node list view kinda works

app/build.gradle

@@ -77,6 +77,8 @@ dependencies {
     implementation 'androidx.appcompat:appcompat:1.1.0'
     implementation 'androidx.core:core-ktx:1.2.0'
     implementation "androidx.fragment:fragment-ktx:1.2.4"
+    implementation 'androidx.cardview:cardview:1.0.0'
+    implementation 'androidx.recyclerview:recyclerview:1.1.0'
     implementation 'androidx.constraintlayout:constraintlayout:2.0.0-beta4'
     implementation 'com.google.android.material:material:1.1.0'
     implementation 'androidx.viewpager2:viewpager2:1.0.0'

app/src/main/java/com/geeksville/mesh/MainActivity.kt

@@ -30,6 +30,7 @@ import com.geeksville.mesh.model.UIViewModel
 import com.geeksville.mesh.service.*
 import com.geeksville.mesh.ui.ChannelFragment
 import com.geeksville.mesh.ui.MapFragment
+import com.geeksville.mesh.ui.UsersFragment
 import com.geeksville.util.Exceptions
 import com.geeksville.util.exceptionReporter
 import com.google.android.gms.auth.api.signin.GoogleSignIn
@@ -112,6 +113,11 @@ class MainActivity : AppCompatActivity(), Logging,
 
     // private val tabIndexes = generateSequence(0) { it + 1 } FIXME, instead do withIndex or zip? to get the ids below, also stop duplicating strings
     private val tabInfos = arrayOf(
+        TabInfo(
+            "Users",
+            R.drawable.ic_twotone_people_24,
+            UsersFragment()
+        ),
         TabInfo(
             "Channel",
             R.drawable.ic_twotone_contactless_24,
@@ -128,10 +134,7 @@ class MainActivity : AppCompatActivity(), Logging,
             R.drawable.ic_twotone_message_24,
             ComposeFragment("Messages", 1) { MessagesContent() }),
 
-        TabInfo(
-            "Users",
-            R.drawable.ic_twotone_people_24,
-            ComposeFragment("Users", 3) { UsersContent() }),
+
         TabInfo(
             "Settings",
             R.drawable.ic_twotone_settings_applications_24,
@@ -470,9 +473,12 @@ class MainActivity : AppCompatActivity(), Logging,
         ServiceClient<com.geeksville.mesh.IMeshService>({
             com.geeksville.mesh.IMeshService.Stub.asInterface(it)
         }) {
-        override fun onConnected(service: com.geeksville.mesh.IMeshService) {
+        override fun onConnected(service: com.geeksville.mesh.IMeshService) = exceptionReporter {
             model.meshService = service
 
+            debug("Getting latest radioconfig from service")
+            model.radioConfig.value = MeshProtos.RadioConfig.parseFrom(service.radioConfig)
+
             // We don't start listening for packets until after we are connected to the service
             registerMeshReceiver()
 

app/src/main/java/com/geeksville/mesh/model/UIState.kt

@@ -59,22 +59,6 @@ class UIViewModel : ViewModel(), Logging {
 
     /// various radio settings (including the channel)
     val radioConfig = object : MutableLiveData<MeshProtos.RadioConfig?>(null) {
-        /**
-         * Called when the number of active observers change to 1 from 0.
-         *
-         *
-         * This callback can be used to know that this LiveData is being used thus should be kept
-         * up to date.
-         */
-        override fun onActive() {
-            super.onActive()
-
-            // Get the current radio config from the service
-            meshService?.let {
-                debug("Getting latest radioconfig from service")
-                value = MeshProtos.RadioConfig.parseFrom(it.radioConfig)
-            }
-        }
     }
 
     override fun onCleared() {

app/src/main/java/com/geeksville/mesh/ui/ChannelFragment.kt

@@ -17,9 +17,6 @@ import com.google.android.material.snackbar.Snackbar
 import kotlinx.android.synthetic.main.channel_fragment.*
 
