UI Automator

UI Automator is a UI testing framework introduced by Google to facilitate automation on an Android emulator or device. UI Automator is especially useful for cross-app testing, where your test needs to interact with multiple apps or system UI components

Appium leverages this UIAutomator with its own wrapper and came up with UIAutomator2 Driver to automate the Android applications.

In short:

• UI Automator (v1) is Google’s official Android testing framework for instrumented UI tests.
• UI Automator2 is not an official Google framework—it’s Appium’s Android automation driver that uses UI Automator (and Android Accessibility) under the hood but exposes a WebDriver-compatible interface.

Features

Some of the features are as follows:

• Cross-app interaction: Test interactions between your app and other apps or system UI.
• Device-wide UI access: Access UI elements outside your app’s package (e.g., status bar, home screen).
• Robust selectors: Locate UI elements using properties like text, content description, class name, resource ID, etc.
• Supports Android 4.3 (API 18) and higher.
• Works well with JUnit 4 and AndroidJUnitRunner

Core Components

• UiDevice
  Represents the device state. You can use it to:
  • Press hardware buttons ()
  • Take screenshots ()
  • Access system dialogs
• UiObject
  Represents a UI element (e.g., button, text field). You can:
  • Click, long-click, drag
  • Get text or properties
  • Wait for existence
• UiCollection
  Enumerates UI elements for searching within a container.
• UiScrollable
  Enables scrolling to find a target UI element (e.g., in a ListView or RecyclerView).
• UiSelector
  Used to query for specific UI elements using attributes:

UI Automator vs UI Automator2

Some of the differences are as follows:

	UI Automator (v1)	UI Automator2
Framework Type	Android native testing framework (part of Android SDK)	Appium’s custom automation driver built on top of UI Automator (v1) and later Android Accessibility APIs
Maintained By	Google (as part of Android Testing Support Library)	Appium (Open-source project, not Google)
Primary Use Case	Instrumented Android UI tests (run via AndroidJUnitRunner)	Remote automation of Android apps via WebDriver protocol (used with Appium)
Execution Environment	Runs directly on Android device/emulator as an instrumentation test	Runs as a background server (UiAutomator2 driver) on device; controlled remotely via Appium server
Language Support	Java/Kotlin (Android test code)	Any language that supports WebDriver (e.g., Python, Java, JavaScript, C#, Ruby)
Test Runner	AndroidJUnitRunner	Appium (uses UiAutomator2 as its Android automation backend)
API Access	Direct access to UiDevice, UiObject, etc.	Access via WebDriver JSON Wire Protocol / W3C WebDriver commands
Cross-App Testing	Yes (native support)	Yes (inherited from UI Automator v1 capabilities)
Support for Android Versions	API 18+ (Android 4.3+)	API 21+ (Android 5.0+) — better support for modern Android versions
Performance & Stability	Stable but limited to instrumentation context	Improved stability, faster element location, better handling of async UI (e.g., RecyclerView)
Element Finding	Uses UiSelector with Java API	Uses XPath, ID, accessibility ID, class name, etc. via WebDriver locators
Debugging & Logs	Logcat + Android Studio test logs	Appium server logs + device logs; easier remote debugging
Integration	Integrated with Android Studio and Gradle	Integrated with Appium, Selenium Grid, CI/CD pipelines (cross-platform)
Open Source	Yes (part of AndroidX)	Yes (part of Appium project on GitHub)