.core.platform.EmptyAction
-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.call.webrtc.WebRtcCall
-import org.matrix.android.sdk.api.session.Session
+import im.vector.app.features.call.webrtc.WebRtcCallManager
+import kotlinx.coroutines.launch
+import org.matrix.android.sdk.api.session.call.CallState
+import org.matrix.android.sdk.api.session.call.MxCall
 import timber.log.Timber
 
-class CallTransferViewModel @AssistedInject constructor(@Assisted initialState: CallTransferViewState)
+class CallTransferViewModel @AssistedInject constructor(@Assisted initialState: CallTransferViewState,
-    : VectorViewModel<CallTransferViewState, EmptyAction, EmptyViewEvents>(initialState) {
+                                                        private val callManager: WebRtcCallManager)
+    : VectorViewModel<CallTransferViewState, CallTransferAction, CallTransferViewEvents>(initialState) {
 
     @AssistedInject.Factory
     interface Factory {
@@ -45,6 +48,43 @@ class CallTransferViewModel @AssistedInject constructor(@Assisted initialState:
         }
     }
 
-    override fun handle(action: EmptyAction) {}
+    private var call: WebRtcCall? = null
+    private val callListener = object : WebRtcCall.Listener {
+        override fun onStateUpdate(call: MxCall) {
+            if (call.state == CallState.Terminated) {
+                _viewEvents.post(CallTransferViewEvents.Dismiss)
+            }
+        }
+    }
 
+    init {
+        val webRtcCall = callManager.getCallById(initialState.callId)
+        if (webRtcCall == null) {
+            _viewEvents.post(CallTransferViewEvents.Dismiss)
+        } else {
+            call = webRtcCall
+            webRtcCall.addListener(callListener)
+        }
+    }
+
+    override fun onCleared() {
+        super.onCleared()
+        call?.removeListener(callListener)
+    }
+
+    override fun handle(action: CallTransferAction) {
+        when (action) {
+            is CallTransferAction.Connect -> transferCall(action)
+        }
+    }
+
+    private fun transferCall(action: CallTransferAction.Connect) {
+        viewModelScope.launch {
+            try {
+                call?.mxCall?.transfer(action.selectedUserId, null)
+            } catch (failure: Throwable) {
+                Timber.v("Fail to transfer call: $failure")
+            }
+        }
+    }
 }

vector/src/main/java/im/vector/app/features/contactsbook/ContactsBookFragment.kt

@@ -32,7 +32,7 @@ import im.vector.app.core.extensions.configureWith
 import im.vector.app.core.extensions.hideKeyboard
 import im.vector.app.core.platform.VectorBaseFragment
 import im.vector.app.databinding.FragmentContactsBookBinding
-import im.vector.app.features.userdirectory.PendingInvitee
+import im.vector.app.features.userdirectory.PendingSelection
 import im.vector.app.features.userdirectory.UserListAction
 import im.vector.app.features.userdirectory.UserListSharedAction
 import im.vector.app.features.userdirectory.UserListSharedActionViewModel
@@ -132,13 +132,13 @@ class ContactsBookFragment @Inject constructor(
 
     override fun onMatrixIdClick(matrixId: String) {
         view?.hideKeyboard()
-        viewModel.handle(UserListAction.SelectPendingInvitee(PendingInvitee.UserPendingInvitee(User(matrixId))))
+        viewModel.handle(UserListAction.AddPendingSelection(PendingSelection.UserPendingSelection(User(matrixId))))
         sharedActionViewModel.post(UserListSharedAction.GoBack)
     }
 
     override fun onThreePidClick(threePid: ThreePid) {
         view?.hideKeyboard()
-        viewModel.handle(UserListAction.SelectPendingInvitee(PendingInvitee.ThreePidPendingInvitee(threePid)))
+        viewModel.handle(UserListAction.AddPendingSelection(PendingSelection.ThreePidPendingSelection(threePid)))
         sharedActionViewModel.post(UserListSharedAction.GoBack)
     }
 }

vector/src/main/java/im/vector/app/features/createdirect/CreateDirectRoomAction.kt

