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Bottom of one layout in the middle of another layout vertically in android xml?

I want to create the below layout, but not sure how to do it.
height of both blue layout and white layout is set to "wrap_content" and therefor they don't have a constant height.
The point is, I want the bottom of blue layout to always be in the middle of white layout(vertically). I have no idea how to do it using constraint or relative layout.
I searched but couldn't find any solution to this problem.

modify this accordingly
<?xml version="1.0" encoding="utf-8"?>
<androidx.constraintlayout.widget.ConstraintLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:layout_width="match_parent"
android:layout_height="match_parent"
xmlns:app="http://schemas.android.com/apk/res-auto"
xmlns:tools="http://schemas.android.com/tools">
<androidx.constraintlayout.widget.ConstraintLayout
android:id="#+id/credentials_card"
android:layout_width="match_parent"
android:layout_height="0dp"
android:layout_marginTop="20dp"
android:padding="#dimen/spacing_mlarge"
app:layout_constraintLeft_toLeftOf="parent"
app:layout_constraintRight_toRightOf="parent"
app:layout_constraintTop_toBottomOf="#+id/image_logo">
<androidx.cardview.widget.CardView
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:layout_margin="#dimen/spacing_medium"
android:visibility="visible"
app:cardBackgroundColor="#color/white"
app:cardCornerRadius="6dp"
app:cardElevation="5dp"
app:cardUseCompatPadding="true"
tools:ignore="MissingConstraints">
<LinearLayout
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:orientation="vertical"
android:padding="#dimen/spacing_xmlarge">
<TextView
android:id="#+id/textView"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_gravity="center_horizontal"
android:layout_marginBottom="25dp"
android:fontFamily="#string/font_family_light"
android:text="L O G I N"
android:textAppearance="#style/Base.TextAppearance.AppCompat.Large"
android:textColor="#color/colorPrimary"
android:textStyle="bold" />
<TextView
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="MOBILE"
android:textAlignment="center"
android:textAppearance="#style/Base.TextAppearance.AppCompat.Caption"
android:textColor="#color/colorPrimary" />
<com.google.android.material.textfield.TextInputEditText
android:id="#+id/mobileNumberET"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:inputType="number"
android:maxLength="10"
android:maxLines="1"
android:singleLine="true"
android:textAppearance="#style/Base.TextAppearance.AppCompat.Large"
android:textColor="#color/colorPrimary"
android:textStyle="bold" />
<TextView
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_marginTop="20dp"
android:text="PASSWORD"
android:textAlignment="center"
android:textAppearance="#style/Base.TextAppearance.AppCompat.Caption"
android:textColor="#color/colorPrimary" />
<com.google.android.material.textfield.TextInputEditText
android:id="#+id/passwordET"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:inputType="textPassword"
android:maxLength="50"
android:maxLines="1"
android:singleLine="true"
android:textAppearance="#style/Base.TextAppearance.AppCompat.Large"
android:textColor="#color/colorPrimary"
android:textStyle="bold" />
</LinearLayout>
</androidx.cardview.widget.CardView>
</androidx.constraintlayout.widget.ConstraintLayout>
<Button
android:id="#+id/loginButton"
android:layout_width="match_parent"
android:layout_height="57dp"
android:layout_marginLeft="50dp"
android:layout_marginRight="50dp"
android:background="#drawable/button_round"
android:text="L O G I N"
android:fontFamily="#string/font_family_light"
android:textAllCaps="false"
android:textColor="#android:color/white"
android:textStyle="bold"
app:layout_constraintBottom_toBottomOf="#+id/credentials_card"
app:layout_constraintEnd_toEndOf="parent"
app:layout_constraintStart_toStartOf="parent" />
</androidx.constraintlayout.widget.ConstraintLayout>

You can try this (I don't include border radius so take care of it..)
<androidx.constraintlayout.widget.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="match_parent">
<androidx.constraintlayout.widget.ConstraintLayout
android:id="#+id/constraintLayout"
android:layout_width="match_parent"
android:layout_height="250dp"
android:background="#8F2A2A"
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="70dp"
android:layout_marginStart="50dp"
android:layout_marginEnd="50dp"
android:layout_marginTop="200dp"
android:background="#B8C159"
app:layout_constraintTop_toTopOf="#+id/constraintLayout" />
</androidx.constraintlayout.widget.ConstraintLayout>

