Add2App: Fix crash resulted from hard-code module 'app' based resource copy. (#27154)

packages/flutter_tools/gradle/flutter.gradle

@@ -429,8 +429,16 @@ class FlutterPlugin implements Plugin<Project> {
             }
 
             if (packageAssets) {
+                String mainModuleName = "app"
+                try {
+                    String tmpModuleName = project.rootProject.ext.mainModuleName
+                    if (tmpModuleName != null && !tmpModuleName.empty) {
+                        mainModuleName = tmpModuleName
+                    }
+                } catch (Exception e) {
+                }
                 // Only include configurations that exist in parent project.
-                Task mergeAssets = project.tasks.findByPath(":app:merge${variant.name.capitalize()}Assets")
+                Task mergeAssets = project.tasks.findByPath(":${mainModuleName}:merge${variant.name.capitalize()}Assets")
                 if (mergeAssets) {
                     mergeAssets.dependsOn(copyFlutterAssetsTask)
                 }

packages/flutter_tools/templates/module/android/library/include_flutter.groovy.copy.tmpl

@@ -19,6 +19,12 @@ plugins.each { name, path ->
 }
 
 gradle.getGradle().projectsLoaded { g ->
+    g.rootProject.beforeEvaluate { p ->
+        _mainModuleName = binding.variables['mainModuleName']
+        if (_mainModuleName != null && !_mainModuleName.empty) {
+            p.ext.mainModuleName = _mainModuleName
+        }
+    }
     g.rootProject.afterEvaluate { p ->
         p.subprojects { sp ->
             if (sp.name != 'flutter') {