We Keep Coding

FrameLayout with Recyclerview

I want to put the bottom navigation menu with my recyclerview at the bottom of the view. It is currently at the top and I need help sending it to the bottom.
This is how it look now:
This is my xml code:
<?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">
<TextView
android:id="#+id/titleTextView"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_marginStart="20dp"
android:layout_marginTop="20dp"
android:text="Oficinas Credenciadas"
android:textColor="#android:color/black"
android:textSize="30sp"
android:textStyle="bold"
app:layout_constraintStart_toStartOf="parent"
app:layout_constraintTop_toTopOf="parent" />
<androidx.recyclerview.widget.RecyclerView
android:id="#+id/listRecyclerView"
android:layout_width="0dp"
android:layout_height="0dp"
android:layout_marginStart="1dp"
android:layout_marginTop="8dp"
android:layout_marginEnd="1dp"
android:layout_marginBottom="1dp"
app:layout_constraintBottom_toBottomOf="parent"
app:layout_constraintEnd_toEndOf="parent"
app:layout_constraintStart_toStartOf="parent"
app:layout_constraintTop_toBottomOf="#+id/titleTextView" />
<FrameLayout
android:id="#+id/frame"
android:layout_width="match_parent"
android:layout_height="0dp"
android:layout_weight="1"
app:layout_constraintTop_toBottomOf="#+id/titleTextView"
/>
<com.google.android.material.bottomnavigation.BottomNavigationView
android:layout_width="match_parent"
android:layout_height="wrap_content"
app:menu="#menu/botton_nav_menu"
tools:ignore="MissingConstraints" />
</androidx.constraintlayout.widget.ConstraintLayout>

Add
app:layout_constraintBottom_toBottomOf="parent"
To bottom navigation item so code will be like that
<com.google.android.material.bottomnavigation.BottomNavigationView
android:layout_width="match_parent"
android:layout_height="wrap_content"
app:layout_constraintBottom_toBottomOf="parent"
app:menu="#menu/botton_nav_menu"
tools:ignore="MissingConstraints" />

I have made some changes and this is how it the items are positioned now.
This is how the code looks now. If this helps you, an upvote would be appreciated. Thanks
<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">
<TextView
android:id="#+id/titleTextView"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_marginTop="20dp"
android:text="Oficinas Credenciadas"
android:textColor="#android:color/black"
android:textSize="30sp"
android:textStyle="bold"
app:layout_constraintEnd_toEndOf="parent"
app:layout_constraintStart_toStartOf="parent"
app:layout_constraintTop_toTopOf="parent" />
<androidx.recyclerview.widget.RecyclerView
android:id="#+id/listRecyclerView"
android:layout_width="0dp"
android:layout_height="0dp"
android:layout_marginStart="1dp"
android:layout_marginTop="8dp"
android:layout_marginEnd="1dp"
android:layout_marginBottom="1dp"
app:layout_constraintBottom_toTopOf="#+id/bottom_menu"
app:layout_constraintEnd_toEndOf="parent"
app:layout_constraintStart_toStartOf="parent"
app:layout_constraintTop_toBottomOf="#+id/titleTextView" />
<!-- NOT SURE WHY YOU HAVE THE FRAMELAYOUT AND RECYCLERVIEW OCCUPYING THE SAME SPACE BUT IF YOU INTEND TO HIDE AND SHOW THEM AT DIFFERENT TIMES, I HAVE IMPROVED THEIR CONSTRAINTS -->
<FrameLayout
android:id="#+id/frame"
android:layout_width="match_parent"
android:layout_height="0dp"
android:layout_weight="1"
app:layout_constraintBottom_toTopOf="#+id/bottom_menu"
app:layout_constraintEnd_toEndOf="parent"
app:layout_constraintStart_toStartOf="parent"
app:layout_constraintTop_toBottomOf="#+id/titleTextView"
/>
<com.google.android.material.bottomnavigation.BottomNavigationView
android:id="#+id/bottom_menu"
android:layout_width="match_parent"
android:layout_height="wrap_content"
app:layout_constraintBottom_toBottomOf="parent"
app:layout_constraintEnd_toEndOf="parent"
app:layout_constraintStart_toStartOf="parent"
app:menu="#menu/sample_menu"
tools:ignore="MissingConstraints" />
</androidx.constraintlayout.widget.ConstraintLayout>

Why is my RecyclerView is invisible inside ScrollView?