@@ -17,11 +17,11 @@
 package im.vector.app.features.createdirect
 
 import im.vector.app.core.platform.VectorViewModelAction
-import im.vector.app.features.userdirectory.PendingInvitee
+import im.vector.app.features.userdirectory.PendingSelection
 
 sealed class CreateDirectRoomAction : VectorViewModelAction {
     data class CreateRoomAndInviteSelectedUsers(
-            val invitees: Set<PendingInvitee>,
+            val selections: Set<PendingSelection>,
             val existingDmRoomId: String?
     ) : CreateDirectRoomAction()
 }

vector/src/main/java/im/vector/app/features/createdirect/CreateDirectRoomActivity.kt

@@ -146,7 +146,7 @@ class CreateDirectRoomActivity : SimpleFragmentActivity(), UserListViewModel.Fac
     private fun onMenuItemSelected(action: UserListSharedAction.OnMenuItemSelected) {
         if (action.itemId == R.id.action_create_direct_room) {
             viewModel.handle(CreateDirectRoomAction.CreateRoomAndInviteSelectedUsers(
-                    action.invitees,
+                    action.selections,
                     null
             ))
         }

vector/src/main/java/im/vector/app/features/createdirect/CreateDirectRoomByQrCodeFragment.kt

@@ -29,8 +29,7 @@ import im.vector.app.core.utils.PERMISSIONS_FOR_TAKING_PHOTO
 import im.vector.app.core.utils.checkPermissions
 import im.vector.app.core.utils.registerForPermissionsResult
 import im.vector.app.databinding.FragmentQrCodeScannerBinding
-import im.vector.app.features.userdirectory.PendingInvitee
+import im.vector.app.features.userdirectory.PendingSelection
-
 import me.dm7.barcodescanner.zxing.ZXingScannerView
 import org.matrix.android.sdk.api.session.permalinks.PermalinkData
 import org.matrix.android.sdk.api.session.permalinks.PermalinkParser
@@ -107,7 +106,7 @@ class CreateDirectRoomByQrCodeFragment @Inject constructor() : VectorBaseFragmen
                 val qrInvitee = if (viewModel.session.getUser(mxid) != null) viewModel.session.getUser(mxid)!! else User(mxid, null, null)
 
                 viewModel.handle(
-                        CreateDirectRoomAction.CreateRoomAndInviteSelectedUsers(setOf(PendingInvitee.UserPendingInvitee(qrInvitee)), existingDm)
+                        CreateDirectRoomAction.CreateRoomAndInviteSelectedUsers(setOf(PendingSelection.UserPendingSelection(qrInvitee)), existingDm)
                 )
             }
         }

vector/src/main/java/im/vector/app/features/createdirect/CreateDirectRoomViewModel.kt

@@ -26,10 +26,9 @@ import com.squareup.inject.assisted.Assisted
 import com.squareup.inject.assisted.AssistedInject
 import im.vector.app.core.extensions.exhaustive
 import im.vector.app.core.platform.VectorViewModel
-import im.vector.app.features.contactsbook.ContactsBookViewModel
 import im.vector.app.features.raw.wellknown.getElementWellknown
 import im.vector.app.features.raw.wellknown.isE2EByDefault
-import im.vector.app.features.userdirectory.PendingInvitee
+import im.vector.app.features.userdirectory.PendingSelection
 import kotlinx.coroutines.Dispatchers
 import kotlinx.coroutines.launch
 import org.matrix.android.sdk.api.raw.RawService
@@ -77,11 +76,11 @@ class CreateDirectRoomViewModel @AssistedInject constructor(@Assisted
             }
         } else {
             // Create the DM
-            createRoomAndInviteSelectedUsers(action.invitees)
+            createRoomAndInviteSelectedUsers(action.selections)
         }
     }
 
-    private fun createRoomAndInviteSelectedUsers(invitees: Set<PendingInvitee>) {
+    private fun createRoomAndInviteSelectedUsers(selections: Set<PendingSelection>) {
         viewModelScope.launch(Dispatchers.IO) {
             val adminE2EByDefault = rawService.getElementWellknown(session.myUserId)
                     ?.isE2EByDefault()
@@ -89,10 +88,10 @@ class CreateDirectRoomViewModel @AssistedInject constructor(@Assisted
 
