Long-click in home or gallery to toggle hide group.

Add keyboard dpad page turning for bluetooth pedals.

app/src/main/java/com/lhw/pdf/MainActivity.kt

@@ -8,6 +8,7 @@ import android.hardware.display.DisplayManager.DisplayListener
 import android.os.Bundle
 import android.util.DisplayMetrics
 import android.view.Display
+import android.view.KeyEvent
 import android.view.Menu
 import android.view.WindowManager
 import android.widget.ImageView
@@ -45,11 +46,17 @@ class MainActivity : AppCompatActivity() {
     private var renderAutoCrop = true
     private var pagesPerLandscape = 3F
     private var thumbnailScrollProgress = 0F
+    private var scrollNumPagesProgress: Float
+        get() = viewModel.scrollNumPagesProgress.value ?: 0F
+        set(f) { viewModel.scrollNumPagesProgress.value = f }
     private var usePdfBox = false
     private val presentations = mutableMapOf<Int, MyPresentation>()
     private lateinit var pdfDocument: PdfDocument
     private val hiddenPageGroups = mutableSetOf<Int>()
     private val pageGroups = mutableListOf<Int>()
+    private var enabledPageIds: List<Int>
+        get() = viewModel.enabledPageIds.value ?: listOf()
+        set(ids) { viewModel.enabledPageIds.value = ids }
     private val defaultCachedFileName = "cached.pdf"
 
     private fun setPagesPerLandscape(pages: Float) {
@@ -94,12 +101,12 @@ class MainActivity : AppCompatActivity() {
         updateBitmaps(maxWidth, maxHeight)
         val key = Pair(maxWidth, maxHeight)
         val bitmapPages = pdfDocument.bitmapPages[key]
-        val bitmaps = viewModel.enabledPageIds.value?.mapNotNull { bitmapPages?.get(it) }?.toList() ?: listOf()
+        val bitmaps = enabledPageIds.mapNotNull { bitmapPages?.get(it) }.toList()
         p.updateImages(bitmaps)
     }
 
     private fun updatePresentations(reRender: Boolean = true) {
-        viewModel.enabledPageIds.value = pageGroups.mapIndexedNotNull { i, group -> if (group !in hiddenPageGroups) i else null }.toList()
+        enabledPageIds = pageGroups.mapIndexedNotNull { i, group -> if (group !in hiddenPageGroups) i else null }.toList()
 
         if (reRender) pdfDocument.invalidateCache()
         presentations.values.forEach(::updatePresentationImages)
@@ -187,7 +194,6 @@ class MainActivity : AppCompatActivity() {
         viewModel.pageGroups.value = pageGroups.toList()
         viewModel.pageThumbnails.value = pdfDocument.bitmapThumbnails.toSortedMap().values.toList()
 
-
         viewModel.pagesPerLandscape.observe(this) {
             setPagesPerLandscape(it)
         }
@@ -211,7 +217,10 @@ class MainActivity : AppCompatActivity() {
             updatePresentations(false)
         }
         viewModel.thumbnailScrollProgress.observe(this) { thumbnailScrollProgress ->
-            presentations.values.forEach {it.setScrollProgress(thumbnailScrollProgress)}
+            presentations.values.forEach { it.setScrollProgress(thumbnailScrollProgress) }
+        }
+        viewModel.scrollNumPagesProgress.observe(this) { scrollNumPagesProgress ->
+            presentations.values.forEach { it.setScrollPagesProgress(scrollNumPagesProgress) }
         }
 
         val drawerLayout: DrawerLayout = binding.drawerLayout
@@ -255,4 +264,27 @@ class MainActivity : AppCompatActivity() {
         val navController = findNavController(R.id.nav_host_fragment_content_main)
         return navController.navigateUp(appBarConfiguration) || super.onSupportNavigateUp()
     }
+
+    override fun onKeyUp(keyCode: Int, event: KeyEvent): Boolean {
+        // Use the directional arrows to turn pages
+        return when (keyCode) {
+            KeyEvent.KEYCODE_DPAD_LEFT, KeyEvent.KEYCODE_DPAD_UP -> {
+                scrollNumPagesProgress = max(scrollNumPagesProgress - 1F, 0F)
+                true
+            }
+            KeyEvent.KEYCODE_DPAD_RIGHT, KeyEvent.KEYCODE_DPAD_DOWN -> {
+                scrollNumPagesProgress = min(scrollNumPagesProgress + 1F, enabledPageIds.size - 1F)
+                true
+            }
+            else -> super.onKeyUp(keyCode, event)
+        }
+    }
+    override fun onKeyDown(keyCode: Int, event: KeyEvent): Boolean {
+        // Block the directional arrows from interacting with other views
+        return when (keyCode) {
+            KeyEvent.KEYCODE_DPAD_LEFT, KeyEvent.KEYCODE_DPAD_UP -> { true }
+            KeyEvent.KEYCODE_DPAD_RIGHT, KeyEvent.KEYCODE_DPAD_DOWN -> { true }
+            else -> super.onKeyDown(keyCode, event)
+        }
+    }
 }

