Layout animations

app/src/main/java/it/danieleverducci/subitobeers/MainActivity.kt

@@ -4,6 +4,7 @@ import android.os.Bundle
 import android.view.Menu
 import android.view.MenuInflater
 import androidx.appcompat.app.AppCompatActivity
+import androidx.fragment.app.FragmentManager
 import it.danieleverducci.subitobeers.entities.Beer
 import it.danieleverducci.subitobeers.ui.BeerDetailFragment
 
@@ -17,6 +18,7 @@ class MainActivity : AppCompatActivity(), BeerNavigation {
     override fun showBeerDetail(beer: Beer) {
         val detailFragment = BeerDetailFragment(beer)
         supportFragmentManager.beginTransaction()
+            .setCustomAnimations(R.anim.slide_in_right, R.anim.slide_out_left, android.R.anim.slide_in_left, android.R.anim.slide_out_right)
             .replace(R.id.fragment_container, detailFragment)
             .addToBackStack(null)
             .commit()

app/src/main/java/it/danieleverducci/subitobeers/ui/BeersFragment.kt

@@ -24,9 +24,15 @@ class BeersFragment : Fragment(), BeersRepository.Listener, BeerRecyclerAdapter.
 
     enum class FILTERTYPE {SINCE, TO, CLEAR}
 
+    companion object {
+        val INSTANCESTATE_FILTER_OPEN = "filter_open"
+        val INSTANCESTATE_FILTER_SINCE = "filter_since"
+        val INSTANCESTATE_FILTER_TO = "filter_to"
+    }
+
     private val rvAdapter = BeerRecyclerAdapter()
     private val repo = BeersRepository()
-    lateinit var binding: FragmentBeersListBinding
+    private var binding: FragmentBeersListBinding? = null
 
     override fun onCreateView(
         inflater: LayoutInflater, container: ViewGroup?,
@@ -34,36 +40,52 @@ class BeersFragment : Fragment(), BeersRepository.Listener, BeerRecyclerAdapter.
     ): View? {
         setHasOptionsMenu(true);
 
-        // Inflate layout
+        if (binding == null) {
-        binding = FragmentBeersListBinding.inflate(
+            // Inflate layout
-            LayoutInflater.from(container!!.context),
+            binding = FragmentBeersListBinding.inflate(
-            container,
+                LayoutInflater.from(container!!.context),
-            false
+                container,
-        )
+                false
+            )
 
-        // Register filter buttons listeners
+            // Register filter buttons listeners
-        binding.listFilterSinceBt.setOnClickListener { onFilterButtonClicked(FILTERTYPE.SINCE) }
+            binding!!.listFilterSinceBt.setOnClickListener { onFilterButtonClicked(FILTERTYPE.SINCE) }
-        binding.listFilterToBt.setOnClickListener { onFilterButtonClicked(FILTERTYPE.TO) }
+            binding!!.listFilterToBt.setOnClickListener { onFilterButtonClicked(FILTERTYPE.TO) }
-        binding.listFilterClear.setOnClickListener { onFilterButtonClicked(FILTERTYPE.CLEAR) }
+            binding!!.listFilterClear.setOnClickListener { onFilterButtonClicked(FILTERTYPE.CLEAR) }
 
-        // Set the adapter
+            // Set the adapter
-        with(binding.list) {
+            with(binding!!.list) {
-            layoutManager = LinearLayoutManager(context)
+                layoutManager = LinearLayoutManager(context)
-            adapter = rvAdapter
+                adapter = rvAdapter
+            }
+
+            // Register for recyclerview adapter events
+            rvAdapter.listener = this
+
+            // Register for network completed events
+            repo.listener = this
+
+            // Restore state
+            repo.filter.brewedBefore = savedInstanceState?.getString(INSTANCESTATE_FILTER_TO)
+            repo.filter.brewedAfter = savedInstanceState?.getString(INSTANCESTATE_FILTER_SINCE)
+            binding!!.listFilterDropdown.visibility =
+                if (savedInstanceState?.getBoolean(INSTANCESTATE_FILTER_OPEN) == true) View.VISIBLE else View.GONE
+
+            // Load first page
+            loadBeers(true)
         }
 
-        // Register for recyclerview adapter events
+        return binding!!.root
-        rvAdapter.listener = this
-
-        // Register for network completed events
-        repo.listener = this
-
-        // Load first page
-        loadBeers(true)
-
-        return binding.root
     }
 