Here My Ans check
<?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:layout_width="match_parent"
android:layout_height="match_parent">
<androidx.cardview.widget.CardView
android:layout_width="match_parent"
android:layout_height="0dp"
android:layout_marginLeft="#dimen/dp_16"
android:layout_marginRight="#dimen/dp_16"
app:cardBackgroundColor="#color/blue"
app:cardCornerRadius="#dimen/dp_10"
app:cardElevation="#dimen/dp_5"
app:cardUseCompatPadding="true"
android:id="#+id/card_container"
app:layout_constraintBottom_toBottomOf="#id/guideline"
app:layout_constraintTop_toTopOf="parent">
</androidx.cardview.widget.CardView>
<androidx.constraintlayout.widget.Guideline
android:id="#+id/guideline"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:orientation="horizontal"
app:layout_constraintGuide_percent="0.42" />
<androidx.cardview.widget.CardView
android:layout_width="0dp"
android:layout_height="100dp"
app:cardBackgroundColor="#color/white"
app:cardCornerRadius="#dimen/dp_10"
app:cardElevation="#dimen/dp_5"
app:cardUseCompatPadding="true"
android:layout_marginStart="#dimen/dp_20"
android:layout_marginEnd="#dimen/dp_20"
app:layout_constraintStart_toStartOf="#id/card_container"
app:layout_constraintEnd_toEndOf="#id/card_container"
app:layout_constraintTop_toTopOf="#id/guideline"
app:layout_constraintBottom_toTopOf="#id/guideline">
</androidx.cardview.widget.CardView>
</androidx.constraintlayout.widget.ConstraintLayout>

Use constraint layout as parent and then constraint the topOfSmallComponent to the bottomOfBigComponent. Then again constraint the bottomOfSmallComponent to the bottomOf BigComponent.
Example code below:
app:layout_constraintTop_toBottomOf="your_blue_items_id"
app:layout_constraintBottom_toBottomOf="your_blue_items_id"

TextViews in ConstraintLayout not wrapping properly despite setting properties

For some strange reason, the TextViews in my ConstraintLayout won't budge to show all text and it appears to go over the screen's boundaries. I already tried using app:layout_constrainedWidth="true" with android:layout_width="wrap_content" but that didn't have any effect in changing the positioning, leading me to think what would happen to the '1C' and '1D' text views when I add longer text in those.
Current result
<?xml version="1.0" encoding="utf-8"?>
<androidx.cardview.widget.CardView
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="wrap_content"
android:layout_marginBottom="20dp"
app:cardUseCompatPadding="true"
android:background="#android:color/white">
<LinearLayout
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:orientation="vertical"
android:id="#+id/linearLayoutA"
android:padding="12dp"
android:foreground="?android:attr/selectableItemBackground">
<!--Constraint 1-->
<androidx.constraintlayout.widget.ConstraintLayout
android:layout_width="match_parent"
android:layout_height="match_parent"
android:id="#+id/constraintLayoutTitle"
android:layout_marginBottom="10dp">
<ImageView
android:id="#+id/ibA"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_marginTop="8dp"
app:layout_constraintStart_toStartOf="parent"
app:layout_constraintTop_toTopOf="parent"
app:srcCompat="#mipmap/ic_launcher_round" />
<TextView
android:id="#+id/tvA"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_marginStart="10dp"
app:layout_constraintStart_toEndOf="#+id/ibA"
app:layout_constraintTop_toTopOf="parent"
app:layout_constrainedWidth="true"
style="#android:style/TextAppearance.Medium"/>
</androidx.constraintlayout.widget.ConstraintLayout>
<!--Constraint 2-->
<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:id="#+id/constraintLayout">
<ImageView
android:id="#+id/ivA"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
app:layout_constraintStart_toStartOf="parent"
app:layout_constraintTop_toTopOf="parent"
app:srcCompat="#mipmap/ic_launcher_round" />
<TextView
android:id="#+id/tvB"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_marginStart="10dp"
app:layout_constraintStart_toEndOf="#+id/ivA"
app:layout_constraintTop_toTopOf="#+id/ivA"
style="#android:style/TextAppearance.Medium"/>
<TextView
android:id="#+id/tvC"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_marginStart="10dp"
android:layout_marginBottom="10dp"
android:layout_marginTop="10dp"
app:layout_constraintBottom_toTopOf="#+id/tvD"
app:layout_constraintStart_toEndOf="#+id/ivA"
app:layout_constraintTop_toBottomOf="#+id/tvB"
style="#android:style/TextAppearance.Medium"/>
<ImageView
android:id="#+id/ivD"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_marginTop="20dp"
app:layout_constraintEnd_toEndOf="#+id/ivA"
app:layout_constraintStart_toStartOf="#+id/ivA"
app:layout_constraintTop_toBottomOf="#+id/ivA"
app:layout_constraintTop_toTopOf="#+id/tvD"
app:srcCompat="#mipmap/ic_launcher_round" />
<TextView
android:id="#+id/tvD"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_marginStart="10dp"
app:layout_constraintStart_toEndOf="#+id/ivD"
app:layout_constraintTop_toBottomOf="#+id/tvC"
style="#android:style/TextAppearance.Medium"/>
</androidx.constraintlayout.widget.ConstraintLayout>
</LinearLayout>
</androidx.cardview.widget.CardView>
Suraj Vaishnav's suggestion

