Add split pane UI for new conversation screen.

app/src/main/java/org/thoughtcrime/securesms/conversation/NewConversationActivityV2.kt

@@ -0,0 +1,152 @@
+/*
+ * Copyright 2025 Signal Messenger, LLC
+ * SPDX-License-Identifier: AGPL-3.0-only
+ */
+
+package org.thoughtcrime.securesms.conversation
+
+import android.content.Context
+import android.content.Intent
+import android.os.Bundle
+import androidx.activity.compose.setContent
+import androidx.compose.foundation.layout.Box
+import androidx.compose.foundation.layout.fillMaxSize
+import androidx.compose.foundation.layout.padding
+import androidx.compose.foundation.layout.widthIn
+import androidx.compose.material3.ExperimentalMaterial3Api
+import androidx.compose.material3.MaterialTheme
+import androidx.compose.material3.Text
+import androidx.compose.material3.adaptive.ExperimentalMaterial3AdaptiveApi
+import androidx.compose.runtime.Composable
+import androidx.compose.runtime.getValue
+import androidx.compose.ui.Alignment
+import androidx.compose.ui.Modifier
+import androidx.compose.ui.graphics.vector.ImageVector
+import androidx.compose.ui.res.stringResource
+import androidx.compose.ui.res.vectorResource
+import androidx.compose.ui.unit.dp
+import androidx.lifecycle.compose.collectAsStateWithLifecycle
+import org.signal.core.ui.compose.AllDevicePreviews
+import org.signal.core.ui.compose.Previews
+import org.signal.core.ui.compose.Scaffolds
+import org.signal.core.ui.compose.theme.SignalTheme
+import org.thoughtcrime.securesms.PassphraseRequiredActivity
+import org.thoughtcrime.securesms.R
+import org.thoughtcrime.securesms.components.compose.ScreenTitlePane
+import org.thoughtcrime.securesms.util.viewModel
+import org.thoughtcrime.securesms.window.AppScaffoldWithTopBar
+import org.thoughtcrime.securesms.window.WindowSizeClass
+import org.thoughtcrime.securesms.window.rememberAppScaffoldNavigator
+
+/**
+ * Allows the user to start a new conversation by selecting a recipient.
+ *
+ * A modernized compose-based replacement for [org.thoughtcrime.securesms.NewConversationActivity].
+ */
+class NewConversationActivityV2 : PassphraseRequiredActivity() {
+  companion object {
+    @JvmStatic
+    fun createIntent(context: Context): Intent = Intent(context, NewConversationActivityV2::class.java)
+  }
+
+  private val viewModel by viewModel { NewConversationViewModel() }
+
+  override fun onCreate(savedInstanceState: Bundle?, ready: Boolean) {
+    super.onCreate(savedInstanceState, ready)
+
+    setContent {
+      val uiState by viewModel.uiState.collectAsStateWithLifecycle()
+
+      SignalTheme {
+        NewConversationScreen(
+          uiState = uiState,
+          callbacks = object : Callbacks {
+            override fun onBackPressed() = onBackPressedDispatcher.onBackPressed()
+          }
+        )
+      }
+    }
+  }
+}
+
+@OptIn(ExperimentalMaterial3Api::class, ExperimentalMaterial3AdaptiveApi::class)
+@Composable
+private fun NewConversationScreen(
+  uiState: NewConversationUiState,
+  callbacks: Callbacks
+) {
+  val windowSizeClass = WindowSizeClass.rememberWindowSizeClass()
+  val isSplitPane = windowSizeClass.isSplitPane(forceSplitPaneOnCompactLandscape = uiState.forceSplitPaneOnCompactLandscape)
+
+  AppScaffoldWithTopBar(
+    topBarContent = {
+      Scaffolds.DefaultTopAppBar(
+        title = if (!isSplitPane) stringResource(R.string.NewConversationActivity__new_message) else "",
+        titleContent = { _, title -> Text(text = title, style = MaterialTheme.typography.titleLarge) },
+        navigationIcon = ImageVector.vectorResource(R.drawable.symbol_arrow_start_24),
+        navigationContentDescription = stringResource(R.string.DefaultTopAppBar__navigate_up_content_description),
+        onNavigationClick = callbacks::onBackPressed
+      )
+    },
+    listContent = {
+      if (isSplitPane) {
+        ScreenTitlePane(
+          title = stringResource(R.string.NewConversationActivity__new_message),
+          modifier = Modifier.fillMaxSize()
+        )
+      } else {
+        DetailPaneContent()
+      }
+    },
+
+    detailContent = {
+      Box(
+        contentAlignment = Alignment.Center,
+        modifier = Modifier.fillMaxSize()
+      ) {
+        DetailPaneContent(
+          modifier = Modifier
+            .widthIn(max = windowSizeClass.detailPaneMaxContentWidth)
+        )
+      }
+    },
+
+    navigator = rememberAppScaffoldNavigator(
+      isSplitPane = isSplitPane
+    )
+  )
+}
+
+private interface Callbacks {
+  fun onBackPressed()
+
+  object Empty : Callbacks {
+    override fun onBackPressed() = Unit
+  }
+}
+
+@Composable
+private fun DetailPaneContent(
+  modifier: Modifier = Modifier
+) {
+  RecipientPicker(
+    showFindByUsernameAndPhoneOptions = true,
+    callbacks = RecipientPickerCallbacks.Empty, // TODO(jeffrey) implement callbacks
+    modifier = modifier
+      .fillMaxSize()
+      .padding(vertical = 12.dp)
+  )
+}
+
+@AllDevicePreviews
+@Composable
+private fun NewConversationScreenPreview() {
+  Previews.Preview {
+    NewConversationScreen(
+      uiState = NewConversationUiState(
+        forceSplitPaneOnCompactLandscape = false
+      ),
+      callbacks = Callbacks.Empty
+    )
+  }
+}