+    override fun onSaveInstanceState(outState: Bundle) {
+        outState.putBoolean(INSTANCESTATE_FILTER_OPEN, binding!!.listFilterDropdown.visibility == View.VISIBLE)
+        outState.putString(INSTANCESTATE_FILTER_SINCE, repo.filter.brewedAfter)
+        outState.putString(INSTANCESTATE_FILTER_TO, repo.filter.brewedBefore)
+        super.onSaveInstanceState(outState)
+    }
+
+
     override fun onCreateOptionsMenu(menu: Menu, inflater: MenuInflater) {
         super.onCreateOptionsMenu(menu, inflater)
         requireActivity().menuInflater.inflate(R.menu.list_menu, menu)
@@ -101,8 +123,8 @@ class BeersFragment : Fragment(), BeersRepository.Listener, BeerRecyclerAdapter.
         if (type == FILTERTYPE.CLEAR) {
             repo.filter.clear()
             loadBeers(true)
-            binding.listFilterSinceBt.setText(R.string.list_filter_brewed_after)
+            binding!!.listFilterSinceBt.setText(R.string.list_filter_brewed_after)
-            binding.listFilterToBt.setText(R.string.list_filter_brewed_before)
+            binding!!.listFilterToBt.setText(R.string.list_filter_brewed_before)
             return
         }
 
@@ -111,10 +133,10 @@ class BeersFragment : Fragment(), BeersRepository.Listener, BeerRecyclerAdapter.
 
             if (type == FILTERTYPE.SINCE) {
                 repo.filter.setBrewedAfter(selMonth, selYear)
-                binding.listFilterSinceBt.setText(repo.filter.brewedAfter)
+                binding!!.listFilterSinceBt.setText(repo.filter.brewedAfter)
             } else {
                 repo.filter.setBrewedBefore(selMonth, selYear)
-                binding.listFilterToBt.setText(repo.filter.brewedBefore)
+                binding!!.listFilterToBt.setText(repo.filter.brewedBefore)
             }
 
             // Update list
@@ -146,8 +168,8 @@ class BeersFragment : Fragment(), BeersRepository.Listener, BeerRecyclerAdapter.
      * Toggles beer filter visibility
      */
     private fun toggleFilter() {
-        binding.listFilterDropdown.visibility =
+        binding!!.listFilterDropdown.visibility =
-            if (binding.listFilterDropdown.visibility == View.VISIBLE) View.GONE else View.VISIBLE
+            if (binding!!.listFilterDropdown.visibility == View.VISIBLE) View.GONE else View.VISIBLE
     }
 
     /**

app/src/main/res/anim/slide_in_right.xml

@@ -0,0 +1,26 @@
+<?xml version="1.0" encoding="utf-8"?>
+<!--
+/* //device/apps/common/res/anim/slide_in_right.xml
+**
+** Copyright 2007, The Android Open Source Project
+**
+** Licensed under the Apache License, Version 2.0 (the "License"); 
+** you may not use this file except in compliance with the License. 
+** You may obtain a copy of the License at 
+**
+**     http://www.apache.org/licenses/LICENSE-2.0 
+**
+** Unless required by applicable law or agreed to in writing, software 
+** distributed under the License is distributed on an "AS IS" BASIS, 
+** WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. 
+** See the License for the specific language governing permissions and 
+** limitations under the License.
+*/
+-->
+
+<set xmlns:android="http://schemas.android.com/apk/res/android">
+	<translate android:fromXDelta="50%p" android:toXDelta="0"
+            android:duration="@android:integer/config_mediumAnimTime"/>
+	<alpha android:fromAlpha="0.0" android:toAlpha="1.0"
+            android:duration="@android:integer/config_mediumAnimTime" />
+</set>

app/src/main/res/anim/slide_out_left.xml

@@ -0,0 +1,26 @@
+<?xml version="1.0" encoding="utf-8"?>
+<!--
+/* //device/apps/common/res/anim/slide_out_left.xml
+**
+** Copyright 2007, The Android Open Source Project
+**
+** Licensed under the Apache License, Version 2.0 (the "License"); 
+** you may not use this file except in compliance with the License. 
+** You may obtain a copy of the License at 
+**
+**     http://www.apache.org/licenses/LICENSE-2.0 
+**
+** Unless required by applicable law or agreed to in writing, software 
+** distributed under the License is distributed on an "AS IS" BASIS, 
+** WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. 
+** See the License for the specific language governing permissions and 
+** limitations under the License.
+*/
+-->
+
+<set xmlns:android="http://schemas.android.com/apk/res/android">
+	<translate android:fromXDelta="0" android:toXDelta="-50%p"
+            android:duration="@android:integer/config_mediumAnimTime"/>
+	<alpha android:fromAlpha="1.0" android:toAlpha="0.0"
+            android:duration="@android:integer/config_mediumAnimTime" />
+</set>

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

@@ -4,7 +4,8 @@
     xmlns:tools="http://schemas.android.com/tools"
     android:layout_width="match_parent"
     android:layout_height="match_parent"
-    android:orientation="vertical">
+    android:orientation="vertical"
+    android:animateLayoutChanges="true">
 
     <LinearLayout
         android:id="@+id/list_filter_dropdown"