Add UiAutomator screenshot strategy (#5621)

Refactors `Screengrab` into more collaborators, while keeping the existing `Screengrab` interface working.

The goal is to introduce a new strategy for screenshot capture based on [UiAutomation](#2080 (comment)). It allows capture on Android N, and more correctly captures multi-layer/window situations (dialogs, etc.) Some verification is needed to determine if it also helps Google Maps & video player use-cases.

The new strategy depends on `UiAutomation` which has an API >= 18 requirement. We enforce that in code, and override the manifest merger checks that would force the (optional) API level requirement onto consuming apps. So, our `minSdkVersion` remains **8** for the library.

The `JUnit3StyleTests` are removed, as they are not a recommended configuration.

The example application and tests have been slightly expanded to include a button that opens a dialog to verify multi-window capture by `UiAutomatorScreenshotStrategy`

screengrab/README.md

@@ -84,7 +84,21 @@ Ensure that the following permissions exist in your **src/debug/AndroidManifest.
   - You can create your APKs with `./gradlew assembleDebug assembleAndroidTest`
 - Once complete run `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 in a /screenshots directory in the directory where you ran `screengrab`
+- 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](https://developer.android.com/topic/libraries/testing-support-library/index.html#UIAutomator) 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
+
+However, UI Automator requires a device with **API level >= 18**, so it is not yet the default strategy. To enable it for all screenshots by default, make the following call before your tests run:
+
+```java
+Screengrab.setDefaultScreenshotStrategy(new UiAutomatorScreenshotStrategy());
+```
 
 ## Advanced Screengrabfile Configuration
 

screengrab/build.gradle

@@ -5,7 +5,7 @@ buildscript {
         jcenter()
     }
     dependencies {
-        classpath 'com.android.tools.build:gradle:1.5.0'
+        classpath 'com.android.tools.build:gradle:2.1.2'
     }
 }
 

screengrab/example/src/androidTest/java/tools/fastlane/localetester/JUnit4StyleTests.java

@@ -16,6 +16,7 @@
 import static android.support.test.espresso.assertion.ViewAssertions.matches;
 import static android.support.test.espresso.matcher.ViewMatchers.isDisplayed;
 import static android.support.test.espresso.matcher.ViewMatchers.withId;
+import static android.support.test.espresso.matcher.ViewMatchers.withText;
 
 @RunWith(JUnit4.class)
 public class JUnit4StyleTests {
@@ -27,21 +28,25 @@ public class JUnit4StyleTests {
 
     @Test
     public void testTakeScreenshot() {
+        onView(withId(R.id.greeting)).check(matches(isDisplayed()));
+
         Screengrab.screenshot("beforeFabClick");
 
-        onView(withId(tools.fastlane.localetester.R.id.fab)).perform(click());
+        onView(withId(R.id.fab)).perform(click());
 
         Screengrab.screenshot("afterFabClick");
     }
 
     @Test
     public void testTakeMoreScreenshots() {
-        Screengrab.screenshot("mainActivity");
-
-        onView(withId(tools.fastlane.localetester.R.id.nav_button)).perform(click());
+        onView(withId(R.id.nav_button)).perform(click());
 
         Screengrab.screenshot("anotherActivity");
 
-        onView(withId(R.id.hello)).check(matches(isDisplayed()));
+        onView(withId(R.id.show_dialog_button)).perform(click());
+
+        Screengrab.screenshot("anotherActivity-dialog");
+
+        onView(withText(android.R.string.ok)).perform(click());
     }
 }

screengrab/example/src/main/java/tools/fastlane/localetester/AnotherActivity.java

@@ -1,13 +1,39 @@
 package tools.fastlane.localetester;
 