             val roomParams = CreateRoomParams()
                     .apply {
-                        invitees.forEach {
+                        selections.forEach {
                             when (it) {
-                                is PendingInvitee.UserPendingInvitee     -> invitedUserIds.add(it.user.userId)
+                                is PendingSelection.UserPendingSelection     -> invitedUserIds.add(it.user.userId)
-                                is PendingInvitee.ThreePidPendingInvitee -> invite3pids.add(it.threePid)
+                                is PendingSelection.ThreePidPendingSelection -> invite3pids.add(it.threePid)
                             }.exhaustive
                         }
                         setDirectMessage()

vector/src/main/java/im/vector/app/features/invite/InviteUsersToRoomAction.kt

@@ -17,8 +17,8 @@
 package im.vector.app.features.invite
 
 import im.vector.app.core.platform.VectorViewModelAction
-import im.vector.app.features.userdirectory.PendingInvitee
+import im.vector.app.features.userdirectory.PendingSelection
 
 sealed class InviteUsersToRoomAction : VectorViewModelAction {
-    data class InviteSelectedUsers(val invitees: Set<PendingInvitee>) : InviteUsersToRoomAction()
+    data class InviteSelectedUsers(val selections: Set<PendingSelection>) : InviteUsersToRoomAction()
 }

vector/src/main/java/im/vector/app/features/invite/InviteUsersToRoomActivity.kt

@@ -95,7 +95,6 @@ class InviteUsersToRoomActivity : SimpleFragmentActivity(), UserListViewModel.Fa
                 }
                 .disposeOnDestroy()
         if (isFirstCreation()) {
-            val args: InviteUsersToRoomArgs? = intent.extras?.getParcelable(MvRx.KEY_ARG)
             addFragment(
                     R.id.container,
                     UserListFragment::class.java,
@@ -103,7 +102,7 @@ class InviteUsersToRoomActivity : SimpleFragmentActivity(), UserListViewModel.Fa
                             title = getString(R.string.invite_users_to_room_title),
                             menuResId = R.menu.vector_invite_users_to_room,
                             excludedUserIds = viewModel.getUserIdsOfRoomMembers(),
-                            existingRoomId = args?.roomId
+                            showInviteActions = false
                     )
             )
         }
@@ -113,7 +112,7 @@ class InviteUsersToRoomActivity : SimpleFragmentActivity(), UserListViewModel.Fa
 
     private fun onMenuItemSelected(action: UserListSharedAction.OnMenuItemSelected) {
         if (action.itemId == R.id.action_invite_users_to_room_invite) {
-            viewModel.handle(InviteUsersToRoomAction.InviteSelectedUsers(action.invitees))
+            viewModel.handle(InviteUsersToRoomAction.InviteSelectedUsers(action.selections))
         }
     }
 

vector/src/main/java/im/vector/app/features/invite/InviteUsersToRoomViewModel.kt

@@ -25,8 +25,7 @@ import com.squareup.inject.assisted.AssistedInject
 import im.vector.app.R
 import im.vector.app.core.platform.VectorViewModel
 import im.vector.app.core.resources.StringProvider
-import im.vector.app.features.contactsbook.ContactsBookViewModel
+import im.vector.app.features.userdirectory.PendingSelection
-import im.vector.app.features.userdirectory.PendingInvitee
 import io.reactivex.Observable
 import org.matrix.android.sdk.api.session.Session
 import org.matrix.android.sdk.rx.rx
@@ -58,30 +57,30 @@ class InviteUsersToRoomViewModel @AssistedInject constructor(@Assisted
 
     override fun handle(action: InviteUsersToRoomAction) {
         when (action) {
-            is InviteUsersToRoomAction.InviteSelectedUsers -> inviteUsersToRoom(action.invitees)
+            is InviteUsersToRoomAction.InviteSelectedUsers -> inviteUsersToRoom(action.selections)
         }
     }
 
-    private fun inviteUsersToRoom(invitees: Set<PendingInvitee>) {
+    private fun inviteUsersToRoom(selections: Set<PendingSelection>) {
         _viewEvents.post(InviteUsersToRoomViewEvents.Loading)
 