 
-object ChannelLog : Logging
-
-
 class ChannelFragment : ScreenFragment("Channel"), Logging {
 
     private val model: UIViewModel by activityViewModels()
@@ -67,7 +64,7 @@ class ChannelFragment : ScreenFragment("Channel"), Logging {
                 channelNameEdit.visibility = View.VISIBLE
                 channelNameEdit.setText(channel.name)
                 editableCheckbox.isEnabled = true
-                
+
                 qrView.setImageBitmap(channel.getChannelQR())
                 // Share this particular channel if someone clicks share
                 shareButton.setOnClickListener {

app/src/main/java/com/geeksville/mesh/ui/Users.kt

@@ -1,24 +1,133 @@
 package com.geeksville.mesh.ui
 
-/*
-import androidx.compose.Composable
-import androidx.ui.core.ContextAmbient
-import androidx.ui.foundation.Text
-import androidx.ui.layout.Column
-import androidx.ui.layout.LayoutPadding
-import androidx.ui.layout.Row
-import androidx.ui.material.Button
-import androidx.ui.unit.dp
+
+import android.os.Bundle
+import android.view.LayoutInflater
+import android.view.View
+import android.view.ViewGroup
+import androidx.fragment.app.activityViewModels
+import androidx.lifecycle.Observer
+import androidx.recyclerview.widget.LinearLayoutManager
+import androidx.recyclerview.widget.RecyclerView
+import com.geeksville.android.Logging
+import com.geeksville.mesh.NodeInfo
 import com.geeksville.mesh.R
-import com.geeksville.mesh.model.NodeDB
-import com.geeksville.mesh.model.UIState
-import com.geeksville.mesh.service.MeshService
-import com.geeksville.mesh.service.RadioInterfaceService
-import com.geeksville.mesh.service.SoftwareUpdateService
+import com.geeksville.mesh.model.UIViewModel
+import kotlinx.android.synthetic.main.adapter_node_layout.view.*
+import kotlinx.android.synthetic.main.nodelist_fragment.*
 
 
+class UsersFragment : ScreenFragment("Users"), Logging {
+
+    private val model: UIViewModel by activityViewModels()
+
+    // Provide a direct reference to each of the views within a data item
+    // Used to cache the views within the item layout for fast access
+    class ViewHolder(itemView: View) : RecyclerView.ViewHolder(itemView) {
+        val nodeNameView = itemView.nodeNameView
+    }
+
+    private val nodesAdapter = object : RecyclerView.Adapter<ViewHolder>() {
+
+        /**
+         * Called when RecyclerView needs a new [ViewHolder] of the given type to represent
+         * an item.
+         *
+         *
+         * This new ViewHolder should be constructed with a new View that can represent the items
+         * of the given type. You can either create a new View manually or inflate it from an XML
+         * layout file.
+         *
+         *
+         * The new ViewHolder will be used to display items of the adapter using
+         * [.onBindViewHolder]. Since it will be re-used to display
+         * different items in the data set, it is a good idea to cache references to sub views of
+         * the View to avoid unnecessary [View.findViewById] calls.
+         *
+         * @param parent The ViewGroup into which the new View will be added after it is bound to
+         * an adapter position.
+         * @param viewType The view type of the new View.
+         *
+         * @return A new ViewHolder that holds a View of the given view type.
+         * @see .getItemViewType
+         * @see .onBindViewHolder
+         */
+        override fun onCreateViewHolder(parent: ViewGroup, viewType: Int): ViewHolder {
+            val inflater = LayoutInflater.from(requireContext())
+
+            // Inflate the custom layout
+
+            // Inflate the custom layout
+            val contactView: View = inflater.inflate(R.layout.adapter_node_layout, parent, false)
+
+            // Return a new holder instance
+            return ViewHolder(contactView)
+        }
+
+        /**
+         * Returns the total number of items in the data set held by the adapter.
+         *
+         * @return The total number of items in this adapter.
+         */
+        override fun getItemCount(): Int = nodes.size
+
+        /**
+         * Called by RecyclerView to display the data at the specified position. This method should
+         * update the contents of the [ViewHolder.itemView] to reflect the item at the given
+         * position.
+         *
+         *
+         * Note that unlike [android.widget.ListView], RecyclerView will not call this method
+         * again if the position of the item changes in the data set unless the item itself is
+         * invalidated or the new position cannot be determined. For this reason, you should only
+         * use the `position` parameter while acquiring the related data item inside
+         * this method and should not keep a copy of it. If you need the position of an item later
+         * on (e.g. in a click listener), use [ViewHolder.getAdapterPosition] which will
+         * have the updated adapter position.
+         *
+         * Override [.onBindViewHolder] instead if Adapter can
+         * handle efficient partial bind.
+         *
+         * @param holder The ViewHolder which should be updated to represent the contents of the
+         * item at the given position in the data set.
+         * @param position The position of the item within the adapter's data set.
+         */
+        override fun onBindViewHolder(holder: ViewHolder, position: Int) {
+            val n = nodes[position]
+
+            holder.nodeNameView.text = n.user?.longName ?: n.user?.id ?: "Unknown node"
+        }
+
+        private var nodes = arrayOf<NodeInfo>()
+
+        /// Called when our node DB changes
+        fun onNodesChanged(nodesIn: Collection<NodeInfo>) {
+            nodes = nodesIn.toTypedArray()
+            notifyDataSetChanged() // FIXME, this is super expensive and redraws all nodes
+        }
+    }
+
+    override fun onCreateView(
+        inflater: LayoutInflater, container: ViewGroup?,
+        savedInstanceState: Bundle?
+    ): View? {
+        return inflater.inflate(R.layout.nodelist_fragment, container, false)
+    }
+
+    override fun onViewCreated(view: View, savedInstanceState: Bundle?) {
+        super.onViewCreated(view, savedInstanceState)
+
+        nodeListView.adapter = nodesAdapter
+        nodeListView.layoutManager = LinearLayoutManager(requireContext())
+
+        model.nodeDB.nodes.observe(viewLifecycleOwner, Observer { it ->
+            nodesAdapter.onNodesChanged(it.values)
+        })
+    }
+}
 
