chore(android): Add Nav2 sample app

Adds a Nav2 sample app for validating Sentry's fragment and Compose navigation integrations under different tracing setups.

Developers can configure active transactions (nav vs ui.load vs user interaction), navigation data (breadcrumbs and screen names), and work performed at each nav destination (HTTP requets, manual spans, or nothing). They can also view transaction/span generation in real time via the Transaction History Bottom Sheet.

Co-Authored-By: OpenAI GPT-5.4 <noreply@openai.com>

Author: 0xadam-brown

gradle/libs.versions.toml

@@ -103,6 +103,7 @@ androidx-lifecycle-common-java8 = { module = "androidx.lifecycle:lifecycle-commo
 androidx-lifecycle-process = { module = "androidx.lifecycle:lifecycle-process", version.ref = "androidxLifecycle" }
 androidx-navigation-runtime = { module = "androidx.navigation:navigation-runtime", version.ref = "androidxNavigation" }
 androidx-navigation-compose = { module = "androidx.navigation:navigation-compose", version.ref = "androidxNavigation" }
+androidx-navigation-fragment = { module = "androidx.navigation:navigation-fragment-ktx", version.ref = "androidxNavigation" }
 androidx-room-compiler = { module = "androidx.room:room-compiler", version.ref = "room2" }
 androidx-room-ktx = { module = "androidx.room:room-ktx", version.ref = "room2" }
 androidx-room-runtime = { module = "androidx.room:room-runtime", version.ref = "room2" }

sentry-samples/sentry-samples-android/build.gradle.kts

@@ -185,6 +185,7 @@ dependencies {
 
   implementation(projects.sentryAndroid)
   implementation(projects.sentryAndroidFragment)
+  implementation(projects.sentryAndroidNavigation)
   implementation(projects.sentryAndroidSqlite)
   implementation(projects.sentryAndroidTimber)
   implementation(projects.sentryCompose)
@@ -209,6 +210,7 @@ dependencies {
   implementation(libs.androidx.compose.material.icons.core)
   implementation(libs.androidx.compose.material.icons.extended)
   implementation(libs.androidx.navigation.compose)
+  implementation(libs.androidx.navigation.fragment)
   implementation(libs.androidx.recyclerview)
   implementation(libs.androidx.browser)
   implementation(libs.androidx.room3.runtime)

sentry-samples/sentry-samples-android/src/main/AndroidManifest.xml

@@ -101,6 +101,16 @@
       android:name=".compose.ComposeActivity"
       android:exported="false" />
 
+    <activity
+      android:name=".navigation.Nav2SetupActivity"
+      android:exported="false"
+      android:theme="@style/AppTheme.Main" />
+
+    <activity
+      android:name=".navigation.Nav2Activity"
+      android:exported="false"
+      android:theme="@style/AppTheme.Main" />
+
     <activity
       android:name=".FrameDataForSpansActivity"
       android:exported="false" />

sentry-samples/sentry-samples-android/src/main/java/io/sentry/samples/android/MainActivity.kt

@@ -893,6 +893,20 @@ fun IntegrationsScreen() {
         }
       }
     }
+    item {
+      SentryTraced("open_nav2_activity") {
+        OutlinedButton(
+          onClick = {
+            activity.startActivity(
+              Intent(activity, io.sentry.samples.android.navigation.Nav2SetupActivity::class.java)
+            )
+          },
+          modifier = Modifier,
+        ) {
+          Text("Open Nav2Activity", maxLines = 2, overflow = TextOverflow.Ellipsis)
+        }
+      }
+    }
     item {
       SentryTraced("open_sample_fragment") {
         OutlinedButton(

sentry-samples/sentry-samples-android/src/main/java/io/sentry/samples/android/SampleBeforeSendTransactionHook.kt

@@ -0,0 +1,75 @@
+package io.sentry.samples.android
+
+import io.sentry.SentryOptions
+import io.sentry.protocol.SentryTransaction
+import java.util.concurrent.CopyOnWriteArrayList
+
+/**
+ * Owns the single global beforeSendTransaction hook used by sample screens that inspect finished
+ * transactions.
+ *
+ * Multiple sample activities can overlap briefly during configuration changes or relaunches. If
+ * each screen installs and restores its own callback, a later uninstall can resurrect a stale
+ * wrapper callback that still retains dead state and drops the original callback chain.
+ *
+ * Keep one stable callback installed and let sample screens register lightweight listeners against
+ * it instead.
+ */
+internal object SampleBeforeSendTransactionHook {
+
+  private val listeners = CopyOnWriteArrayList<(SentryTransaction, String?) -> Unit>()
+
+  @Volatile private var installedCallback: SentryOptions.BeforeSendTransactionCallback? = null
+  @Volatile private var previousCallback: SentryOptions.BeforeSendTransactionCallback? = null
+
+  fun installIfNeeded(options: SentryOptions) {
+    if (installedCallback != null) {
+      return
+    }
+
+    synchronized(this) {
+      if (installedCallback != null) {
+        return
+      }
+
+      previousCallback = options.beforeSendTransaction
+      val callback = SentryOptions.BeforeSendTransactionCallback { transaction, hint ->
+        val previous = previousCallback
+
+        val processedTransaction =
+          if (previous == null) {
+            transaction
+          } else {
+            previous.execute(transaction, hint)
+          }
+
+        processedTransaction?.let { processed ->
+          listeners.forEach { listener ->
+            try {
+              listener(processed, options.dsn)
+            } catch (e: RuntimeException) {
+              options.logger.log(
+                io.sentry.SentryLevel.ERROR,
+                "Sample transaction listener failed.",
+                e,
+              )
+            }
+          }
+        }
+
+        processedTransaction
+      }
+
+      installedCallback = callback
+      options.beforeSendTransaction = callback
+    }
+  }
+
+  fun addListener(listener: (SentryTransaction, String?) -> Unit) {
+    listeners.addIfAbsent(listener)
+  }
+
+  fun removeListener(listener: (SentryTransaction, String?) -> Unit) {
+    listeners.remove(listener)
+  }
+}