feat(ui): use Chrome Custom Tabs for explorer launches (#138)

android/app/build.gradle.kts

@@ -145,6 +145,9 @@ dependencies {
     implementation(libs.androidx.material.icons.extended)
     implementation(libs.androidx.navigation.compose)
     implementation(libs.compose.icons.lucide)
+    // Chrome Custom Tabs — keeps explorer-link round-trip inside the app's
+    // task so the OEM auth gate doesn't re-engage on return (#138).
+    implementation(libs.androidx.browser)
     debugImplementation(libs.androidx.ui.tooling)
 
     // Hilt

android/app/src/main/java/com/rjnr/pocketnode/ui/screens/activity/ActivityScreen.kt

@@ -278,11 +278,7 @@ fun ActivityScreen(
                         retryDialogTx = failed
                     },
                     onOpenExplorer = { url ->
-                        try {
-                            context.startActivity(Intent(Intent.ACTION_VIEW, Uri.parse(url)))
-                        } catch (e: android.content.ActivityNotFoundException) {
-                            // No browser available — silently ignore
-                        }
+                        com.rjnr.pocketnode.ui.util.openInBrowser(context, url)
                     }
                 )
             }

android/app/src/main/java/com/rjnr/pocketnode/ui/screens/home/HomeScreen.kt

@@ -178,9 +178,8 @@ fun HomeScreen(
     val onLookupBlockHeight: (() -> Unit)? = uiState.address.takeIf { it.isNotBlank() }?.let { addr ->
         {
             val url = buildExplorerAddressUrl(addr, uiState.currentNetwork)
-            try {
-                context.startActivity(Intent(Intent.ACTION_VIEW, Uri.parse(url)))
-            } catch (_: android.content.ActivityNotFoundException) {
+            // Custom Tabs first, falls back to ACTION_VIEW under the hood (#138).
+            if (!com.rjnr.pocketnode.ui.util.openInBrowser(context, url)) {
                 scope.launch {
                     snackbarHostState.showSnackbar("No browser available to open the explorer")
                 }
@@ -362,11 +361,7 @@ fun HomeScreen(
                 }
             },
             onOpenExplorer = { url ->
-                try {
-                    context.startActivity(Intent(Intent.ACTION_VIEW, Uri.parse(url)))
-                } catch (_: android.content.ActivityNotFoundException) {
-                    // No browser available
-                }
+                com.rjnr.pocketnode.ui.util.openInBrowser(context, url)
             },
             onRetry = { tx ->
                 selectedTransaction = null

android/app/src/main/java/com/rjnr/pocketnode/ui/screens/send/SendScreen.kt

@@ -821,16 +821,9 @@ fun TransactionStatusDialog(
                                     } else {
                                         "https://explorer.nervos.org/transaction/"
                                     }
-                                    try {
-                                        context.startActivity(
-                                            Intent(
-                                                Intent.ACTION_VIEW,
-                                                Uri.parse("$explorerBase$txHash")
-                                            )
-                                        )
-                                    } catch (e: android.content.ActivityNotFoundException) {
-                                        // No browser available — silently ignore
-                                    }
+                                    com.rjnr.pocketnode.ui.util.openInBrowser(
+                                        context, "$explorerBase$txHash",
+                                    )
                                 },
                                 contentPadding = PaddingValues(horizontal = 4.dp, vertical = 0.dp)
                             ) {

android/app/src/main/java/com/rjnr/pocketnode/ui/screens/settings/SettingsScreen.kt

