Fixes part of #5345: Fixing restarting of app on config change. (#5953)

Fixes part of #5345 :
This pull request improves the handling of dialog persistence in the
Feature Flags and Platform Parameters developer options screens,
specifically ensuring that pending changes and restart dialogs remain
visible after configuration changes (such as device rotation). It
introduces a new state variable to track dialog visibility, updates
fragment and presenter logic to restore dialogs, and adds tests to
verify this behavior. Additionally, it refines the app restart logic to
avoid unnecessary restarts during configuration changes.

**Dialog Persistence and State Management**

* Added an `PendingDialogListener` and implemented in
`PlatformParametersFragment` and `FeatureFlagsFragment` when the save
and discard are called from `PendingChangesDialogFragment`.

**App Restart Logic**

* Modified the app restart logic in both presenters to only restart the
app if the configuration is not changing, preventing unnecessary
restarts during device rotation.

**Testing**

* Added new instrumented tests for both fragments to verify that dialogs
(pending changes and restart dialogs) persist after configuration
changes, improving reliability and user experience.

**Code Cleanup**

* Removed extra `onBackNavigation` code in the
`PlatformParametersFragmentPresenter.kt` that might have been
duplicated.

These changes ensure a smoother and more predictable experience for
developers using the feature flags and platform parameters screens,
especially when making changes that require confirmation dialogs.

#### Screenrecording: 



https://github.com/user-attachments/assets/4642d72f-bfce-4179-9524-0e7aaa3971a9





## Essential Checklist
<!-- Please tick the relevant boxes by putting an "x" in them. -->
- [x] The PR title and explanation each start with "Fix #bugnum: " (If
this PR fixes part of an issue, prefix the title with "Fix part of
#bugnum: ...".)
- [x] Any changes to
[scripts/assets](https://github.com/oppia/oppia-android/tree/develop/scripts/assets)
files have their rationale included in the PR explanation.
- [x] The PR follows the [style
guide](https://github.com/oppia/oppia-android/wiki/Coding-style-guide).
- [x] The PR does not contain any unnecessary code changes from Android
Studio
([reference](https://github.com/oppia/oppia-android/wiki/Guidance-on-submitting-a-PR#undo-unnecessary-changes)).
- [x] The PR is made from a branch that's **not** called "develop" and
is up-to-date with "develop".
- [x] The PR is **assigned** to the appropriate reviewers
([reference](https://github.com/oppia/oppia-android/wiki/Guidance-on-submitting-a-PR#clarification-regarding-assignees-and-reviewers-section)).

---------

Co-authored-by: theayushyadav11 <[email protected]>
Co-authored-by: Manas <[email protected]>
Co-authored-by: Adhiambo Peres <[email protected]>
Co-authored-by: RD Rama Devi <[email protected]>

Author: 5 people

app/BUILD.bazel

@@ -92,6 +92,7 @@ LISTENERS = [
     "src/main/java/org/oppia/android/app/devoptions/RouteToMathExpressionParserTestListener.kt",
     "src/main/java/org/oppia/android/app/devoptions/RouteToPlatformParametersListener.kt",
     "src/main/java/org/oppia/android/app/devoptions/RouteToViewEventLogsListener.kt",
+    "src/main/java/org/oppia/android/app/devoptions/SavePendingChangesDialogListener.kt",
     "src/main/java/org/oppia/android/app/drawer/RouteToProfileProgressListener.kt",
     "src/main/java/org/oppia/android/app/help/LoadFaqListFragmentListener.kt",
     "src/main/java/org/oppia/android/app/help/LoadLicenseListFragmentListener.kt",

app/src/main/java/org/oppia/android/app/devoptions/AppRestartDialogFragmentPresenter.kt

@@ -22,14 +22,15 @@ class AppRestartDialogFragmentPresenter @Inject constructor(
     )
     binding.lifecycleOwner = fragment
 
