Automated localized screenshots of your Android app on every device

screengrab generates localized screenshots of your Android app for different device types and languages for Google Play and can be uploaded using supply.

Why should I automate this process?

Create hundreds of screenshots in multiple languages on emulators or real devices, saving you hours
Easily verify that localizations fit into labels on all screen dimensions to find UI mistakes before you ship
You only need to configure it once for anyone on your team to run it
Keep your screenshots perfectly up-to-date with every app update. Your customers deserve it!
Fully integrates with fastlane and supply

Installation

Install the gem

gem install fastlane

Gradle dependency

androidTestImplementation 'tools.fastlane:screengrab:x.x.x'

The latest version is

As of screengrab version 2.0.0, all Android test dependencies are AndroidX dependencies. This means a device with API 18+, Android 4.3 or greater is required. If you wish to capture screenshots with an older Android OS, then you must use a 1.x.x version.

Configuring your Manifest Permissions

Ensure that the following permissions exist in your src/debug/AndroidManifest.xml

Configuring your UI Tests for Screenshots

Add LocaleTestRule to your tests class to handle automatic switching of locales.

If you’re using Java use:

   @ClassRule
   public static final LocaleTestRule localeTestRule = new LocaleTestRule();

If you’re using Kotlin use:

   @Rule @JvmField
   val localeTestRule = LocaleTestRule()

The @JvmField annotation is important. It won’t work like this:

   companion object {
       @get:ClassRule
       val localeTestRule = LocaleTestRule()
   }

To capture screenshots, add the following to your tests Screengrab.screenshot("name_of_screenshot_here"); on the appropriate screens

Generating Screenshots with screengrab

Then, before running fastlane screengrab you’ll need a debug and test apk
- You can create your APKs manually with ./gradlew assembleDebug assembleAndroidTest
- You can also create a lane and use build_android_app:
```
desc "Build debug and test APK for screenshots"
lane :build_and_screengrab do
  build_android_app(
    task: 'assemble',
    build_type: 'Debug'
  )
  build_android_app(
    task: 'assemble',
    build_type: 'AndroidTest'
  )
  screengrab()
end
```
Once complete run fastlane screengrab in your app project directory to generate screenshots
- You will be prompted to provide any required parameters which are not in your Screengrabfile or provided as command line arguments
Your screenshots will be saved to fastlane/metadata/android in the directory where you ran screengrab

Improved screenshot capture with UI Automator

As of screengrab 0.5.0, you can specify different strategies to control the way screengrab captures screenshots. The newer strategy delegates to UI Automator which fixes a number of problems compared to the original strategy:

Shadows/elevation are correctly captured for Material UI
Multi-window situations are correctly captured (dialogs, etc.)
Works on Android N

UI Automator is the default strategy. However, UI Automator requires a device with API level >= 18. If you need to grab screenshots on an older Android version, use the latest 1.x.x version of this library and set the DecorView ScreenshotStrategy.

Screengrab.setDefaultScreenshotStrategy(new DecorViewScreenshotStrategy());

Improved screenshot capture with Falcon

As of screengrab 1.2.0, you can specify a new strategy to delegate to Falcon. Falcon may work better than UI Automator in some situations and also provides similar benefits as UI Automator:

Multi-window situations are correctly captured (dialogs, etc.)
Works on Android N

Falcon requires a device with API level >= 10. To enable it for all screenshots by default, make the following call before your tests run:

Screengrab.setDefaultScreenshotStrategy(new FalconScreenshotStrategy(activityRule.getActivity()));

Advanced Screengrabfile Configuration

Running fastlane screengrab init generated a Screengrabfile which can store all of your configuration options. Since most values will not change often for your project, it is recommended to store them there.

The Screengrabfile is written in Ruby, so you may find it helpful to use an editor that highlights Ruby syntax to modify this file.

# remove the leading '#' to uncomment lines

# app_package_name('your.app.package')
# use_tests_in_packages(['your.screenshot.tests.package'])

# app_apk_path('path/to/your/app.apk')
# tests_apk_path('path/to/your/tests.apk')

locales(['en-US', 'fr-FR', 'it-IT'])

# clear all previously generated screenshots in your local output directory before creating new ones
clear_previous_screenshots(true)

For more information about all available options run

fastlane action screengrab

Tips

UI Tests

Check out Testing UI for a Single App for an introduction to using Espresso for UI testing.

