Refactor PromotedStoryListView.kt BindableAdapterTest.kt classes to p…

…rovide Adapter through injection for isuue oppia#2658.

app/src/main/java/org/oppia/android/app/home/promotedlist/PromotedStoryListView.kt

@@ -41,18 +41,30 @@ class PromotedStoryListView @JvmOverloads constructor(
   lateinit var promotedDataList: List<PromotedStoryViewModel>
 
   override fun onAttachedToWindow() {
-    super.onAttachedToWindow()
-    val viewComponentFactory =
-      FragmentManager.findFragment<Fragment>(this) as ViewComponentFactory
-    val viewComponent = viewComponentFactory.createViewComponent(this) as ViewComponentImpl
-    viewComponent.inject(this)
+    try {
+      super.onAttachedToWindow()
+      val viewComponentFactory =
+        FragmentManager.findFragment<Fragment>(this) as ViewComponentFactory
+      val viewComponent = viewComponentFactory.createViewComponent(this) as ViewComponentImpl
+      viewComponent.inject(this)
 
-    // The StartSnapHelper is used to snap between items rather than smooth scrolling, so that
-    // the item is completely visible in [HomeFragment] as soon as learner lifts the finger
-    // after scrolling.
-    val snapHelper = StartSnapHelper()
-    onFlingListener = null
-    snapHelper.attachToRecyclerView(this)
+      // The StartSnapHelper is used to snap between items rather than smooth scrolling, so that
+      // the item is completely visible in [HomeFragment] as soon as learner lifts the finger
+      // after scrolling.
+      val snapHelper = StartSnapHelper()
+      onFlingListener = null
+      snapHelper.attachToRecyclerView(this)
+
+      checkIfComponentsInitialized()
+    } catch (e: IllegalStateException) {
+      if (::oppiaLogger.isInitialized) {
+        oppiaLogger.e(
+          "PromotedStoryListView",
+          "Throws exception on attach to window",
+          e
+        )
+      }
+    }
   }
 
   private fun checkIfComponentsInitialized() {

app/src/main/java/org/oppia/android/app/recyclerview/BindableAdapter.kt

@@ -5,7 +5,9 @@ import android.view.View
 import android.view.ViewGroup
 import androidx.databinding.ViewDataBinding
 import androidx.fragment.app.Fragment
+import androidx.lifecycle.LifecycleOwner
 import androidx.recyclerview.widget.RecyclerView
+import java.lang.ref.WeakReference
 import javax.inject.Inject
 import kotlin.reflect.KClass
 
@@ -93,6 +95,34 @@ class BindableAdapter<T : Any> internal constructor(
     internal abstract fun bind(data: T)
   }
 
+  /**
+   * The base builder for [BindableAdapter]. This class should not be used directly--use either
+   * [SingleTypeBuilder] or [MultiTypeBuilder] instead.
+   */
+  abstract class BaseBuilder(fragment: Fragment) {
+    /**
+     * A [WeakReference] to a [LifecycleOwner] for databinding inflation.
+     * Note that this needs to be a weak reference so that long-held references to the adapter do
+     * not potentially leak lifecycle owners (such as fragments and activities).
+     */
+    private var lifecycleOwnerRef: WeakReference<LifecycleOwner> = WeakReference(fragment)
+
+    /**
+     * Returns the [LifecycleOwner] bound to this adapter, or null if there isn't one. This method
+     * will throw if there was a lifecycle owner bound but is now expired.
+     */
+    protected fun getLifecycleOwner(): LifecycleOwner? {
+      // Crash if the lifecycle owner has been cleaned up since it's not valid to use the adapter
+      // with an old lifecycle owner, and silently ignoring this may result in part of the layout
+      // not responding to events.
+      return lifecycleOwnerRef?.let { ref ->
+        checkNotNull(ref.get()) {
+          "Attempted to inflate data binding with expired lifecycle owner"
+        }
+      }
+    }
+  }
+
   /**
    * Constructs a new [BindableAdapter] that for a single view type.
    *
@@ -101,7 +131,7 @@ class BindableAdapter<T : Any> internal constructor(
   class SingleTypeBuilder<T : Any>(
     private val dataClassType: KClass<T>,
     private val fragment: Fragment
-  ) {
+  ) : BaseBuilder(fragment) {
     private lateinit var viewHolderFactory: ViewHolderFactory<T>
 
     /**
@@ -173,10 +203,10 @@ class BindableAdapter<T : Any> internal constructor(
           /* attachToRoot= */ false
         )
 
-        binding.lifecycleOwner = fragment.viewLifecycleOwner
         object : BindableViewHolder<T>(binding.root) {
           override fun bind(data: T) {
             setViewModel(binding, data)
+            binding.lifecycleOwner = getLifecycleOwner()
           }
         }
       }
@@ -216,7 +246,7 @@ class BindableAdapter<T : Any> internal constructor(
     private val dataClassType: KClass<T>,
     private val computeViewType: ComputeViewType<T, E>,
     private val fragment: Fragment
-  ) {
+  ) : BaseBuilder(fragment) {
     private var viewHolderFactoryMap: MutableMap<E, ViewHolderFactory<T>> = HashMap()
 
     /**
@@ -301,10 +331,10 @@ class BindableAdapter<T : Any> internal constructor(
           /* attachToRoot= */ false
         )
 
-        binding.lifecycleOwner = fragment.viewLifecycleOwner
         object : BindableViewHolder<T>(binding.root) {
           override fun bind(data: T) {
             setViewModel(binding, transformViewModel(data))
+            binding.lifecycleOwner = getLifecycleOwner()
           }
         }
       }

app/src/main/java/org/oppia/android/app/testing/BindableAdapterTestFragmentPresenter.kt

@@ -12,6 +12,8 @@ import javax.inject.Inject
 /** The test-only fragment presenter corresponding to [BindableAdapterTestFragment]. */
 class BindableAdapterTestFragmentPresenter @Inject constructor(
   private val fragment: Fragment,
+  private val singleTypeBuilder: BindableAdapter.SingleTypeBuilder.Factory,
+  private val multiTypeBuilder: BindableAdapter.MultiTypeBuilder.Factory,
   private val testBindableAdapterFactory: BindableAdapterFactory,
   @VisibleForTesting val viewModel: BindableAdapterTestViewModel
 ) {
@@ -22,7 +24,7 @@ class BindableAdapterTestFragmentPresenter @Inject constructor(
       /* attachToRoot= */ false
     )
     binding.testRecyclerView.apply {
-      adapter = testBindableAdapterFactory.create(fragment)
+      adapter = testBindableAdapterFactory.create(singleTypeBuilder, multiTypeBuilder)
     }
     binding.let {
       it.viewModel = viewModel
@@ -33,6 +35,9 @@ class BindableAdapterTestFragmentPresenter @Inject constructor(
 
   /** Factory for creating new [BindableAdapter]s for the current fragment. */
   interface BindableAdapterFactory {
-    fun create(fragment: Fragment): BindableAdapter<BindableAdapterTestDataModel>
+    fun create(
+      singleTypeBuilder: BindableAdapter.SingleTypeBuilder.Factory,
+      multiTypeBuilder: BindableAdapter.MultiTypeBuilder.Factory
+    ): BindableAdapter<BindableAdapterTestDataModel>
   }
 }