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"

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>

Using Fragments

Having problem getting fragment showing correctly on device. I have a frame on an activity and a Frame on a Fragment. Trying to do a replace frame on activity with frame from Fragment. however what I am getting is Frame on activity being smushed together and fragment frame underneath on display.
Here is code calling the Fragment.
public void setupMultiItems(String mScan){
Timber.d("Multiple matching Items");
Bundle bundle = new Bundle();
bundle.putString("valuesArray",mScan);
SelectItemFragment fragobj = new SelectItemFragment();
fragobj.setArguments(bundle);
FragmentManager fragmentManager=getFragmentManager();
FragmentTransaction fragmentTransaction = fragmentManager.beginTransaction();
fragmentTransaction.replace(R.id.FragmentFrame, fragobj);
fragmentTransaction.addToBackStack(null);
fragmentTransaction.commit();
Here is XML for the activity.
<?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_width="match_parent"
android:layout_height="match_parent"
android:background="#color/colorBackgroundGray"
tools:layout="#layout/fragment_select_item"
tools:context="com.procatdt.stockright.activities.PutAwayAreaActivity">
<LinearLayout
android:layout_width="fill_parent"
android:layout_height="wrap_content"
android:orientation="vertical"
>
<include
android:id="#+id/include2"
layout="#layout/frm1"
android:layout_width="wrap_content"
android:layout_height="0dp"
android:layout_gravity="left"
android:layout_weight="1" />
<FrameLayout
android:id="#+id/FragmentFrame"
android:layout_width="match_parent"
android:layout_height="0dp"
android:layout_weight="1">
</FrameLayout>
</LinearLayout>
<LinearLayout
android:layout_width="fill_parent"
android:layout_height="match_parent"
android:paddingLeft="5dp"
android:orientation="vertical">
<include
android:id="#+id/include"
layout="#layout/layout_numpad5"
android:layout_width="match_parent"
android:layout_height="0dp"
android:layout_marginStart="220dp"
android:layout_weight="1"
android:layout_gravity="right"
/>
</LinearLayout>
</RelativeLayout>
Here is XML for the fragment.
<FrameLayout xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:tools="http://schemas.android.com/tools"
android:layout_width="match_parent"
android:layout_height="match_parent"
tools:context="com.procatdt.stockright.activities.SelectItemFragment">
<!-- TODO: Update blank fragment layout -->
<RelativeLayout
android:layout_width="match_parent"
android:layout_height="match_parent">
<FrameLayout
android:id="#+id/newFrame"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:layout_alignParentStart="true"
android:layout_alignParentTop="true">
<Button
android:id="#+id/btnSelectItem"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_marginTop="10dp"
android:text="Select Item" />
</FrameLayout>
</RelativeLayout>
</FrameLayout>
all the controls on activity are being shrunk and jammed together with the button from the fragment showing underneath.
Any help on what I am missing.
My background has been in VB for last 18 years. This is my first Android Studio Java project and have been muddling by getting hung up on fragments.

