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View is overlapped by another view in NestedScrollView with ConstrainLayout

I have the following layout:
<?xml version="1.0" encoding="utf-8"?>
<androidx.core.widget.NestedScrollView xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:app="http://schemas.android.com/apk/res-auto"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:fillViewport="true">
<androidx.constraintlayout.widget.ConstraintLayout
android:layout_width="match_parent"
android:layout_height="match_parent">
<LinearLayout
android:id="#+id/content_ll"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:layout_marginBottom="#dimen/margin_32"
android:orientation="vertical"
app:layout_constraintEnd_toEndOf="parent"
app:layout_constraintStart_toStartOf="parent"
app:layout_constraintTop_toTopOf="parent">
<androidx.cardview.widget.CardView
android:id="#+id/online_card_cv"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:layout_marginHorizontal="#dimen/margin_16"
android:layout_marginTop="#dimen/margin_25"
android:background="#color/white"
app:cardCornerRadius="#dimen/margin_8">
<androidx.constraintlayout.widget.ConstraintLayout
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:layout_marginVertical="#dimen/margin_8">
<androidx.appcompat.widget.AppCompatRadioButton
android:id="#+id/online_card_rb"
android:layout_width="#dimen/margin_22"
android:layout_height="#dimen/margin_22"
android:layout_marginStart="#dimen/margin_16"
app:layout_constraintBottom_toBottomOf="#id/online_card_ll"
app:layout_constraintEnd_toStartOf="#id/online_card_ll"
app:layout_constraintStart_toStartOf="parent"
app:layout_constraintTop_toTopOf="#id/online_card_ll" />
<LinearLayout
android:id="#+id/online_card_ll"
android:layout_width="0dp"
android:layout_height="wrap_content"
android:layout_marginStart="#dimen/margin_16"
android:background="#color/white"
android:gravity="start"
android:orientation="vertical"
android:paddingVertical="#dimen/padding_16"
app:layout_constraintEnd_toStartOf="#id/cards_iv"
app:layout_constraintStart_toEndOf="#id/online_card_rb"
app:layout_constraintTop_toTopOf="parent">
<androidx.appcompat.widget.AppCompatTextView
android:id="#+id/online_card_tv"
style="#style/OnlineCardTitleTextStyle"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="#string/online_card_title"
app:lineHeight="#dimen/default_text_size_28" />
<androidx.appcompat.widget.AppCompatTextView
style="#style/OnlineCardSubTitleTextStyle"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="#string/online_card_now" />
</LinearLayout>
<androidx.appcompat.widget.AppCompatImageView
android:id="#+id/cards_iv"
android:layout_width="#dimen/margin_80"
android:layout_height="#dimen/margin_20"
android:layout_marginEnd="#dimen/margin_16"
android:src="#drawable/ic_visa_master"
app:layout_constraintBottom_toBottomOf="#id/online_card_ll"
app:layout_constraintEnd_toEndOf="parent"
app:layout_constraintTop_toTopOf="#id/online_card_ll" />
<androidx.constraintlayout.widget.ConstraintLayout
android:id="#+id/online_card_expanded_info_cl"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:visibility="gone"
app:layout_constraintTop_toBottomOf="#id/online_card_ll">
<View
android:id="#+id/online_card_divider"
style="#style/ViewDividerStyle"
android:layout_width="match_parent"
android:layout_height="1dp"
android:layout_marginTop="#dimen/margin_16"
app:layout_constraintTop_toTopOf="parent" />
<androidx.recyclerview.widget.RecyclerView
android:id="#+id/cards_list"
android:layout_width="match_parent"
android:layout_height="wrap_content"
app:layout_constraintTop_toBottomOf="#id/online_card_divider" />
<View
android:id="#+id/cards_list_divider"
style="#style/ViewDividerStyle"
android:layout_width="match_parent"
android:layout_height="1dp"
app:layout_constraintTop_toBottomOf="#id/cards_list" />
<TextView
android:id="#+id/read_more_tv"
style="#style/OnlineCardReadMoreTextStyle"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_marginStart="#dimen/margin_16"
android:layout_marginTop="#dimen/margin_16"
android:layout_marginBottom="#dimen/margin_8"
android:text="#string/read_more"
android:visibility="visible"
app:layout_constraintBottom_toBottomOf="parent"
app:layout_constraintStart_toStartOf="parent"
app:layout_constraintTop_toBottomOf="#id/cards_list_divider" />
<LinearLayout
android:id="#+id/additional_info_ll"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:layout_marginStart="#dimen/margin_21"
android:layout_marginTop="#dimen/margin_16"
android:layout_marginEnd="#dimen/margin_10"
android:layout_marginBottom="#dimen/margin_8"
android:orientation="vertical"
android:visibility="gone"
app:layout_constraintBottom_toBottomOf="parent"
app:layout_constraintStart_toStartOf="parent"
app:layout_constraintTop_toBottomOf="#id/cards_list_divider">
<TextView
android:id="#+id/online_card_less_info_tv"
style="#style/OnlineCardReadMoreTextStyle"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="#string/online_card_less_info" />
<TextView
android:id="#+id/check_card_type_title_tv"
style="#style/OnlineCardBottomTitleTextStyle"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:layout_marginTop="#dimen/margin_4"
android:text="#string/online_check_card" />
