feat(previewer): motion controllers

Author: BrayanDSO

AnkiDroid/src/main/java/com/ichi2/anki/previewer/PreviewerFragment.kt

@@ -24,6 +24,7 @@ import android.view.MenuItem
 import android.view.View
 import android.webkit.WebView
 import androidx.appcompat.widget.Toolbar
+import androidx.coordinatorlayout.widget.CoordinatorLayout
 import androidx.core.os.BundleCompat
 import androidx.core.os.bundleOf
 import androidx.core.view.isVisible
@@ -45,6 +46,7 @@ import com.ichi2.anki.reviewer.BindingProcessor
 import com.ichi2.anki.reviewer.MappableBinding
 import com.ichi2.anki.snackbar.BaseSnackbarBuilderProvider
 import com.ichi2.anki.snackbar.SnackbarBuilder
+import com.ichi2.anki.utils.ext.collectIn
 import com.ichi2.anki.utils.ext.sharedPrefs
 import com.ichi2.annotations.NeedsTest
 import com.ichi2.utils.performClickIfEnabled
@@ -178,6 +180,16 @@ class PreviewerFragment :
             viewModel.onPreviousButtonClick()
         }
 
+        view.setOnGenericMotionListener { _, event ->
+            bindingMap.onGenericMotionEvent(event)
+        }
+
+        viewModel.showingAnswer.collectIn(lifecycleScope) {
+            // focus on the whole layout so motion controllers can be captured
+            // without navigating the other View elements
+            view.findViewById<CoordinatorLayout>(R.id.root_layout).requestFocus()
+        }
+
         view.findViewById<MaterialToolbar>(R.id.toolbar).apply {
             setOnMenuItemClickListener(this@PreviewerFragment)
             setNavigationOnClickListener { requireActivity().onBackPressedDispatcher.onBackPressed() }

AnkiDroid/src/main/res/layout/previewer.xml

@@ -7,6 +7,7 @@
     android:layout_height="match_parent"
     android:fitsSystemWindows="true"
     android:background="?attr/alternativeBackgroundColor"
+    android:focusableInTouchMode="true"
     tools:context=".previewer.PreviewerFragment">
 
     <androidx.constraintlayout.widget.ConstraintLayout