-        Observable.fromIterable(invitees).flatMapCompletable { user ->
+        Observable.fromIterable(selections).flatMapCompletable { user ->
             when (user) {
-                is PendingInvitee.UserPendingInvitee     -> room.rx().invite(user.user.userId, null)
+                is PendingSelection.UserPendingSelection     -> room.rx().invite(user.user.userId, null)
-                is PendingInvitee.ThreePidPendingInvitee -> room.rx().invite3pid(user.threePid)
+                is PendingSelection.ThreePidPendingSelection -> room.rx().invite3pid(user.threePid)
             }
         }.subscribe(
                 {
-                    val successMessage = when (invitees.size) {
+                    val successMessage = when (selections.size) {
                         1    -> stringProvider.getString(R.string.invitation_sent_to_one_user,
-                                invitees.first().getBestName())
+                                selections.first().getBestName())
                         2    -> stringProvider.getString(R.string.invitations_sent_to_two_users,
-                                invitees.first().getBestName(),
+                                selections.first().getBestName(),
-                                invitees.last().getBestName())
+                                selections.last().getBestName())
                         else -> stringProvider.getQuantityString(R.plurals.invitations_sent_to_one_and_more_users,
-                                invitees.size - 1,
+                                selections.size - 1,
-                                invitees.first().getBestName(),
+                                selections.first().getBestName(),
-                                invitees.size - 1)
+                                selections.size - 1)
                     }
                     _viewEvents.post(InviteUsersToRoomViewEvents.Success(successMessage))
                 },

vector/src/main/java/im/vector/app/features/userdirectory/PendingSelection.kt

@@ -19,14 +19,14 @@ package im.vector.app.features.userdirectory
 import org.matrix.android.sdk.api.session.identity.ThreePid
 import org.matrix.android.sdk.api.session.user.model.User
 
-sealed class PendingInvitee {
+sealed class PendingSelection {
-    data class UserPendingInvitee(val user: User) : PendingInvitee()
+    data class UserPendingSelection(val user: User) : PendingSelection()
-    data class ThreePidPendingInvitee(val threePid: ThreePid) : PendingInvitee()
+    data class ThreePidPendingSelection(val threePid: ThreePid) : PendingSelection()
 
     fun getBestName(): String {
         return when (this) {
-            is UserPendingInvitee     -> user.getBestName()
+            is UserPendingSelection     -> user.getBestName()
-            is ThreePidPendingInvitee -> threePid.value
+            is ThreePidPendingSelection -> threePid.value
         }
     }
 }

vector/src/main/java/im/vector/app/features/userdirectory/UserListAction.kt

@@ -21,7 +21,7 @@ import im.vector.app.core.platform.VectorViewModelAction
 sealed class UserListAction : VectorViewModelAction {
     data class SearchUsers(val value: String) : UserListAction()
     object ClearSearchUsers : UserListAction()
-    data class SelectPendingInvitee(val pendingInvitee: PendingInvitee) : UserListAction()
+    data class AddPendingSelection(val pendingSelection: PendingSelection) : UserListAction()
-    data class RemovePendingInvitee(val pendingInvitee: PendingInvitee) : UserListAction()
+    data class RemovePendingSelection(val pendingSelection: PendingSelection) : UserListAction()
     object ComputeMatrixToLinkForSharing : UserListAction()
 }

vector/src/main/java/im/vector/app/features/userdirectory/UserListController.kt

@@ -54,10 +54,7 @@ class UserListController @Inject constructor(private val session: Session,
 
         // Build generic items
         if (currentState.searchTerm.isBlank()) {
-            // For now we remove this option if in invite to existing room flow (and not create DM)
+            if (currentState.showInviteActions()) {
-            if (currentState.pendingInvitees.isEmpty()
-                    // For now we remove this option if in invite to existing room flow (and not create DM)
-                    && currentState.existingRoomId == null) {
                 actionItem {
                     id(R.drawable.ic_share)
                     title(stringProvider.getString(R.string.invite_friends))
@@ -75,9 +72,7 @@ class UserListController @Inject constructor(private val session: Session,
                     callback?.onContactBookClick()
                 })
             }
-            if (currentState.pendingInvitees.isEmpty()
+            if (currentState.showInviteActions()) {
-                    // For now we remove this option if in invite to existing room flow (and not create DM)
-                    && currentState.existingRoomId == null) {
                 actionItem {
                     id(R.drawable.ic_qr_code_add)
                     title(stringProvider.getString(R.string.qr_code))