<TextView
android:id="#+id/check_card_type_info_tv"
style="#style/OnlineCardBottomDescriptionTextStyle"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:layout_marginStart="#dimen/margin_8"
android:layout_marginTop="#dimen/margin_4"
android:text="#string/online_check_card_info" />
<TextView
android:id="#+id/online_card_data_title_tv"
style="#style/OnlineCardBottomTitleTextStyle"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:layout_marginTop="#dimen/margin_4"
android:text="#string/online_card_data" />
<TextView
android:id="#+id/online_card_data_info_tv"
style="#style/OnlineCardBottomDescriptionTextStyle"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:layout_marginStart="#dimen/margin_8"
android:layout_marginTop="#dimen/margin_4"
android:text="#string/online_card_data_info" />
<TextView
android:id="#+id/online_card_confirmation_title_tv"
style="#style/OnlineCardBottomTitleTextStyle"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:layout_marginTop="#dimen/margin_4"
android:text="#string/online_card_confirmation" />
<TextView
android:id="#+id/online_card_confirmation_info_tv"
style="#style/OnlineCardBottomDescriptionTextStyle"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:layout_marginStart="#dimen/margin_8"
android:layout_marginTop="#dimen/margin_4"
android:text="#string/online_card_confirmation_info" />
</LinearLayout>
</androidx.constraintlayout.widget.ConstraintLayout>
</androidx.constraintlayout.widget.ConstraintLayout>
</androidx.cardview.widget.CardView>
<androidx.cardview.widget.CardView
android:id="#+id/bank_account_cv"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:layout_marginHorizontal="#dimen/margin_16"
android:layout_marginTop="25dp"
android:background="#color/white"
app:cardCornerRadius="#dimen/margin_8">
<androidx.constraintlayout.widget.ConstraintLayout
android:layout_width="match_parent"
android:layout_height="match_parent"
android:layout_marginVertical="#dimen/margin_24">
<androidx.appcompat.widget.AppCompatRadioButton
android:id="#+id/bank_account_rb"
android:layout_width="#dimen/margin_22"
android:layout_height="#dimen/margin_22"
android:layout_marginStart="#dimen/margin_16"
app:layout_constraintBottom_toBottomOf="#id/bank_account_tv"
app:layout_constraintStart_toStartOf="parent"
app:layout_constraintTop_toTopOf="#id/bank_account_tv" />
<androidx.appcompat.widget.AppCompatTextView
android:id="#+id/bank_account_tv"
style="#style/OnlineCardTitleTextStyle"
android:layout_width="0dp"
android:layout_height="wrap_content"
android:layout_marginStart="#dimen/margin_14"
android:text="#string/title_on_bank"
android:textAlignment="textStart"
app:layout_constraintEnd_toEndOf="parent"
app:layout_constraintStart_toEndOf="#id/bank_account_rb"
app:layout_constraintTop_toTopOf="parent" />
<View
android:id="#+id/bank_account_divider"
android:layout_width="match_parent"
android:layout_height="1dp"
android:layout_marginTop="#dimen/margin_16"
android:alpha="0.5"
android:background="#000001"
app:layout_constraintTop_toBottomOf="#id/bank_account_tv" />
<androidx.appcompat.widget.AppCompatTextView
android:id="#+id/iban_hint_tv"
style="#style/OnlineCardEditTextHintTextStyle"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_marginStart="#dimen/margin_16"
android:layout_marginTop="15dp"
android:text="#string/step7_iban_hint"
app:layout_constraintStart_toStartOf="parent"
app:layout_constraintTop_toBottomOf="#id/bank_account_divider" />
<androidx.appcompat.widget.AppCompatEditText
android:id="#+id/step1_phone"
android:layout_width="match_parent"
android:layout_height="#dimen/height_edittext"
android:layout_marginHorizontal="#dimen/margin_16"
android:layout_marginTop="#dimen/margin_2"
android:background="#drawable/rounded_edittext_with_border"
android:maxLines="1"
app:layout_constraintTop_toBottomOf="#id/iban_hint_tv" />
<androidx.constraintlayout.widget.Group
android:id="#+id/group"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:visibility="gone"
app:constraint_referenced_ids="step1_phone, iban_hint_tv, bank_account_divider" />
</androidx.constraintlayout.widget.ConstraintLayout>
</androidx.cardview.widget.CardView>
</LinearLayout>
<androidx.appcompat.widget.AppCompatButton
android:id="#+id/step7_next_btn"
android:layout_width="#dimen/width_button_next"
android:layout_height="#dimen/height_button_next"
android:layout_marginBottom="#dimen/margin_10"
android:background="#drawable/rounded_button_next"
android:text="#string/next"
android:textColor="#color/button_text_green"
app:layout_constraintBottom_toBottomOf="parent"
app:layout_constraintEnd_toEndOf="parent"
app:layout_constraintStart_toStartOf="parent" />
</androidx.constraintlayout.widget.ConstraintLayout>
</androidx.core.widget.NestedScrollView>
When the part of the view has gone visibility, my screen looks like this:
As you can see, button is placed in the bottom and it's not overlapped by any other views. But when card is expanded, it looks like this:
As you can see, now button overlaps another card, and I need to place button under the card. So, how can I prevent existing behavior and place the button under all cards in the bottom? Thanks in advance, I will appreciate any help!

