feat: read main activity from AndroidManifest.xml automatically

docs/platforms.md

@@ -84,6 +84,7 @@ type AndroidProjectConfig = {
   sourceDir: string;
   appName: string;
   packageName: string;
+  mainActivity: string;
   dependencyConfiguration?: string;
   watchModeCommandParams: string;
 };

packages/cli-platform-android/package.json

@@ -10,6 +10,7 @@
     "@react-native-community/cli-tools": "12.0.0-alpha.4",
     "chalk": "^4.1.2",
     "execa": "^5.0.0",
+    "fast-xml-parser": "^4.2.4",
     "glob": "^7.1.3",
     "logkitty": "^0.7.1"
   },

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

@@ -46,6 +46,10 @@ async function runAndroid(_argv: Array<string>, config: Config, args: Flags) {
     link.setVersion(config.reactNativeVersion);
   }
 
+  if (!args.mainActivity && config.project.android?.mainActivity) {
+    args.mainActivity = config.project.android?.mainActivity;
+  }
+
   if (args.binaryPath) {
     if (args.tasks) {
       throw new CLIError(
@@ -283,7 +287,6 @@ export default {
     {
       name: '--main-activity <string>',
       description: 'Name of the activity to start',
-      default: 'MainActivity',
     },
     {
       name: '--deviceId <string>',

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

@@ -22,6 +22,7 @@ import {findLibraryName} from './findLibraryName';
 import {findComponentDescriptors} from './findComponentDescriptors';
 import {findBuildGradle} from './findBuildGradle';
 import {CLIError} from '@react-native-community/cli-tools';
+import readAndroidManifest from './readAndroidManifest';
 
 /**
  * Gets android project config by analyzing given folder and taking some
@@ -59,10 +60,17 @@ export function projectConfig(
     );
   }
 
+  const mainActivity = readAndroidManifest(manifestPath || '');
+
+  if (!mainActivity) {
+    throw new CLIError(`Main activity not found in ${manifestPath}`);
+  }
+
   return {
     sourceDir,
     appName,
     packageName,
+    mainActivity,
     dependencyConfiguration: userConfig.dependencyConfiguration,
     watchModeCommandParams: userConfig.watchModeCommandParams,
     unstable_reactLegacyComponentNames:

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

@@ -0,0 +1,110 @@
+import fs from 'fs';
+import {XMLParser, XMLValidator} from 'fast-xml-parser';
+
+const MAIN_ACTION = 'android.intent.action.MAIN';
+const LAUNCHER = 'android.intent.category.LAUNCHER';
+
+interface Activity {
+  [x: string]: any;
+}
+
+interface IntentFilter {
+  action:
+    | {
+        '@_android:name': string;
+      }
+    | {
+        '@_android:name': string;
+      }[];
+  category:
+    | {
+        '@_android:name': string;
+      }
+    | {
+        '@_android:name': string;
+      }[];
+}
+
+/**
+ * Reads the AndroidManifest.xml file and returns the name of the main activity.
+ */
+
+export default function readAndroidManifest(
+  manifestPath: string,
+): string | null {
+  try {
+    const xmlParser = new XMLParser({ignoreAttributes: false});
+    const manifestContent = fs.readFileSync(manifestPath, {encoding: 'utf8'});
+
+    if (XMLValidator.validate(manifestContent)) {
+      const {manifest} = xmlParser.parse(manifestContent);
+
+      const application = manifest.application || {};
+      const activity = application.activity || {};
+
+      let activities: Activity[] = [];
+
+      if (!Array.isArray(activity)) {
+        activities = [activity];
+      } else {
+        activities = activity;
+      }
+
+      const mainActivity = activities.find((act: Activity) => {
+        let intentFilters = act['intent-filter'];
+
+        if (!intentFilters) {
+          return false;
+        }
+
+        if (!Array.isArray(intentFilters)) {
+          intentFilters = [intentFilters];
+        }
+
+        return intentFilters.find((intentFilter: IntentFilter) => {
+          const {action, category} = intentFilter;
+
+          let actions;
+          let categories;
+
+          if (!Array.isArray(action)) {
+            actions = [action];
+          } else {
+            actions = action;
+          }
+
+          if (!Array.isArray(category)) {
+            categories = [category];
+          } else {
+            categories = category;
+          }
+
+          if (actions && categories) {
+            const parsedActions: string[] = actions.map(
+              ({'@_android:name': name}) => name,
+            );
+
+            const parsedCategories: string[] = categories.map(
+              ({'@_android:name': name}) => name,
+            );
+
+            return (
+              parsedActions.includes(MAIN_ACTION) &&
+              parsedCategories.includes(LAUNCHER)
+            );
+          }
+
+          return false;
+        });
+      });
+
+      return mainActivity
+        ? mainActivity['@_android:name'].replace('.', '')
+        : null;
+    } else {
+      return null;
+    }
+  } catch {
+    return null;
+  }
+}

packages/cli-types/src/android.ts

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

yarn.lock

@@ -6104,6 +6104,13 @@ fast-xml-parser@^4.0.12:
   dependencies:
     strnum "^1.0.5"
 
+fast-xml-parser@^4.2.4:
+  version "4.2.4"
+  resolved "https://registry.yarnpkg.com/fast-xml-parser/-/fast-xml-parser-4.2.4.tgz#6e846ede1e56ad9e5ef07d8720809edf0ed07e9b"
+  integrity sha512-fbfMDvgBNIdDJLdLOwacjFAPYt67tr31H9ZhWSm45CDAxvd0I6WTlSOUo7K2P/K5sA5JgMKG64PI3DMcaFdWpQ==
+  dependencies:
+    strnum "^1.0.5"
+
 fastparse@^1.1.1:
   version "1.1.2"
   resolved "https://registry.yarnpkg.com/fastparse/-/fastparse-1.1.2.tgz#91728c5a5942eced8531283c79441ee4122c35a9"