When scroll bottom navigation bar does not hide - BottomNavigationBehavior

Question

i want to hide bottom navigation bar so i am using bottom navigation behavior it works when i had other code but in this it seems not working i tried but bottom navigation bar

Answer 1

There are two things:

1) You should not override onNestedScroll, it should be onNestedPreScroll, delete onNestedScroll and replace it with that:

@Override
public void onNestedPreScroll(@NonNull CoordinatorLayout coordinatorLayout, @NonNull View child, @NonNull View target, int dx, int dy, @NonNull int[] consumed, int type) {
    super.onNestedPreScroll(coordinatorLayout, child, target, dx, dy, consumed, type);
    child.setTranslationY(Math.max(0f,
            Math.min(Float.parseFloat(String.valueOf(child.getHeight())),child.getTranslationY()+dy)));
}

2) In your XML file, you put

app:layout_behavior=".Helper.BottomNavigationBehavior"

And your class name is

BottomNavigationBehaviour

As you can see one is Behaviour, and the other is Behavior, normally it should throw a runtime error, and the app shouldn't be able to run, it may be a typo on your part, but I mentioned it just in case.

But be aware that this code has a bug, if you try to scroll all the way down or up, the RecyclerView item will not be clickable for a couple of seconds, I have a similar bug. For now, my choice is to use animation to hide the BottomNavigationView as explained in this post.

EDIT:

It's possible that the behaviour is not applied because BottomNavigationView is not a direct child of CoordinatorLayout, so you can either delete the RelativeLayout entirely or take the BottomNavigationView out:

<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"
    app:layout_behavior="@string/appbar_scrolling_view_behavior"
    tools:context="com.blipclap.creativegraphy.HomeActivity"
    tools:showIn="@layout/app_bar_home">

    <RelativeLayout
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:background="@android:color/white">

        <android.support.design.widget.TabLayout
            android:id="@+id/tabLayout"
            android:layout_width="match_parent"
            android:layout_height="wrap_content"></android.support.design.widget.TabLayout>

        <android.support.v4.view.ViewPager
            android:id="@+id/viewPager"
            android:layout_width="match_parent"
            android:layout_height="match_parent"
            app:layoutManager="android.support.v7.widget.LinearLayoutManager"
            app:layout_behavior="@string/appbar_scrolling_view_behavior"
            android:layout_above="@+id/navigation"
            android:layout_below="@+id/tabLayout"></android.support.v4.view.ViewPager>


    </RelativeLayout>


    <android.support.design.widget.BottomNavigationView
            android:id="@+id/navigation"
            android:layout_gravity="bottom"
            app:layout_behavior=".Helper.BottomNavigationBehavior"
            android:layout_width="match_parent"
            android:layout_height="wrap_content"
            android:layout_alignParentBottom="true"
            android:background="@color/colorPrimary"
            app:itemIconTint="@android:color/background_dark"
            app:itemTextColor="@android:color/background_dark"
            app:menu="@menu/bottom_navigation_menu">

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

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

Answer 2

BottomLayoutBehavior.java

package com.utility.behaviour;

import android.content.Context;
import android.util.AttributeSet;
import android.view.View;

import androidx.annotation.NonNull;
import androidx.coordinatorlayout.widget.CoordinatorLayout;
import androidx.core.view.ViewCompat;

public class BottomLayoutBehavior<V extends View> extends CoordinatorLayout.Behavior<V> {

    public BottomLayoutBehavior(Context context, AttributeSet attrs) {
        super(context, attrs);
    }

    @Override
    public boolean onStartNestedScroll(@NonNull CoordinatorLayout coordinatorLayout, @NonNull V child,
                                       @NonNull View directTargetChild, @NonNull View target, int axes, int type) {
        return axes == ViewCompat.SCROLL_AXIS_VERTICAL;
    }

    @Override
    public void onNestedPreScroll(@NonNull CoordinatorLayout coordinatorLayout, @NonNull V child,
                                  @NonNull View target, int dx, int dy, @NonNull int[] consumed, int type) {
        child.setTranslationY(Math.max(0f, Math.min(child.getHeight(), child.getTranslationY() + dy)));
        super.onNestedPreScroll(coordinatorLayout, child, target, dx, dy, consumed, type);
    }
}

activity_main.xml

<androidx.coordinatorlayout.widget.CoordinatorLayout
    android:layout_width="match_parent"
    android:layout_height="match_parent">

    <com.google.android.material.appbar.AppBarLayout
        android:id="@+id/appbar"
        android:layout_width="match_parent"
        android:layout_height="wrap_content">

        <include layout="@layout/app_bar" />
    </com.google.android.material.appbar.AppBarLayout>

    <com.utility.viewpager.SwipeOnOffViewPager
        android:id="@+id/viewpager"
        android:layout_width="match_parent"
        android:layout_height="match_parent"
        app:layout_behavior="@string/appbar_scrolling_view_behavior" />

    <com.google.android.material.bottomnavigation.BottomNavigationView
        android:id="@+id/bnvHome"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:layout_gravity="bottom"
        android:background="@color/white"
        app:itemIconTint="@color/home_tab_bg"
        app:itemTextColor="@color/home_tab_bg"
        app:labelVisibilityMode="labeled"
        app:layout_anchorGravity="center"
        app:layout_behavior="com.utility.behaviour.BottomLayoutBehavior"
        app:menu="@menu/home_bottom_navigation_items" />
    <!--app:itemBackground="@drawable/home_bottom_bar_gap"-->
</androidx.coordinatorlayout.widget.CoordinatorLayout>

NB: android:layout_gravity="bottom" & app:layout_behavior="com.utility.behaviour.BottomLayoutBehavior" is mandatory.