See below for an updated answer.
Old
I don't see the purpose of ConstraintLayout. You can remove that and place the button as last item in LinearLayout. The XML would then be like:
NestedScrollingView
LinearLayout
CardView ...
CardView ...
AppCompatButton
You can also use ConstraintLayout instead of LinearLayout, but I don't see the need for both.
This introduces a problem: the button is not at the bottom, when the content does not fill out the screen. For an easy fix, you can use ConstraintLayout with appropriate constraints.
New
I suggest you to use a ConstraintLayout. With it, you can achieve a flat layout hierarchy. You can use chains and vertical bias as such:
Chain the first card to the top of your parent
Chain the button to the bottom of your parent
Chain the second card to the bottom of the first card and to the top of the button. Apply a vertical bias of 0.0.
The result:
And the simple code for the example:
<?xml version="1.0" encoding="utf-8"?>
<androidx.core.widget.NestedScrollView xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:app="http://schemas.android.com/apk/res-auto"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:background="#dddddd"
android:fillViewport="true">
<androidx.constraintlayout.widget.ConstraintLayout
android:layout_width="match_parent"
android:layout_height="match_parent">
<androidx.cardview.widget.CardView
android:id="#+id/card1"
android:layout_width="0dp"
android:layout_height="200dp"
android:layout_margin="16dp"
app:cardCornerRadius="8dp"
app:cardElevation="8dp"
app:layout_constraintEnd_toEndOf="parent"
app:layout_constraintStart_toStartOf="parent"
app:layout_constraintTop_toTopOf="parent">
<TextView
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_gravity="center"
android:text="First card" />
</androidx.cardview.widget.CardView>
<androidx.cardview.widget.CardView
android:id="#+id/card2"
android:layout_width="0dp"
android:layout_height="800dp"
android:layout_margin="16dp"
app:cardCornerRadius="8dp"
app:cardElevation="8dp"
app:layout_constraintBottom_toTopOf="#id/button"
app:layout_constraintEnd_toEndOf="parent"
app:layout_constraintStart_toStartOf="parent"
app:layout_constraintTop_toBottomOf="#id/card1"
app:layout_constraintVertical_bias="0.0">
<TextView
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_gravity="center"
android:text="Second card" />
</androidx.cardview.widget.CardView>
<androidx.appcompat.widget.AppCompatButton
android:id="#+id/button"
android:layout_width="0dp"
android:layout_height="64dp"
android:layout_marginBottom="16dp"
android:background="#ffffff"
android:text="Button text"
app:layout_constraintBottom_toBottomOf="parent"
app:layout_constraintEnd_toEndOf="parent"
app:layout_constraintStart_toStartOf="parent"
app:layout_constraintWidth_percent="0.5" />
</androidx.constraintlayout.widget.ConstraintLayout>
</androidx.core.widget.NestedScrollView>