@@ -179,9 +179,7 @@ fun SettingsScreen(
                 val url = com.rjnr.pocketnode.ui.screens.home.buildExplorerAddressUrl(
                     addr, uiState.currentNetwork
                 )
-                try {
-                    context.startActivity(Intent(Intent.ACTION_VIEW, Uri.parse(url)))
-                } catch (_: android.content.ActivityNotFoundException) {
+                if (!com.rjnr.pocketnode.ui.util.openInBrowser(context, url)) {
                     scope.launch {
                         snackbarHostState.showSnackbar("No browser available to open the explorer")
                     }
@@ -534,8 +532,9 @@ private fun SettingsScreenUI(
                     title = "Open Source",
                     badgeText = "Github",
                     onClick = {
-                        val intent = Intent(Intent.ACTION_VIEW, Uri.parse(GITHUB_URL))
-                        context.startActivity(intent)
+                        // Custom Tabs keeps the GitHub round-trip inside the app
+                        // task, same reasoning as the explorer launches (#138).
+                        com.rjnr.pocketnode.ui.util.openInBrowser(context, GITHUB_URL)
                     }
                 )
             }

android/app/src/main/java/com/rjnr/pocketnode/ui/util/CustomTabsLauncher.kt

@@ -0,0 +1,52 @@
+package com.rjnr.pocketnode.ui.util
+
+import android.content.ActivityNotFoundException
+import android.content.Context
+import android.content.Intent
+import android.net.Uri
+import androidx.browser.customtabs.CustomTabsIntent
+
+/**
+ * Open [url] in a Chrome Custom Tab when one is available, falling back to
+ * [Intent.ACTION_VIEW] otherwise.
+ *
+ * Why Custom Tabs over `ACTION_VIEW`:
+ * - The Custom Tab runs inside Pocket Node's task instead of starting Chrome's
+ *   own task. The OS treats the round-trip as part of Pocket Node, so the auth
+ *   gate does not re-engage on return and the user is not bounced through PIN
+ *   re-entry.
+ * - Process death by aggressive memory managers (Tecno / Infinix / MIUI) is
+ *   much less likely because the Custom Tab and host app share a task.
+ * - Browser back arrow drops the user straight back where they were.
+ *
+ * Returns `true` if either path launched successfully, `false` if neither did
+ * (rare: a stripped ROM with no browser at all). Callers can surface a
+ * snackbar in that case.
+ *
+ * Issue: #138
+ */
+fun openInBrowser(context: Context, url: String): Boolean {
+    val uri = Uri.parse(url)
+    return try {
+        CustomTabsIntent.Builder()
+            .setShowTitle(true)
+            .setUrlBarHidingEnabled(false)
+            .build()
+            .launchUrl(context, uri)
+        true
+    } catch (_: ActivityNotFoundException) {
+        // No Custom Tabs provider AND no fallback browser — Custom Tabs lib
+        // resolves through ACTION_VIEW under the hood when no provider exists,
+        // so reaching here means the device truly has no web browser.
+        false
+    } catch (_: Throwable) {
+        // Defensive: if the Custom Tabs launch crashes for any other reason
+        // (e.g. a misconfigured browser), try plain ACTION_VIEW one more time.
+        try {
+            context.startActivity(Intent(Intent.ACTION_VIEW, uri))
+            true
+        } catch (_: ActivityNotFoundException) {
+            false
+        }
+    }
+}

android/gradle/libs.versions.toml

@@ -25,6 +25,7 @@ lucide = "1.1.0"
 mockk = "1.13.16"
 coroutinesTest = "1.10.1"
 paging = "3.3.6"
+androidxBrowser = "1.8.0"
 
 [libraries]
 kotlinx-serialization-json = { group = "org.jetbrains.kotlinx", name = "kotlinx-serialization-json", version.ref = "serializationJson" }
@@ -77,6 +78,7 @@ camerax-view = { group = "androidx.camera", name = "camera-view", version.ref =
 accompanist-permissions = { group = "com.google.accompanist", name = "accompanist-permissions", version.ref = "accompanistPermissions" }
 zxing-core = { module = "com.google.zxing:core", version.ref = "zxing" }
 compose-icons-lucide = { group = "com.composables", name = "icons-lucide", version.ref = "lucide" }
+androidx-browser = { group = "androidx.browser", name = "browser", version.ref = "androidxBrowser" }
 
 # Testing
 mockk = { group = "io.mockk", name = "mockk", version.ref = "mockk" }