+import android.content.DialogInterface;
 import android.os.Bundle;
 import android.support.v7.app.ActionBarActivity;
+import android.support.v7.app.AlertDialog;
+import android.view.View;
+import android.widget.Button;
 
 public class AnotherActivity extends ActionBarActivity {
 
+    private Button showDialogButton;
+
     @Override
     protected void onCreate(Bundle savedInstanceState) {
         super.onCreate(savedInstanceState);
         setContentView(tools.fastlane.localetester.R.layout.activity_another);
+
+        showDialogButton = (Button)findViewById(R.id.show_dialog_button);
+        showDialogButton.setOnClickListener(new View.OnClickListener() {
+            @Override
+            public void onClick(View v) {
+                showDialog();
+            }
+        });
+    }
+
+    private void showDialog() {
+        new AlertDialog.Builder(this)
+                .setMessage(R.string.hello)
+                .setPositiveButton(android.R.string.ok, new DialogInterface.OnClickListener() {
+                    @Override
+                    public void onClick(DialogInterface dialog, int which) {
+                        dialog.dismiss();
+                    }
+                })
+                .show();
     }
 }

screengrab/example/src/main/res/layout/activity_another.xml

@@ -13,4 +13,13 @@
         android:layout_height="wrap_content"
         android:gravity="center"/>
 
+    <Button
+        android:id="@+id/show_dialog_button"
+        android:layout_marginTop="16dp"
+        android:layout_below="@+id/hello"
+        android:layout_centerHorizontal="true"
+        android:layout_width="wrap_content"
+        android:layout_height="wrap_content"
+        android:text="@string/show_dialog"/>
+
 </RelativeLayout>

screengrab/example/src/main/res/values/strings.xml

@@ -4,4 +4,5 @@
     <string name="hello">Hello</string>
     <string name="title_activity_another">AnotherActivity</string>
     <string name="navigate">Navigate</string>
+    <string name="show_dialog">Show Dialog</string>
 </resources>

screengrab/gradle.properties

@@ -17,4 +17,5 @@
 # http://www.gradle.org/docs/current/userguide/multi_project_builds.html#sec:decoupled_projects
 # org.gradle.parallel=true
 
-org.gradle.daemon=true
+org.gradle.daemon=true
+org.gradle.jvmargs=-Xmx2048M

screengrab/gradle/wrapper/gradle-wrapper.properties

@@ -1,6 +1,6 @@
-#Wed Oct 21 11:34:03 PDT 2015
+#Wed Aug 03 15:15:30 EDT 2016
 distributionBase=GRADLE_USER_HOME
 distributionPath=wrapper/dists
 zipStoreBase=GRADLE_USER_HOME
 zipStorePath=wrapper/dists
-distributionUrl=https\://services.gradle.org/distributions/gradle-2.8-all.zip
+distributionUrl=https\://services.gradle.org/distributions/gradle-2.10-all.zip

screengrab/lib/screengrab/runner.rb

@@ -220,7 +220,7 @@ def run_tests(device_serial, test_classes_to_use, test_packages_to_use)
                                         print_all: true,
                                         print_command: true)
 
-        UI.user_error! "Tests failed" if test_output.include?("FAILURES!!!")
+        UI.user_error!("Tests failed", show_github_issues: false) if test_output.include?("FAILURES!!!")
       end
     end
 
@@ -303,6 +303,9 @@ def if_device_path_exists(device_serial, device_path)
                                   print_command: false).include?('No such file')
 
       yield device_path
+    rescue
+      # Some versions of ADB will have a non-zero exit status for this, which will cause the executor to raise.
+      # We can safely ignore that and treat it as if it returned 'No such file'
     end
 
     def open_screenshots_summary(device_type_dir_name)

screengrab/screengrab-lib/build.gradle

@@ -50,4 +50,5 @@ dependencies {
     compile 'com.android.support.test:runner:0.4.1'
     compile 'com.android.support.test:rules:0.4.1'
     compile 'com.android.support.test.espresso:espresso-core:2.2.1'
+    compile 'com.android.support.test.uiautomator:uiautomator-v18:2.1.2'
 }

screengrab/screengrab-lib/src/main/AndroidManifest.xml

@@ -1,4 +1,6 @@
-<manifest xmlns:android="http://schemas.android.com/apk/res/android"
+<manifest xmlns:tools="http://schemas.android.com/tools"
     package="tools.fastlane.screengrab">
 
+    <!-- We will manually check for API level >= 18 before using UiAutomator -->
+    <uses-sdk tools:overrideLibrary="android.support.test.uiautomator.v18" />
 </manifest>

screengrab/screengrab-lib/src/main/java/tools.fastlane.screengrab/DecorViewScreenshotStrategy.java

