feat: migrate to react delegate wrapper

android/src/main/java/com/callstack/reactnativebrownfield/ReactDelegateWrapper.kt

@@ -0,0 +1,31 @@
+package com.callstack.reactnativebrownfield
+
+import android.os.Bundle
+import androidx.activity.ComponentActivity
+import com.facebook.react.ReactDelegate
+import com.facebook.react.ReactHost
+import com.facebook.react.modules.core.DefaultHardwareBackBtnHandler
+
+class ReactDelegateWrapper(
+    private val activity: ComponentActivity?,
+    private val reactHost: ReactHost,
+    moduleName: String,
+    launchOptions: Bundle?
+): ReactDelegate(activity, reactHost, moduleName, launchOptions){
+    private lateinit var hardwareBackHandler: () -> Unit
+    private val backBtnHandler = DefaultHardwareBackBtnHandler {
+        hardwareBackHandler()
+    }
+
+    /**
+     * This is invoked when there is no more RN Stack to pop.
+     * What it means that this is now the initial RN screen.
+     */
+    fun setHardwareBackHandler(backHandler: () -> Unit) {
+        hardwareBackHandler = backHandler
+    }
+
+    override fun onHostResume() {
+        reactHost.onHostResume(activity, backBtnHandler)
+    }
+}

android/src/main/java/com/callstack/reactnativebrownfield/ReactNativeBrownfield.kt

@@ -4,10 +4,10 @@ import android.app.Application
 import android.content.Context
 import android.os.Bundle
 import android.widget.FrameLayout
+import androidx.activity.OnBackPressedCallback
 import androidx.fragment.app.FragmentActivity
 import androidx.lifecycle.DefaultLifecycleObserver
 import androidx.lifecycle.LifecycleOwner
-import com.facebook.react.ReactDelegate
 import com.facebook.react.ReactInstanceEventListener
 import com.facebook.react.ReactInstanceManager
 import com.facebook.react.ReactNativeHost
@@ -99,32 +99,44 @@ class ReactNativeBrownfield private constructor(val reactNativeHost: ReactNative
     context: Context,
     activity: FragmentActivity?,
     moduleName: String,
+    reactDelegate: ReactDelegateWrapper? = null,
     launchOptions: Bundle? = null,
   ): FrameLayout {
     if (BuildConfig.IS_NEW_ARCHITECTURE_ENABLED) {
       val reactHost = getDefaultReactHost(
         context,
         shared.reactNativeHost
       )
-      val reactDelegate = ReactDelegate(activity, reactHost, moduleName, launchOptions)
 
-      activity?.lifecycle?.addObserver(object : DefaultLifecycleObserver {
-        override fun onResume(owner: LifecycleOwner) {
-          reactDelegate.onHostResume()
-        }
+      val resolvedDelegate = reactDelegate ?: ReactDelegateWrapper(activity, reactHost, moduleName, launchOptions)
 
-        override fun onPause(owner: LifecycleOwner) {
-          reactDelegate.onHostPause()
+      val mBackPressedCallback: OnBackPressedCallback = object : OnBackPressedCallback(true) {
+        override fun handleOnBackPressed() {
+          // invoked for JS stack back navigation
+          resolvedDelegate.onBackPressed()
         }
+      }
 
-        override fun onDestroy(owner: LifecycleOwner) {
-          reactDelegate.onHostDestroy()
-          owner.lifecycle.removeObserver(this) // Cleanup to avoid leaks
-        }
-      })
+      // Register back press callback
+      activity?.onBackPressedDispatcher?.addCallback(mBackPressedCallback)
+      // invoked on the last RN screen exit
+      resolvedDelegate.setHardwareBackHandler {
+        mBackPressedCallback.isEnabled = false
+        activity?.onBackPressedDispatcher?.onBackPressed()
+      }
 
-      reactDelegate.loadApp()
-      return reactDelegate.reactRootView!!
+      /**
+       * When createView method is called in ReactNativeFragment, a reactDelegate
+       * instance is required. In such a case, we use the lifeCycle events of the fragment.
+       * When createView method is called elsewhere, then reactDelegate is not required.
+       * In such a case, we set the lifeCycle observer.
+       */
+      if (reactDelegate == null) {
+        activity?.lifecycle?.addObserver(getLifeCycleObserver(resolvedDelegate))
+      }
+
+      resolvedDelegate.loadApp()
+      return resolvedDelegate.reactRootView!!
     }
 
     val instanceManager: ReactInstanceManager? = shared.reactNativeHost?.reactInstanceManager
@@ -137,5 +149,22 @@ class ReactNativeBrownfield private constructor(val reactNativeHost: ReactNative
 
