Floating button doesn't seen because of Bottom Nav-CodePudding

On Main activity XML I have one buttom nav and on another fragment I have a floating button. This button is not visible because of the buttom nav. If I add on floating buttom this line -> android:layout_marginBottom="64dp" instead of android:layout_marginBottom="32dp" it works fine but I think it is not best practice. How can I show the button?

MainActivity 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"
    xmlns:tools="http://schemas.android.com/tools"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    tools:context=".MainActivity">
    <fragment
        android:id="@ id/fragmentContainerView"
        android:name="androidx.navigation.fragment.NavHostFragment"
        android:layout_width="match_parent"
        android:layout_height="match_parent"
        app:defaultNavHost="true"
        app:layout_constraintBottom_toBottomOf="parent"
        app:layout_constraintEnd_toEndOf="parent"
        app:layout_constraintStart_toStartOf="parent"
        app:layout_constraintTop_toTopOf="parent"
        app:navGraph="@navigation/my_nav" />

    <com.google.android.material.bottomnavigation.BottomNavigationView
        android:id="@ id/bottomNavigationView"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        app:itemIconTint="@drawable/selector_buttom_navigation"
        app:itemTextColor="@drawable/selector_buttom_navigation"
        app:layout_constraintBottom_toBottomOf="parent"
        app:layout_constraintEnd_toEndOf="parent"
        app:layout_constraintStart_toStartOf="parent"
        app:menu="@menu/bottom_nav_menu" />

</androidx.constraintlayout.widget.ConstraintLayout>

Fragment Floating button

<com.google.android.material.floatingactionbutton.FloatingActionButton
        android:id="@ id/floatingActionButton"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_marginEnd="32dp"
        android:layout_marginBottom="32dp"
        android:clickable="true"
        android:contentDescription="TODO"
        android:focusable="true"
        android:src="@drawable/ic_add_timeliner"
        app:layout_constraintBottom_toBottomOf="parent"
        app:layout_constraintEnd_toEndOf="parent" />

CodePudding user response：

You should change this in <fragment>

app:layout_constraintBottom_toBottomOf="parent"

app:layout_constraintBottom_toTopOf="@id/bottomNavigationView"

the reason is that the fragment is now underneath the BottomNavigationView while you want it to be on top of it

CodePudding user response：

It would make more sense to make the fragment height 0dp.

 <fragment
    android:id="@ id/fragmentContainerView"
    android:name="androidx.navigation.fragment.NavHostFragment"
    android:layout_width="match_parent"
    android:layout_height="0dp"
    app:defaultNavHost="true"
    app:layout_constraintBottom_toTopOf="@id/bottomNavigationView"
    app:layout_constraintEnd_toEndOf="parent"
    app:layout_constraintStart_toStartOf="parent"
    app:layout_constraintTop_toTopOf="parent"
    app:navGraph="@navigation/my_nav" />