@@ -0,0 +1,127 @@
+package tools.fastlane.screengrab;
+
+import android.app.Activity;
+import android.content.Context;
+import android.content.ContextWrapper;
+import android.graphics.Bitmap;
+import android.graphics.Canvas;
+import android.os.Looper;
+import android.support.test.espresso.Espresso;
+import android.support.test.espresso.UiController;
+import android.support.test.espresso.ViewAction;
+import android.support.test.espresso.matcher.ViewMatchers;
+import android.view.View;
+
+import org.hamcrest.Matcher;
+
+import java.io.IOException;
+import java.util.concurrent.CountDownLatch;
+
+/**
+ * <p>Screenshot strategy that captures the contents of a Window's decor view.</p>
+ *
+ * <p>Advantages compared to {@link UiAutomatorScreenshotStrategy}:</p>
+ *
+ * <ul>
+ *     <li>Works down to API level 8</li>
+ *     <li>Uses Espresso for action synchronization internally, so requires less matching
+ *         setup in your tests</li>
+ * </ul>
+ *
+ * Known limitations:
+ * <ul>
+ *     <li>Does not work on Android N</li>
+ *     <li>Does not correctly capture depth/shadows in Material UI</li>
+ *     <li>Does not correctly capture multi-window situations (dialogs, etc.)</li>
+ *     <li>Does not correctly capture specialized surface views (Google Maps, video players, etc.)</li>
+ * </ul>
+ */
+public class DecorViewScreenshotStrategy implements ScreenshotStrategy {
+    @Override
+    public void takeScreenshot(String screenshotName, ScreenshotCallback callback) {
+        Espresso.onView(ViewMatchers.isRoot()).perform(new ScreenshotViewAction(screenshotName, callback));
+    }
+
+    static class ScreenshotViewAction implements ViewAction {
+        private final String screenshotName;
+        private final ScreenshotCallback callback;
+
+        public ScreenshotViewAction(String screenshotName, ScreenshotCallback callback) {
+            this.screenshotName = screenshotName;
+            this.callback = callback;
+        }
+
+        @Override
+        public Matcher<View> getConstraints() {
+            return ViewMatchers.isDisplayed();
+        }
+
+        @Override
+        public String getDescription() {
+            return "taking screenshot of the Activity";
+        }
+
+        @Override
+        public void perform(UiController uiController, View view) {
+            final Activity activity = scanForActivity(view.getContext());
+
+            if (activity == null) {
+                throw new IllegalStateException("Couldn't get the activity from the view context");
+            }
+
+            try {
+                callback.screenshotCaptured(screenshotName, takeScreenshot(activity));
+            } catch (Exception e) {
+                throw new RuntimeException("Unable to capture screenshot.", e);
+            }
+        }
+
+        private Activity scanForActivity(Context context) {
+            if (context == null) {
+                return null;
+
+            } else if (context instanceof Activity) {
+                return (Activity) context;
+
+            } else if (context instanceof ContextWrapper) {
+                return scanForActivity(((ContextWrapper) context).getBaseContext());
+            }
+
+            return null;
+        }
+
+        private static Bitmap takeScreenshot(final Activity activity) throws IOException {
+            View view = activity.getWindow().getDecorView();
+            final Bitmap bitmap = Bitmap.createBitmap(view.getWidth(), view.getHeight(), Bitmap.Config.ARGB_8888);
+
+            if (Looper.myLooper() == Looper.getMainLooper()) {
+                // On main thread already, Just Do It™.
+                drawDecorViewToBitmap(activity, bitmap);
+            } else {
+                // On a background thread, post to main.
+                final CountDownLatch latch = new CountDownLatch(1);
+                activity.runOnUiThread(new Runnable() {
+                    @Override
+                    public void run() {
+                        try {
+                            drawDecorViewToBitmap(activity, bitmap);
+                        } finally {
+                            latch.countDown();
+                        }
+                    }
+                });
+                try {
+                    latch.await();
+                } catch (InterruptedException e) {
+                    throw new RuntimeException("Unable to capture screenshot", e);
+                }
+            }
+
+            return bitmap;
+        }
+
+        private static void drawDecorViewToBitmap(Activity activity, Bitmap bitmap) {
+            activity.getWindow().getDecorView().draw(new Canvas(bitmap));
+        }
+    }
+}