 
+/*
 @Composable
 fun UsersContent() {
     Column {

app/src/main/res/layout/adapter_node_layout.xml

@@ -0,0 +1,25 @@
+<?xml version="1.0" encoding="utf-8"?>
+<com.google.android.material.card.MaterialCardView xmlns:android="http://schemas.android.com/apk/res/android"
+    xmlns:app="http://schemas.android.com/apk/res-auto"
+    style="@style/Widget.App.CardView"
+    android:layout_width="match_parent"
+    android:layout_height="wrap_content"
+    app:cardCornerRadius="5dp">
+
+    <androidx.constraintlayout.widget.ConstraintLayout
+        android:layout_width="match_parent"
+        android:layout_height="wrap_content">
+
+        <TextView
+            android:id="@+id/nodeNameView"
+            android:layout_width="wrap_content"
+            android:layout_height="wrap_content"
+            android:layout_marginStart="16dp"
+            android:layout_marginTop="16dp"
+            android:layout_marginBottom="16dp"
+            android:text="Unknown Username"
+            app:layout_constraintBottom_toBottomOf="parent"
+            app:layout_constraintStart_toStartOf="parent"
+            app:layout_constraintTop_toTopOf="parent" />
+    </androidx.constraintlayout.widget.ConstraintLayout>
+</com.google.android.material.card.MaterialCardView>

app/src/main/res/layout/nodelist_fragment.xml

@@ -0,0 +1,19 @@
+<?xml version="1.0" encoding="utf-8"?>
+<androidx.constraintlayout.widget.ConstraintLayout xmlns:android="http://schemas.android.com/apk/res/android"
+    xmlns:app="http://schemas.android.com/apk/res-auto"
+    android:layout_width="match_parent"
+    android:layout_height="match_parent">
+
+    <androidx.recyclerview.widget.RecyclerView
+        android:id="@+id/nodeListView"
+        android:layout_width="match_parent"
+        android:layout_height="match_parent"
+        android:layout_marginStart="8dp"
+        android:layout_marginTop="8dp"
+        android:layout_marginEnd="8dp"
+        android:layout_marginBottom="8dp"
+        app:layout_constraintBottom_toBottomOf="parent"
+        app:layout_constraintEnd_toEndOf="parent"
+        app:layout_constraintStart_toStartOf="parent"
+        app:layout_constraintTop_toTopOf="parent" />
+</androidx.constraintlayout.widget.ConstraintLayout>

app/src/main/res/values/styles.xml

@@ -28,4 +28,5 @@
         <item name="android:minHeight">48dp</item>
     </style>
 
+    <style name="Widget.App.CardView" parent="Widget.MaterialComponents.CardView"></style>
 </resources>