Because there is no constraint from the right(or end) side, add this app:layout_constraintEnd_toEndOf="parent" to tvA,tvB and so on.
Update:
apply both constraints: start and end and set the width 0dp. here are the working properties for tvB:
<TextView
android:id="#+id/tvB"
app:layout_constraintStart_toEndOf="#+id/ivA"
android:layout_width="0dp"
app:layout_constraintEnd_toEndOf="parent"
...
I guess you can do the same things for tvC & tvD, let me know if you face any issue.

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" />

Can I put a Button to bottom of a ConstraintLayout inside ScrollView?

I have a ScrollView contains a ConstraintLayout. Inside the ConstraintLayout, I put many views with an attribute layout_constraintTop_toBottomOf to make a relation between the view and the view top of it, and I used layout_marginTop to put spaces between the views.
In my design, I have a Button that should be in the bottom of the layout and it cannot happen with the layout_marginTop because it should have a relation with the bottom of the ConstraintLayout.
Here's my code:
<ScrollView 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.support.constraint.ConstraintLayout
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:paddingTop="10dp"
android:paddingBottom="10dp">
<TextView
android:id="#+id/logo"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_centerInParent="true"
android:layout_margin="120dp"
android:text="Logo"
app:layout_constraintLeft_toLeftOf="parent"
app:layout_constraintRight_toRightOf="parent"
app:layout_constraintTop_toTopOf="parent" />
<EditText
android:id="#+id/un_et"
android:layout_width="match_parent"
android:layout_height="50dp"
android:layout_marginLeft="28dp"
android:layout_marginTop="25dp"
android:layout_marginRight="28dp"
android:gravity="center"
android:hint="User name"
android:textColor="#bebebe"
android:textCursorDrawable="#null"
app:layout_constraintLeft_toLeftOf="parent"
app:layout_constraintRight_toRightOf="parent"
app:layout_constraintTop_toBottomOf="#id/logo" />
<EditText
android:id="#+id/pw_et"
android:layout_width="match_parent"
android:layout_height="50dp"
android:layout_marginLeft="28dp"
android:layout_marginTop="13dp"
android:layout_marginRight="28dp"
android:gravity="center"
android:hint="Password"
android:inputType="textPassword"
android:textColor="#bebebe"
android:textCursorDrawable="#null"
app:layout_constraintLeft_toLeftOf="parent"
app:layout_constraintRight_toRightOf="parent"
app:layout_constraintTop_toBottomOf="#id/un_et" />
<RelativeLayout
android:id="#+id/save_pw"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:layout_marginTop="8dp"
android:paddingLeft="28dp"
android:paddingRight="28dp"
app:layout_constraintTop_toBottomOf="#id/pw_et">
<CheckBox
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_centerVertical="true"
android:buttonTint="#bebebe"
android:text="Save account"
android:textColor="#bebebe" />
<TextView
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_alignParentRight="true"
android:layout_centerVertical="true"
android:text="Forget password?"
android:textColor="#a40000" />
</RelativeLayout>
<Button
android:id="#+id/btn"
android:layout_width="match_parent"
android:layout_height="50dp"
android:layout_marginLeft="28dp"
android:layout_marginTop="17dp"
android:layout_marginRight="28dp"
android:text="Login"
android:textAllCaps="false"
android:textColor="#FFFFFF"
app:layout_constraintTop_toBottomOf="#id/save_pw" />
<Button
android:id="#+id/btn2"
android:layout_width="match_parent"
android:layout_height="50dp"
android:text="Sign up"
android:textAllCaps="false"
android:textColor="#FFFFFF"
app:layout_constraintTop_toBottomOf="#id/btn" />
</android.support.constraint.ConstraintLayout>
</ScrollView>

