Develop Reference

Below a widget in XML

i've tried to fix this problem but every way that i tried went wrong. i'm trying to add a BottomNavigationView below the FrameLayout but everytime the BottomNavigationView keep up of the FrameLayout or inside it. What could i do?
<?xml version="1.0" encoding="utf-8"?>
<RelativeLayout
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_height="match_parent"
android:layout_width="match_parent"
android:background="#2b2b2b"
android:id="#+id/coordinator"
tools:context=".Home">
<android.widget.FrameLayout
android:id="#+id/bottom_nav_frame"
android:layout_width="match_parent"
android:layout_height="match_parent"
app:layout_constraintStart_toStartOf="parent"
app:layout_constraintEnd_toEndOf="parent"
app:layout_constraintTop_toTopOf="parent">
(...)
</android.widget.FrameLayout>
<com.google.android.material.bottomnavigation.BottomNavigationView
android:id="#+id/bottom_nav"
android:layout_width="match_parent"
android:layout_height="wrap_content"
app:layout_constraintBottom_toBottomOf="parent"
app:layout_constraintStart_toStartOf="parent"
app:layout_constraintEnd_toEndOf="parent"
app:layout_constraintTop_toBottomOf="#id/bottom_nav_frame"
android:background="#2b2b2b"
app:iconTint="#ffffff"
app:menu="#menu/bottom_nav_menu"/>
</RelativeLayout>

In your BottomNavigationView add this line
android:layout_alignParentBottom="true"

I Have a horizontal recyclerview with images in it but they are way too far from each other

Ok so I have a horizontal recycler view and I'm putting images into it but they are way too far from each other how could I fix it?
Layout code where I have my image
<?xml version="1.0" encoding="utf-8"?>
<androidx.constraintlayout.widget.ConstraintLayout 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="wrap_content">
<ImageView
android:id="#+id/imageView"
android:layout_width="106dp"
android:layout_height="171dp"
android:layout_marginStart="19dp"
android:layout_marginLeft="19dp"
android:scaleType="centerCrop"
app:layout_constraintBottom_toBottomOf="parent"
app:layout_constraintStart_toStartOf="parent"
app:layout_constraintTop_toTopOf="parent"
tools:srcCompat="#tools:sample/avatars" />
</androidx.constraintlayout.widget.ConstraintLayout>
Layout code where I have the recycler view
<?xml version="1.0" encoding="utf-8"?>
<androidx.constraintlayout.widget.ConstraintLayout 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"
tools:context=".MainActivity">
<androidx.recyclerview.widget.RecyclerView
android:id="#+id/recyclerView"
android:layout_width="416dp"
android:layout_height="174dp"
android:orientation="horizontal"
app:layout_constraintBottom_toBottomOf="parent"
app:layout_constraintEnd_toEndOf="parent"
app:layout_constraintHorizontal_bias="0.0"
app:layout_constraintStart_toStartOf="parent"
app:layout_constraintTop_toTopOf="parent"
app:layout_constraintVertical_bias="0.0" />
</androidx.constraintlayout.widget.ConstraintLayout>

change your constraintLayout android:layout_width="match_parent" to
android:layout_width="wrap_content"
change your recyclerView android:layout_width="416dp" to
android:layout_width="match_parent"

How to keep the floatingActionButton fixed at is original position when scrolling the recyclerview

I need help to keep the fab shown in pics at a fixed position when scrolling up or down i cant find anything on google as most search results return information on hiding the fab when scrolling
Here is my xml
<?xml version="1.0" encoding="utf-8"?>
<android.support.constraint.ConstraintLayout
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:background="#color/accent"> <android.support.constraint.ConstraintLayout
android:layout_width="match_parent"
android:layout_height="match_parent"
android:background="#color/accent"
>
<android.support.v7.widget.RecyclerView
android:id="#+id/listView"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:dividerHeight="1dp"
/>
</android.support.constraint.ConstraintLayout>
<android.support.design.widget.FloatingActionButton
android:id="#+id/addmorefab"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
app:layout_constraintRight_toRightOf="parent"
app:layout_constraintBottom_toBottomOf="parent"
android:layout_marginBottom="#dimen/fab_marginBottom"
android:layout_marginRight="#dimen/fab_marginRight"
android:clickable="true"
app:backgroundTint="#color/primary"
app:srcCompat="#drawable/ic_action_new"
app:layout_anchor="#id/listView"
app:layout_anchorGravity="bottom|right|end"
/></android.support.constraint.ConstraintLayout>
I even tried to make two constraint layouts it didnt work
I also tried using recyclerView.setNestedScrollingEnabled(false);
It worked but it was limiting the scrolling of the recyclerview.
On the second picture i want the fab to remain fixed where it is not scrolling

You can use this view if you want your bright button to remain fixed while scrolling through the recycler.
I used Android X libraries and you can use lower version libraries.
<?xml version="1.0" encoding="utf-8"?>
<androidx.constraintlayout.widget.ConstraintLayout
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">
<androidx.recyclerview.widget.RecyclerView
android:id="#+id/listView"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:dividerHeight="1dp"
app:layout_constraintBottom_toBottomOf="parent"
app:layout_constraintEnd_toEndOf="parent"
app:layout_constraintStart_toStartOf="parent"
app:layout_constraintTop_toTopOf="parent" />
<com.google.android.material.floatingactionbutton.FloatingActionButton
android:id="#+id/addmorefab"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_marginRight="18dp"
android:layout_marginBottom="18dp"
android:clickable="true"
app:backgroundTint="#color/colorPrimary"
app:layout_constraintBottom_toBottomOf="parent"
app:layout_constraintRight_toRightOf="parent"
app:srcCompat="#android:drawable/ic_input_add" />
</androidx.constraintlayout.widget.ConstraintLayout>

Why does the UI become a fullscreen, when I add a fragment in Android Studio?

