FIX: Allow Maestro to work on Android API levels 25 and lower (Android 7.1.1 and lower)

maestro-android/build.gradle

@@ -38,7 +38,7 @@ android {
 
     defaultConfig {
         applicationId "dev.mobile.maestro"
-        minSdk 21
+        minSdk 24
         targetSdk 31
         versionCode 1
         versionName "1.0"

maestro-android/src/androidTest/java/dev/mobile/maestro/AccessibilityNodeInfoExt.kt

@@ -0,0 +1,24 @@
+package dev.mobile.maestro
+
+import android.os.Build
+import android.view.accessibility.AccessibilityNodeInfo
+
+object AccessibilityNodeInfoExt {
+
+    /**
+     * Retrieves the hint text associated with this [android.view.accessibility.AccessibilityNodeInfo].
+     *
+     * If the device API level is below 26 (Oreo) or the hint text is null, this function provides a fallback
+     * by returning an empty CharSequence instead.
+     *
+     * @return [CharSequence] representing the hint text or its fallback.
+     */
+    fun AccessibilityNodeInfo.getHintOrFallback(): CharSequence {
+        return if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.O && this.hintText != null) {
+            this.hintText
+        } else {
+            ""
+        }
+    }
+
+}

maestro-android/src/androidTest/java/dev/mobile/maestro/ViewHierarchy.kt

@@ -15,6 +15,7 @@ import android.widget.ListView
 import android.widget.TableLayout
 import androidx.test.platform.app.InstrumentationRegistry
 import androidx.test.uiautomator.UiDevice
+import dev.mobile.maestro.AccessibilityNodeInfoExt.getHintOrFallback
 import org.xmlpull.v1.XmlSerializer
 import java.io.IOException
 import java.io.OutputStream
@@ -120,7 +121,7 @@ object ViewHierarchy {
             serializer.attribute("", "NAF", java.lang.Boolean.toString(true))
         }
         serializer.attribute("", "index", Integer.toString(index))
-        serializer.attribute("", "hintText", safeCharSeqToString(node.hintText))
+        serializer.attribute("", "hintText", safeCharSeqToString(node.getHintOrFallback()))
         serializer.attribute("", "text", safeCharSeqToString(node.text))
         serializer.attribute("", "resource-id", safeCharSeqToString(node.viewIdResourceName))
         serializer.attribute("", "class", safeCharSeqToString(node.className))
@@ -276,4 +277,4 @@ object ViewHierarchy {
         }
     }
 
-}
+}

maestro-client/src/main/java/maestro/drivers/AndroidDriver.kt

@@ -88,9 +88,15 @@ class AndroidDriver(
 
     private fun startInstrumentationSession() {
         val startTime = System.currentTimeMillis()
-        val instrumentationCommand = "am instrument -w -m -e debug false " +
-                "-e class 'dev.mobile.maestro.MaestroDriverService#grpcServer' " +
-                "dev.mobile.maestro.test/androidx.test.runner.AndroidJUnitRunner &\n"
+        val apiLevel = getDeviceApiLevel()
+
+        val instrumentationCommand = buildString {
+            append("am instrument -w ")
+            if (apiLevel >= 26) append("-m ")
+            append("-e debug false ")
+            append("-e class 'dev.mobile.maestro.MaestroDriverService#grpcServer' ")
+            append("dev.mobile.maestro.test/androidx.test.runner.AndroidJUnitRunner &\n")
+        }
 
         while (System.currentTimeMillis() - startTime < getStartupTimeout()) {
             instrumentationSession = dadb.openShell(instrumentationCommand)
@@ -105,6 +111,15 @@ class AndroidDriver(
         throw AndroidInstrumentationSetupFailure("Maestro instrumentation could not be initialized")
     }
 
+    private fun getDeviceApiLevel(): Int {
+        val response = dadb.openShell("getprop ro.build.version.sdk").readAll()
+        if (response.exitCode != 0) {
+            throw IOException("Failed to get device API level: ${response.errorOutput}")
+        }
+        return response.output.trim().toIntOrNull() ?: throw IOException("Invalid API level: ${response.output}")
+    }
+
+
     private fun allocateForwarder() {
         PORT_TO_FORWARDER[hostPort]?.close()
         PORT_TO_ALLOCATION_POINT[hostPort]?.let {