Add support for exporting to Google Play Instant

Author: kojurohan42

platform/android/doc_classes/EditorExportPlatformAndroid.xml

@@ -55,6 +55,11 @@
 		<member name="gradle_build/export_format" type="int" setter="" getter="">
 			Application export format (*.apk or *.aab).
 		</member>
+		<member name="gradle_build/google_play_instant" type="bool" setter="" getter="">
+			If [code]true[/code], configures the exported project for Play Instant Build.
+			Use this option when targeting Play Instant to allow users to launch the app without installation. See [url=https://developer.android.com/topic/google-play-instant/overview]Google Play Instant[/url].
+			[b]Note:[/b] Instant play games also need to be optimized for size. See [url=https://docs.godotengine.org/en/stable/contributing/development/compiling/optimizing_for_size.html]Optimizing a build for size[/url].
+		</member>
 		<member name="gradle_build/gradle_build_directory" type="String" setter="" getter="">
 			Path to the Gradle build directory. If left empty, then [code]res://android[/code] will be used.
 		</member>

platform/android/export/export_plugin.cpp

@@ -280,6 +280,7 @@ static const int EXPORT_FORMAT_AAB = 1;
 
 static const char *APK_ASSETS_DIRECTORY = "assets";
 static const char *AAB_ASSETS_DIRECTORY = "assetPackInstallTime/src/main/assets";
+static const char *INSTANT_APP_ASSETS_DIRECTORY = "assets"; // instant build doesn't support installTime assetspacks, so using the same directory as APK
 
 static const int DEFAULT_MIN_SDK_VERSION = 24; // Should match the value in 'platform/android/java/app/config.gradle#minSdk'
 static const int DEFAULT_TARGET_SDK_VERSION = 35; // Should match the value in 'platform/android/java/app/config.gradle#targetSdk'
@@ -524,6 +525,12 @@ String EditorExportPlatformAndroid::get_valid_basename(const Ref<EditorExportPre
 
 String EditorExportPlatformAndroid::get_assets_directory(const Ref<EditorExportPreset> &p_preset, int p_export_format) const {
 	String gradle_build_directory = ExportTemplateManager::get_android_build_directory(p_preset);
+
+	bool google_play_instant_build = p_preset->get("gradle_build/google_play_instant");
+	if (google_play_instant_build) {
+		return gradle_build_directory.path_join(INSTANT_APP_ASSETS_DIRECTORY); // Always use base APK asset format
+	}
+
 	return gradle_build_directory.path_join(p_export_format == EXPORT_FORMAT_AAB ? AAB_ASSETS_DIRECTORY : APK_ASSETS_DIRECTORY);
 }
 
@@ -993,10 +1000,19 @@ void EditorExportPlatformAndroid::_get_manifest_info(const Ref<EditorExportPrese
 
 void EditorExportPlatformAndroid::_write_tmp_manifest(const Ref<EditorExportPreset> &p_preset, bool p_give_internet, bool p_debug) {
 	print_verbose("Building temporary manifest...");
+
+	bool google_play_instant_build = (bool)p_preset->get("gradle_build/google_play_instant");
+
 	String manifest_text =
 			"<?xml version=\"1.0\" encoding=\"utf-8\"?>\n"
 			"<manifest xmlns:android=\"http://schemas.android.com/apk/res/android\"\n"
-			"    xmlns:tools=\"http://schemas.android.com/tools\">\n";
+			"    xmlns:tools=\"http://schemas.android.com/tools\"";
+
+	if (google_play_instant_build) {
+		manifest_text += " android:targetSandboxVersion=\"2\" \n    xmlns:dist=\"http://schemas.android.com/apk/distribution\"";
+	}
+
+	manifest_text += ">\n";
 
 	manifest_text += _get_screen_sizes_tag(p_preset);
 	manifest_text += _get_gles_tag();
@@ -1030,6 +1046,7 @@ void EditorExportPlatformAndroid::_write_tmp_manifest(const Ref<EditorExportPres
 	}
 
 	manifest_text += _get_application_tag(Ref<EditorExportPlatform>(this), p_preset, _has_read_write_storage_permission(perms), p_debug, manifest_metadata);
+
 	manifest_text += "</manifest>\n";
 	String manifest_path = ExportTemplateManager::get_android_build_directory(p_preset).path_join(vformat("src/%s/AndroidManifest.xml", (p_debug ? "debug" : "release")));
 
