Use databinding for some widgets

app/build.gradle.kts

@@ -34,6 +34,7 @@ android {
         jvmTarget = "1.8"
     }
     buildFeatures {
+        dataBinding = true
         viewBinding = true
     }
 }

app/src/main/java/com/lhw/pdf/ui/gallery/GalleryFragment.kt

@@ -33,6 +33,7 @@ class GalleryFragment : Fragment() {
 //        val galleryViewModel = ViewModelProvider(this)[GalleryViewModel::class.java]
 
         _binding = FragmentGalleryBinding.inflate(inflater, container, false)
+        binding.viewModel = galleryViewModel
         val root: View = binding.root
 
         val chipGroupPages = binding.chipGroupPages
@@ -45,19 +46,12 @@ class GalleryFragment : Fragment() {
             pageZoomLevelChips[pages] = chip
         }
         pageZoomLevelChips[galleryViewModel.pagesPerLandscape.value]?.isChecked = true
-        binding.chipAutoCrop.isChecked = galleryViewModel.renderAutoCrop.value!!
-        binding.chipUsePdfBox.isChecked = galleryViewModel.usePdfBox.value!!
 
-        galleryViewModel.textDisplays.observe(viewLifecycleOwner) { binding.textDisplays.text = it }
-        galleryViewModel.usePdfBox.observe(viewLifecycleOwner) { binding.chipUsePdfBox.isChecked = it }
-        galleryViewModel.renderAutoCrop.observe(viewLifecycleOwner) { binding.chipAutoCrop.isChecked = it }
+        galleryViewModel.textDisplays.observe(viewLifecycleOwner) { binding.textDisplays.text = it }  // TODO: Investigate why the binding, even when set @=, in the XML is insufficient for live updates
         galleryViewModel.pagesPerLandscape.observe(viewLifecycleOwner) {
             pageZoomLevelChips[it]?.isChecked = true
         }
 
-        binding.chipAutoCrop.setOnCheckedChangeListener { _, checked -> galleryViewModel.renderAutoCrop.value = checked }
-        binding.chipUsePdfBox.setOnCheckedChangeListener { _, checked -> galleryViewModel.usePdfBox.value = checked }
-
         galleryViewModel.pageThumbnails.observe(viewLifecycleOwner, ::populateThumbnails)
 
         val container = binding.thumbnailsLayout

app/src/main/res/layout/fragment_gallery.xml

@@ -1,4 +1,8 @@
 <?xml version="1.0" encoding="utf-8"?>
+<layout>
+    <data>
+        <variable name="viewModel" type="com.lhw.pdf.ui.gallery.GalleryViewModel" />
+    </data>
 <androidx.constraintlayout.widget.ConstraintLayout xmlns:android="http://schemas.android.com/apk/res/android"
     xmlns:app="http://schemas.android.com/apk/res-auto"
     xmlns:tools="http://schemas.android.com/tools"
@@ -45,6 +49,7 @@
             android:layout_height="wrap_content"
             android:layout_marginStart="8dp"
             android:layout_marginEnd="8dp"
+            android:text="@{viewModel.textDisplays}"
             android:textAlignment="center"
             android:textSize="20sp" />
 
@@ -66,7 +71,7 @@
             <com.google.android.material.chip.Chip
                 android:id="@+id/chip_auto_crop"
                 android:checkable="true"
-                android:checked="true"
+                android:checked="@={viewModel.renderAutoCrop}"
                 android:layout_width="wrap_content"
                 android:layout_height="wrap_content"
                 android:text="Auto Crop" />
@@ -74,6 +79,7 @@
             <com.google.android.material.chip.Chip
                 android:id="@+id/chip_use_pdf_box"
                 android:checkable="true"
+                android:checked="@={viewModel.usePdfBox}"
                 android:layout_width="wrap_content"
                 android:layout_height="wrap_content"
                 android:text="Use PdfBox renderer (slower)" />
@@ -81,3 +87,4 @@
 
     </LinearLayout>
 </androidx.constraintlayout.widget.ConstraintLayout>
+</layout>