     return reactView
   }
+
+  private fun getLifeCycleObserver(reactDelegate: ReactDelegateWrapper): DefaultLifecycleObserver {
+    return object : DefaultLifecycleObserver {
+      override fun onResume(owner: LifecycleOwner) {
+        reactDelegate.onHostResume()
+      }
+
+      override fun onPause(owner: LifecycleOwner) {
+        reactDelegate.onHostPause()
+      }
+
+      override fun onDestroy(owner: LifecycleOwner) {
+        reactDelegate.onHostDestroy()
+        owner.lifecycle.removeObserver(this) // Cleanup to avoid leaks
+      }
+    }
+  }
 }
 

android/src/main/java/com/callstack/reactnativebrownfield/ReactNativeFragment.kt

@@ -3,30 +3,60 @@ package com.callstack.reactnativebrownfield;
 import android.annotation.TargetApi
 import android.os.Build
 import android.os.Bundle
+import android.util.Log
 import android.view.KeyEvent
+import android.view.LayoutInflater
+import android.view.View
+import android.view.ViewGroup
 import com.facebook.infer.annotation.Assertions
 import com.facebook.react.ReactFragment
 import com.facebook.react.ReactHost
 import com.facebook.react.ReactNativeHost
 import com.facebook.react.bridge.Callback
 import com.facebook.react.bridge.WritableMap
-import com.facebook.react.common.LifecycleState
 import com.facebook.react.defaults.DefaultReactHost.getDefaultReactHost
 import com.facebook.react.devsupport.DoubleTapReloadRecognizer
-import com.facebook.react.modules.core.DefaultHardwareBackBtnHandler
 import com.facebook.react.modules.core.PermissionAwareActivity
 import com.facebook.react.modules.core.PermissionListener
 
 class ReactNativeFragment : ReactFragment(), PermissionAwareActivity {
   private lateinit var doubleTapReloadRecognizer: DoubleTapReloadRecognizer
   private lateinit var permissionsCallback: Callback
   private var permissionListener: PermissionListener? = null
+  private lateinit var moduleName: String
 
   override fun onCreate(savedInstanceState: Bundle?) {
-    super.onCreate(savedInstanceState)
+    /**
+     * ReactFragment.onCreate will throw an exception if we do not provide arg_component_name as arguments.
+     * We silently catch this exception. The reason is we want to invoke the super<Fragment>.onCreate in
+     * ReactFragment. Then initialise the mReactDelegate with ReactDelegateWrapper instead of ReactDelegate.
+     *
+     * So we purposely force ReactFragment.onCreate to throw an exception, so that we can provide our own
+     * implementation for mReactDelegate: ReactDelegateWrapper
+     */
+    try{
+      super.onCreate(savedInstanceState)
+    } catch (e: IllegalStateException){
+      Log.w("ReactNativeFragment", "ReactFragment threw due to missing arg_component_name: ${e.message} - This is an expected behaviour.")
+    }
+
+    moduleName = arguments?.getString(ARG_MODULE_NAME)!!
+    this.mReactDelegate = this.reactHost?.let {
+      ReactDelegateWrapper(activity,
+        it, moduleName, arguments?.getBundle("arg_launch_options"))
+    }
+
     doubleTapReloadRecognizer = DoubleTapReloadRecognizer()
   }
 
+  override fun onCreateView(
+    inflater: LayoutInflater,
+    container: ViewGroup?,
+    savedInstanceState: Bundle?
+  ): View {
+    return ReactNativeBrownfield.shared.createView(this.requireContext(), activity, moduleName, this.mReactDelegate as ReactDelegateWrapper)
+  }
+
   override fun getReactHost(): ReactHost? {
     return activity?.let {
       getDefaultReactHost(
@@ -40,36 +70,6 @@ class ReactNativeFragment : ReactFragment(), PermissionAwareActivity {
     return ReactNativeBrownfield.shared.reactNativeHost
   }
 
