From 48e6ed28d17f0bc38550bf4e59c61e3d2a91ca07 Mon Sep 17 00:00:00 2001
From: HissPirat <franslukas@gmail.com>
Date: Tue, 14 Jul 2020 11:34:43 +0200
Subject: [PATCH] #2186 scrolling finally works for reader with two bars

---
 ...rollingViewWithBottomNavigationBehavior.kt | 64 +++++++++++++++++++
 .../res/layout/activity_new_navigation.xml    | 42 ++++++------
 2 files changed, 87 insertions(+), 19 deletions(-)
 create mode 100644 app/src/main/java/org/kiwix/kiwixmobile/nav/helper/ScrollingViewWithBottomNavigationBehavior.kt

diff --git a/app/src/main/java/org/kiwix/kiwixmobile/nav/helper/ScrollingViewWithBottomNavigationBehavior.kt b/app/src/main/java/org/kiwix/kiwixmobile/nav/helper/ScrollingViewWithBottomNavigationBehavior.kt
new file mode 100644
index 000000000..f42d1ec02
--- /dev/null
+++ b/app/src/main/java/org/kiwix/kiwixmobile/nav/helper/ScrollingViewWithBottomNavigationBehavior.kt
@@ -0,0 +1,64 @@
+/*
+ * Kiwix Android
+ * Copyright (c) 2020 Kiwix <android.kiwix.org>
+ * This program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation, either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program. If not, see <http://www.gnu.org/licenses/>.
+ *
+ */
+
+package org.kiwix.kiwixmobile.nav.helper
+
+import android.content.Context
+import android.util.AttributeSet
+import android.view.View
+import android.view.ViewGroup
+import androidx.coordinatorlayout.widget.CoordinatorLayout
+import com.google.android.material.appbar.AppBarLayout
+import com.google.android.material.bottomappbar.BottomAppBar
+import com.google.android.material.bottomnavigation.BottomNavigationView
+import org.kiwix.kiwixmobile.R
+
+class ScrollingViewWithBottomNavigationBehavior(context: Context, attrs: AttributeSet) :
+  AppBarLayout.ScrollingViewBehavior(context, attrs) {
+  // We add a bottom margin to avoid the bottom navigation bar
+  private var bottomMargin = 0
+
+  override fun layoutDependsOn(parent: CoordinatorLayout, child: View, dependency: View): Boolean =
+    super.layoutDependsOn(parent, child, dependency) || dependency is BottomNavigationView
+
+  override fun onDependentViewChanged(
+    parent: CoordinatorLayout,
+    child: View,
+    dependency: View
+  ): Boolean {
+    val result = super.onDependentViewChanged(parent, child, dependency)
+    val readerBottomAppBar: BottomAppBar? = child.findViewById(R.id.bottom_toolbar)
+    if (readerBottomAppBar != null) {
+      val navBarYPosition = dependency.y
+      val coordinatorHeight = parent.height
+      val readerNavNewMargin = (coordinatorHeight - navBarYPosition).toInt()
+      if (dependency is BottomNavigationView && readerNavNewMargin != bottomMargin) {
+        bottomMargin = readerNavNewMargin
+        val layout = readerBottomAppBar.layoutParams as ViewGroup.MarginLayoutParams
+        layout.bottomMargin = bottomMargin
+        readerBottomAppBar.requestLayout()
+        return true
+      }
+    }
+    return result
+  }
+
+  override fun onDependentViewRemoved(parent: CoordinatorLayout, child: View, dependency: View) {
+    super.onDependentViewRemoved(parent, child, dependency)
+  }
+}
diff --git a/app/src/main/res/layout/activity_new_navigation.xml b/app/src/main/res/layout/activity_new_navigation.xml
index 969c31672..13fd44600 100644
--- a/app/src/main/res/layout/activity_new_navigation.xml
+++ b/app/src/main/res/layout/activity_new_navigation.xml
@@ -22,28 +22,32 @@
   android:id="@+id/container"
   android:layout_width="match_parent"
   android:layout_height="match_parent"
-  android:orientation="vertical"
-  android:weightSum="1">
+  android:orientation="vertical">
 
-  <fragment
-    android:id="@+id/nav_host_fragment"
-    android:name="org.kiwix.kiwixmobile.main.NavigationHostFragment"
+  <org.kiwix.kiwixmobile.core.utils.NestedCoordinatorLayout
     android:layout_width="match_parent"
-    android:layout_height="0dp"
-    android:layout_gravity="bottom"
-    android:layout_weight="1"
-    app:defaultNavHost="true"
-    app:layout_dodgeInsetEdges="bottom"
-    app:navGraph="@navigation/kiwix_nav_graph"
-    tools:ignore="FragmentTagUsage" />
+    android:layout_height="match_parent">
 
-  <com.google.android.material.bottomnavigation.BottomNavigationView
-    android:id="@+id/nav_view"
-    android:layout_width="fill_parent"
-    android:layout_height="wrap_content"
-    android:layout_gravity="bottom"
-    app:layout_behavior="@string/hide_bottom_view_on_scroll_behavior"
-    app:menu="@menu/menu_bottom_nav" />
+    <fragment
+      android:id="@+id/nav_host_fragment"
+      android:name="org.kiwix.kiwixmobile.main.NavigationHostFragment"
+      android:layout_width="match_parent"
+      android:layout_height="match_parent"
+      android:layout_gravity="bottom"
+      app:defaultNavHost="true"
+      app:layout_behavior=".nav.helper.ScrollingViewWithBottomNavigationBehavior"
+      app:layout_dodgeInsetEdges="bottom"
+      app:navGraph="@navigation/kiwix_nav_graph"
+      tools:ignore="FragmentTagUsage" />
+
+    <com.google.android.material.bottomnavigation.BottomNavigationView
+      android:id="@+id/nav_view"
+      android:layout_width="fill_parent"
+      android:layout_height="wrap_content"
+      android:layout_gravity="bottom"
+      app:layout_behavior="@string/hide_bottom_view_on_scroll_behavior"
+      app:menu="@menu/menu_bottom_nav" />
+  </org.kiwix.kiwixmobile.core.utils.NestedCoordinatorLayout>
 
 
 </LinearLayout>