BottomAppBar navigation items are not clickable because of NestedScrollView

My app bar is located below my scroll view and therefore the items are not clickable
My scroll view should stop just above my BottomAppBar
how to do that ?
And how to make the BottomAppBar always visible
Useless text for my post to pass, very restrictive this rule
The story of a cat who wanted to eat the dog's bowl.
I hope there is enough unnecessary text
Layout
<?xml version="1.0" encoding="utf-8"?>
<androidx.coordinatorlayout.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"
android:fitsSystemWindows="true">
<com.google.android.material.bottomappbar.BottomAppBar
android:id="#+id/bottomAppBar"
style="#style/Widget.MaterialComponents.BottomAppBar.Colored"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:layout_gravity="bottom"
app:menu="#menu/menu_show_bottom"
app:navigationIcon="#drawable/ic_action_home_blank" />
<include
android:id="#+id/contentScroll"
layout="#layout/content_scrolling" />
<com.google.android.material.floatingactionbutton.FloatingActionButton
android:id="#+id/btnAddClean"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
app:layout_anchor="#id/bottomAppBar"
app:layout_anchorGravity="bottom|end"
app:srcCompat="#drawable/ic_action_clean" />
</androidx.coordinatorlayout.widget.CoordinatorLayout>
Content scrolled
<?xml version="1.0" encoding="utf-8"?>
<androidx.core.widget.NestedScrollView 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:showIn="#layout/fragment_avaloir_show">
<androidx.constraintlayout.widget.ConstraintLayout
android:layout_width="match_parent"
android:layout_height="wrap_content">
<TextView
android:id="#+id/rueTextView"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:textAppearance="#style/TextAppearance.MaterialComponents.Headline5"
app:layout_constraintStart_toStartOf="parent"
app:layout_constraintTop_toTopOf="parent"
tools:text="Rue des jolis bois " />
<ImageView
android:id="#+id/avaloirImageView"
android:layout_width="263dp"
android:layout_height="350dp"
android:contentDescription="#string/content_description"
android:src="#drawable/aval2"
app:layout_constraintStart_toStartOf="parent"
app:layout_constraintTop_toBottomOf="#+id/rueTextView" />
<TextView
android:id="#+id/coordinatesTextView"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_marginTop="16dp"
app:layout_constraintEnd_toEndOf="parent"
app:layout_constraintHorizontal_bias="0.5"
app:layout_constraintStart_toStartOf="parent"
app:layout_constraintTop_toBottomOf="#+id/avaloirImageView"
tools:text="50.235621, 5.23658" />
<com.google.android.gms.maps.MapView
android:id="#+id/mapView"
android:layout_width="match_parent"
android:layout_height="350dp"
app:layout_constraintStart_toStartOf="parent"
app:layout_constraintTop_toBottomOf="#+id/coordinatesTextView" />
<TextView
android:id="#+id/titreDatesNettoyageTextView"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_marginStart="8dp"
android:layout_marginTop="24dp"
android:text="#string/title_dates_nettoyage"
android:textAppearance="#style/TextAppearance.MaterialComponents.Headline5"
app:layout_constraintStart_toStartOf="parent"
app:layout_constraintTop_toBottomOf="#+id/mapView" />
<View
android:id="#+id/dividerView"
android:layout_width="match_parent"
android:layout_height="2dp"
android:layout_marginTop="16dp"
android:background="#color/colorPrimaryDark"
app:layout_constraintBottom_toBottomOf="#+id/titreDatesNettoyageTextView" />
<TextView
android:id="#+id/datesTextView"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_marginTop="16dp"
app:layout_constraintEnd_toEndOf="parent"
app:layout_constraintHorizontal_bias="0.5"
app:layout_constraintStart_toStartOf="parent"
app:layout_constraintTop_toBottomOf="#+id/dividerView"
tools:text="10 avril 2019" />
<TextView
android:id="#+id/titreCommentairesTextView"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_marginStart="8dp"
android:layout_marginTop="24dp"
android:text="#string/title_commentaires"
android:textAppearance="#style/TextAppearance.MaterialComponents.Headline5"
app:layout_constraintStart_toStartOf="parent"
app:layout_constraintTop_toBottomOf="#+id/datesTextView" />
<View
android:id="#+id/commentDividerView"
android:layout_width="match_parent"
android:layout_height="2dp"
android:layout_marginTop="16dp"
android:background="#color/colorPrimaryDark"
app:layout_constraintBottom_toBottomOf="#+id/titreCommentairesTextView" />
<TextView
android:id="#+id/commentairesTextView"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_marginTop="16dp"
app:layout_constraintEnd_toEndOf="parent"
app:layout_constraintHorizontal_bias="0.5"
app:layout_constraintStart_toStartOf="parent"
app:layout_constraintTop_toBottomOf="#+id/commentDividerView"
tools:text="Il est cassé il faut le remplacer" />
</androidx.constraintlayout.widget.ConstraintLayout>
</androidx.core.widget.NestedScrollView>

