Reimplement contact chips with a recyclerview.

app/src/main/java/org/thoughtcrime/securesms/contacts/ContactChipViewModel.kt

@@ -0,0 +1,72 @@
+package org.thoughtcrime.securesms.contacts
+
+import androidx.lifecycle.ViewModel
+import io.reactivex.rxjava3.android.schedulers.AndroidSchedulers
+import io.reactivex.rxjava3.core.BackpressureStrategy
+import io.reactivex.rxjava3.core.Flowable
+import io.reactivex.rxjava3.core.Single
+import io.reactivex.rxjava3.disposables.CompositeDisposable
+import io.reactivex.rxjava3.disposables.Disposable
+import io.reactivex.rxjava3.kotlin.plusAssign
+import io.reactivex.rxjava3.schedulers.Schedulers
+import org.thoughtcrime.securesms.dependencies.ApplicationDependencies
+import org.thoughtcrime.securesms.recipients.Recipient
+import org.thoughtcrime.securesms.recipients.RecipientId
+import org.thoughtcrime.securesms.util.rx.RxStore
+
+/**
+ * ViewModel expressly for displaying the current state of the contact chips
+ * in the contact selection fragment.
+ */
+class ContactChipViewModel : ViewModel() {
+
+  private val store = RxStore(emptyList<SelectedContacts.Model>())
+
+  val state: Flowable<List<SelectedContacts.Model>> = store.stateFlowable
+    .distinctUntilChanged()
+    .observeOn(AndroidSchedulers.mainThread())
+
+  val count = store.state.size
+
+  private val disposables = CompositeDisposable()
+  private val disposableMap: MutableMap<RecipientId, Disposable> = mutableMapOf()
+
+  override fun onCleared() {
+    disposables.clear()
+    disposableMap.values.forEach { it.dispose() }
+    disposableMap.clear()
+  }
+
+  fun add(selectedContact: SelectedContact) {
+    disposables += getOrCreateRecipientId(selectedContact).map { Recipient.resolved(it) }.observeOn(Schedulers.io()).subscribe { recipient ->
+      store.update { it + SelectedContacts.Model(selectedContact, recipient) }
+      disposableMap[recipient.id]?.dispose()
+      disposableMap[recipient.id] = store.update(recipient.live().asObservable().toFlowable(BackpressureStrategy.LATEST)) { changedRecipient, state ->
+        val index = state.indexOfFirst { it.selectedContact.matches(selectedContact) }
+        when {
+          index == 0 -> {
+            listOf(SelectedContacts.Model(selectedContact, changedRecipient)) + state.drop(index + 1)
+          }
+          index > 0 -> {
+            state.take(index) + SelectedContacts.Model(selectedContact, changedRecipient) + state.drop(index + 1)
+          }
+          else -> {
+            state
+          }
+        }
+      }
+    }
+  }
+
+  fun remove(selectedContact: SelectedContact) {
+    store.update { list ->
+      list.filterNot { it.selectedContact.matches(selectedContact) }
+    }
+  }
+
+  private fun getOrCreateRecipientId(selectedContact: SelectedContact): Single<RecipientId> {
+    return Single.fromCallable {
+      selectedContact.getOrCreateRecipientId(ApplicationDependencies.getApplication())
+    }
+  }
+}

app/src/main/java/org/thoughtcrime/securesms/contacts/SelectedContacts.kt

@@ -0,0 +1,42 @@
+package org.thoughtcrime.securesms.contacts
+
+import android.view.View
+import org.thoughtcrime.securesms.R
+import org.thoughtcrime.securesms.mms.GlideApp
+import org.thoughtcrime.securesms.recipients.Recipient
+import org.thoughtcrime.securesms.util.adapter.mapping.LayoutFactory
+import org.thoughtcrime.securesms.util.adapter.mapping.MappingAdapter
+import org.thoughtcrime.securesms.util.adapter.mapping.MappingModel
+import org.thoughtcrime.securesms.util.adapter.mapping.MappingViewHolder
+
+object SelectedContacts {
+  @JvmStatic
+  fun register(adapter: MappingAdapter, onCloseIconClicked: (Model) -> Unit) {
+    adapter.registerFactory(Model::class.java, LayoutFactory({ ViewHolder(it, onCloseIconClicked) }, R.layout.contact_selection_list_chip))
+  }
+
+  class Model(val selectedContact: SelectedContact, val recipient: Recipient) : MappingModel<Model> {
+    override fun areItemsTheSame(newItem: Model): Boolean {
+      return newItem.selectedContact.matches(selectedContact) && recipient == newItem.recipient
+    }
+
+    override fun areContentsTheSame(newItem: Model): Boolean {
+      return areItemsTheSame(newItem) && recipient.hasSameContent(newItem.recipient)
+    }
+  }
+
+  private class ViewHolder(itemView: View, private val onCloseIconClicked: (Model) -> Unit) : MappingViewHolder<Model>(itemView) {
+
+    private val chip: ContactChip = itemView.findViewById(R.id.contact_chip)
+
+    override fun bind(model: Model) {
+      chip.text = model.recipient.getShortDisplayName(context)
+      chip.setContact(model.selectedContact)
+      chip.isCloseIconVisible = true
+      chip.setOnCloseIconClickListener {
+        onCloseIconClicked(model)
+      }
+      chip.setAvatar(GlideApp.with(itemView), model.recipient, null)
+    }
+  }
+}