I have created a new project with "Bottom Navigation Activity" as template. If I add a fragment in my fragment_home.xml file a white bar at the bottom appears and the android taskbar disappears.
Here is a screenshot and the code without the fragment:
<FrameLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:layout_width="match_parent"
android:layout_height="match_parent">
</FrameLayout>
And here a screenshot with the fragment:
<FrameLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:layout_width="match_parent"
android:layout_height="match_parent">
<fragment
android:id="#+id/ux_fragment"
android:name="com.google.ar.sceneform.ux.ArFragment"
android:layout_width="match_parent"
android:layout_height="match_parent" />
</FrameLayout>
I want the green bar at the top and under this, the fragment.
activity_main.xml:
<?xml version="1.0" encoding="utf-8"?>
<androidx.constraintlayout.widget.ConstraintLayout xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:app="http://schemas.android.com/apk/res-auto"
android:id="#+id/container"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:paddingTop="?attr/actionBarSize">
<com.google.android.material.bottomnavigation.BottomNavigationView
android:id="#+id/nav_view"
android:layout_width="0dp"
android:layout_height="wrap_content"
android:layout_marginStart="0dp"
android:layout_marginEnd="0dp"
android:background="?android:attr/windowBackground"
app:layout_constraintBottom_toBottomOf="parent"
app:layout_constraintLeft_toLeftOf="parent"
app:layout_constraintRight_toRightOf="parent"
app:menu="#menu/bottom_nav_menu" />
<fragment
android:id="#+id/nav_host_fragment"
android:name="androidx.navigation.fragment.NavHostFragment"
android:layout_width="match_parent"
android:layout_height="match_parent"
app:defaultNavHost="true"
app:layout_constraintBottom_toTopOf="#id/nav_view"
app:layout_constraintLeft_toLeftOf="parent"
app:layout_constraintRight_toRightOf="parent"
app:layout_constraintTop_toTopOf="parent"
app:navGraph="#navigation/mobile_navigation" />
</androidx.constraintlayout.widget.ConstraintLayout>

How to set fill items in BottomNavigationView on Android

In my application i want use BottomNavigationView view to show some fragments.I have 4 fragments and i set this fragments into BottomNavigationView.
I write below codes but in large device screens such as Tables show me this items in center of BottomNavigationView.
such as below image :
But i want show this items fill of BottomNavigationView, such as below image :
My XML codes :
<?xml version="1.0" encoding="utf-8"?>
<RelativeLayout
android:id="#+id/container"
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"
tools:context=".MainActivity">
<fragment
android:id="#+id/mainNavigationFragment"
android:name="androidx.navigation.fragment.NavHostFragment"
android:layout_width="match_parent"
android:layout_height="match_parent"
app:defaultNavHost="true"
android:layout_above="#+id/bottomNavigationView"
app:navGraph="#navigation/navigation_graph"/>
<com.google.android.material.bottomnavigation.BottomNavigationView
android:id="#+id/bottomNavigationView"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:background="?android:attr/windowBackground"
android:layout_alignParentBottom="true"
app:menu="#menu/navigation"/>
</RelativeLayout>
How can i change my codes for show items such as image two?

Try use ConstraintLayout and see whether the issue is solved
<?xml version="1.0" encoding="utf-8"?>
<android.support.constraint.ConstraintLayout
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/container"
android:layout_width="match_parent"
android:layout_height="match_parent"
tools:context=".MainActivity">
<com.google.android.material.bottomnavigation.BottomNavigationView
app:labelVisibilityMode="labeled"
android:id="#+id/bottomNavigationView"
app:menu="#menu/navigation_manager"
android:layout_width="0dp"
android:layout_height="wrap_content"
app:layout_constraintBottom_toBottomOf="parent"
app:layout_constraintLeft_toLeftOf="parent"
app:layout_constraintRight_toRightOf="parent"/>
<fragment
android:id="#+id/nav_host_fragment"
android:name="androidx.navigation.fragment.NavHostFragment"
android:layout_width="0dp"
android:layout_height="0dp"
app:layout_constraintBottom_toTopOf="#+id/bottomNavigationView"
app:layout_constraintEnd_toEndOf="parent"
app:layout_constraintStart_toStartOf="parent"
app:layout_constraintTop_toTopOf="parent"
app:menu="#menu/navigation_graph"
app:layout_constraintHorizontal_bias="0.0"
app:layout_constraintVertical_bias="0.0"/>
</android.support.constraint.ConstraintLayout>