android: move node search to background and fix avatar padding (#574)

android: use background search and fix avatar padding

fixes tailscale/corp#24847
fixes tailsacle/corp#24848

Search jobs are moved to the default dispatcher so they
do not block the UI thread.

The avatar boxing is now used only conditionally on AndroidTV.

Signed-off-by: Jonathan Nobels <jonathan@tailscale.com>

android/src/main/java/com/tailscale/ipn/App.kt

@@ -163,7 +163,7 @@ class App : UninitializedApp(), libtailscale.AppContext, ViewModelStoreOwner {
     NetworkChangeCallback.monitorDnsChanges(connectivityManager, dns)
     initViewModels()
     applicationScope.launch {
-      Notifier.state.collect { state ->
+      Notifier.state.collect { _ ->
         combine(Notifier.state, MDMSettings.forceEnabled.flow) { state, forceEnabled ->
               Pair(state, forceEnabled)
             }

android/src/main/java/com/tailscale/ipn/ui/util/ModifierUtil.kt

@@ -0,0 +1,18 @@
+// Copyright (c) Tailscale Inc & AUTHORS
+// SPDX-License-Identifier: BSD-3-Clause
+
+package com.tailscale.ipn.ui.util
+
+import androidx.compose.ui.Modifier
+
+/// Applies different modifiers to the receiver based on a condition.
+inline fun Modifier.conditional(
+    condition: Boolean,
+    ifTrue: Modifier.() -> Modifier,
+    ifFalse: Modifier.() -> Modifier = { this },
+): Modifier =
+    if (condition) {
+      then(ifTrue(Modifier))
+    } else {
+      then(ifFalse(Modifier))
+    }

android/src/main/java/com/tailscale/ipn/ui/view/Avatar.kt

@@ -31,6 +31,8 @@ import coil.annotation.ExperimentalCoilApi
 import coil.compose.AsyncImage
 import com.tailscale.ipn.R
 import com.tailscale.ipn.ui.model.IpnLocal
+import com.tailscale.ipn.ui.util.AndroidTVUtil
+import com.tailscale.ipn.ui.util.conditional
 
 @OptIn(ExperimentalCoilApi::class)
 @Composable
@@ -46,17 +48,18 @@ fun Avatar(
   // Outer Box for the larger focusable and clickable area
   Box(
       contentAlignment = Alignment.Center,
-        modifier = Modifier
-            .padding(4.dp) 
-            .size((size * 1.5f).dp) // Focusable area is larger than the avatar
+      modifier =
+          Modifier.conditional(AndroidTVUtil.isAndroidTV(), { padding(4.dp) })
+              .conditional(
+                  AndroidTVUtil.isAndroidTV(),
+                  {
+                    size((size * 1.5f).dp) // Focusable area is larger than the avatar
+                  })
               .clip(CircleShape) // Ensure both the focus and click area are circular
               .background(
-                if (isFocused.value) MaterialTheme.colorScheme.surface
-                else Color.Transparent, 
+                  if (isFocused.value) MaterialTheme.colorScheme.surface else Color.Transparent,
               )
-            .onFocusChanged { focusState ->
-                isFocused.value = focusState.isFocused 
-            }
+              .onFocusChanged { focusState -> isFocused.value = focusState.isFocused }
               .focusable() // Make this outer Box focusable (after onFocusChanged)
               .clickable(
                   interactionSource = remember { MutableInteractionSource() },
@@ -64,22 +67,17 @@ fun Avatar(
                   onClick = {
                     action?.invoke()
                     focusManager.clearFocus() // Clear focus after clicking the avatar
-                }
-            )
-    ) {
+                  })) {
         // Inner Box to hold the avatar content (Icon or AsyncImage)
         Box(
             contentAlignment = Alignment.Center,
-            modifier = Modifier
-                .size(size.dp)
-                .clip(CircleShape) 
-        ) { 
+            modifier = Modifier.size(size.dp).clip(CircleShape)) {
               // Always display the default icon as a background layer
               Icon(
                   imageVector = Icons.Default.Person,
                   contentDescription = stringResource(R.string.settings_title),
                   modifier =
-                  Modifier.size((size * 0.8f).dp)
+                      Modifier.conditional(AndroidTVUtil.isAndroidTV(), { size((size * 0.8f).dp) })
                           .clip(CircleShape) // Icon size slightly smaller than the Box
                   )
 

android/src/main/java/com/tailscale/ipn/ui/viewModel/MainViewModel.kt

@@ -23,7 +23,9 @@ import com.tailscale.ipn.ui.util.PeerCategorizer
 import com.tailscale.ipn.ui.util.PeerSet
 import com.tailscale.ipn.ui.util.TimeUtil
 import com.tailscale.ipn.ui.util.set
+import kotlinx.coroutines.Dispatchers
 import kotlinx.coroutines.FlowPreview
+import kotlinx.coroutines.Job
 import kotlinx.coroutines.flow.MutableStateFlow
 import kotlinx.coroutines.flow.StateFlow
 import kotlinx.coroutines.flow.combine
@@ -77,6 +79,8 @@ class MainViewModel(private val vpnViewModel: VpnViewModel) : IpnViewModel() {
 
   val isVpnActive: StateFlow<Boolean> = vpnViewModel.vpnActive
 
+  var searchJob: Job? = null
+
   // Icon displayed in the button to present the health view
   val healthIcon: StateFlow<Int?> = MutableStateFlow(null)
 
@@ -130,18 +134,25 @@ class MainViewModel(private val vpnViewModel: VpnViewModel) : IpnViewModel() {
 
     viewModelScope.launch {
       _searchTerm.debounce(250L).collect { term ->
+        // run the search as a background task
+        searchJob?.cancel()
+        searchJob =
+            launch(Dispatchers.Default) {
               val filteredPeers = peerCategorizer.groupedAndFilteredPeers(term)
               _peers.value = filteredPeers
             }
       }
+    }
 
     viewModelScope.launch {
       Notifier.netmap.collect { it ->
         it?.let { netmap ->
+          searchJob?.cancel()
+          launch(Dispatchers.Default) {
             peerCategorizer.regenerateGroupedPeers(netmap)
-
-          // Immediately update _peers with the full peer list
-          _peers.value = peerCategorizer.groupedAndFilteredPeers(searchTerm.value)
+            val filteredPeers = peerCategorizer.groupedAndFilteredPeers(searchTerm.value)
+            _peers.value = filteredPeers
+          }
 
           if (netmap.SelfNode.keyDoesNotExpire) {
             showExpiry.set(false)