Scrolling Recycler View programmatically does not update CoordinatorLayout.Behaviour while scrolling it by touch update CoordinatorLayout.Behaviour

Question

I referred This Question but no answers works for me. So basically I have a BottomNavigationView which hide on scroll down and show on scroll up. it works fine when I scroll Recycler View by touch but does not work when I scroll the RecyclerView programmatically. Seems like it does not trigger CoordinatorLayout.Behaviour when programmatically scrolled. In a certain case I have to open that fragment which contains RecyclerView with scroll to some position, and BottomNavigationView hiding it have to came back when user scroll up That means I don't want to hide visibility of BottomNavigationView just hide on scroll either scroll by programmatically or by touch.

activity_main.xml

<?xml version="1.0" encoding="utf-8"?>
<android.support.v4.widget.DrawerLayout 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"
    android:id="@+id/drawer_layout"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    tools:context="com.kliff.digitaldwarka.activity.MainActivity">
    <android.support.design.widget.CoordinatorLayout
        android:layout_width="match_parent"
        android:layout_height="match_parent">
        <android.support.design.widget.AppBarLayout
            android:layout_width="match_parent"
            android:layout_height="?attr/actionBarSize"
            android:id="@+id/myAppBar"
            app:elevation="0dp"
            android:theme="@style/AppTheme.AppBarOverlay">
            <android.support.v7.widget.Toolbar
                android:id="@+id/toolbar"
                android:layout_width="match_parent"
                android:layout_height="?attr/actionBarSize"
                android:background="?attr/colorPrimary"
                app:contentInsetStart="0dp"
                app:popupTheme="@style/AppTheme.PopupOverlay"/>
        </android.support.design.widget.AppBarLayout>
        <FrameLayout
            android:id="@+id/container"
            android:layout_width="match_parent"
            android:layout_height="match_parent"
            app:layout_behavior="@string/appbar_scrolling_view_behavior"/>

        <android.support.design.widget.BottomNavigationView
            android:layout_width="match_parent"
            android:layout_height="wrap_content"
            app:itemBackground="@android:color/white"
            android:id="@+id/bottom_nav"
            android:layout_gravity="bottom"
            app:menu="@menu/bottom_nav_menu"/>
    </android.support.design.widget.CoordinatorLayout>
    <com.appeaser.sublimenavigationviewlibrary.SublimeNavigationView
    android:id="@+id/nav_view"
    android:layout_height="match_parent"
    android:layout_width="match_parent"
    android:layout_gravity="start"
    app:snvHeaderLayout="@layout/nav_header"
    app:snvMenu="@menu/nav_menu"
    style="@style/NavigationViewStyle"
    app:snvItemTextColor="#555555"
    app:snvSubheaderItemTextColor="#555555"
    app:snvItemIconTint="#555555"
    app:snvBadgeTextColor="#555555"
    app:snvHintTextColor="#757575"
    app:snvHintTypefaceStyle="normal"
    app:snvBadgeTypefaceStyle="normal"
    app:snvSubheaderItemTypefaceStyle="normal"
    app:snvItemTypefaceStyle="normal" />
</android.support.v4.widget.DrawerLayout>

fragment_category.xml

<android.support.v7.widget.CardView
xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:app="http://schemas.android.com/apk/res-auto"
    android:layout_width="match_parent"
    android:layout_height="wrap_content"
    app:cardElevation="1dp"
    app:cardUseCompatPadding="true">
    <android.support.v7.widget.RecyclerView
        app:layout_behavior="@string/appbar_scrolling_view_behavior"
        android:id="@+id/recycler_view"
        android:layout_width="match_parent"
        android:layout_height="match_parent"
        android:scrollbars="vertical" />
</android.support.v7.widget.CardView>

Code For scrolling

 mRecyclerView.getLayoutManager().scrollToPosition(34); //specific postion

By scrolling this way how can I achive the behaviour. Any Help Would be appricited thanks.

