[Fragment] Add onNewInstance callback.

instacart · Dec 12, 2023 · ab6dd4c · ab6dd4c
1 parent 877827f
commit ab6dd4c
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Showing 4 changed files with 53 additions and 57 deletions.
diff --git a/formula-android/src/main/java/com/instacart/formula/android/FormulaFragment.kt b/formula-android/src/main/java/com/instacart/formula/android/FormulaFragment.kt
@@ -1,8 +1,6 @@
 package com.instacart.formula.android
 
-import android.content.Context
 import android.os.Bundle
-import android.os.SystemClock
 import android.view.LayoutInflater
 import android.view.View
 import android.view.ViewGroup
@@ -30,25 +28,38 @@ class FormulaFragment : Fragment(), BaseFormulaFragment<Any> {
         requireArguments().getParcelable<FragmentKey>(ARG_CONTRACT)!!
     }
 
+    private val formulaFragmentId: FragmentId by lazy {
+        getFormulaFragmentId()
+    }
+
+    private val environment: FragmentEnvironment
+        get() = FormulaFragmentDelegate.fragmentEnvironment()
+
+    private val fragmentDelegate: FragmentEnvironment.FragmentDelegate
+        get() = environment.fragmentDelegate
+
+    private var calledNewInstance = false
+
     private var featureView: FeatureView<Any>? = null
     private var output: Any? = null
 
-    private var initializedAtMillis: Long? = SystemClock.uptimeMillis()
-    private var firstRender = true
-
     private val lifecycleCallback: FragmentLifecycleCallback?
         get() = featureView?.lifecycleCallbacks
 
-    override fun onAttach(context: Context) {
-        super.onAttach(context)
-        if (initializedAtMillis == null) {
-            initializedAtMillis = SystemClock.uptimeMillis()
+    override fun setArguments(args: Bundle?) {
+        super.setArguments(args)
+
+        /**
+         * To ensure that we have both fragment key and formula instance id, we need
+         * to wait for arguments to be set.
+         */
+        if (!calledNewInstance) {
+            calledNewInstance = true
+            fragmentDelegate.onNewInstance(formulaFragmentId)
         }
     }
 
     override fun onCreateView(inflater: LayoutInflater, container: ViewGroup?, savedInstanceState: Bundle?): View? {
-        firstRender = true
-
         val viewFactory = FormulaFragmentDelegate.viewFactory(this) ?: run {
             // No view factory, no view
             return null
@@ -102,8 +113,6 @@ class FormulaFragment : Fragment(), BaseFormulaFragment<Any> {
     }
 
     override fun onDestroyView() {
-        initializedAtMillis = null
-
         lifecycleCallback?.onDestroyView()
         super.onDestroyView()
         featureView = null
@@ -130,22 +139,8 @@ class FormulaFragment : Fragment(), BaseFormulaFragment<Any> {
         val output = output ?: return
         val view = featureView ?: return
 
-        val fragmentId = getFormulaFragmentId()
-        val environment = FormulaFragmentDelegate.fragmentEnvironment()
-        val fragmentDelegate = environment.fragmentDelegate
-
         try {
-            fragmentDelegate.setOutput(fragmentId, output, view.setOutput)
-
-            if (firstRender) {
-                val end = SystemClock.uptimeMillis()
-
-                firstRender = false
-                fragmentDelegate.onFirstModelRendered(
-                    fragmentId = fragmentId,
-                    durationInMillis = end - (initializedAtMillis ?: SystemClock.uptimeMillis()),
-                )
-            }
+            fragmentDelegate.setOutput(formulaFragmentId, output, view.setOutput)
         } catch (exception: Exception) {
             environment.onScreenError(key, exception)
         }

diff --git a/formula-android/src/main/java/com/instacart/formula/android/FragmentEnvironment.kt b/formula-android/src/main/java/com/instacart/formula/android/FragmentEnvironment.kt
@@ -14,6 +14,13 @@ data class FragmentEnvironment(
      */
     open class FragmentDelegate {
 