I have a scrollView in my xml. There's ConstraintLayout inside of it. In the ConstraintLayout is my RecyclerView. It's invisible. When I change ScrollView to ConstraintLayout everything gets back to normal. Here is my xml:
<?xml version="1.0" encoding="utf-8"?>
<ScrollView xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:tools="http://schemas.android.com/tools"
xmlns:app="http://schemas.android.com/apk/res-auto"
android:layout_height="match_parent"
android:layout_width="match_parent"
android:fillViewport="true"
tools:context=".ui.fragments.ChannelAudioFragment">
<androidx.constraintlayout.widget.ConstraintLayout
android:layout_width="match_parent"
android:layout_height="wrap_content">
<ProgressBar
android:id="#+id/allChannelAudiosProgressBar"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:visibility="gone"
app:layout_constraintBottom_toBottomOf="parent"
app:layout_constraintEnd_toEndOf="parent"
app:layout_constraintHorizontal_bias="0.5"
app:layout_constraintStart_toStartOf="parent"
app:layout_constraintTop_toTopOf="parent" />
<com.google.android.material.textview.MaterialTextView
android:id="#+id/noAudiosTitle"
android:layout_width="0dp"
android:layout_height="wrap_content"
android:visibility="gone"
android:gravity="center|left"
android:text="No audios"
android:layout_marginTop="5dp"
android:textSize="15dp"
app:layout_constraintStart_toStartOf="parent"
app:layout_constraintTop_toTopOf="parent" />
<androidx.swiperefreshlayout.widget.SwipeRefreshLayout
android:id="#+id/channelAudiosRefreshSwipe"
android:layout_width="match_parent"
android:layout_height="match_parent"
tools:ignore="MissingConstraints">
<androidx.recyclerview.widget.RecyclerView
android:id="#+id/rvAllChannelAudios"
android:layout_width="match_parent"
android:layout_weight="1"
android:layout_height="match_parent" />
</androidx.swiperefreshlayout.widget.SwipeRefreshLayout>
</androidx.constraintlayout.widget.ConstraintLayout>
</ScrollView>
I don't get any errors in console. Why is this happening?
UPDATE
Additional info: I'm using it in ViewPager. Here it is
<?xml version="1.0" encoding="utf-8"?>
<androidx.constraintlayout.widget.ConstraintLayout 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"
xmlns:app="http://schemas.android.com/apk/res-auto"
tools:context=".ui.fragments.ChannelFragment">
<androidx.constraintlayout.widget.ConstraintLayout
android:id="#+id/channelBlock"
android:layout_width="match_parent"
app:layout_constraintTop_toTopOf="parent"
app:layout_constraintStart_toStartOf="parent"
android:layout_margin="30dp"
android:background="#drawable/main_background"
android:padding="20dp"
android:layout_height="wrap_content">
<ImageView
android:id="#+id/ivChannelImage"
android:layout_width="100dp"
android:layout_height="100dp"
android:src="#drawable/ic_person_flat"
app:layout_constraintStart_toStartOf="parent"
app:layout_constraintEnd_toEndOf="parent"
app:layout_constraintTop_toTopOf="parent" />
<com.google.android.material.textview.MaterialTextView
android:id="#+id/channelName"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="Qewbite"
android:textColor="#color/whiteColor"
android:layout_marginTop="8dp"
android:textSize="26sp"
android:textStyle="bold"
app:layout_constraintStart_toStartOf="parent"
app:layout_constraintEnd_toEndOf="parent"
app:layout_constraintTop_toBottomOf="#id/ivChannelImage" />
<LinearLayout
android:id="#+id/subscriptionBlock"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
app:layout_constraintStart_toStartOf="parent"
app:layout_constraintEnd_toEndOf="parent"
app:layout_constraintTop_toBottomOf="#id/channelName"
android:gravity="center_vertical">
<Button
android:id="#+id/subscribeButton"
android:layout_width="wrap_content"
android:textAllCaps="false"
android:layout_height="40dp"
android:textSize="12dp"
android:gravity="center"
android:background="#drawable/subscribed_background"
android:padding="0dp"
app:backgroundTint="#color/colorDark"
android:textColor="#color/whiteColor"
android:layout_marginLeft="5dp"
android:text="Unfollow" />
<ImageButton
android:id="#+id/notificationButton"
android:layout_width="40dp"
android:textAllCaps="false"
android:layout_height="40dp"
android:textSize="12dp"
android:tint="#color/whiteColor"
android:src="#drawable/ic_notification"
app:backgroundTint="#color/colorDark"
android:background="#drawable/subscribe_notification_background"
android:padding="0dp"
android:textColor="#color/whiteColor" />
</LinearLayout>
<View
android:id="#+id/headerHr"
android:layout_width="match_parent"
android:layout_height="1dp"
android:background="#color/colorNavbarGray"
app:layout_constraintTop_toBottomOf="#id/subscriptionBlock"
android:layout_marginTop="10dp"
/>
<com.google.android.material.textview.MaterialTextView
android:id="#+id/channelSubscribers"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="10M"
android:textColor="#color/whiteColor"
android:layout_marginTop="8dp"
android:textSize="16sp"
android:textStyle="bold"
app:layout_constraintStart_toStartOf="#id/channelSubscribersTitle"
app:layout_constraintEnd_toEndOf="#id/channelSubscribersTitle"
app:layout_constraintTop_toBottomOf="#id/headerHr" />
<com.google.android.material.textview.MaterialTextView
android:id="#+id/channelSubscribersTitle"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="Followers"
android:textColor="#color/colorLightGray"
android:textSize="12sp"
app:layout_constraintStart_toStartOf="parent"
app:layout_constraintTop_toBottomOf="#id/channelSubscribers" />
<com.google.android.material.textview.MaterialTextView
android:id="#+id/channelListened"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="120M"
android:textColor="#color/whiteColor"
android:layout_marginTop="8dp"
android:textSize="16sp"
android:textStyle="bold"
app:layout_constraintStart_toStartOf="#id/channelListenedTitle"
app:layout_constraintEnd_toEndOf="#id/channelListenedTitle"
app:layout_constraintTop_toBottomOf="#id/headerHr" />
<com.google.android.material.textview.MaterialTextView
android:id="#+id/channelListenedTitle"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="Auditions"
android:textColor="#color/colorLightGray"
android:textSize="12sp"
app:layout_constraintStart_toStartOf="parent"
app:layout_constraintEnd_toEndOf="parent"
app:layout_constraintTop_toBottomOf="#id/channelListened" />
<com.google.android.material.textview.MaterialTextView
android:id="#+id/channelYear"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="2021"
android:textColor="#color/whiteColor"
android:layout_marginTop="8dp"
android:textSize="16sp"
android:textStyle="bold"
app:layout_constraintEnd_toEndOf="parent"
app:layout_constraintTop_toBottomOf="#id/headerHr" />
<com.google.android.material.textview.MaterialTextView
android:id="#+id/channelYearTitle"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="Year"
android:textColor="#color/colorLightGray"
android:textSize="12sp"
app:layout_constraintStart_toStartOf="#id/channelYear"
app:layout_constraintEnd_toEndOf="#id/channelYear"
app:layout_constraintTop_toBottomOf="#id/channelSubscribers" />
</androidx.constraintlayout.widget.ConstraintLayout>
<com.google.android.material.tabs.TabLayout
android:id="#+id/tab"
android:layout_width="match_parent"
android:layout_height="wrap_content"
app:tabSelectedTextColor="#color/colorPrimary"
app:layout_constraintTop_toBottomOf="#id/channelBlock"
app:layout_constraintStart_toStartOf="#id/channelBlock"
app:tabRippleColor="#color/colorGray"
android:layout_marginTop="8dp" />
<androidx.viewpager2.widget.ViewPager2
android:id="#+id/channelViewPager"
android:layout_height="wrap_content"
android:layout_width="match_parent"
app:layout_constraintTop_toBottomOf="#id/tab"
app:layout_constraintStart_toStartOf="#id/tab" />
</androidx.constraintlayout.widget.ConstraintLayout>

