Fix: Retain scroll position for privacy policy screen after orientati…

…on change
oppia · Dec 22, 2024 · 37cd0a8 · 37cd0a8
1 parent bc0483d
commit 37cd0a8
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Showing 2 changed files with 31 additions and 3 deletions.
diff --git a/app/src/main/java/org/oppia/android/app/policies/PoliciesFragment.kt b/app/src/main/java/org/oppia/android/app/policies/PoliciesFragment.kt
@@ -48,6 +48,11 @@ class PoliciesFragment : InjectableFragment() {
         POLICIES_FRAGMENT_POLICY_PAGE_ARGUMENT_PROTO,
         PoliciesFragmentArguments.getDefaultInstance()
       )
-    return policiesFragmentPresenter.handleCreateView(inflater, container, policies)
+    return policiesFragmentPresenter.handleCreateView(inflater, container, policies, savedInstanceState)
+  }
+
+  override fun onSaveInstanceState(outState: Bundle) {
+    super.onSaveInstanceState(outState)
+    policiesFragmentPresenter.handleSaveInstanceState(outState)
   }
 }
diff --git a/app/src/main/java/org/oppia/android/app/policies/PoliciesFragmentPresenter.kt b/app/src/main/java/org/oppia/android/app/policies/PoliciesFragmentPresenter.kt
@@ -1,8 +1,10 @@
 package org.oppia.android.app.policies
 
+import android.os.Bundle
 import android.view.LayoutInflater
 import android.view.View
 import android.view.ViewGroup
+import android.widget.ScrollView
 import androidx.appcompat.app.AppCompatActivity
 import org.oppia.android.R
 import org.oppia.android.app.fragment.FragmentScope
@@ -22,22 +24,39 @@ class PoliciesFragmentPresenter @Inject constructor(
   private val resourceHandler: AppLanguageResourceHandler
 ) : HtmlParser.PolicyOppiaTagActionListener {
 
+  private lateinit var binding: PoliciesFragmentBinding
+  private var scrollPosition = 0
+
   /** Handles onCreate() method of the [PoliciesFragment]. */
   fun handleCreateView(
     inflater: LayoutInflater,
     container: ViewGroup?,
-    policiesFragmentArguments: PoliciesFragmentArguments
+    policiesFragmentArguments: PoliciesFragmentArguments,
+    savedInstanceState: Bundle?
   ): View {
-    val binding = PoliciesFragmentBinding.inflate(
+    binding = PoliciesFragmentBinding.inflate(
       inflater,
       container,
       /* attachToRoot= */ false
     )
+
+    savedInstanceState?.let {
+      scrollPosition = it.getInt(KEY_SCROLL_Y, 0)
+    }
+
     setUpContentForTextViews(policiesFragmentArguments.policyPage, binding)
 
+    (binding.root as ScrollView).viewTreeObserver.addOnGlobalLayoutListener {
+      binding.root.scrollTo(0, scrollPosition)
+    }
+
     return binding.root
   }
 
+  fun handleSaveInstanceState(outState: Bundle) {
+    outState.putInt(KEY_SCROLL_Y, (binding.root as ScrollView).scrollY)
+  }
+
   private fun setUpContentForTextViews(
     policyPage: PolicyPage,
     binding: PoliciesFragmentBinding
@@ -86,4 +105,8 @@ class PoliciesFragmentPresenter @Inject constructor(
         (activity as RouteToPoliciesListener).onRouteToPolicies(PolicyPage.TERMS_OF_SERVICE)
     }
   }
+
+  companion object {
+    private const val KEY_SCROLL_Y = "policies_scroll_y"
+  }
 }