+    val appRestartInterface = fragment.parentFragment as AppRestartListener
     val dialog = AlertDialog.Builder(activity, R.style.OppiaAlertDialogTheme)
       .setView(binding.root)
       .create()
     dialog.setCanceledOnTouchOutside(false)
 
     binding.restartButton.setOnClickListener {
+      appRestartInterface.restartApp()
       dialog.dismiss()
-      activity.finishAffinity()
     }
     return dialog
   }

app/src/main/java/org/oppia/android/app/devoptions/PendingChangesDialogFragment.kt

@@ -0,0 +1,30 @@
+package org.oppia.android.app.devoptions
+
+import android.app.Dialog
+import android.content.Context
+import android.os.Bundle
+import org.oppia.android.app.fragment.FragmentComponentImpl
+import org.oppia.android.app.fragment.InjectableDialogFragment
+import javax.inject.Inject
+
+/** Dialog fragment shown to prompt the user to save/discard the changes. */
+class PendingChangesDialogFragment : InjectableDialogFragment() {
+  @Inject
+  lateinit var pendingChangesDialogFragmentPresenter:
+    PendingChangesDialogFragmentPresenter
+
+  companion object {
+    /** Returns a new instance of [PendingChangesDialogFragment]. */
+    fun newInstance(): PendingChangesDialogFragment =
+      PendingChangesDialogFragment()
+  }
+
+  override fun onAttach(context: Context) {
+    super.onAttach(context)
+    (fragmentComponent as FragmentComponentImpl).inject(this)
+  }
+
+  override fun onCreateDialog(savedInstanceState: Bundle?): Dialog {
+    return pendingChangesDialogFragmentPresenter.handleOnCreateDialog()
+  }
+}

app/src/main/java/org/oppia/android/app/devoptions/PendingChangesDialogFragmentPresenter.kt

@@ -0,0 +1,42 @@
+package org.oppia.android.app.devoptions
+
+import android.app.AlertDialog
+import android.app.Dialog
+import androidx.appcompat.app.AppCompatActivity
+import androidx.fragment.app.Fragment
+import org.oppia.android.app.databinding.databinding.PendingChangesDialogFragmentBinding
+import org.oppia.android.app.ui.R
+import javax.inject.Inject
+
+/** Presenter for the [PendingChangesDialogFragment]. */
+class PendingChangesDialogFragmentPresenter @Inject constructor(
+  private val fragment: Fragment,
+  private val activity: AppCompatActivity,
+) {
+  /** Creates a dialog that prompts the user to save or discard the changes in the dashboard. */
+  fun handleOnCreateDialog(): Dialog {
+    val binding = PendingChangesDialogFragmentBinding.inflate(
+      activity.layoutInflater,
+      /* parent= */ null,
+      /* attachToRoot= */ false
+    )
+    binding.lifecycleOwner = fragment
+
+    val pendingChangesInterface = fragment.parentFragment as SavePendingChangesDialogListener
+    val dialog = AlertDialog.Builder(activity, R.style.OppiaAlertDialogTheme)
+      .setView(binding.root)
+      .create()
+    dialog.setCanceledOnTouchOutside(true)
+
+    binding.saveButton.setOnClickListener {
+      pendingChangesInterface.savePendingChanges()
+      dialog.dismiss()
+    }
+
+    binding.discardButton.setOnClickListener {
+      pendingChangesInterface.discardPendingChanges()
+      dialog.dismiss()
+    }
+    return dialog
+  }
+}

app/src/main/java/org/oppia/android/app/devoptions/SavePendingChangesDialogListener.kt

@@ -0,0 +1,11 @@
+package org.oppia.android.app.devoptions
+
+/** Interface to be implemented by classes that need to handle pending changes. */
+interface SavePendingChangesDialogListener {
+
+  /** Saves the pending changes. */
+  fun savePendingChanges()
+
+  /** Discards the pending changes and exits the screen. */
+  fun discardPendingChanges()
+}

app/src/main/java/org/oppia/android/app/devoptions/featureflags/FeatureFlagsFragment.kt

