adding android main activity path to cli config (#4294)

Co-authored-by: Jonathan Kelley <jkelleyrtp@gmail.com>

packages/cli/src/build/request.rs

@@ -2939,13 +2939,18 @@ impl BuildRequest {
         )?;
 
         // Write the main activity manually since tao dropped support for it
-        write(
+        let main_activity = match self.config.application.android_main_activity.as_deref() {
-            self.wry_android_kotlin_files_out_dir()
+            Some(activity) => std::fs::read_to_string(self.package_manifest_dir().join(activity))
-                .join("MainActivity.kt"),
+                .context("Failed to locate custom MainActivity.kt")?,
-            hbs.render_template(
+            _ => hbs.render_template(
                 include_str!("../../assets/android/MainActivity.kt.hbs"),
                 &hbs_data,
             )?,
+        };
+        write(
+            self.wry_android_kotlin_files_out_dir()
+                .join("MainActivity.kt"),
+            main_activity,
         )?;
 
         // Write the res folder, containing stuff like default icons, colors, and menubars.

packages/cli/src/config/app.rs

@@ -34,4 +34,8 @@ pub(crate) struct ApplicationConfig {
     /// `dx` will merge any required settings into this file required to build the app
     #[serde(default)]
     pub(crate) android_manifest: Option<PathBuf>,
+
+    /// Use this file for the MainActivity.kt associated with the Android app.
+    #[serde(default)]
+    pub(crate) android_main_activity: Option<PathBuf>,
 }

packages/cli/src/config/dioxus_config.rs

@@ -21,6 +21,7 @@ impl Default for DioxusConfig {
                 tailwind_output: None,
                 ios_info_plist: None,
                 android_manifest: None,
+                android_main_activity: None,
                 macos_info_plist: None,
                 ios_entitlements: None,
                 macos_entitlements: None,