Example UI Test Class (Using JUnit4)

Java:

@RunWith(JUnit4.class)
public class JUnit4StyleTests {
    @ClassRule
    public static final LocaleTestRule localeTestRule = new LocaleTestRule();

    @Rule
    public ActivityScenarioRule activityRule = new ActivityScenarioRule&lt;&gt;(MainActivity.class);

    @Test
    public void testTakeScreenshot() {
        Screengrab.screenshot("before_button_click");

        onView(withId(R.id.fab)).perform(click());

        Screengrab.screenshot("after_button_click");
    }
}

Kotlin:

@RunWith(JUnit4.class)
class JUnit4StyleTests {
    @get:Rule
    var activityRule = ActivityScenarioRule(MainActivity::class.java)

    @Rule @JvmField
    val localeTestRule = LocaleTestRule()

    @Test
    fun testTakeScreenshot() {
        Screengrab.screenshot("before_button_click")

        onView(withId(R.id.fab)).perform(click())

        Screengrab.screenshot("after_button_click")
    }
}

There is an example project showing how to use JUnit 3 or 4 and Espresso with the screengrab Java library to capture screenshots during a UI test run.

Using JUnit 4 is preferable because of its ability to perform actions before and after the entire test class is run. This means you will change the device’s locale far fewer times when compared with JUnit 3 running those commands before and after each test method.

When using JUnit 3 you’ll need to add a bit more code:

Use LocaleUtil.changeDeviceLocaleTo(LocaleUtil.getTestLocale()); in setUp()
Use LocaleUtil.changeDeviceLocaleTo(LocaleUtil.getEndingLocale()); in tearDown()
Use Screengrab.screenshot("name_of_screenshot_here"); to capture screenshots at the appropriate points in your tests

Clean Status Bar

screengrab can clean your status bar to make your screenshots even more beautiful.
It is simply a wrapper that allows configuring SystemUI DemoMode in your code.
Note: the clean status bar feature is only supported on devices with API level >= 23.

You can enable and disable the clean status bar at any moment during your tests.
In most cases you probably want to do this in the @BeforeClass and @AfterClass methods.

@BeforeClass
public static void beforeAll() {
    CleanStatusBar.enableWithDefaults();
}

@AfterClass
public static void afterAll() {
    CleanStatusBar.disable();
}

Have a look at the methods of the CleanStatusBar class to customize the status bar even more.
You could for example show the Bluetooth icon and the LTE text.

new CleanStatusBar()
    .setBluetoothState(BluetoothState.DISCONNECTED)
    .setMobileNetworkDataType(MobileDataType.LTE)
    .enable();

Advanced screengrab

Launch Arguments

You can provide additional arguments to your test cases on launch. These strings will be available in your tests through InstrumentationRegistry.getArguments().

screengrab(
  launch_arguments: [
    "username hjanuschka",
    "build_number 201"
  ]
)

Bundle extras = InstrumentationRegistry.getArguments();
String peerID = null;
if (extras != null) {
  if (extras.containsKey("username")) {
    username = extras.getString("username");
    System.out.println("Username: " + username);
  } else {
    System.out.println("No username in extras");
  }
} else {
  System.out.println("No extras");
}

Detecting screengrab at runtime

For some apps, it is helpful to know when screengrab is running so that you can display specific data for your screenshots. For iOS fastlane users, this is much like “FASTLANE_SNAPSHOT”. In order to do this, you’ll need to have at least two product flavors of your app.

Add two product flavors to the app-level build.gradle file:

android {
...
    flavorDimensions "mode"
    productFlavors {
        screengrab {
            dimension "mode"
        }
        regular {
            dimension "mode"
        }
    }
...
}

Check for the existence of that flavor (i.e screengrab) in your app code as follows in order to use mock data or customize data for screenshots:

if (BuildConfig.FLAVOR == "screengrab") {
    System.out.println("screengrab is running!");
}

When running screengrab, do the following to build the flavor you want as well as the test apk. Note that you use “assembleFlavor_name” where Flavor_name is the flavor name, capitalized (i.e. Screengrab).

./gradlew assembleScreengrab assembleAndroidTest

Run screengrab:

fastlane screengrab

screengrab will ask you to select the debug and test apps (which you can then add to your Screengrabfile to skip this step later).

The debug apk should be somewhere like this:

app/build/outputs/apk/screengrab/debug/app-screengrab-debug.apk

The test apk should be somewhere like this:

app/build/outputs/apk/androidTest/screengrab/debug/app-screengrab-debug-androidTest.apk

Sit back and enjoy your new screenshots!

Note: while this could also be done by creating a new build variant (i.e. debug, release and creating a new one called screengrab), Android only allows one build type to be tested which defaults to debug. That’s why we use product flavors.

fastlane/lib/fastlane/actions/docs/capture_android_screenshots