Replace ScrollView with NestedScrollView & also add android:fillViewport="true" like this
<androidx.core.widget.NestedScrollView
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">
// rest of code
<Button
android:id="#+id/btn2"
android:layout_width="match_parent"
android:layout_height="50dp"
android:text="Sign up"
android:textAllCaps="false"
android:textColor="#FFFFFF"
app:layout_constraintVertical_bias="1"
app:layout_constraintTop_toBottomOf="#id/btn"
app:layout_constraintBottom_toBottomOf="parent"/>
</androidx.constraintlayout.widget.ConstraintLayout>
</androidx.core.widget.NestedScrollView>

Just set this property to your button:
app:layout_constraintBottom_toBottomOf="parent"
Then add this to your last view this property:
app:layout_constraintBottom_toTopOf="#+id/button"
Also, add to your last view:
android:layout_marginBottom="height_of_button"
However, if you are adding a lot of views it would be better to populate them inside a RecyclerView using an Adapter. Decide what you want to do. Also, tell me if I understood your question correctly, it was a bit confusing.

I found one solution to keep the button at the bottom, doesn't matter is your text is dynamic, read about app:layout_constraintVertical_bias https://developer.android.com/reference/androidx/constraintlayout/widget/ConstraintLayout#Bias
<?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:layout_width="match_parent"
android:layout_height="match_parent">
<TextView
android:id="#+id/text_gallery"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:layout_marginStart="8dp"
android:layout_marginTop="8dp"
android:layout_marginEnd="8dp"
android:textAlignment="center"
android:textSize="20sp"
android:text="Title"
app:layout_constraintTop_toTopOf="parent"/>
<androidx.core.widget.NestedScrollView
android:layout_width="match_parent"
android:layout_height="0dp"
android:fillViewport="true"
app:layout_constraintTop_toBottomOf="#id/text_gallery"
app:layout_constraintBottom_toBottomOf="parent">
<androidx.constraintlayout.widget.ConstraintLayout
android:layout_width="match_parent"
android:layout_height="match_parent"
android:isScrollContainer="true">
<androidx.appcompat.widget.AppCompatTextView
app:layout_constraintTop_toTopOf="parent"
android:id="#+id/texto"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:textSize="30sp"
android:text=" Text \n Text" />
<androidx.appcompat.widget.AppCompatButton
android:id="#+id/button"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:text="Buton1"
app:layout_constraintVertical_bias="1"
app:layout_constraintTop_toBottomOf="#+id/texto"
app:layout_constraintBottom_toBottomOf="parent" />
</androidx.constraintlayout.widget.ConstraintLayout>
</androidx.core.widget.NestedScrollView>
</androidx.constraintlayout.widget.ConstraintLayout>

ANDROID ConstraintLayout - how to make a view stetch to the entire width and height of remainder of screen?