@@ -1955,6 +1972,12 @@ String EditorExportPlatformAndroid::get_export_option_warning(const EditorExport
 			if (int(p_preset->get("gradle_build/export_format")) == EXPORT_FORMAT_AAB && !gradle_build_enabled) {
 				return TTR("\"Export AAB\" is only valid when \"Use Gradle Build\" is enabled.");
 			}
+		} else if (p_name == "gradle_build/google_play_instant") {
+			bool instant_enabled = p_preset->get("gradle_build/google_play_instant");
+			bool gradle_build_enabled = p_preset->get("gradle_build/use_gradle_build");
+			if (instant_enabled && !gradle_build_enabled) {
+				return TTR("\"Instant Build\" is only valid when \"Use Gradle Build\" is enabled.");
+			}
 		} else if (p_name == "gradle_build/min_sdk") {
 			String min_sdk_str = p_preset->get("gradle_build/min_sdk");
 			bool gradle_build_enabled = p_preset->get("gradle_build/use_gradle_build");
@@ -2022,6 +2045,7 @@ void EditorExportPlatformAndroid::get_export_options(List<ExportOption> *r_optio
 	r_options->push_back(ExportOption(PropertyInfo(Variant::STRING, "gradle_build/gradle_build_directory", PROPERTY_HINT_PLACEHOLDER_TEXT, "res://android"), "", false, false));
 	r_options->push_back(ExportOption(PropertyInfo(Variant::STRING, "gradle_build/android_source_template", PROPERTY_HINT_GLOBAL_FILE, "*.zip"), ""));
 	r_options->push_back(ExportOption(PropertyInfo(Variant::INT, "gradle_build/export_format", PROPERTY_HINT_ENUM, "Export APK,Export AAB"), EXPORT_FORMAT_APK, false, true));
+	r_options->push_back(ExportOption(PropertyInfo(Variant::BOOL, "gradle_build/google_play_instant"), false, true, true));
 	// Using String instead of int to default to an empty string (no override) with placeholder for instructions (see GH-62465).
 	// This implies doing validation that the string is a proper int.
 	r_options->push_back(ExportOption(PropertyInfo(Variant::STRING, "gradle_build/min_sdk", PROPERTY_HINT_PLACEHOLDER_TEXT, vformat("%d (default)", DEFAULT_MIN_SDK_VERSION)), "", false, true));
@@ -3494,6 +3518,7 @@ Error EditorExportPlatformAndroid::export_project_helper(const Ref<EditorExportP
 		String enabled_abi_string = join_abis(enabled_abis, "|", false);
 		String sign_flag = should_sign ? "true" : "false";
 		String zipalign_flag = "true";
+		String play_instant_flag = bool_to_string(p_preset->get("gradle_build/google_play_instant"));
 
 		Vector<String> android_libraries;
 		Vector<String> android_dependencies;
@@ -3568,6 +3593,7 @@ Error EditorExportPlatformAndroid::export_project_helper(const Ref<EditorExportP
 		cmdline.push_back("-Pplugins_maven_repos=" + combined_android_dependencies_maven_repos); // argument to specify the list of maven repos for android dependencies provided by plugins.
 		cmdline.push_back("-Pperform_zipalign=" + zipalign_flag); // argument to specify whether the build should be zipaligned.
 		cmdline.push_back("-Pperform_signing=" + sign_flag); // argument to specify whether the build should be signed.
+		cmdline.push_back("-Pplay_instant_app=" + play_instant_flag); // argument to specify whether the build is for Google Play Instant.
 
 		// NOTE: The release keystore is not included in the verbose logging
 		// to avoid accidentally leaking sensitive information when sharing verbose logs for troubleshooting.

platform/android/export/gradle_export_util.cpp

@@ -315,6 +315,8 @@ String _get_application_tag(const Ref<EditorExportPlatform> &p_export_platform,
 	int app_category_index = (int)(p_preset->get("package/app_category"));
 	bool is_game = app_category_index == APP_CATEGORY_GAME;
 
+	bool google_play_instant_build = (bool)p_preset->get("gradle_build/google_play_instant");
+
 	String manifest_application_text = vformat(
 			"    <application android:label=\"@string/godot_project_name_string\"\n"
 			"        android:allowBackup=\"%s\"\n"
@@ -335,6 +337,10 @@ String _get_application_tag(const Ref<EditorExportPlatform> &p_export_platform,
 	}
 	manifest_application_text += "        tools:ignore=\"GoogleAppIndexingWarning\">\n\n";
 
+	if (google_play_instant_build) {
+		manifest_application_text += "        <dist:module dist:instant=\"true\" />\n";
+	}
+
 	for (int i = 0; i < p_metadata.size(); i++) {
 		manifest_application_text += vformat("        <meta-data tools:node=\"replace\" android:name=\"%s\" android:value=\"%s\" />\n", p_metadata[i].name, p_metadata[i].value);
 	}

platform/android/java/app/build.gradle

@@ -37,6 +37,10 @@ dependencies {
     implementation "androidx.fragment:fragment:$versions.fragmentVersion"
     implementation "androidx.core:core-splashscreen:$versions.splashscreenVersion"
 
+    if (isInstantApp()) {
+        implementation "com.google.android.gms:play-services-instantapps:$versions.instantAppsVersion"
+    }
+
     if (rootProject.findProject(":lib")) {
         implementation project(":lib")
     } else if (rootProject.findProject(":godot:lib")) {
@@ -90,7 +94,7 @@ android {
         jvmTarget = versions.javaVersion
     }
 
-    assetPacks = [":assetPackInstallTime"]
+    assetPacks = isInstantApp() ? [] : [":assetPackInstallTime"]
 
     namespace = 'com.godot.game'
 

platform/android/java/app/config.gradle

@@ -15,7 +15,8 @@ ext.versions = [
     // Also update 'platform/android/detect.py#get_ndk_version()' when this is updated.
     ndkVersion         : '28.1.13356709',
     splashscreenVersion: '1.0.1',
-    openxrVendorsVersion: '4.0.0-stable'
+    openxrVendorsVersion: '4.0.0-stable',
+    instantAppsVersion: '17.0.0'
 
 ]
 
@@ -379,3 +380,8 @@ ext.getAddonsDirectory = { ->
     String addonsDirectory = project.hasProperty("addons_directory") ? project.property("addons_directory") : ""
     return addonsDirectory
 }
+
+ext.isInstantApp = { ->
+    String instantApp = project.hasProperty("play_instant_app") ? project.property("play_instant_app") : ""
+    return Boolean.parseBoolean(instantApp)
+}