Answer 1

For me nothing did work, until I wrapped Bhavesh Jabuvanis answer in a post

mRecyclerView?.post  {
  mRecyclerView?.startNestedScroll(ViewCompat.SCROLL_AXIS_VERTICAL, ViewCompat.TYPE_NON_TOUCH)
  mRecyclerView?.smoothScrollToPosition(scrollToPosition)
}

Answer 2

CoordinatorLayout.Behaviour is works with only NestedScroll event. When you try to scroll RecyclerView programmatically it is treat as normal scroll.

Write below line to inform RecyclerView start NesteadScroll, With ViewCompat.SCROLL_AXIS_VERTICAL and ViewCompat.TYPE_NON_TOUCH

ViewCompat.SCROLL_AXIS_VERTICAL: Indicates scrolling along the vertical axis. ViewCompat.TYPE_NON_TOUCH: Indicates that the input type for the gesture is caused by something which is not a user touching a screen. This is usually from a fling which is settling.

recycler_view.startNestedScroll(ViewCompat.SCROLL_AXIS_VERTICAL, ViewCompat.TYPE_NON_TOUCH)
recycler_view.smoothScrollBy(0,200)

Answer 3

I have use this code please check if its suitable for you :-

activity_mail.xml

<?xml version="1.0" encoding="utf-8"?>
<android.support.design.widget.CoordinatorLayout 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"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:fitsSystemWindows="true"
    tools:context="com.example.constraintlayout.ScrollingActivity">

    <android.support.design.widget.AppBarLayout
        android:id="@+id/app_bar"
        android:layout_width="match_parent"
        android:layout_height="@dimen/app_bar_height"
        android:fitsSystemWindows="true"
        android:theme="@style/AppTheme.AppBarOverlay">

        <android.support.design.widget.CollapsingToolbarLayout
            android:id="@+id/toolbar_layout"
            android:layout_width="match_parent"
            android:layout_height="match_parent"
            android:fitsSystemWindows="true"
            app:contentScrim="?attr/colorPrimary"
            app:layout_scrollFlags="scroll|exitUntilCollapsed">

            <android.support.v7.widget.Toolbar
                android:id="@+id/toolbar"
                android:layout_width="match_parent"
                android:layout_height="?attr/actionBarSize"
                app:layout_collapseMode="pin"
                app:popupTheme="@style/AppTheme.PopupOverlay" />

        </android.support.design.widget.CollapsingToolbarLayout>
    </android.support.design.widget.AppBarLayout>

    <include layout="@layout/content_scrolling" />

    <android.support.design.widget.FloatingActionButton
        android:id="@+id/fab"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_margin="@dimen/fab_margin"
        app:layout_anchor="@id/app_bar"
        app:layout_anchorGravity="bottom|end"
        app:srcCompat="@android:drawable/ic_dialog_email" />

</android.support.design.widget.CoordinatorLayout>

content_scrolling.xml

<?xml version="1.0" encoding="utf-8"?>
<android.support.v4.widget.NestedScrollView 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"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    app:layout_behavior="@string/appbar_scrolling_view_behavior"
    tools:context="com.example.constraintlayout.ScrollingActivity"
    tools:showIn="@layout/activity_scrolling">

   <android.support.v7.widget.RecyclerView
       android:id="@+id/recycler_view"
       android:layout_width="match_parent"
       android:layout_height="match_parent"
       android:scrollbars="vertical" />

</android.support.v4.widget.NestedScrollView>

Answer 4

Try the following code. Its working for me. I am using the BottomBar Library.

public void showBottomBar(boolean show) {
    CoordinatorLayout.LayoutParams params = (CoordinatorLayout.LayoutParams) mBottomBar.getLayoutParams();
    CoordinatorLayout.Behavior behavior2 = params.getBehavior();
    if (behavior2 != null) {
        behavior2.onNestedFling(coordinator, mBottomBar, null, 0, show ? -10000 : 10000, true);
    }
}