Migrate ReactActivity (#50871)

Summary:
Pull Request resolved: #50871

# Changelog:
[Android][Changed] - ReactActivity has been migrated to Kotlin.

Reviewed By: cortinico

Differential Revision: D73507044

fbshipit-source-id: 936263100ca93dafd643a53e5cb799fd5ed7e584

Author: rshest

packages/helloworld/android/app/src/main/java/com/helloworld/MainActivity.kt

@@ -18,7 +18,8 @@ class MainActivity : ReactActivity() {
    * Returns the name of the main component registered from JavaScript. This is used to schedule
    * rendering of the component.
    */
-  override fun getMainComponentName(): String = "HelloWorld"
+  override val mainComponentName: String?
+    get() = "HelloWorld"
 
   /**
    * Returns the instance of the [ReactActivityDelegate]. We use [DefaultReactActivityDelegate]

packages/react-native/ReactAndroid/src/main/java/com/facebook/react/ReactActivity.java

@@ -0,0 +1,136 @@
+/*
+ * Copyright (c) Meta Platforms, Inc. and affiliates.
+ *
+ * This source code is licensed under the MIT license found in the
+ * LICENSE file in the root directory of this source tree.
+ */
+
+package com.facebook.react
+
+import android.content.Intent
+import android.content.res.Configuration
+import android.os.Bundle
+import android.view.KeyEvent
+import androidx.appcompat.app.AppCompatActivity
+import com.facebook.react.modules.core.DefaultHardwareBackBtnHandler
+import com.facebook.react.modules.core.PermissionAwareActivity
+import com.facebook.react.modules.core.PermissionListener
+
+/** Base Activity for React Native applications. */
+public abstract class ReactActivity protected constructor() :
+    AppCompatActivity(), DefaultHardwareBackBtnHandler, PermissionAwareActivity {
+
+  public open val reactActivityDelegate: ReactActivityDelegate = createReactActivityDelegate()
+
+  public open val reactDelegate: ReactDelegate?
+    get() = reactActivityDelegate.reactDelegate
+
+  protected open val reactHost: ReactHost?
+    get() = reactActivityDelegate.reactHost
+
+  protected val reactNativeHost: ReactNativeHost
+    get() = reactActivityDelegate.reactNativeHost
+
+  protected val reactInstanceManager: ReactInstanceManager
+    get() = reactActivityDelegate.reactInstanceManager
+
+  /**
+   * Returns the name of the main component registered from JavaScript. This is used to schedule
+   * rendering of the component. e.g. "MoviesApp"
+   */
+  protected open val mainComponentName: String?
+    get() = null
+
+  /** Called at construction time, override if you have a custom delegate implementation. */
+  protected open fun createReactActivityDelegate(): ReactActivityDelegate {
+    return ReactActivityDelegate(this, mainComponentName)
+  }
+
+  override fun onCreate(savedInstanceState: Bundle?) {
+    super.onCreate(savedInstanceState)
+    reactActivityDelegate.onCreate(savedInstanceState)
+  }
+
+  override fun onPause() {
+    super.onPause()
+    reactActivityDelegate.onPause()
+  }
+
+  override fun onResume() {
+    super.onResume()
+    reactActivityDelegate.onResume()
+  }
+
+  override fun onDestroy() {
+    super.onDestroy()
+    reactActivityDelegate.onDestroy()
+  }
+
+  override public fun onActivityResult(requestCode: Int, resultCode: Int, data: Intent?) {
+    super.onActivityResult(requestCode, resultCode, data)
+    reactActivityDelegate.onActivityResult(requestCode, resultCode, data)
+  }
+
+  override fun onKeyDown(keyCode: Int, event: KeyEvent?): Boolean =
+      reactActivityDelegate.onKeyDown(keyCode, event) || super.onKeyDown(keyCode, event)
+
+  override fun onKeyUp(keyCode: Int, event: KeyEvent?): Boolean =
+      reactActivityDelegate.onKeyUp(keyCode, event) || super.onKeyUp(keyCode, event)
+
+  override fun onKeyLongPress(keyCode: Int, event: KeyEvent?): Boolean =
+      reactActivityDelegate.onKeyLongPress(keyCode, event) || super.onKeyLongPress(keyCode, event)
+
+  @Suppress("DEPRECATION")
+  @Deprecated("Deprecated in Java")
+  override fun onBackPressed() {
+    if (!reactActivityDelegate.onBackPressed()) {
+      super.onBackPressed()
+    }
+  }
+
+  override fun invokeDefaultOnBackPressed() {
+    @Suppress("DEPRECATION") super.onBackPressed()
+  }
+
+  override public fun onNewIntent(intent: Intent) {
+    if (!reactActivityDelegate.onNewIntent(intent)) {
+      super.onNewIntent(intent)
+    }
+  }
+
+  override public fun onUserLeaveHint() {
+    super.onUserLeaveHint()
+    reactActivityDelegate.onUserLeaveHint()
+  }
+
+  override fun requestPermissions(
+      permissions: Array<String>,
+      requestCode: Int,
+      listener: PermissionListener?
+  ) {
+    reactActivityDelegate.requestPermissions(permissions, requestCode, listener)
+  }
+
+  override fun onRequestPermissionsResult(
+      requestCode: Int,
+      permissions: Array<String>,
+      grantResults: IntArray
+  ) {
+    super.onRequestPermissionsResult(requestCode, permissions, grantResults)
+    reactActivityDelegate.onRequestPermissionsResult(requestCode, permissions, grantResults)
+  }
+
+  override fun onWindowFocusChanged(hasFocus: Boolean) {
+    super.onWindowFocusChanged(hasFocus)
+    reactActivityDelegate.onWindowFocusChanged(hasFocus)
+  }
+
+  override fun onConfigurationChanged(newConfig: Configuration) {
+    super.onConfigurationChanged(newConfig)
+    reactActivityDelegate.onConfigurationChanged(newConfig)
+  }
+
+  protected fun loadApp(appKey: String?) {
+    reactActivityDelegate.loadApp(appKey)
+  }
+}