finally I added a linearLayout
<?xml version="1.0" encoding="utf-8"?>
<androidx.coordinatorlayout.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">
<androidx.core.widget.NestedScrollView
android:layout_width="match_parent"
android:layout_height="match_parent">
<LinearLayout
android:layout_width="match_parent"
android:layout_height="wrap_content">
<include
android:id="#+id/contentScroll"
layout="#layout/content_scrolling" />
</LinearLayout>
</androidx.core.widget.NestedScrollView>
<com.google.android.material.bottomappbar.BottomAppBar
android:id="#+id/bottomAppBar"
style="#style/Widget.MaterialComponents.BottomAppBar.Colored"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:layout_gravity="bottom"
app:menu="#menu/menu_show_bottom"
app:navigationIcon="#drawable/ic_action_home_blank" />
<com.google.android.material.floatingactionbutton.FloatingActionButton
android:id="#+id/btnAddClean"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
app:layout_anchor="#id/bottomAppBar"
app:srcCompat="#drawable/ic_action_clean" />
</androidx.coordinatorlayout.widget.CoordinatorLayout>
<?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">
<TextView
android:id="#+id/rueTextView"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:textAppearance="#style/TextAppearance.MaterialComponents.Headline5"
app:layout_constraintStart_toStartOf="parent"
app:layout_constraintTop_toTopOf="parent"
tools:text="Rue des jolis bois " />
<ImageView
android:id="#+id/avaloirImageView"
android:layout_width="263dp"
android:layout_height="350dp"
android:contentDescription="#string/content_description"
android:src="#drawable/aval2"
app:layout_constraintStart_toStartOf="parent"
app:layout_constraintTop_toBottomOf="#+id/rueTextView" />
<TextView
android:id="#+id/coordinatesTextView"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_marginTop="16dp"
app:layout_constraintEnd_toEndOf="parent"
app:layout_constraintHorizontal_bias="0.5"
app:layout_constraintStart_toStartOf="parent"
app:layout_constraintTop_toBottomOf="#+id/avaloirImageView"
tools:text="50.235621, 5.23658" />
<com.google.android.gms.maps.MapView
android:id="#+id/mapView"
android:layout_width="match_parent"
android:layout_height="350dp"
app:layout_constraintStart_toStartOf="parent"
app:layout_constraintTop_toBottomOf="#+id/coordinatesTextView" />
<TextView
android:id="#+id/titreDatesNettoyageTextView"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_marginStart="8dp"
android:layout_marginTop="24dp"
android:text="#string/title_dates_nettoyage"
android:textAppearance="#style/TextAppearance.MaterialComponents.Headline5"
app:layout_constraintStart_toStartOf="parent"
app:layout_constraintTop_toBottomOf="#+id/mapView" />
<View
android:id="#+id/dividerView"
android:layout_width="match_parent"
android:layout_height="2dp"
android:layout_marginTop="16dp"
android:background="#color/colorPrimaryDark"
app:layout_constraintBottom_toBottomOf="#+id/titreDatesNettoyageTextView" />
<TextView
android:id="#+id/datesTextView"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_marginTop="16dp"
app:layout_constraintEnd_toEndOf="parent"
app:layout_constraintHorizontal_bias="0.5"
app:layout_constraintStart_toStartOf="parent"
app:layout_constraintTop_toBottomOf="#+id/dividerView"
tools:text="10 avril 2019" />
<TextView
android:id="#+id/titreCommentairesTextView"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_marginStart="8dp"
android:layout_marginTop="24dp"
android:text="#string/title_commentaires"
android:textAppearance="#style/TextAppearance.MaterialComponents.Headline5"
app:layout_constraintStart_toStartOf="parent"
app:layout_constraintTop_toBottomOf="#+id/datesTextView" />
<View
android:id="#+id/commentDividerView"
android:layout_width="match_parent"
android:layout_height="2dp"
android:layout_marginTop="16dp"
android:background="#color/colorPrimaryDark"
app:layout_constraintBottom_toBottomOf="#+id/titreCommentairesTextView" />
<TextView
android:id="#+id/commentairesTextView"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_marginTop="16dp"
app:layout_constraintEnd_toEndOf="parent"
app:layout_constraintHorizontal_bias="0.5"
app:layout_constraintStart_toStartOf="parent"
app:layout_constraintTop_toBottomOf="#+id/commentDividerView"
tools:text="Il est cassé il faut le remplacer" />
</androidx.constraintlayout.widget.ConstraintLayout>