Most probably that is because you put more than 1 view inside ScrollView , ScrollView expects 1 view from you. If you want to put more than one consider using a viewGroup view and put your views inside it. For Instance , you can use a vertical LinearLayout to wrap the Views you used. Also , consider using NestedScrollView instead.

Try this one
<?xml version="1.0" encoding="utf-8"?>
<androidx.swiperefreshlayout.widget.SwipeRefreshLayout
android:id="#+id/swipe_refresh"
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.core.widget.NestedScrollView
android:layout_width="match_parent"
android:layout_height="match_parent">
<androidx.constraintlayout.widget.ConstraintLayout
android:layout_width="match_parent"
android:layout_height="0dp"
>
<ProgressBar
android:id="#+id/allChannelAudiosProgressBar"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:visibility="gone"
app:layout_constraintBottom_toBottomOf="parent"
app:layout_constraintEnd_toEndOf="parent"
app:layout_constraintHorizontal_bias="0.5"
app:layout_constraintStart_toStartOf="parent"
app:layout_constraintTop_toTopOf="parent" />
<com.google.android.material.textview.MaterialTextView
android:id="#+id/noAudiosTitle"
android:layout_width="0dp"
android:layout_height="wrap_content"
android:visibility="gone"
android:gravity="center|left"
android:text="No audios"
android:layout_marginTop="5dp"
android:textSize="15dp"
app:layout_constraintStart_toStartOf="parent"
app:layout_constraintTop_toTopOf="parent" />
<androidx.recyclerview.widget.RecyclerView
android:id="#+id/rvAllChannelAudios"
tools:listitem="#layout/event_near_items"
app:layout_constraintStart_toStartOf="parent"
app:layout_constraintEnd_toEndOf="parent"
app:layout_constraintTop_toTopOf="parent"
tools:itemCount="10"
app:layout_constraintBottom_toBottomOf="parent"
android:layout_width="match_parent"
android:layout_height="match_parent"
/>
</androidx.constraintlayout.widget.ConstraintLayout>
</androidx.core.widget.NestedScrollView>
</androidx.swiperefreshlayout.widget.SwipeRefreshLayout>
swipe_refresh.setOnRefreshListener {
swipe_refresh.isRefreshing = false
// refresh the list here
}

Why not try a nested scroll view.

Android Textview not aligning to top of page

I am having trouble aligning my UI components to top of the constraint layout even though I have constraint them to the start of the page. There is a tiny gap between the ToolBar and where the UI components start. app:layout_constraintTop_toTopOf="parent" -> this line of code always works but I believe the problem could be that I am using a tabbed activity that it might not be compatible.Problem in UI
Any help or guidance would be greatly appreciated.
This is my XML class ->
<ScrollView android:layout_width="match_parent"
android:layout_height="match_parent"
app:layout_constraintBottom_toBottomOf="parent"
app:layout_constraintEnd_toEndOf="parent"
app:layout_constraintStart_toStartOf="parent"
app:layout_constraintTop_toTopOf="parent"
xmlns:app="http://schemas.android.com/apk/res-auto"
xmlns:android="http://schemas.android.com/apk/res/android">
<androidx.constraintlayout.widget.ConstraintLayout
android:layout_height="wrap_content"
android:layout_width="match_parent">
<TextView
android:id="#+id/breakfastTV"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:layout_marginStart="9dp"
android:layout_weight="10"
android:text="Breakfast"
android:textAppearance="#style/TextAppearance.AppCompat.Body2"
app:layout_constraintEnd_toEndOf="parent"
app:layout_constraintStart_toStartOf="parent"
app:layout_constraintTop_toTopOf="parent" />
<androidx.recyclerview.widget.RecyclerView
android:id="#+id/breakfastRecyclerView"
android:layout_width="match_parent"
android:layout_height="200dp"
android:layout_weight="1"
app:layout_constraintEnd_toEndOf="parent"
app:layout_constraintHorizontal_bias="0.0"
app:layout_constraintStart_toStartOf="parent"
app:layout_constraintTop_toBottomOf="#+id/breakfastTV" />
<TextView