app/src/main/java/com/lhw/pdf/MyPresentation.kt

@@ -94,4 +94,12 @@ class MyPresentation(outerContext: Context, display: Display) : Presentation(out
         println("Scrolling view to x=$progressPx of scrollable ${layout.width} (visible width ${scroll.width})")
         scroll.scrollTo(progressPx, 0)
     }
+
+    fun setScrollPagesProgress(pagesProgress: Float) {
+        // NB this is nonlinear with unequal page widths
+        val p = pagesProgress.toInt()
+        val progressPx = bitmapCumWidths[p] + (bitmaps[p].width * (pagesProgress % 1F))
+        val progress = progressPx / (bitmapCumWidths.last() - scroll.width).toFloat()
+        setScrollProgress(progress)
+    }
 }

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

@@ -87,6 +87,10 @@ class GalleryFragment : Fragment() {
             val img = ImageView(context)
             img.setImageBitmap(bitmap)
             img.setOnClickListener {
+                val idx = galleryViewModel.enabledPageIds.value?.indexOf(index) ?: 0
+                galleryViewModel.scrollNumPagesProgress.value = idx.toFloat()
+            }
+            img.setOnLongClickListener {
                 val hiddenPageGroups = galleryViewModel.hiddenPageGroups.value!!.toMutableSet()
                 val group = galleryViewModel.pageGroups.value!![index]
                 if (group in hiddenPageGroups) {
@@ -96,6 +100,7 @@ class GalleryFragment : Fragment() {
                 }
                 galleryViewModel.hiddenPageGroups.value = hiddenPageGroups.toSet()
                 reLayoutThumbnails()
+                true
             }
             thumbnailImageViews.add(img)
         }

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

@@ -10,6 +10,7 @@ class GalleryViewModel : ViewModel() {
     val pageGroups = MutableLiveData<List<Int>>().apply { value = listOf() }
     val enabledPageIds = MutableLiveData<List<Int>>().apply { value = listOf() }
     val thumbnailScrollProgress = MutableLiveData<Float>().apply { value = 0F }
+    val scrollNumPagesProgress = MutableLiveData<Float>().apply { value = 0F }
     val textDisplays = MutableLiveData<String>().apply { value = "" }
     val pagesPerLandscape = MutableLiveData<Float>().apply { value = 3F }
     val renderAutoCrop = MutableLiveData<Boolean>().apply { value = true }

app/src/main/java/com/lhw/pdf/ui/home/HomeFragment.kt

@@ -46,6 +46,16 @@ class HomeFragment : Fragment() {
         _binding = null
     }
 
+    private fun toggleGroupHide(group: Int) {
+        val hiddenPageGroups = galleryViewModel.hiddenPageGroups.value!!.toMutableSet()
+        if (group in hiddenPageGroups) {
+            hiddenPageGroups -= group
+        } else {
+            hiddenPageGroups += group
+        }
+        galleryViewModel.hiddenPageGroups.value = hiddenPageGroups.toSet()
+    }
+
     private val groupContainers = mutableMapOf<Int, LinearLayout>()
     private fun reLayoutThumbnails() {
         val container = binding.thumbnailsLayout
@@ -62,6 +72,7 @@ class HomeFragment : Fragment() {
                         c.setBackgroundColor(Color.RED)
                     }
                 }
+                c.setOnLongClickListener { toggleGroupHide(groupIdx); true }
                 groupContainers[groupIdx] = c
                 container.addView(c)
             }
@@ -74,6 +85,11 @@ class HomeFragment : Fragment() {
             val img = ImageView(context)
             img.setImageBitmap(bitmap)
             img.setPadding(2, 0, 2, 0)
+            img.setOnLongClickListener {
+                val group = galleryViewModel.pageGroups.value!![index]
+                toggleGroupHide(group)
+                true
+            }
             if (index > 0) {
                 img.setOnClickListener {
                     val pageGroups = galleryViewModel.pageGroups.value!!.toMutableList()