packages/react-native/ReactAndroid/src/main/java/com/facebook/react/ReactActivity.kt

@@ -110,7 +110,7 @@ public ReactInstanceManager getReactInstanceManager() {
     return mReactDelegate.getReactInstanceManager();
   }
 
-  public String getMainComponentName() {
+  public @Nullable String getMainComponentName() {
     return mMainComponentName;
   }
 

packages/react-native/ReactAndroid/src/main/java/com/facebook/react/ReactActivityDelegate.java

@@ -21,7 +21,7 @@ import com.facebook.react.ReactActivityDelegate
  */
 public open class DefaultReactActivityDelegate(
     activity: ReactActivity,
-    mainComponentName: String,
+    mainComponentName: String?,
     private val fabricEnabled: Boolean = false,
 ) : ReactActivityDelegate(activity, mainComponentName) {
 

packages/react-native/ReactAndroid/src/main/java/com/facebook/react/defaults/DefaultReactActivityDelegate.kt

@@ -22,7 +22,7 @@ import java.io.FileDescriptor
 import java.io.PrintWriter
 
 internal class RNTesterActivity : ReactActivity() {
-  class RNTesterActivityDelegate(val activity: ReactActivity, mainComponentName: String) :
+  class RNTesterActivityDelegate(val activity: ReactActivity, mainComponentName: String?) :
       DefaultReactActivityDelegate(activity, mainComponentName, fabricEnabled) {
     private val PARAM_ROUTE = "route"
     private lateinit var initialProps: Bundle
@@ -43,6 +43,9 @@ internal class RNTesterActivity : ReactActivity() {
         if (this::initialProps.isInitialized) initialProps else Bundle()
   }
 
+  override val mainComponentName: String?
+    get() = "RNTesterApp"
+
   override fun onCreate(savedInstanceState: Bundle?) {
     super.onCreate(savedInstanceState)
 
@@ -52,7 +55,7 @@ internal class RNTesterActivity : ReactActivity() {
     this.window?.setBackgroundDrawable(ColorDrawable(Color.BLACK))
     // register insets listener to update margins on the ReactRootView to avoid overlap w/ system
     // bars
-    getReactDelegate()?.getReactRootView()?.let { rootView ->
+    reactDelegate?.getReactRootView()?.let { rootView ->
       val insetsType: Int =
           WindowInsetsCompat.Type.systemBars() or WindowInsetsCompat.Type.displayCutout()
 
@@ -71,8 +74,6 @@ internal class RNTesterActivity : ReactActivity() {
 
   override fun createReactActivityDelegate() = RNTesterActivityDelegate(this, mainComponentName)
 
-  override fun getMainComponentName() = "RNTesterApp"
-
   override fun dump(
       prefix: String,
       fd: FileDescriptor?,