@@ -5,6 +5,8 @@ import android.os.Bundle
 import android.view.LayoutInflater
 import android.view.View
 import android.view.ViewGroup
+import org.oppia.android.app.devoptions.AppRestartListener
+import org.oppia.android.app.devoptions.SavePendingChangesDialogListener
 import org.oppia.android.app.fragment.FragmentComponentImpl
 import org.oppia.android.app.fragment.InjectableFragment
 import org.oppia.android.app.model.FeatureFlagId
@@ -15,7 +17,10 @@ import org.oppia.android.util.extensions.putProto
 import javax.inject.Inject
 
 /** Fragment to provide functionality to view and modify feature flags of the app. */
-class FeatureFlagsFragment : InjectableFragment() {
+class FeatureFlagsFragment :
+  InjectableFragment(),
+  AppRestartListener,
+  SavePendingChangesDialogListener {
   @Inject
   lateinit var featureFlagsFragmentPresenter: FeatureFlagsFragmentPresenter
 
@@ -86,8 +91,15 @@ class FeatureFlagsFragment : InjectableFragment() {
     outState.putProto(FEATURE_FLAGS_FRAGMENT_SAVED_STATE_KEY, proto)
   }
 
-  override fun onDestroy() {
-    super.onDestroy()
-    featureFlagsFragmentPresenter.handleOnDestroy()
+  override fun restartApp() {
+    featureFlagsFragmentPresenter.restartApp()
+  }
+
+  override fun savePendingChanges() {
+    featureFlagsFragmentPresenter.savePendingChanges()
+  }
+
+  override fun discardPendingChanges() {
+    featureFlagsFragmentPresenter.discardPendingChanges()
   }
 }

app/src/main/java/org/oppia/android/app/devoptions/featureflags/FeatureFlagsFragmentPresenter.kt

@@ -1,6 +1,5 @@
 package org.oppia.android.app.devoptions.featureflags
 
-import android.app.AlertDialog
 import android.content.Intent
 import android.view.LayoutInflater
 import android.view.View
@@ -12,8 +11,8 @@ import androidx.fragment.app.Fragment
 import androidx.recyclerview.widget.LinearLayoutManager
 import org.oppia.android.app.databinding.databinding.FeatureFlagsFragmentBinding
 import org.oppia.android.app.databinding.databinding.FeatureFlagsItemBinding
-import org.oppia.android.app.databinding.databinding.PendingChangesDialogFragmentBinding
 import org.oppia.android.app.devoptions.AppRestartDialogFragment
+import org.oppia.android.app.devoptions.PendingChangesDialogFragment
 import org.oppia.android.app.fragment.FragmentScope
 import org.oppia.android.app.model.FeatureFlagId
 import org.oppia.android.app.model.OverriddenFeatureFlag
@@ -31,6 +30,9 @@ import kotlin.system.exitProcess
 /** Tag for displaying [AppRestartDialogFragment]. */
 const val TAG_FEATURE_FLAG_RESTART_DIALOG = "FEATURE_FLAG_RESTART_DIALOG_TAG"
 
+/** Tag for displaying [PendingChangesDialogFragment]. */
+const val TAG_FEATURE_FLAG_PENDING_CHANGES_DIALOG = "FEATURE_FLAG_PENDING_CHANGES_DIALOG_TAG"
+
 /** The presenter for [FeatureFlagsFragment]. */
 @FragmentScope
 class FeatureFlagsFragmentPresenter @Inject constructor(
@@ -44,7 +46,6 @@ class FeatureFlagsFragmentPresenter @Inject constructor(
   private lateinit var binding: FeatureFlagsFragmentBinding
   private lateinit var linearLayoutManager: LinearLayoutManager
   private lateinit var bindingAdapter: BindableAdapter<FeatureFlagItemViewModel>
-  private var restartRequired: Boolean = false
 