android:id="#+id/lunchTV"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:layout_marginStart="9dp"
android:layout_weight="10"
android:text="Lunch"
android:textAppearance="#style/TextAppearance.AppCompat.Body2"
app:layout_constraintEnd_toEndOf="parent"
app:layout_constraintStart_toStartOf="parent"
app:layout_constraintTop_toBottomOf="#+id/breakfastRecyclerView" />
<androidx.recyclerview.widget.RecyclerView
android:id="#+id/lunchRecyclerView"
android:layout_width="match_parent"
android:layout_height="200dp"
android:layout_weight="1"
app:layout_constraintEnd_toEndOf="parent"
app:layout_constraintStart_toStartOf="parent"
app:layout_constraintTop_toBottomOf="#+id/lunchTV" />
<TextView
android:id="#+id/dinnerTV"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:layout_marginStart="9dp"
android:layout_weight="10"
android:text="Dinner"
android:textAppearance="#style/TextAppearance.AppCompat.Body2"
app:layout_constraintEnd_toEndOf="parent"
app:layout_constraintStart_toStartOf="parent"
app:layout_constraintTop_toBottomOf="#+id/lunchRecyclerView" />
<androidx.recyclerview.widget.RecyclerView
android:id="#+id/dinnerRecyclerView"
android:layout_width="match_parent"
android:layout_height="200dp"
android:layout_weight="1"
app:layout_constraintEnd_toEndOf="parent"
app:layout_constraintStart_toStartOf="parent"
app:layout_constraintTop_toBottomOf="#+id/dinnerTV" />
<TextView
android:id="#+id/otherTV"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:layout_marginStart="9dp"
android:layout_weight="10"
android:text="Other"
android:textAppearance="#style/TextAppearance.AppCompat.Body2"
app:layout_constraintEnd_toEndOf="parent"
app:layout_constraintStart_toStartOf="parent"
app:layout_constraintTop_toBottomOf="#+id/dinnerRecyclerView" />
<androidx.recyclerview.widget.RecyclerView
android:id="#+id/otherRecyclerView"
android:layout_width="match_parent"
android:layout_height="200dp"
android:layout_weight="1"
app:layout_constraintEnd_toEndOf="parent"
app:layout_constraintStart_toStartOf="parent"
app:layout_constraintTop_toBottomOf="#+id/otherTV" />
</androidx.constraintlayout.widget.ConstraintLayout>
CLASS WITH Toolbar ->
<?xml version="1.0" encoding="utf-8"?>
<androidx.drawerlayout.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/a"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:fitsSystemWindows="true"
tools:context=".Management"
tools:openDrawer="start">
<LinearLayout
android:layout_width="match_parent"
android:layout_height="match_parent"
android:orientation="vertical">
<androidx.appcompat.widget.Toolbar
android:id="#+id/toolbar"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:elevation="4dp"
android:theme="#style/ThemeOverlay.AppCompat.Dark.ActionBar"
app:popupTheme="#style/ThemeOverlay.AppCompat.Light">
</androidx.appcompat.widget.Toolbar>
</LinearLayout>
<FrameLayout
android:id="#+id/fragLayout"
android:layout_width="match_parent"
android:layout_height="0dp"
app:layout_constraintBottom_toTopOf="#+id/topNavigation"
app:layout_constraintEnd_toEndOf="parent"
app:layout_constraintStart_toStartOf="parent"
app:layout_constraintTop_toTopOf="parent" />
<androidx.constraintlayout.widget.ConstraintLayout
android:layout_width="match_parent"
android:layout_height="match_parent">
<com.google.android.material.bottomnavigation.BottomNavigationView
android:id="#+id/topNavigation"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:background="?android:attr/windowBackground"
app:layout_constraintBottom_toBottomOf="parent"
app:layout_constraintEnd_toEndOf="parent"
app:layout_constraintStart_toStartOf="parent"
app:menu="#menu/mgmt_bottom_nav_bar" />
</androidx.constraintlayout.widget.ConstraintLayout>
<com.google.android.material.navigation.NavigationView
android:id="#+id/nav_view"
android:layout_width="wrap_content"
android:layout_height="match_parent"
android:layout_gravity="start"
app:headerLayout="#layout/nav_header"
app:menu="#menu/drawer_menu" />
</androidx.drawerlayout.widget.DrawerLayout>