vector/src/main/java/im/vector/app/features/userdirectory/UserListFragment.kt

@@ -67,18 +67,22 @@ class UserListFragment @Inject constructor(
     override fun onViewCreated(view: View, savedInstanceState: Bundle?) {
         super.onViewCreated(view, savedInstanceState)
         sharedActionViewModel = activityViewModelProvider.get(UserListSharedActionViewModel::class.java)
-        views.userListTitle.text = args.title
+        if(args.showToolbar) {
-        vectorBaseActivity.setSupportActionBar(views.userListToolbar)
+            views.userListTitle.text = args.title
-
+            vectorBaseActivity.setSupportActionBar(views.userListToolbar)
+            setupCloseView()
+            views.userListToolbar.isVisible = true
+        }else{
+            views.userListToolbar.isVisible = false
+        }
         setupRecyclerView()
         setupSearchView()
-        setupCloseView()
 
         homeServerCapabilitiesViewModel.subscribe {
             views.userListE2EbyDefaultDisabled.isVisible = !it.isE2EByDefault
         }
 
-        viewModel.selectSubscribe(this, UserListViewState::pendingInvitees) {
+        viewModel.selectSubscribe(this, UserListViewState::pendingSelections) {
             renderSelectedUsers(it)
         }
 
@@ -105,7 +109,7 @@ class UserListFragment @Inject constructor(
 
     override fun onPrepareOptionsMenu(menu: Menu) {
         withState(viewModel) {
-            val showMenuItem = it.pendingInvitees.isNotEmpty()
+            val showMenuItem = it.pendingSelections.isNotEmpty()
             menu.forEach { menuItem ->
                 menuItem.isVisible = showMenuItem
             }
@@ -114,7 +118,7 @@ class UserListFragment @Inject constructor(
     }
 
     override fun onOptionsItemSelected(item: MenuItem): Boolean = withState(viewModel) {
-        sharedActionViewModel.post(UserListSharedAction.OnMenuItemSelected(item.itemId, it.pendingInvitees))
+        sharedActionViewModel.post(UserListSharedAction.OnMenuItemSelected(item.itemId, it.pendingSelections))
         return@withState true
     }
 
@@ -156,14 +160,14 @@ class UserListFragment @Inject constructor(
         userListController.setData(it)
     }
 
-    private fun renderSelectedUsers(invitees: Set<PendingInvitee>) {
+    private fun renderSelectedUsers(selections: Set<PendingSelection>) {
         invalidateOptionsMenu()
 
         val currentNumberOfChips = views.chipGroup.childCount
-        val newNumberOfChips = invitees.size
+        val newNumberOfChips = selections.size
 
         views.chipGroup.removeAllViews()
-        invitees.forEach { addChipToGroup(it) }
+        selections.forEach { addChipToGroup(it) }
 
         // Scroll to the bottom when adding chips. When removing chips, do not scroll
         if (newNumberOfChips >= currentNumberOfChips) {
@@ -173,20 +177,22 @@ class UserListFragment @Inject constructor(
         }
     }
 
-    private fun addChipToGroup(pendingInvitee: PendingInvitee) {
+    private fun addChipToGroup(pendingSelection: PendingSelection) {
         val chip = Chip(requireContext())
         chip.setChipBackgroundColorResource(android.R.color.transparent)
         chip.chipStrokeWidth = dimensionConverter.dpToPx(1).toFloat()
-        chip.text = pendingInvitee.getBestName()
+        chip.text = pendingSelection.getBestName()
         chip.isClickable = true
         chip.isCheckable = false
         chip.isCloseIconVisible = true
         views.chipGroup.addView(chip)
         chip.setOnCloseIconClickListener {
-            viewModel.handle(UserListAction.RemovePendingInvitee(pendingInvitee))
+            viewModel.handle(UserListAction.RemovePendingSelection(pendingSelection))
         }
     }
 
+    fun getCurrentState() = withState(viewModel){ it }
+
     override fun onInviteFriendClick() {
         viewModel.handle(UserListAction.ComputeMatrixToLinkForSharing)
     }
@@ -197,17 +203,17 @@ class UserListFragment @Inject constructor(
 
     override fun onItemClick(user: User) {
         view?.hideKeyboard()
-        viewModel.handle(UserListAction.SelectPendingInvitee(PendingInvitee.UserPendingInvitee(user)))
+        viewModel.handle(UserListAction.AddPendingSelection(PendingSelection.UserPendingSelection(user)))
     }
 
