Move some OnBackPressed logics to OnBackPressedCallbacks

app/src/main/java/org/koitharu/kotatsu/favourites/ui/categories/FavouriteCategoriesActivity.kt

@@ -9,6 +9,7 @@ import android.view.Menu
 import android.view.MenuItem
 import android.view.View
 import android.view.ViewGroup
+import androidx.activity.OnBackPressedCallback
 import androidx.activity.viewModels
 import androidx.core.graphics.Insets
 import androidx.core.view.isVisible
@@ -19,7 +20,6 @@ import androidx.recyclerview.widget.RecyclerView
 import coil.ImageLoader
 import com.google.android.material.snackbar.Snackbar
 import dagger.hilt.android.AndroidEntryPoint
-import javax.inject.Inject
 import org.koitharu.kotatsu.R
 import org.koitharu.kotatsu.base.ui.BaseActivity
 import org.koitharu.kotatsu.base.ui.list.ListSelectionController
@@ -32,8 +32,8 @@ import org.koitharu.kotatsu.list.ui.adapter.ListStateHolderListener
 import org.koitharu.kotatsu.list.ui.model.ListModel
 import org.koitharu.kotatsu.parsers.model.SortOrder
 import org.koitharu.kotatsu.utils.ext.getDisplayMessage
-import org.koitharu.kotatsu.utils.ext.measureHeight
 import org.koitharu.kotatsu.utils.ext.scaleUpActivityOptionsOf
+import javax.inject.Inject
 
 @AndroidEntryPoint
 class FavouriteCategoriesActivity :
@@ -47,6 +47,7 @@ class FavouriteCategoriesActivity :
 
 	private val viewModel by viewModels<FavouritesCategoriesViewModel>()
 
+	private lateinit var exitReorderModeCallback: ExitReorderModeCallback
 	private lateinit var adapter: CategoriesAdapter
 	private lateinit var selectionController: ListSelectionController
 	private var reorderHelper: ItemTouchHelper? = null
@@ -55,6 +56,7 @@ class FavouriteCategoriesActivity :
 		super.onCreate(savedInstanceState)
 		setContentView(ActivityCategoriesBinding.inflate(layoutInflater))
 		supportActionBar?.setDisplayHomeAsUpEnabled(true)
+		exitReorderModeCallback = ExitReorderModeCallback(viewModel)
 		adapter = CategoriesAdapter(coil, this, this, this)
 		selectionController = ListSelectionController(
 			activity = this,
@@ -67,6 +69,7 @@ class FavouriteCategoriesActivity :
 		binding.recyclerView.setHasFixedSize(true)
 		binding.recyclerView.adapter = adapter
 		binding.fabAdd.setOnClickListener(this)
+		onBackPressedDispatcher.addCallback(exitReorderModeCallback)
 
 		viewModel.detalizedCategories.observe(this, ::onCategoriesChanged)
 		viewModel.onError.observe(this, ::onError)
@@ -90,15 +93,8 @@ class FavouriteCategoriesActivity :
 				viewModel.setReorderMode(true)
 				true
 			}
-			else -> super.onOptionsItemSelected(item)
-		}
-	}
 
-	override fun onBackPressed() {
-		if (viewModel.isInReorderMode()) {
-			viewModel.setReorderMode(false)
-		} else {
-			super.onBackPressed()
+			else -> super.onOptionsItemSelected(item)
 		}
 	}
 
@@ -138,7 +134,7 @@ class FavouriteCategoriesActivity :
 		}
 		binding.root.updatePadding(
 			left = insets.left,
-			right = insets.right
+			right = insets.right,
 		)
 		binding.recyclerView.updatePadding(
 			bottom = insets.bottom,
@@ -174,6 +170,7 @@ class FavouriteCategoriesActivity :
 		binding.recyclerView.isNestedScrollingEnabled = !isReorderMode
 		invalidateOptionsMenu()
 		binding.buttonDone.isVisible = isReorderMode
+		exitReorderModeCallback.isEnabled = isReorderMode
 	}
 
 	private inner class ReorderHelperCallback : ItemTouchHelper.SimpleCallback(
@@ -211,6 +208,15 @@ class FavouriteCategoriesActivity :
 		override fun isLongPressDragEnabled(): Boolean = false
 	}
 
+	private class ExitReorderModeCallback(
+		private val viewModel: FavouritesCategoriesViewModel,
+	) : OnBackPressedCallback(viewModel.isInReorderMode()) {
+
+		override fun handleOnBackPressed() {
+			viewModel.setReorderMode(false)
+		}
+	}
+
 	companion object {
 
 		val SORT_ORDERS = arrayOf(

app/src/main/java/org/koitharu/kotatsu/main/ui/MainActivity.kt

@@ -117,6 +117,7 @@ class MainActivity :
 		binding.navRail?.headerView?.setOnClickListener(this)
 		binding.searchView.isVoiceSearchEnabled = voiceInputLauncher.resolve(this, null) != null
 
+		onBackPressedDispatcher.addCallback(navigationDelegate)
 		onBackPressedDispatcher.addCallback(ExitCallback(this, binding.container))
 		navigationDelegate = MainNavigationDelegate(checkNotNull(bottomNav ?: binding.navRail), supportFragmentManager)
 		navigationDelegate.addOnFragmentChangedListener(this)
@@ -150,9 +151,7 @@ class MainActivity :
 				setTransition(FragmentTransaction.TRANSIT_FRAGMENT_FADE)
 				runOnCommit { onSearchClosed() }
 			}
-			navigationDelegate.primaryFragment !is ShelfFragment -> {
-				bottomNav?.selectedItemId = R.id.nav_shelf
-			}
+
 			else -> super.onBackPressed()
 		}
 	}

app/src/main/java/org/koitharu/kotatsu/main/ui/MainNavigationDelegate.kt

@@ -2,6 +2,7 @@ package org.koitharu.kotatsu.main.ui
 
 import android.os.Bundle
 import android.view.MenuItem
+import androidx.activity.OnBackPressedCallback
 import androidx.annotation.IdRes
 import androidx.core.view.iterator
 import androidx.fragment.app.Fragment
@@ -21,7 +22,7 @@ private const val TAG_PRIMARY = "primary"
 class MainNavigationDelegate(
 	private val navBar: NavigationBarView,
 	private val fragmentManager: FragmentManager,
-) : NavigationBarView.OnItemSelectedListener, NavigationBarView.OnItemReselectedListener {
+) : OnBackPressedCallback(false), NavigationBarView.OnItemSelectedListener, NavigationBarView.OnItemReselectedListener {
 
 	private val listeners = LinkedList<OnFragmentChangedListener>()
 
@@ -46,6 +47,10 @@ class MainNavigationDelegate(
 		recyclerView.smoothScrollToPosition(0)
 	}
 
+	override fun handleOnBackPressed() {
+		navBar.selectedItemId = R.id.nav_shelf
+	}
+
 	fun onCreate(savedInstanceState: Bundle?) {
 		primaryFragment?.let {
 			onFragmentChanged(it, fromUser = false)
@@ -117,6 +122,7 @@ class MainNavigationDelegate(
 	}
 
 	private fun onFragmentChanged(fragment: Fragment, fromUser: Boolean) {
+		isEnabled = fragment !is ShelfFragment
 		listeners.forEach { it.onFragmentChanged(fragment, fromUser) }
 	}