TabLayout load Fragments but its BottomNavigationView not showing on bottom

TabLayout call and load Fragments. Fragments preview no problem, everythink ok. Problem start after load fragments. BottomNavigationView
android:layout_alignParentBottom="true"
not show in bottom. But change position to top there is no problem, it is show.
<?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">
<TextView
android:id="#+id/message"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_marginLeft="#dimen/activity_horizontal_margin"
android:layout_marginStart="#dimen/activity_horizontal_margin"
android:layout_marginTop="#dimen/activity_vertical_margin"
android:text="#string/yazarlar"
app:layout_constraintLeft_toLeftOf="parent"
app:layout_constraintTop_toTopOf="parent" />
<android.support.design.widget.BottomNavigationView
android:id="#+id/navigation"
android:layout_width="0dp"
android:layout_height="wrap_content"
android:background="?android:attr/windowBackground"
app:layout_constraintBottom_toBottomOf="parent"
app:layout_constraintEnd_toEndOf="parent"
app:layout_constraintHorizontal_bias="0.0"
app:layout_constraintLeft_toLeftOf="parent"
app:layout_constraintRight_toRightOf="parent"
app:layout_constraintStart_toStartOf="parent"
app:menu="#menu/navigation" />
</android.support.constraint.ConstraintLayout>