     override fun onMatrixIdClick(matrixId: String) {
         view?.hideKeyboard()
-        viewModel.handle(UserListAction.SelectPendingInvitee(PendingInvitee.UserPendingInvitee(User(matrixId))))
+        viewModel.handle(UserListAction.AddPendingSelection(PendingSelection.UserPendingSelection(User(matrixId))))
     }
 
     override fun onThreePidClick(threePid: ThreePid) {
         view?.hideKeyboard()
-        viewModel.handle(UserListAction.SelectPendingInvitee(PendingInvitee.ThreePidPendingInvitee(threePid)))
+        viewModel.handle(UserListAction.AddPendingSelection(PendingSelection.ThreePidPendingSelection(threePid)))
     }
 
     override fun onUseQRCode() {

vector/src/main/java/im/vector/app/features/userdirectory/UserListFragmentArgs.kt

@@ -24,5 +24,7 @@ data class UserListFragmentArgs(
         val title: String,
         val menuResId: Int,
         val excludedUserIds: Set<String>? = null,
-        val existingRoomId: String? = null
+        val singleSelection: Boolean = false,
+        val showInviteActions: Boolean = true,
+        val showToolbar: Boolean = true
 ) : Parcelable

vector/src/main/java/im/vector/app/features/userdirectory/UserListSharedAction.kt

@@ -21,7 +21,7 @@ import im.vector.app.core.platform.VectorSharedAction
 sealed class UserListSharedAction : VectorSharedAction {
     object Close : UserListSharedAction()
     object GoBack : UserListSharedAction()
-    data class OnMenuItemSelected(val itemId: Int, val invitees: Set<PendingInvitee>) : UserListSharedAction()
+    data class OnMenuItemSelected(val itemId: Int, val selections: Set<PendingSelection>) : UserListSharedAction()
     object OpenPhoneBook : UserListSharedAction()
     object AddByQrCode : UserListSharedAction()
 }

vector/src/main/java/im/vector/app/features/userdirectory/UserListViewModel.kt

@@ -68,21 +68,15 @@ class UserListViewModel @AssistedInject constructor(@Assisted initialState: User
     }
 
     init {
-        setState {
-            copy(
-                    myUserId = session.myUserId,
-                    existingRoomId = initialState.existingRoomId
-            )
-        }
         observeUsers()
     }
 
     override fun handle(action: UserListAction) {
         when (action) {
-            is UserListAction.SearchUsers                -> handleSearchUsers(action.value)
+            is UserListAction.SearchUsers -> handleSearchUsers(action.value)
-            is UserListAction.ClearSearchUsers           -> handleClearSearchUsers()
+            is UserListAction.ClearSearchUsers -> handleClearSearchUsers()
-            is UserListAction.SelectPendingInvitee       -> handleSelectUser(action)
+            is UserListAction.AddPendingSelection -> handleSelectUser(action)
-            is UserListAction.RemovePendingInvitee       -> handleRemoveSelectedUser(action)
+            is UserListAction.RemovePendingSelection -> handleRemoveSelectedUser(action)
             UserListAction.ComputeMatrixToLinkForSharing -> handleShareMyMatrixToLink()
         }.exhaustive
     }
@@ -168,13 +162,13 @@ class UserListViewModel @AssistedInject constructor(@Assisted initialState: User
                 .disposeOnClear()
     }
 
-    private fun handleSelectUser(action: UserListAction.SelectPendingInvitee) = withState { state ->
+    private fun handleSelectUser(action: UserListAction.AddPendingSelection) = withState { state ->
-        val selectedUsers = state.pendingInvitees.toggle(action.pendingInvitee)
+        val selections = state.pendingSelections.toggle(action.pendingSelection, singleElement = state.singleSelection)
-        setState { copy(pendingInvitees = selectedUsers) }
+        setState { copy(pendingSelections = selections) }
     }
 