+        /**
+         * Called when new instance of [FormulaFragment] is created.
+         */
+        open fun onNewInstance(
+            fragmentId: FragmentId
+        ) = Unit
+
         /**
          * Instantiates the feature.
          */
@@ -44,11 +51,5 @@ data class FragmentEnvironment(
         open fun setOutput(fragmentId: FragmentId, output: Any, applyOutputToView: (Any) -> Unit) {
             applyOutputToView(output)
         }
-
-        /**
-         * Called after first render model is rendered. The [durationInMillis] starts
-         * when formula fragment is initialized and ends after first render model is applied.
-         */
-        open fun onFirstModelRendered(fragmentId: FragmentId, durationInMillis: Long) = Unit
     }
 }
diff --git a/...la-android/src/main/java/com/instacart/formula/android/internal/FragmentFlowRenderView.kt b/...la-android/src/main/java/com/instacart/formula/android/internal/FragmentFlowRenderView.kt
@@ -95,8 +95,6 @@ internal class FragmentFlowRenderView(
 
         override fun onFragmentAttached(fm: FragmentManager, f: Fragment, context: Context) {
             super.onFragmentAttached(fm, f, context)
-            initializeFragmentInstanceIdIfNeeded(f)
-
             if (FragmentLifecycle.shouldTrack(f)) {
                 onLifecycleEvent(FragmentLifecycle.createAddedEvent(f))
             } else {
@@ -141,7 +139,6 @@ internal class FragmentFlowRenderView(
     }
 
     fun viewFactory(fragment: FormulaFragment): ViewFactory<Any> {
-        initializeFragmentInstanceIdIfNeeded(fragment)
         return FormulaFragmentViewFactory(
             environment = fragmentEnvironment,
             fragmentId = fragment.getFormulaFragmentId(),
@@ -162,23 +159,4 @@ internal class FragmentFlowRenderView(
             }
         }
     }
-
-    /**
-     * Creates a unique identifier the first time fragment is attached that
-     * is persisted across configuration changes.
-     */
-    private fun initializeFragmentInstanceIdIfNeeded(f: Fragment) {
-        if (f is BaseFormulaFragment<*>) {
-            val arguments = f.arguments ?: run {
-                Bundle().apply {
-                    f.arguments = this
-                }
-            }
-            val id = arguments.getString(FormulaFragment.ARG_FORMULA_ID, "")
-            if (id.isNullOrBlank()) {
-                val initializedId = UUID.randomUUID().toString()
-                arguments.putString(FormulaFragment.ARG_FORMULA_ID, initializedId)
-            }
-        }
-    }
 }
diff --git a/formula-android/src/main/java/com/instacart/formula/android/internal/FragmentLifecycle.kt b/formula-android/src/main/java/com/instacart/formula/android/internal/FragmentLifecycle.kt
@@ -1,5 +1,6 @@
 package com.instacart.formula.android.internal
 
+import android.os.Bundle
 import androidx.fragment.app.Fragment
 import androidx.fragment.app.FragmentInspector
 import androidx.fragment.app.FragmentManager
@@ -8,6 +9,7 @@ import com.instacart.formula.android.FragmentKey
 import com.instacart.formula.android.BaseFormulaFragment
 import com.instacart.formula.android.FormulaFragment
 import com.instacart.formula.android.events.FragmentLifecycleEvent
+import java.util.UUID
 
 /**
  * Provides utility method [lifecycleEvents] to track what fragments are added and removed from the backstack.
@@ -37,8 +39,28 @@ private fun Fragment.getFragmentKey(): FragmentKey {
     return fragment?.getFragmentKey() ?: EmptyFragmentKey(tag.orEmpty())
 }
 
+/**
+ * Gets a persisted across configuration changes fragment identifier or initializes
+ * one if it doesn't exist.
+ */
 private fun Fragment.getFragmentInstanceId(): String {
-    return arguments?.getString(FormulaFragment.ARG_FORMULA_ID) ?: ""
+    return if (this is BaseFormulaFragment<*>) {
+        val arguments = arguments ?: run {
+            Bundle().apply {
+                arguments = this
+            }
+        }
+        val id = arguments.getString(FormulaFragment.ARG_FORMULA_ID, "")
+        if (id.isNullOrBlank()) {
+            val initializedId = UUID.randomUUID().toString()
+            arguments.putString(FormulaFragment.ARG_FORMULA_ID, initializedId)
+            initializedId
+        } else {
+            id
+        }
+    } else {
+        ""
+    }
 }
 
 internal fun Fragment.getFormulaFragmentId(): FragmentId {