app/src/main/java/org/thoughtcrime/securesms/conversation/NewConversationViewModel.kt

@@ -0,0 +1,21 @@
+/*
+ * Copyright 2025 Signal Messenger, LLC
+ * SPDX-License-Identifier: AGPL-3.0-only
+ */
+
+package org.thoughtcrime.securesms.conversation
+
+import androidx.lifecycle.ViewModel
+import kotlinx.coroutines.flow.MutableStateFlow
+import kotlinx.coroutines.flow.StateFlow
+import kotlinx.coroutines.flow.asStateFlow
+import org.thoughtcrime.securesms.keyvalue.SignalStore
+
+class NewConversationViewModel : ViewModel() {
+  private val _uiState = MutableStateFlow(NewConversationUiState())
+  val uiState: StateFlow<NewConversationUiState> = _uiState.asStateFlow()
+}
+
+data class NewConversationUiState(
+  val forceSplitPaneOnCompactLandscape: Boolean = SignalStore.internal.forceSplitPaneOnCompactLandscape
+)

app/src/main/java/org/thoughtcrime/securesms/conversation/RecipientPicker.kt

@@ -0,0 +1,155 @@
+/*
+ * Copyright 2025 Signal Messenger, LLC
+ * SPDX-License-Identifier: AGPL-3.0-only
+ */
+
+package org.thoughtcrime.securesms.conversation
+
+import androidx.annotation.StringRes
+import androidx.compose.foundation.layout.Column
+import androidx.compose.foundation.layout.fillMaxSize
+import androidx.compose.foundation.layout.fillMaxWidth
+import androidx.compose.foundation.layout.padding
+import androidx.compose.runtime.Composable
+import androidx.compose.runtime.DisposableEffect
+import androidx.compose.runtime.LaunchedEffect
+import androidx.compose.runtime.getValue
+import androidx.compose.runtime.mutableStateOf
+import androidx.compose.runtime.remember
+import androidx.compose.runtime.saveable.rememberSaveable
+import androidx.compose.runtime.setValue
+import androidx.compose.ui.Modifier
+import androidx.compose.ui.platform.LocalContext
+import androidx.compose.ui.unit.dp
+import androidx.compose.ui.viewinterop.AndroidView
+import androidx.fragment.compose.rememberFragmentState
+import org.signal.core.ui.compose.DayNightPreviews
+import org.signal.core.ui.compose.Fragments
+import org.thoughtcrime.securesms.ContactSelectionListFragment
+import org.thoughtcrime.securesms.components.ContactFilterView
+import org.thoughtcrime.securesms.recipients.RecipientId
+
+/**
+ * Provides a recipient search and selection UI.
+ */
+@Composable
+fun RecipientPicker(
+  showFindByUsernameAndPhoneOptions: Boolean,
+  callbacks: RecipientPickerCallbacks,
+  modifier: Modifier = Modifier
+) {
+  var searchQuery by rememberSaveable { mutableStateOf("") }
+
+  Column(
+    modifier = modifier
+  ) {
+    RecipientSearchField(
+      onFilterChanged = { filter ->
+        searchQuery = filter
+      },
+      modifier = Modifier
+        .fillMaxWidth()
+        .padding(horizontal = 16.dp)
+    )
+
+    RecipientSearchResultsList(
+      searchQuery = searchQuery,