-    private fun handleRemoveSelectedUser(action: UserListAction.RemovePendingInvitee) = withState { state ->
+    private fun handleRemoveSelectedUser(action: UserListAction.RemovePendingSelection) = withState { state ->
-        val selectedUsers = state.pendingInvitees.minus(action.pendingInvitee)
+        val selections = state.pendingSelections.minus(action.pendingSelection)
-        setState { copy(pendingInvitees = selectedUsers) }
+        setState { copy(pendingSelections = selections) }
     }
 }

vector/src/main/java/im/vector/app/features/userdirectory/UserListViewState.kt

@@ -28,24 +28,28 @@ data class UserListViewState(
         val knownUsers: Async<PagedList<User>> = Uninitialized,
         val directoryUsers: Async<List<User>> = Uninitialized,
         val filteredMappedContacts: List<MappedContact> = emptyList(),
-        val pendingInvitees: Set<PendingInvitee> = emptySet(),
+        val pendingSelections: Set<PendingSelection> = emptySet(),
-        val createAndInviteState: Async<String> = Uninitialized,
         val searchTerm: String = "",
         val myUserId: String = "",
-        val existingRoomId: String? = null
+        val singleSelection: Boolean,
+        private val showInviteActions: Boolean
 ) : MvRxState {
 
     constructor(args: UserListFragmentArgs) : this(
-            existingRoomId = args.existingRoomId
+            singleSelection = args.singleSelection,
+            showInviteActions = args.showInviteActions
     )
 
     fun getSelectedMatrixId(): List<String> {
-        return pendingInvitees
+        return pendingSelections
                 .mapNotNull {
                     when (it) {
-                        is PendingInvitee.UserPendingInvitee -> it.user.userId
+                        is PendingSelection.UserPendingSelection     -> it.user.userId
-                        is PendingInvitee.ThreePidPendingInvitee -> null
+                        is PendingSelection.ThreePidPendingSelection -> null
                     }
                 }
     }
+    
+    fun showInviteActions() = showInviteActions && pendingSelections.isEmpty()
+
 }

vector/src/main/res/drawable/ic_call_transfer.xml

@@ -0,0 +1,17 @@
+<vector xmlns:android="http://schemas.android.com/apk/res/android"
+    android:width="24dp"
+    android:height="24dp"
+    android:viewportWidth="24"
+    android:viewportHeight="24">
+  <group>
+    <clip-path
+        android:pathData="M0,0h24v24h-24z"/>
+    <path
+        android:pathData="M8.027,15.9613C9.168,17.1932 11.9148,19.3263 12.6635,19.7641C12.7078,19.79 12.7585,19.8201 12.8152,19.8538C13.9576,20.5329 17.5373,22.6609 20.1454,20.6694C22.1661,19.1266 21.5091,17.3909 20.8289,16.875C20.3633,16.5128 18.9914,15.5145 17.7006,14.6152C16.4331,13.7322 15.7268,14.4397 15.2492,14.918C15.2404,14.9268 15.2317,14.9355 15.2231,14.9442L14.2621,15.9051C14.0174,16.1498 13.6451,16.0605 13.2886,15.7804C12.0092,14.8061 11.0681,13.8659 10.5972,13.395L10.5933,13.391C10.1225,12.9202 9.1939,11.9908 8.2196,10.7114C7.9395,10.3548 7.8502,9.9826 8.0949,9.7379L9.0559,8.7769C9.0645,8.7683 9.0732,8.7596 9.082,8.7508C9.5603,8.2732 10.2678,7.5668 9.3848,6.2994C8.4855,5.0086 7.4872,3.6367 7.125,3.1711C6.6091,2.4909 4.8734,1.8339 3.3306,3.8546C1.3391,6.4627 3.4671,10.0424 4.1462,11.1848C4.1799,11.2415 4.2101,11.2922 4.2359,11.3365C4.6737,12.0851 6.7951,14.8203 8.027,15.9613Z"
+        android:fillColor="#C1C6CD"/>
+    <path
+        android:pathData="M13.3084,9.7333C12.9179,10.1238 12.9179,10.757 13.3084,11.1475C13.6989,11.538 14.3321,11.538 14.7226,11.1475L20.4401,5.43L20.4401,9.9101C20.4401,10.4624 20.8878,10.9101 21.4401,10.9101C21.9924,10.9101 22.4401,10.4624 22.4401,9.9101L22.4401,3.0158C22.4401,2.4635 21.9924,2.0158 21.4401,2.0158H14.5458C13.9935,2.0158 13.5458,2.4635 13.5458,3.0158C13.5458,3.5681 13.9935,4.0158 14.5458,4.0158L19.0259,4.0158L13.3084,9.7333Z"
+        android:fillColor="#C1C6CD"
+        android:fillType="evenOdd"/>
+  </group>
+</vector>