Actually, I don't see in your code anything like
android:layout_alignParentBottom="true"
So that means, that in your previous code, you used RelativeLayout as parent, so please post your original code. I would recommend you using something like this:
<android.support.design.widget.BottomNavigationView
android:id="#+id/navigation"
android:layout_width="0dp"
android:layout_height="0dp"
android:background="?android:attr/windowBackground"
app:layout_constraintBottom_toBottomOf="parent"
app:layout_constraintEnd_toEndOf="parent"
app:layout_constraintLeft_toLeftOf="parent"
app:layout_constraintRight_toRightOf="parent"
app:layout_constraintStart_toStartOf="parent"
app:menu="#menu/navigation" />

Insert this code android:layout_alignParentBottom="true" not shown in fragment. I try some layout. Orginal layout
<?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"
android:id="#+id/container"
android:layout_width="match_parent"
android:layout_height="match_parent">
<TextView
android:id="#+id/message"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_marginLeft="#dimen/activity_horizontal_margin"
android:layout_marginStart="#dimen/activity_horizontal_margin"
android:layout_marginTop="#dimen/activity_vertical_margin"
android:text="#string/yazarlar"
app:layout_constraintLeft_toLeftOf="parent"
app:layout_constraintTop_toTopOf="parent" />
<android.support.design.widget.BottomNavigationView
android:id="#+id/navigation"
android:layout_width="0dp"
android:layout_height="wrap_content"
android:background="?android:attr/windowBackground"
android:layout_alignParentBottom="true"
app:layout_constraintBottom_toBottomOf="parent"
app:layout_constraintEnd_toEndOf="parent"
app:layout_constraintHorizontal_bias="0.0"
app:layout_constraintLeft_toLeftOf="parent"
app:layout_constraintRight_toRightOf="parent"
app:layout_constraintStart_toStartOf="parent"
app:menu="#menu/navigation" />
</RelativeLayout>

Little blank space between toolbar and settings bar

I have a strange issue that i cannot solve, i have a little spacing between my settings bar and the toolbar, watch here
my xml for the toolbar:
<android.support.v7.widget.Toolbar
android:id="#+id/my_toolbar"
android:layout_width="match_parent"
android:layout_height="?attr/actionBarSize"
android:background="?attr/colorPrimary"
android:elevation="4dp"
android:theme="#style/ThemeOverlay.AppCompat.ActionBar"
app:popupTheme="#style/ThemeOverlay.AppCompat.Light"/>
on activity i call it like this:
Toolbar myToolbar = (Toolbar) findViewById(R.id.my_toolbar);
setSupportActionBar(myToolbar);
All Acitivity XML (put all my code in external file and include it)
<?xml version="1.0" encoding="utf-8"?>
<android.support.constraint.ConstraintLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:fitsSystemWindows="true"
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="com.example.afcosta.inesctec.pt.android.FamilyLibrary"
android:paddingTop="6dp">
<android.support.design.widget.FloatingActionButton
android:id="#+id/fab"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_gravity="bottom|end"
android:layout_margin="#dimen/fab_margin"
app:srcCompat="#android:drawable/ic_menu_camera"
app:backgroundTint="#f1c40f"
tools:layout_constraintRight_creator="1"
tools:layout_constraintBottom_creator="1"
app:layout_constraintBottom_toBottomOf="parent"
android:layout_marginEnd="37dp"
app:layout_constraintRight_toRightOf="parent"
android:layout_marginBottom="33dp" />
<android.support.v7.widget.RecyclerView
android:id="#+id/gallery"
android:layout_width="0dp"
android:layout_height="562dp"
tools:layout_constraintTop_creator="1"
tools:layout_constraintRight_creator="1"
android:layout_marginStart="8dp"
android:layout_marginEnd="8dp"
app:layout_constraintRight_toRightOf="parent"
android:layout_marginTop="97dp"
tools:layout_constraintLeft_creator="1"
app:layout_constraintLeft_toLeftOf="parent"
app:layout_constraintTop_toTopOf="parent" />
<include
layout="#layout/custom_toolbar"
android:layout_height="wrap_content"
android:layout_width="match_parent"
android:id="#+id/toolbar"/>
<TextView
android:id="#+id/textView3"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="Familias"
android:textAppearance="#style/TextAppearance.AppCompat.Body1"
tools:layout_constraintBottom_creator="1"
app:layout_constraintBottom_toTopOf="#+id/gallery"
android:layout_marginStart="8dp"
tools:layout_constraintLeft_creator="1"
android:layout_marginBottom="15dp"
app:layout_constraintLeft_toLeftOf="parent"
android:textSize="24dp"/>
</android.support.constraint.ConstraintLayout>
it appears, but that strange white space is annoying :/

You have to remove padding from ConstraintLayout:
android:paddingTop="6dp"