+      showFindByUsernameAndPhoneOptions = showFindByUsernameAndPhoneOptions,
+      callbacks = callbacks,
+      modifier = Modifier
+        .fillMaxSize()
+        .padding(top = 8.dp)
+    )
+  }
+}
+
+/**
+ * A search input field for finding recipients.
+ *
+ * Intended to be a compose-based replacement for [ContactFilterView].
+ */
+@Composable
+private fun RecipientSearchField(
+  onFilterChanged: (String) -> Unit,
+  @StringRes hintText: Int? = null,
+  modifier: Modifier = Modifier
+) {
+  val context = LocalContext.current
+  val wrappedView = remember {
+    ContactFilterView(context, null, 0).apply {
+      hintText?.let { setHint(it) }
+    }
+  }
+
+  DisposableEffect(onFilterChanged) {
+    wrappedView.setOnFilterChangedListener { filter -> onFilterChanged(filter) }
+    onDispose {
+      wrappedView.setOnFilterChangedListener(null)
+    }
+  }
+
+  AndroidView(
+    factory = { wrappedView },
+    modifier = modifier
+  )
+}
+
+@Composable
+private fun RecipientSearchResultsList(
+  searchQuery: String,
+  showFindByUsernameAndPhoneOptions: Boolean,
+  callbacks: RecipientPickerCallbacks,
+  modifier: Modifier = Modifier
+) {
+  val fragmentState = rememberFragmentState()
+  var currentFragment by remember { mutableStateOf<ContactSelectionListFragment?>(null) }
+
+  Fragments.Fragment<ContactSelectionListFragment>(
+    fragmentState = fragmentState,
+    onUpdate = { fragment ->
+      currentFragment = fragment
+      currentFragment?.view?.setPadding(0, 0, 0, 0)
+
+      if (showFindByUsernameAndPhoneOptions) {
+        fragment.showFindByUsernameAndPhoneOptions(object : ContactSelectionListFragment.FindByCallback {
+          override fun onFindByUsername() = callbacks.onFindByUsernameClicked()
+          override fun onFindByPhoneNumber() = callbacks.onFindByPhoneNumberClicked()
+        })
+      }
+    },
+    modifier = modifier
+  )
+
+  var previousQueryText by rememberSaveable { mutableStateOf("") }
+  LaunchedEffect(searchQuery) {
+    if (previousQueryText != searchQuery) {
+      if (searchQuery.isNotBlank()) {
+        currentFragment?.setQueryFilter(searchQuery)
+      } else {
+        currentFragment?.resetQueryFilter()
+      }
+      previousQueryText = searchQuery
+    }
+  }
+}
+
+@DayNightPreviews
+@Composable
+private fun RecipientPickerPreview() {
+  RecipientPicker(
+    showFindByUsernameAndPhoneOptions = true,
+    callbacks = RecipientPickerCallbacks.Empty
+  )
+}
+
+interface RecipientPickerCallbacks {
+  fun onFindByUsernameClicked()
+  fun onFindByPhoneNumberClicked()
+  fun onRecipientClicked(id: RecipientId)
+
+  object Empty : RecipientPickerCallbacks {
+    override fun onFindByUsernameClicked() = Unit
+    override fun onFindByPhoneNumberClicked() = Unit
+    override fun onRecipientClicked(id: RecipientId) = Unit
+  }
+}