refactor(core): generate TauriActivity on build script

.changes/generate-tauri-activity.md

@@ -0,0 +1,5 @@
+---
+"tauri": patch
+---
+
+Generate `TauriActivity` Kotlin class on the build script.

.github/workflows/test-android.yml

@@ -2,7 +2,7 @@
 # SPDX-License-Identifier: Apache-2.0
 # SPDX-License-Identifier: MIT
 
-name: test mobile
+name: test android
 
 on:
   pull_request:
@@ -14,6 +14,7 @@ on:
       - '!tooling/cli/src/mobile/ios/**'
       - 'core/tauri-build/src/mobile.rs'
       - 'core/tauri/mobile/android/**'
+      - 'core/tauri/mobile/android-codegen/**'
   workflow_dispatch:
 
 concurrency:

core/tauri-runtime-wry/Cargo.toml

@@ -13,7 +13,7 @@ exclude = [ "CHANGELOG.md", "/target" ]
 readme = "README.md"
 
 [dependencies]
-wry = { version = "0.28.1", default-features = false, features = [ "file-drop", "protocol" ] }
+wry = { version = "0.28.2", default-features = false, features = [ "file-drop", "protocol" ] }
 tauri-runtime = { version = "0.13.0-alpha.4", path = "../tauri-runtime" }
 tauri-utils = { version = "2.0.0-alpha.4", path = "../tauri-utils" }
 uuid = { version = "1", features = [ "v4" ] }

core/tauri/build.rs

@@ -9,6 +9,9 @@ use heck::ToSnakeCase;
 use once_cell::sync::OnceCell;
 
 use std::env::var_os;
+use std::fs::read_dir;
+use std::fs::read_to_string;
+use std::fs::write;
 use std::{
   env::var,
   path::{Path, PathBuf},
@@ -150,7 +153,46 @@ fn main() {
   }
 
   if target_os == "android" {
-    if let Some(project_dir) = var_os("TAURI_ANDROID_PROJECT_PATH").map(PathBuf::from) {
+    if let Ok(kotlin_out_dir) = std::env::var("WRY_ANDROID_KOTLIN_FILES_OUT_DIR") {
+      fn env_var(var: &str) -> String {
+        std::env::var(var).unwrap_or_else(|_| {
+          panic!(
+            "`{}` is not set, which is needed to generate the kotlin files for android.",
+            var
+          )
+        })
+      }
+
+      let package = env_var("WRY_ANDROID_PACKAGE");
+      let library = env_var("WRY_ANDROID_LIBRARY");
+
+      let kotlin_out_dir = PathBuf::from(&kotlin_out_dir)
+        .canonicalize()
+        .unwrap_or_else(move |_| {
+          panic!("Failed to canonicalize `WRY_ANDROID_KOTLIN_FILES_OUT_DIR` path {kotlin_out_dir}")
+        });
+
+      let kotlin_files_path =
+        PathBuf::from(env_var("CARGO_MANIFEST_DIR")).join("mobile/android-codegen");
+      println!("cargo:rerun-if-changed={}", kotlin_files_path.display());
+      let kotlin_files =
+        read_dir(kotlin_files_path).expect("failed to read Android codegen directory");
+
+      for file in kotlin_files {
+        let file = file.unwrap();
+
+        let content = read_to_string(file.path())
+          .expect("failed to read kotlin file as string")
+          .replace("{{package}}", &package)
+          .replace("{{library}}", &library);
+
+        let out_path = kotlin_out_dir.join(file.file_name());
+        write(&out_path, content).expect("Failed to write kotlin file");
+        println!("cargo:rerun-if-changed={}", out_path.display());
+      }
+    }
+
+    if let Some(project_dir) = var_os("WRY_ANDROID_PROJECT_PATH").map(PathBuf::from) {
       let tauri_proguard = include_str!("./mobile/proguard-tauri.pro").replace(
         "$PACKAGE",
         &var("WRY_ANDROID_PACKAGE").expect("missing `WRY_ANDROID_PACKAGE` environment variable"),

tooling/cli/templates/mobile/android/app/src/main/generated/TauriActivity.kt → core/tauri/mobile/android-codegen/TauriActivity.kt

@@ -1,4 +1,10 @@
-package {{reverse-domain app.domain}}.{{snake-case app.name}}
+// Copyright 2019-2023 Tauri Programme within The Commons Conservancy
+// SPDX-License-Identifier: Apache-2.0
+// SPDX-License-Identifier: MIT
+
+/* THIS FILE IS AUTO-GENERATED. DO NOT MODIFY!! */
+
+package {{package}}
 
 import android.os.Bundle
 import app.tauri.plugin.PluginManager