   /** Called when [FeatureFlagsFragment] is created. Handles UI for the fragment. */
   fun handleCreateView(
@@ -58,13 +59,6 @@ class FeatureFlagsFragmentPresenter @Inject constructor(
       container,
       /* attachToRoot= */ false
     )
-    binding.featureFlagsToolbar.setNavigationOnClickListener {
-      onBackNavigation()
-    }
-    binding.saveButton.setOnClickListener {
-      val overriddenFlags = computeOverriddenFlags()
-      savePendingFeatureFlags(overriddenFlags)
-    }
 
     activity.onBackPressedDispatcher.addCallback(
       fragment,
@@ -82,16 +76,23 @@ class FeatureFlagsFragmentPresenter @Inject constructor(
       featureFlagsViewModel.resetFlags.value = resetFlags.toMutableMap()
     }
 
-    binding.apply {
-      this.lifecycleOwner = fragment
-      this.viewModel = featureFlagsViewModel
-    }
-
     linearLayoutManager = LinearLayoutManager(activity.applicationContext)
     bindingAdapter = createRecyclerViewAdapter()
-    binding.featureFlagsRecyclerView.apply {
-      layoutManager = linearLayoutManager
-      adapter = bindingAdapter
+
+    binding.apply {
+      lifecycleOwner = fragment
+      viewModel = featureFlagsViewModel
+      saveButton.setOnClickListener {
+        val overriddenFlags = computeOverriddenFlags()
+        savePendingFeatureFlags(overriddenFlags)
+      }
+      featureFlagsToolbar.setNavigationOnClickListener {
+        onBackNavigation()
+      }
+      featureFlagsRecyclerView.apply {
+        layoutManager = linearLayoutManager
+        adapter = bindingAdapter
+      }
     }
 
     return binding.root
@@ -111,33 +112,15 @@ class FeatureFlagsFragmentPresenter @Inject constructor(
     val resetFlags = getResetFeatureFlags()
 
     if (overriddenFlags.isNotEmpty() || resetFlags.isNotEmpty()) {
-      showPendingChangesDialog(overriddenFlags)
+      showPendingChangesDialog()
     } else {
       activity.finish()
     }
   }
 
-  private fun showPendingChangesDialog(overriddenFlags: List<OverriddenFeatureFlag>) {
-    val dialogBinding = PendingChangesDialogFragmentBinding.inflate(
-      LayoutInflater.from(activity),
-      /* root= */ null,
-      /* attachToRoot= */ false
-    )
-    val dialog = AlertDialog.Builder(activity)
-      .setView(dialogBinding.root)
-      .create()
-
-    dialogBinding.saveButton.setOnClickListener {
-      dialog.dismiss()
-      savePendingFeatureFlags(overriddenFlags)
-    }
-
-    dialogBinding.discardButton.setOnClickListener {
-      dialog.dismiss()
-      activity.finish()
-    }
-
-    dialog.show()
+  private fun showPendingChangesDialog() {
+    val dialog = PendingChangesDialogFragment.newInstance()
+    dialog.showNow(fragment.childFragmentManager, TAG_FEATURE_FLAG_PENDING_CHANGES_DIALOG)
   }
 
   private fun savePendingFeatureFlags(overriddenFlags: List<OverriddenFeatureFlag>) {
@@ -190,7 +173,6 @@ class FeatureFlagsFragmentPresenter @Inject constructor(
       .observe(fragment) { result ->
         when (result) {
           is AsyncResult.Success -> {
-            restartRequired = true
             val dialog = AppRestartDialogFragment.newInstance()
             dialog.showNow(fragment.childFragmentManager, TAG_FEATURE_FLAG_RESTART_DIALOG)
           }
@@ -273,21 +255,15 @@ class FeatureFlagsFragmentPresenter @Inject constructor(
     }
   }
 
