feat: extract android applicationId

packages/cli-platform-android/src/commands/runAndroid/index.ts

@@ -257,6 +257,7 @@ function installAndLaunchOnDevice(
   tryLaunchAppOnDevice(
     selectedDevice,
     androidProject.packageName,
+    androidProject.applicationId,
     adbPath,
     args,
   );

packages/cli-platform-android/src/commands/runAndroid/runOnAllDevices.ts

@@ -115,7 +115,13 @@ async function runOnAllDevices(
       if (args.binaryPath && device) {
         tryInstallAppOnDevice(args, adbPath, device, androidProject);
       }
-      tryLaunchAppOnDevice(device, androidProject.packageName, adbPath, args);
+      tryLaunchAppOnDevice(
+        device,
+        androidProject.packageName,
+        androidProject.applicationId,
+        adbPath,
+        args,
+      );
     },
   );
 }

packages/cli-platform-android/src/commands/runAndroid/tryLaunchAppOnDevice.ts

@@ -13,11 +13,12 @@ import {logger, CLIError} from '@react-native-community/cli-tools';
 function tryLaunchAppOnDevice(
   device: string | void,
   packageName: string,
+  applicationId: string,
   adbPath: string,
   args: Flags,
 ) {
   const {appId, appIdSuffix} = args;
-  const packageNameWithSuffix = [appId || packageName, appIdSuffix]
+  const packageNameWithSuffix = [appId || applicationId, appIdSuffix]
     .filter(Boolean)
     .join('.');
 

packages/cli-platform-android/src/config/__fixtures__/files/build.gradle

@@ -3,6 +3,9 @@ apply package: "com.facebook.react"
 
 android {
     namespace 'com.some.example'
+    defaultConfig {
+        applicationId "com.example"
+    }
 }
 
 react {

packages/cli-platform-android/src/config/__tests__/__snapshots__/getProjectConfig.test.ts.snap

@@ -25,6 +25,7 @@ Object {
 exports[`android::getProjectConfig returns an object with android project configuration for nested structure 1`] = `
 Object {
   "appName": "app",
+  "applicationId": "com.example",
   "dependencyConfiguration": undefined,
   "packageName": "com.some.example",
   "sourceDir": "/nested/android",

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

@@ -106,3 +106,19 @@ export function parseNamespaceFromBuildGradleFile(buildGradle: string) {
 export function validatePackageName(packageName: string) {
   return /^[a-z][a-z0-9_]*(\.[a-z][a-z0-9_]*)+$/i.test(packageName);
 }
+
+// Search for applicationId at defaultConfig object
+export function parseApplicationIdFromBuildGradleFile(buildGradlePath: string) {
+  const buildGradle = fs.readFileSync(buildGradlePath, 'utf8');
+
+  const matchArray = buildGradle.match(/defaultConfig\s*{([\s\S]*?)}/);
+
+  if (matchArray && matchArray.length > 0) {
+    const appIdMatchArray = matchArray[1].match(
+      /applicationId\s*[=]*\s*["'](.+?)["']/,
+    );
+    return appIdMatchArray?.[1] ?? '';
+  } else {
+    return null;
+  }
+}

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

@@ -17,7 +17,10 @@ import {
   AndroidDependencyParams,
   AndroidDependencyConfig,
 } from '@react-native-community/cli-types';
-import {getPackageName} from './getAndroidProject';
+import {
+  getPackageName,
+  parseApplicationIdFromBuildGradleFile,
+} from './getAndroidProject';
 import {findLibraryName} from './findLibraryName';
 import {findComponentDescriptors} from './findComponentDescriptors';
 import {findBuildGradle} from './findBuildGradle';
@@ -59,17 +62,31 @@ export function projectConfig(
     );
   }
 
+  const applicationId =
+    getApplicationId(buildGradlePath as string) || packageName;
+
   return {
     sourceDir,
     appName,
     packageName,
+    applicationId,
     dependencyConfiguration: userConfig.dependencyConfiguration,
     watchModeCommandParams: userConfig.watchModeCommandParams,
     unstable_reactLegacyComponentNames:
       userConfig.unstable_reactLegacyComponentNames,
   };
 }
 
+function getApplicationId(buildGradlePath: string) {
+  let appId = '';
+
+  const applicationId = parseApplicationIdFromBuildGradleFile(buildGradlePath);
+  if (applicationId) {
+    appId = applicationId;
+  }
+  return appId;
+}
+
 function getAppName(sourceDir: string, userConfigAppName: string | undefined) {
   let appName = '';
   if (

packages/cli-types/src/android.ts

@@ -2,6 +2,7 @@ export interface AndroidProjectConfig {
   sourceDir: string;
   appName: string;
   packageName: string;
+  applicationId: string;
   dependencyConfiguration?: string;
   watchModeCommandParams?: string[];
   unstable_reactLegacyComponentNames?: string[] | null;