vector/src/main/res/layout/activity_call_transfer.xml

@@ -0,0 +1,73 @@
+<?xml version="1.0" encoding="utf-8"?>
+<androidx.coordinatorlayout.widget.CoordinatorLayout xmlns:android="http://schemas.android.com/apk/res/android"
+    xmlns:app="http://schemas.android.com/apk/res-auto"
+    android:id="@+id/vector_coordinator_layout"
+    android:layout_width="match_parent"
+    android:layout_height="match_parent">
+
+    <androidx.constraintlayout.widget.ConstraintLayout
+        android:layout_width="match_parent"
+        android:layout_height="match_parent">
+
+        <androidx.appcompat.widget.Toolbar
+            android:id="@+id/callTransferToolbar"
+            style="@style/VectorToolbarStyle"
+            android:layout_width="match_parent"
+            android:layout_height="wrap_content"
+            android:elevation="4dp"
+            app:layout_constraintTop_toTopOf="parent" />
+
+        <androidx.fragment.app.FragmentContainerView
+            android:id="@+id/callTransferFragmentContainer"
+            android:layout_width="0dp"
+            android:layout_height="0dp"
+            app:layout_constraintBottom_toTopOf="@+id/callTransferActionsLayout"
+            app:layout_constraintEnd_toEndOf="parent"
+            app:layout_constraintStart_toStartOf="parent"
+            app:layout_constraintTop_toBottomOf="@id/callTransferToolbar" />
+
+        <RelativeLayout
+            android:background="?riotx_header_panel_background"
+            android:id="@+id/callTransferActionsLayout"
+            android:layout_width="match_parent"
+            android:paddingVertical="8dp"
+            android:paddingHorizontal="16dp"
+            app:layout_constraintBottom_toBottomOf="parent"
+            app:layout_constraintStart_toStartOf="parent"
+            app:layout_constraintStart_toEndOf="parent"
+            android:layout_height="wrap_content">
+
+            <CheckBox
+                android:id="@+id/callTransferConsultCheckBox"
+                android:layout_width="wrap_content"
+                android:layout_centerVertical="true"
+                android:layout_alignParentStart="true"
+                android:layout_height="wrap_content"/>
+
+            <TextView
+                android:id="@+id/callTransferConsultTitle"
+                android:layout_width="wrap_content"
+                android:layout_height="wrap_content"
+                android:layout_centerVertical="true"
+                android:layout_toEndOf="@id/callTransferConsultCheckBox"
+                android:layout_toStartOf="@+id/callTransferConnectAction"
+                android:layout_marginEnd="8dp"
+                android:ellipsize="end"
+                android:text="@string/call_transfer_consult_first" />
+
+            <Button
+                android:id="@+id/callTransferConnectAction"
+                style="@style/VectorButtonStyleText"
+                android:layout_width="wrap_content"
+                android:layout_centerVertical="true"
+                android:layout_alignParentEnd="true"
+                android:text="@string/call_transfer_connect_action"
+                android:layout_height="wrap_content"/>
+
+        </RelativeLayout>
+
+
+        <include layout="@layout/merge_overlay_waiting_view" />
+
+    </androidx.constraintlayout.widget.ConstraintLayout>
+</androidx.coordinatorlayout.widget.CoordinatorLayout>

vector/src/main/res/layout/bottom_sheet_call_controls.xml

@@ -44,4 +44,13 @@
         app:tint="?attr/riotx_text_primary"
         tools:actionDescription="" />
 
+    <im.vector.app.core.ui.views.BottomSheetActionButton
+        android:id="@+id/callControlsTransfer"
+        android:layout_width="match_parent"
+        android:layout_height="wrap_content"
+        app:actionTitle="@string/call_transfer_title"
+        app:leftIcon="@drawable/ic_call_transfer"
+        app:tint="?attr/riotx_text_primary"
+        tools:actionDescription="" />
+
 </LinearLayout>

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

@@ -2782,5 +2782,9 @@
     <string name="call_active_and_multiple_paused">1 active call (%1$s) · %2$d paused calls</string>
     <string name="call_only_multiple_paused">%1$d paused calls</string>
 
+    <string name="call_transfer_consult_first">Consult first</string>
+    <string name="call_transfer_connect_action">Connect</string>
+    <string name="call_transfer_title">Transfer</string>
+
 
 </resources>