Fragment content in activity not properly sized

I am using fragments in an activity with a BottomNavigationView and out of the box I noticed the fragment content goes below the BottomNavigationView
This is the fragment in Android studio before inflating it in the activity:
The app after the fragment has been inflating:
Here is my fragment XML I read on other posts on this site that I needed to use the CoordinatorLayout as parent and add app:layout_behavior="#string/appbar_scrolling_view_behavior" to the first child but it didn't work.
<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_height="match_parent"
android:layout_width="match_parent"
android:orientation="vertical">
<LinearLayout
android:layout_width="match_parent"
android:layout_height="match_parent"
app:layout_behavior="#string/appbar_scrolling_view_behavior"
android:orientation="vertical">
<android.support.v7.widget.Toolbar
android:id="#+id/toolbar"
android:layout_width="match_parent"
android:layout_height="?attr/actionBarSize"
app:popupTheme="#style/ThemeOverlay.AppCompat.Light" />
<android.support.constraint.ConstraintLayout
android:layout_width="match_parent"
android:layout_height="match_parent"
android:orientation="vertical"
app:layout_behavior="#string/appbar_scrolling_view_behavior"
android:layout_margin="16dp"
tools:context="com.brigafrica.koyako.fragments.SendFragment">
<TextView
android:id="#+id/textView"
style="#android:style/TextAppearance.Small"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_gravity="center"
android:layout_marginEnd="8dp"
android:layout_marginStart="8dp"
android:layout_marginTop="36dp"
android:text="#string/amount_to_send"
app:layout_constraintEnd_toEndOf="parent"
app:layout_constraintHorizontal_bias="0.502"
app:layout_constraintStart_toStartOf="parent"
app:layout_constraintTop_toTopOf="parent" />
<android.support.v7.widget.AppCompatEditText
android:id="#+id/edtAmountToSend"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:layout_marginEnd="8dp"
android:layout_marginStart="8dp"
android:layout_marginTop="8dp"
android:digits="0123456789.,"
android:inputType="numberDecimal"
app:layout_constraintBottom_toTopOf="#+id/appCompatButton"
app:layout_constraintEnd_toEndOf="parent"
app:layout_constraintHorizontal_bias="0.0"
app:layout_constraintStart_toStartOf="parent"
app:layout_constraintTop_toBottomOf="#+id/textView"
app:layout_constraintVertical_bias="0.095" />
<android.support.v7.widget.AppCompatButton
android:id="#+id/appCompatButton"
style="#style/AppTheme.RoundedCornerMaterialButton"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:layout_gravity="bottom"
android:layout_margin="10dp"
android:layout_marginBottom="8dp"
android:layout_marginEnd="8dp"
android:layout_marginStart="8dp"
android:text="#string/send"
app:layout_constraintBottom_toBottomOf="parent"
app:layout_constraintEnd_toEndOf="parent"
app:layout_constraintStart_toStartOf="parent" />
</android.support.constraint.ConstraintLayout>
</LinearLayout>
</android.support.design.widget.CoordinatorLayout>

What is necessary to identify the problem is your activity XML content and how you are managing the fragments in your activity.
The simplest way to think is that the fragment is just a content that will be displayed in a piece of your activity, and you should provide the correct information about the dimensions of this piece in your activity.
Explaining with my example
An activity called MainActivity that has one ViewPager and one BottomNavigationView.
<?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_width="match_parent"
android:layout_height="match_parent"
tools:context="newidea.com.br.bottomnavigationexample.MainActivity">
<android.support.v4.view.ViewPager
android:id="#+id/main.viewPager"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:layout_above="#+id/bottom_navigation"
android:layout_alignParentTop="true"
app:layout_behavior="#string/appbar_scrolling_view_behavior" />
<android.support.design.widget.BottomNavigationView
android:id="#+id/bottom_navigation"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:layout_alignParentBottom="true"
app:itemBackground="#color/colorPrimary"
app:itemIconTint="#drawable/nav_item_color_state"
app:itemTextColor="#drawable/nav_item_color_state"
app:menu="#menu/bottom_navigation_main" />
</RelativeLayout>
The ViewPager is the piece where the fragment will be displayed in MainActivity, so I have to tell the activity that the ViewPager can not invade the BottomNavigationView space, if not the fragment content that will be displayed in the ViewPager will goes below the BottomNavigationView.
How to do that ?
In my example I configured the ViewPager with this:
android:layout_width="match_parent"
android:layout_height="match_parent"
android:layout_above="#+id/bottom_navigation"
android:layout_alignParentTop="true"
It means that the ViewPager width and height matchs the parent's width and height, the ViewPager top is aligned with the parent's top, and it is a layout above the BottomNavigationView, so the ViewPager can not invade the BottomNavigationView space.
What you need to understand is that doesn't matter what is in your fragment, what really matter here is the dimensions configuration of the ViewPager, because the ViewPager will display the fragment.
Full example with 3 fragments, each one with a Button in the Bottom
Fragment in Android Studio before inflating
The app after the fragment has been inflated