implement getting Main Activity from an Activity alias on Android

packages/cli-platform-android/src/config/__fixtures__/android.ts

@@ -34,6 +34,10 @@ const customFlavorManifest = fs.readFileSync(
   path.join(__dirname, './files/AndroidManifest-custom-flavor.xml'),
 );
 
+const activityAliasManifest = fs.readFileSync(
+  path.join(__dirname, './files/AndroidManifest-activity-alias.xml'),
+);
+
 const mainManifest = fs.readFileSync(
   path.join(__dirname, './files/AndroidManifest.xml'),
 );
@@ -307,6 +311,12 @@ export const className = {
   },
 };
 
+export const activityAlias = {
+  src: {
+    'AndroidManifest.xml': activityAliasManifest,
+  },
+};
+
 export const customFlavor = {
   src: {
     e2e: {

packages/cli-platform-android/src/config/__fixtures__/files/AndroidManifest-activity-alias.xml

@@ -0,0 +1,21 @@
+<manifest
+  xmlns:android="http://schemas.android.com/apk/res/android">
+  <application android:name=".ExampleApplication">
+    <activity-alias android:name=".MainActivityAlias" android:targetActivity=".OldMainActivity">
+      <intent-filter>
+        <action android:name="android.intent.action.MAIN" />
+        <category android:name="android.intent.category.LAUNCHER" />
+        <category android:name="android.intent.category.LEANBACK_LAUNCHER" />
+      </intent-filter>
+      <intent-filter>
+        <action android:name="android.intent.action.VIEW" />
+        <category android:name="android.intent.category.DEFAULT" />
+        <category android:name="android.intent.category.BROWSABLE" />
+        <data android:scheme="rntester" android:host="example" />
+      </intent-filter>
+    </activity-alias>
+    <activity android:name="com.old.package.OldMainActivity" android:exported="true"/>
+    <activity android:name="com.facebook.react.devsupport.DevSettingsActivity" android:exported="false"/>
+  </application>
+  </queries>
+</manifest>

packages/cli-platform-android/src/config/__tests__/getMainActivity.test.ts

@@ -31,6 +31,11 @@ describe('android::getMainActivity', () => {
           app: mocks.customFlavor,
         },
       },
+      activityAlias: {
+        android: {
+          app: mocks.activityAlias,
+        },
+      },
     });
   });
 
@@ -70,4 +75,12 @@ describe('android::getMainActivity', () => {
     const fakeManifestPath = findManifest('/empty');
     expect(getMainActivity(fakeManifestPath || '')).toBeNull();
   });
+
+  it('returns activity defined as alias in the manifest', () => {
+    const manifestPath = findManifest('/activityAlias');
+    const manifest = getMainActivity(manifestPath || '');
+    expect(manifest).not.toBeNull();
+    expect(typeof manifest).toBe('string');
+    expect(manifest).toBe('.MainActivityAlias');
+  });
 });

packages/cli-platform-android/src/config/getMainActivity.ts

@@ -31,6 +31,7 @@ export default function getMainActivity(manifestPath: string): string | null {
 
       const application = manifest.application || {};
       const activity = application.activity || {};
+      const activityAlias = application['activity-alias'] || {};
 
       let activities: Activity[] = [];
 
@@ -40,6 +41,12 @@ export default function getMainActivity(manifestPath: string): string | null {
         activities = activity;
       }
 
+      if (!Array.isArray(activityAlias)) {
+        activities.push(activityAlias);
+      } else {
+        activities = activities.concat(activityAlias);
+      }
+
       const mainActivity = activities.find((act: Activity) => {
         let intentFilters = act['intent-filter'];