How to set height of a view in percent using ConstraintLayout

Currently I'm learning ConstraintLayout
below is my code that i have tried so far
<?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"
android:background="#000000"
android:fitsSystemWindows="true"
app:layout_behavior="#string/appbar_scrolling_view_behavior"
tools:context=".activity.PhaseListActivity">
<androidx.core.widget.NestedScrollView
android:layout_width="match_parent"
android:layout_height="match_parent"
android:fillViewport="true">
<LinearLayout
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:orientation="vertical"
android:weightSum="1">
<FrameLayout
android:layout_width="match_parent"
android:layout_height="0dp"
android:layout_weight="0.8"
android:background="#color/colorAccent">
<VideoView
android:id="#+id/myVideoView"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:visibility="visible" />
<TextSwitcher
android:id="#+id/tvAnimText"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_centerInParent="true"
android:layout_gravity="center"
android:fontFamily="#font/knowledge_bold"
android:textColor="#color/greenColor"
android:textSize="#dimen/_100ssp"
android:textStyle="bold"
tools:text="1" />
</FrameLayout>
<LinearLayout
android:layout_width="match_parent"
android:layout_height="0dp"
android:layout_weight="0.2"
android:orientation="vertical">
<TextView
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:gravity="center"
android:padding="10dp"
android:text="Scrollbale view below my videoView"
android:textColor="#ff00"
android:textStyle="bold" />
<TextView
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:gravity="center"
android:padding="10dp"
android:text="Scrollbale view below my videoView"
android:textColor="#ff00"
android:textStyle="bold" />
<TextView
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:gravity="center"
android:padding="10dp"
android:text="Scrollbale view below my videoView"
android:textColor="#ff00"
android:textStyle="bold" />
</LinearLayout>
</LinearLayout>
</androidx.core.widget.NestedScrollView>
<LinearLayout
android:id="#+id/bottomView"
android:layout_width="match_parent"
android:layout_height="50dp"
android:layout_gravity="bottom"
android:background="#color/greenColor"
android:orientation="vertical"
app:layout_constraintBottom_toBottomOf="parent"
app:layout_constraintEnd_toEndOf="parent"
app:layout_constraintStart_toStartOf="parent">
<TextView
android:layout_width="match_parent"
android:layout_height="match_parent"
android:gravity="center"
android:text="Fixed Bottombar"
android:textColor="#ff00"
android:textStyle="bold" />
</LinearLayout>
</androidx.constraintlayout.widget.ConstraintLayout>
I want don't want use nested LinearLayout inside ConstraintLayout
Also in above layout my NestedScrollView is not scrolling
I want to create this type of screen using ConstraintLayout
My expected OUTPUT
I have tried to set Guideline but it didn't work for me, because i don't know how to use Guideline in above layout
Can anybody help me create this screen only using ConstraintLayout
If need more information please do let me know. Thanks in advance. Your efforts will be appreciated.

So, after looking at your xml file, I've come up with solution to get rid of nested LinearLayout hierarchy in below solution:
<?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"
android:background="#000000"
android:fitsSystemWindows="true"
app:layout_behavior="#string/appbar_scrolling_view_behavior">
<androidx.core.widget.NestedScrollView
android:layout_width="0dp"
android:layout_height="0dp"
android:fillViewport="true"
app:layout_constraintBottom_toTopOf="#id/tv_bottom_view"
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="wrap_content">
<VideoView
android:id="#+id/myVideoView"
android:layout_width="0dp"
android:layout_height="0dp"
android:visibility="visible"
app:layout_constrainedHeight="true"
app:layout_constraintBottom_toTopOf="#id/tv1"
app:layout_constraintEnd_toEndOf="parent"
app:layout_constraintHeight_default="percent"
app:layout_constraintHeight_percent="0.85"
app:layout_constraintStart_toStartOf="parent"
app:layout_constraintTop_toTopOf="parent"
app:layout_constraintVertical_chainStyle="packed" />
<TextSwitcher
android:id="#+id/tvAnimText"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_centerInParent="true"
android:layout_gravity="center"
android:fontFamily="#font/knowledge_bold"
android:textColor="#color/greenColor"
android:textSize="#dimen/_100ssp"
android:textStyle="bold"
app:layout_constraintBottom_toBottomOf="#id/myVideoView"
app:layout_constraintEnd_toEndOf="#id/myVideoView"
app:layout_constraintStart_toStartOf="#id/myVideoView"
app:layout_constraintTop_toTopOf="#id/myVideoView"
tools:text="1" />
<TextView
android:id="#+id/tv1"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:gravity="center"
android:padding="10dp"
android:text="Scrollbale view below my videoView"
android:textColor="#ff00"
android:textStyle="bold"
app:layout_constraintBottom_toTopOf="#id/tv2"
app:layout_constraintEnd_toEndOf="parent"
app:layout_constraintStart_toStartOf="parent"
app:layout_constraintTop_toBottomOf="#id/myVideoView" />
<TextView
android:id="#+id/tv2"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:gravity="center"
android:padding="10dp"
android:text="Scrollbale view below my videoView"
android:textColor="#ff00"
android:textStyle="bold"
app:layout_constraintBottom_toTopOf="#id/tv3"
app:layout_constraintEnd_toEndOf="parent"
app:layout_constraintStart_toStartOf="parent"
app:layout_constraintTop_toBottomOf="#id/tv1" />
<TextView
android:id="#+id/tv3"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:gravity="center"
android:padding="10dp"
android:text="Scrollbale view below my videoView"
android:textColor="#ff00"
android:textStyle="bold"
app:layout_constraintBottom_toBottomOf="parent"
app:layout_constraintEnd_toEndOf="parent"
app:layout_constraintStart_toStartOf="parent"
app:layout_constraintTop_toBottomOf="#id/tv2" />
</androidx.constraintlayout.widget.ConstraintLayout>
</androidx.core.widget.NestedScrollView>
<TextView
android:id="#+id/tv_bottom_view"
android:layout_width="0dp"
android:layout_height="0dp"
android:gravity="center"
android:text="Fixed Bottombar"
android:textColor="#ff00"
android:textStyle="bold"
app:layout_constrainedHeight="true"
app:layout_constraintBottom_toBottomOf="parent"
app:layout_constraintEnd_toEndOf="parent"
app:layout_constraintHeight_default="percent"
app:layout_constraintHeight_percent="0.08"
app:layout_constraintStart_toStartOf="parent" />
</androidx.constraintlayout.widget.ConstraintLayout>
Let me know if there's any query in comments. For your fixed bottombar TextView, now you can change height percent to whatever you want to change it's height dynamically.