-  /**
-   * Called when [FeatureFlagsFragment] is destroyed.
-   * Performs a fresh restart of the app to load any updated feature flag states, if required.
-   */
-  fun handleOnDestroy() {
-    if (restartRequired) {
-      val intent = Intent(activity, SplashActivity::class.java).also {
-        it.action = Intent.ACTION_MAIN
-        it.addCategory(Intent.CATEGORY_LAUNCHER)
-      }
-      activity.startActivity(intent)
-      // App is terminated to ensure a fresh restart and kill all the current process
-      // so that ProcessState can be reinitialised on the fresh restart.
-      exitProcess(0)
-    }
+  /** Called when user opts to save changes in [PendingChangesDialogFragment]. */
+  fun savePendingChanges() {
+    val overriddenFlags = computeOverriddenFlags()
+    savePendingFeatureFlags(overriddenFlags)
+  }
+
+  /** Called when user opts to discard changes in [PendingChangesDialogFragment]. */
+  fun discardPendingChanges() {
+    activity.finish()
   }
 
   /**
@@ -309,4 +285,20 @@ class FeatureFlagsFragmentPresenter @Inject constructor(
   fun getFeatureFlagStates(): Map<FeatureFlagId, Boolean> {
     return featureFlagsViewModel.featureFlagStates.value ?: mapOf()
   }
+
+  /**
+   * Performs a fresh restart of the app to reload feature flag states and reinitialize
+   * the app processState.
+   */
+  fun restartApp() {
+    val intent = Intent(activity, SplashActivity::class.java).also {
+      it.action = Intent.ACTION_MAIN
+      it.addCategory(Intent.CATEGORY_LAUNCHER)
+    }
+    activity.finishAffinity()
+    activity.startActivity(intent)
+    // App is terminated to ensure a fresh restart and kill all the current process
+    // so that ProcessState can be reinitialised on the fresh restart.
+    exitProcess(0)
+  }
 }

app/src/main/java/org/oppia/android/app/devoptions/platformparameters/PlatformParametersFragment.kt

@@ -5,6 +5,8 @@ import android.os.Bundle
 import android.view.LayoutInflater
 import android.view.View
 import android.view.ViewGroup
+import org.oppia.android.app.devoptions.AppRestartListener
+import org.oppia.android.app.devoptions.SavePendingChangesDialogListener
 import org.oppia.android.app.fragment.FragmentComponentImpl
 import org.oppia.android.app.fragment.InjectableFragment
 import org.oppia.android.app.model.OverriddenPlatformParameter
@@ -16,7 +18,10 @@ import org.oppia.android.util.extensions.putProto
 import javax.inject.Inject
 
 /** Fragment to provide functionality to view and modify platform parameters of the app. */
-class PlatformParametersFragment : InjectableFragment() {
+class PlatformParametersFragment :
+  InjectableFragment(),
+  AppRestartListener,
+  SavePendingChangesDialogListener {
   @Inject
   lateinit var platformParametersFragmentPresenter: PlatformParametersFragmentPresenter
 
@@ -42,7 +47,6 @@ class PlatformParametersFragment : InjectableFragment() {
     val platformParameterStates:
       MutableMap<PlatformParameterId, PlatformParameterValue?> = mutableMapOf()
     val resetParamList: MutableMap<PlatformParameterId, PlatformParameterValue> = mutableMapOf()
-
     if (savedInstanceState != null) {
       val args = savedInstanceState.getProto(
         PLATFORM_PARAMETERS_FRAGMENT_SAVED_STATE_KEY,
@@ -85,6 +89,7 @@ class PlatformParametersFragment : InjectableFragment() {
           .setOverriddenValue(value)
           .build()
       }
+
     val proto = PlatformParametersFragmentStateBundle.newBuilder()
       .addAllPlatformParameterStates(validParameterOverrides)
       .addAllResetPlatformParameters(resetParamList)
@@ -94,8 +99,15 @@ class PlatformParametersFragment : InjectableFragment() {
     )
   }
 
-  override fun onDestroy() {
-    super.onDestroy()
-    platformParametersFragmentPresenter.handleOnDestroy()
+  override fun restartApp() {
+    platformParametersFragmentPresenter.appRestart()
+  }
+
+  override fun savePendingChanges() {
+    platformParametersFragmentPresenter.savePendingChanges()
+  }
+
+  override fun discardPendingChanges() {
+    platformParametersFragmentPresenter.discardPendingChanges()
   }
 }