-  override fun onResume() {
-    super.onResume()
-    if (ReactNativeBrownfield.shared.reactNativeHost.hasInstance()) {
-      ReactNativeBrownfield.shared.reactNativeHost.reactInstanceManager?.onHostResume(
-        activity,
-        activity as DefaultHardwareBackBtnHandler
-      )
-    }
-  }
-
-  override fun onPause() {
-    super.onPause()
-    if (ReactNativeBrownfield.shared.reactNativeHost.hasInstance()) {
-      ReactNativeBrownfield.shared.reactNativeHost.reactInstanceManager?.onHostPause(
-        activity
-      )
-    }
-  }
-
-  override fun onDestroy() {
-    super.onDestroy()
-    if (ReactNativeBrownfield.shared.reactNativeHost.hasInstance()) {
-      val reactInstanceMgr = ReactNativeBrownfield.shared.reactNativeHost.reactInstanceManager
-
-      if (reactInstanceMgr.lifecycleState != LifecycleState.RESUMED) {
-        reactInstanceMgr.onHostDestroy(activity)
-      }
-    }
-  }
-
   override fun onRequestPermissionsResult(
     requestCode: Int,
     permissions: Array<String>,
@@ -118,22 +118,16 @@ class ReactNativeFragment : ReactFragment(), PermissionAwareActivity {
           .didDoubleTapR(keyCode, it)
       }
       if (didDoubleTapR == true) {
-        ReactNativeBrownfield.shared.reactNativeHost.reactInstanceManager.devSupportManager.handleReloadJS()
+        reactDelegate.reload()
         handled = true
       }
     }
     return handled
   }
 
-  fun onBackPressed(backBtnHandler: DefaultHardwareBackBtnHandler) {
-    if (ReactNativeBrownfieldModule.shouldPopToNative) {
-      backBtnHandler.invokeDefaultOnBackPressed()
-    } else if (ReactNativeBrownfield.shared.reactNativeHost.hasInstance()) {
-      ReactNativeBrownfield.shared.reactNativeHost.reactInstanceManager.onBackPressed()
-    }
-  }
-
   companion object {
+    private const val ARG_MODULE_NAME = "arg_module_name"
+
     @JvmStatic
     @JvmOverloads
     fun createReactNativeFragment(
@@ -142,7 +136,7 @@ class ReactNativeFragment : ReactFragment(), PermissionAwareActivity {
     ): ReactNativeFragment {
       val fragment = ReactNativeFragment()
       val args = Bundle()
-      args.putString(ARG_COMPONENT_NAME, moduleName)
+      args.putString(ARG_MODULE_NAME, moduleName)
       if (initialProps != null) {
         args.putBundle(ARG_LAUNCH_OPTIONS, initialProps)
       }

example/kotlin/app/src/main/java/com/callstack/kotlinexample/MainActivity.kt

@@ -22,9 +22,8 @@ import androidx.navigation.compose.NavHost
 import androidx.navigation.compose.composable
 import androidx.navigation.compose.rememberNavController
 import com.callstack.reactnativebrownfield.ReactNativeBrownfield
-import com.facebook.react.modules.core.DefaultHardwareBackBtnHandler
 
-class MainActivity : AppCompatActivity(), DefaultHardwareBackBtnHandler {
+class MainActivity : AppCompatActivity() {
   override fun onCreate(savedInstanceState: Bundle?) {
     super.onCreate(savedInstanceState)
 
@@ -60,10 +59,6 @@ class MainActivity : AppCompatActivity(), DefaultHardwareBackBtnHandler {
     }
   }
 
-  override fun invokeDefaultOnBackPressed() {
-    super.onBackPressed()
-  }
-
   fun startReactNativeFragment() {
     val intent = Intent(this, ReactNativeFragmentActivity::class.java)
     startActivity(intent)

example/kotlin/app/src/main/java/com/callstack/kotlinexample/ReactNativeFragmentActivity.kt

@@ -4,12 +4,8 @@ import android.os.Bundle
 import android.view.KeyEvent
 import androidx.appcompat.app.AppCompatActivity
 import com.callstack.reactnativebrownfield.ReactNativeFragment
-import com.facebook.react.modules.core.DefaultHardwareBackBtnHandler
 
-class ReactNativeFragmentActivity : AppCompatActivity(), DefaultHardwareBackBtnHandler {
-  override fun invokeDefaultOnBackPressed() {
-    super.onBackPressed()
-  }
+class ReactNativeFragmentActivity : AppCompatActivity() {
 
   public override fun onCreate(savedInstanceState: Bundle?) {
     super.onCreate(savedInstanceState)
@@ -31,13 +27,4 @@ class ReactNativeFragmentActivity : AppCompatActivity(), DefaultHardwareBackBtnH
     }
     return handled || super.onKeyUp(keyCode, event)
   }
-
-  override fun onBackPressed() {
-    val activeFragment = supportFragmentManager.findFragmentById(R.id.container_main)
-    if (activeFragment is ReactNativeFragment) {
-      activeFragment.onBackPressed(this)
-    } else {
-      super.onBackPressed()
-    }
-  }
 }