You can use below code for bottom View which remove your Nested LinearLayout :
<TextView
android:id="#+id/bottomView"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:gravity="center"
android:text="Fixed Bottombar"
android:textColor="#ff00"
android:background="#00ff00"
android:padding="15dp"
app:layout_constraintBottom_toBottomOf="parent"
app:layout_constraintEnd_toEndOf="parent"
app:layout_constraintStart_toStartOf="parent"
android:textStyle="bold" />

Is there any way to forbid keyboard to move LinearLayout?

I have a fragment and LinearLayout in my activity. In this fragment I have a textview. If there is no ScrollView in fragment, everything works fine. But if there is ScrollView LinearLayout move to the top of keyboard.
This is how my app looks without Scrollview on the text: https://yapx.ru/v/EPcoQ
And this how it looks with it: https://yapx.ru/v/EPcqd
I don't like that Navigation Bar on the bottom isn't hidden when the keyboard is active. What can I do to make app lok like on the first photo andk make textView scrollable?
I've tried to use "windowSoftInputMode" to forbid keyboard move this LinearLayout, but it didn't helped.
I have also tried "focusableInTouchMode" and "isScrollContainer"
attributes, but they were useless too.
This is the activity file:
<?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/main_chetnost"
android:orientation="vertical"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:background="#86A0FC"
android:windowSoftInputMode="adjustResize"
>
<fragment
android:id="#+id/fragment_theory"
android:name="com.example.user.mathplace_1.theory"
android:layout_width="match_parent"
android:layout_height="match_parent"
app:layout_constraintBottom_toTopOf="#+id/linearLayout"
app:layout_constraintEnd_toEndOf="parent"
app:layout_constraintStart_toStartOf="parent"
app:layout_constraintTop_toBottomOf="#+id/toolbar" />
<fragment
android:id="#+id/fragment_task"
android:name="com.example.user.mathplace_1.Task"
android:layout_width="match_parent"
android:layout_height="match_parent"
app:layout_constraintBottom_toTopOf="#+id/linearLayout"
app:layout_constraintEnd_toEndOf="parent"
app:layout_constraintStart_toStartOf="parent"
app:layout_constraintTop_toBottomOf="#+id/toolbar"
app:layout_constraintVertical_bias="0.0" />
<android.support.v7.widget.Toolbar
android:id="#+id/toolbar"
android:layout_width="0dp"
android:layout_height="60dp"
android:background="?attr/colorPrimary"
android:minHeight="?attr/actionBarSize"
android:theme="?attr/actionBarTheme"
app:layout_constraintEnd_toEndOf="parent"
app:layout_constraintHorizontal_bias="0.0"
app:layout_constraintStart_toStartOf="parent"
app:layout_constraintTop_toTopOf="parent"
app:title="MathPlace"
app:titleTextColor="#fff">
<ImageButton
android:id="#+id/homeButton"
android:layout_width="44dp"
android:layout_height="44dp"
android:layout_alignParentEnd="true"
android:layout_alignParentRight="true"
android:layout_gravity="end"
android:layout_marginStart="8dp"
android:layout_marginTop="6dp"
android:layout_marginEnd="8dp"
android:layout_marginBottom="6dp"
android:background="#drawable/home"
android:contentDescription="#string/report_description"
android:onClick="delete"
app:layout_constraintBottom_toBottomOf="parent"
app:layout_constraintEnd_toEndOf="parent"
app:layout_constraintHorizontal_bias="0.887"
app:layout_constraintStart_toStartOf="parent"
app:layout_constraintTop_toTopOf="parent"
app:layout_constraintVertical_bias="0.987" />
</android.support.v7.widget.Toolbar>
<LinearLayout
android:id="#+id/linearLayout"
android:layout_width="match_parent"
android:layout_height="75dp"
android:background="#FFF"
android:orientation="horizontal"
app:layout_constraintBottom_toBottomOf="parent"
app:layout_constraintEnd_toEndOf="parent"
app:layout_constraintHorizontal_bias="0.0"
app:layout_constraintStart_toStartOf="parent"
android:focusableInTouchMode="false"
android:isScrollContainer="false">
<HorizontalScrollView
android:layout_width="match_parent"
android:layout_height="match_parent"
android:background="#accbff"
android:orientation="horizontal"
android:focusableInTouchMode="false"
android:isScrollContainer="false">
<LinearLayout
android:id="#+id/LinearLayout"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:orientation="horizontal"
android:focusableInTouchMode="false"
android:isScrollContainer="false"/>
</HorizontalScrollView>
</LinearLayout>
</android.support.constraint.ConstraintLayout>
And this is the fragment code:
<?xml version="1.0" encoding="utf-8"?>
<android.support.constraint.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"
android:background="#color/background"
xmlns:app="http://schemas.android.com/apk/res-auto">
<EditText
android:id="#+id/editText"
android:layout_width="237dp"
android:layout_height="46dp"
android:layout_marginTop="8dp"
android:ems="10"
android:hint="Введите ваш ответ"
android:inputType="number"
android:textColor="#5B6175"
android:textSize="23sp"
app:layout_constraintBottom_toBottomOf="parent"
app:layout_constraintStart_toStartOf="#+id/cardView"
app:layout_constraintTop_toBottomOf="#+id/cardView"
app:layout_constraintVertical_bias="0.3" />
<ImageButton
android:id="#+id/send"
android:layout_width="50dp"
android:layout_height="50dp"
android:layout_marginTop="8dp"
android:background="#drawable/send"
android:onClick="send"
android:scaleType="fitXY"
app:layout_constraintBottom_toBottomOf="parent"
app:layout_constraintEnd_toEndOf="#+id/cardView"
app:layout_constraintTop_toBottomOf="#+id/cardView"
app:layout_constraintVertical_bias="0.3" />
<android.support.v7.widget.CardView
android:id="#+id/cardView"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
app:layout_constraintBottom_toBottomOf="parent"
app:layout_constraintEnd_toEndOf="parent"
app:layout_constraintStart_toStartOf="parent"
app:layout_constraintTop_toTopOf="parent"
app:layout_constraintVertical_bias="0.4">
<ScrollView
android:id="#+id/scrollView4"
android:layout_width="310dp"
android:layout_height="375dp">
<LinearLayout
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:orientation="vertical">
<TextView
android:id="#+id/textView3"
android:layout_width="310dp"
android:layout_height="375dp"
android:background="#drawable/text_rounded_corner"
android:padding="8dp"
android:text="dddddddddddddddddddddddd"
android:textColor="#5B6175"
android:textSize="20sp" />
</LinearLayout>
</ScrollView>
</android.support.v7.widget.CardView>
<TextView
android:id="#+id/textView"
android:layout_width="310dp"
android:layout_height="47dp"
android:background="#drawable/title_rounded_corner"
android:padding="8dp"
android:text="Заголовок"
android:textColor="#FFF"
android:textSize="24sp"
app:layout_constraintBottom_toTopOf="#+id/cardView"
app:layout_constraintEnd_toEndOf="parent"
app:layout_constraintHorizontal_bias="0.504"
app:layout_constraintStart_toStartOf="parent" />
<ImageView
android:id="#+id/star2"
android:layout_width="30dp"
android:layout_height="30dp"
android:layout_marginEnd="44dp"
android:layout_marginBottom="8dp"
app:layout_constraintBottom_toBottomOf="#+id/textView"
app:layout_constraintEnd_toEndOf="#+id/textView"
app:layout_constraintTop_toTopOf="#+id/textView"
app:layout_constraintVertical_bias="1.0"
app:srcCompat="#drawable/star" />
<ImageView
android:id="#+id/star1"
android:layout_width="30dp"
android:layout_height="30dp"
android:layout_marginEnd="12dp"
android:layout_marginBottom="8dp"
app:layout_constraintBottom_toBottomOf="#+id/textView"
app:layout_constraintEnd_toEndOf="#+id/textView"
app:layout_constraintTop_toTopOf="#+id/textView"
app:layout_constraintVertical_bias="1.0"
app:srcCompat="#drawable/star" />
<ImageView
android:id="#+id/star3"
android:layout_width="30dp"
android:layout_height="30dp"
android:layout_marginEnd="76dp"
android:layout_marginBottom="8dp"
app:layout_constraintBottom_toBottomOf="#+id/textView"
app:layout_constraintEnd_toEndOf="#+id/textView"
app:layout_constraintTop_toTopOf="#+id/textView"
app:layout_constraintVertical_bias="1.0"
app:srcCompat="#drawable/star" />
</android.support.constraint.ConstraintLayout>

I've found how I can make my text scrollable without breaking old app view.
I just needed to add one line to the java file:
myTextview.setMovementMethod(new ScrollingMovementMethod());

Layout Problems - Not able to create layout properly in android

I am creating a layout in android but the problem is layout is not created as same in design.
I want to create layout like below image i.e.
but the problem is my design distort in some devices like
enter image description here
<RelativeLayout android:layout_width="match_parent"
android:layout_height="wrap_content"
android:layout_below="#id/lay1"
android:layout_margin="#dimen/dp20"
>
<ImageView android:id="#+id/kk"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:src="#drawable/move_stock_bar"
android:background="#android:color/transparent"
android:scaleType="centerCrop"
/>
<ImageButton android:id="#+id/ibPlus"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_weight="1"
android:layout_alignParentRight="true"
android:background="#android:color/transparent"
android:src="#drawable/btn_edit"
android:layout_toRightOf="#id/kk"
android:layout_marginLeft="-100dp"
android:layout_marginTop="#dimen/dp10"
/>
<ImageButton android:id="#+id/ibMinus"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_weight="1"
android:layout_alignParentRight="true"
android:background="#android:color/transparent"
android:src="#drawable/btn_edit"
android:layout_toRightOf="#id/kk"
android:layout_below="#id/ibPlus"
android:layout_marginLeft="-100dp"
android:layout_marginTop="-40dp"
/>
</RelativeLayout>

#mishti I have just used this concept to make the design appear to like what you gave. Try this with ImageView using the weight. It displays the same to all screens if we use weight.
<LinearLayout
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">
<LinearLayout
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:weightSum="10">
<Button
android:layout_width="0dp"
android:layout_height="120dp"
android:layout_weight="6"
android:text="Image View"/>
<LinearLayout
android:layout_width="0dp"
android:layout_height="match_parent"
android:orientation="vertical"
android:layout_weight="4"
android:layout_gravity="start"
android:gravity="start">
<ImageView
android:layout_marginTop="20dp"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:src="#drawable/edit_icon"
android:background="#FF0"
android:layout_gravity="start"
/>
<ImageView
android:layout_marginTop="10dp"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:src="#drawable/edit_icon"
android:background="#FF0"
android:layout_gravity="start"
/>
</LinearLayout>
</LinearLayout>

Use ConstraintLayout for complex layout, it provides you more flexiblity. I did the same layout as in the image attached with question. I am using Guidelines, so i can use this same layout on different screen size and it will work fine.
I am using "app:srcCompat" attribute for setting the image because i am using Vector image here.
<?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"
android:layout_width="match_parent"
android:layout_height="140dp"
android:background="#color/color_black">
<android.support.constraint.Guideline
android:id="#+id/guideline_horizontal_top"
android:layout_width="match_parent"
android:layout_height="1dp"
android:orientation="horizontal"
app:layout_constraintGuide_percent=".01" />
<android.support.constraint.Guideline
android:id="#+id/guideline_horizontal_bottom"
android:layout_width="match_parent"
android:layout_height="1dp"
android:orientation="horizontal"
app:layout_constraintGuide_percent=".99" />
<android.support.constraint.Guideline
android:id="#+id/guideline_vertical_start"
android:layout_width="1dp"
android:layout_height="match_parent"
android:orientation="vertical"
app:layout_constraintGuide_percent=".2" />
<android.support.constraint.Guideline
android:id="#+id/guideline_vertical_mid"
android:layout_width="1dp"
android:layout_height="match_parent"
android:orientation="vertical"
app:layout_constraintGuide_percent=".8" />
<android.support.constraint.ConstraintLayout
android:id="#+id/main_text_container"
android:layout_width="0dp"
android:layout_height="0dp"
android:background="#color/color_red"
app:layout_constraintBottom_toTopOf="#+id/guideline_horizontal_bottom"
app:layout_constraintEnd_toStartOf="#+id/guideline_vertical_mid"
app:layout_constraintStart_toStartOf="parent"
app:layout_constraintTop_toBottomOf="#+id/guideline_horizontal_top">
<android.support.constraint.Guideline
android:id="#+id/guideline_vertical"
android:layout_width="1dp"
android:layout_height="match_parent"
android:orientation="vertical"
app:layout_constraintGuide_percent=".2" />
<ImageView
android:id="#+id/logo_iv"
android:layout_width="56dp"
android:layout_height="56dp"
android:layout_marginStart="10dp"
android:layout_marginEnd="10dp"
app:layout_constraintBottom_toBottomOf="parent"
app:layout_constraintEnd_toStartOf="#+id/guideline_vertical"
app:layout_constraintStart_toStartOf="parent"
app:layout_constraintTop_toTopOf="parent"
app:srcCompat="#drawable/ic_image_placeholder" />
<TextView
android:id="#+id/title_tv"
android:layout_width="0dp"
android:layout_height="wrap_content"
android:layout_marginStart="10dp"
android:layout_marginEnd="10dp"
android:gravity="center"
android:text="MOVE STOCK"
android:textColor="#color/color_white"
android:textSize="18sp"
app:layout_constraintBottom_toBottomOf="parent"
app:layout_constraintEnd_toEndOf="parent"
app:layout_constraintStart_toStartOf="#+id/guideline_vertical"
app:layout_constraintTop_toTopOf="parent" />
</android.support.constraint.ConstraintLayout>
<android.support.constraint.ConstraintLayout
android:id="#+id/button_container"
android:layout_width="0dp"
android:layout_height="0dp"
app:layout_constraintBottom_toTopOf="#+id/guideline_horizontal_bottom"
app:layout_constraintEnd_toEndOf="parent"
app:layout_constraintStart_toEndOf="#+id/guideline_vertical_mid"
app:layout_constraintTop_toBottomOf="#+id/guideline_horizontal_top">
<ImageButton
android:id="#+id/button1"
android:layout_width="54dp"
android:layout_height="54dp"
android:background="#color/color_white"
app:layout_constraintBottom_toTopOf="#+id/button2"
app:layout_constraintHorizontal_bias="0.5"
app:layout_constraintStart_toStartOf="parent"
app:layout_constraintTop_toTopOf="parent"
app:srcCompat="#drawable/ic_image_placeholder" />
<ImageButton
android:id="#+id/button2"
android:layout_width="54dp"
android:layout_height="54dp"
android:background="#color/color_white"
app:layout_constraintBottom_toBottomOf="parent"
app:layout_constraintHorizontal_bias="0.5"
app:layout_constraintStart_toStartOf="parent"
app:layout_constraintTop_toBottomOf="#+id/button1"
app:srcCompat="#drawable/ic_image_placeholder" />
</android.support.constraint.ConstraintLayout>
</android.support.constraint.ConstraintLayout>