hey can someone paste this code and tell me why i am not able to stretch the pink textview to fill the remainder of the empty screen.
Here is my code using constraintLayout primarily:
<?xml version="1.0" encoding="utf-8"?>
<android.support.design.widget.AppBarLayout
android:layout_width="match_parent"
android:layout_height="wrap_content">
<android.support.v7.widget.Toolbar
android:id="#+id/toolbar"
android:layout_width="match_parent"
android:layout_height="?attr/actionBarSize"
android:background="#android:color/white"
android:elevation="4dp">
<TextView
android:id="#+id/toolbar_title"
fontPath="fonts/Medium-Extd.otf"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="#string/check_out"
android:textAllCaps="true"
android:textColor="#000000"
android:textSize="14sp"/>
</android.support.v7.widget.Toolbar>
</android.support.design.widget.AppBarLayout>
<android.support.v4.widget.NestedScrollView
android:id="#+id/nsv_checkout_container"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:layout_above="#+id/footer"
android:background="#dadbdd"
android:fillViewport="true"
app:layout_behavior="#string/appbar_scrolling_view_behavior">
<android.support.constraint.ConstraintLayout
android:layout_width="match_parent"
android:layout_height="match_parent"
android:layout_marginTop="10dp">
<android.support.v7.widget.CardView
android:id="#+id/cvOne"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:layout_marginLeft="6dp"
android:layout_marginRight="6dp"
android:elevation="4dp">
<ViewFlipper
android:id="#+id/switcher"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:background="#color/white"
android:measureAllChildren="false">
<android.support.constraint.ConstraintLayout
android:id="#+id/clPaymentSuccessful"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:layout_marginBottom="25dp"
android:layout_marginTop="30dp"
>
<ImageView
android:id="#+id/iv"
android:layout_width="20dp"
android:layout_height="26dp"
android:src="#drawable/bag_icon_heart"
app:layout_constraintBottom_toTopOf="tvStatus"
app:layout_constraintEnd_toEndOf="parent"
app:layout_constraintHorizontal_bias="0.5"
app:layout_constraintStart_toStartOf="parent"
app:layout_constraintTop_toTopOf="parent"
/>
<TextView
android:id="#+id/tvStatus"
fontPath="fonts/Medium-Extd.otf"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:layout_marginTop="20dp"
android:textAlignment="center"
android:textSize="18sp"
app:layout_constraintHorizontal_bias="0.5"
app:layout_constraintTop_toBottomOf="#id/iv"
tools:text="Payment Successful"/>
<TextView
android:id="#+id/tvAmount"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:layout_marginTop="4dp"
android:textAlignment="center"
android:textSize="18sp"
app:layout_constraintHorizontal_bias="0.5"
app:layout_constraintTop_toBottomOf="#id/tvStatus"
tools:text="$3,800 USD"/>
<TextView
android:id="#+id/tvOrderNum"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:layout_marginTop="4dp"
android:textAlignment="center"
android:textSize="18sp"
app:layout_constraintHorizontal_bias="0.5"
app:layout_constraintTop_toBottomOf="#id/tvAmount"
tools:text="your order is 7900434343"/>
</android.support.constraint.ConstraintLayout>
</ViewFlipper>
</android.support.v7.widget.CardView>
<ViewFlipper
android:id="#+id/switcher_cta"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:layout_marginTop="10dp"
android:background="#color/watermelon"
android:measureAllChildren="false"
app:layout_constraintBottom_toTopOf="#+id/btn_close_cta"
app:layout_constraintEnd_toEndOf="parent"
app:layout_constraintLeft_toLeftOf="parent"
app:layout_constraintRight_toRightOf="parent"
app:layout_constraintTop_toBottomOf="#+id/cvOne">
<android.support.constraint.ConstraintLayout
android:id="#+id/clcta"
android:layout_width="match_parent"
android:layout_height="wrap_content">
<TextView
android:id="#+id/tvShowStaffCta"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:layout_marginTop="4dp"
android:textAlignment="center"
android:textSize="18sp"
app:layout_constraintHorizontal_bias="0.5"
app:layout_constraintTop_toTopOf="parent"
tools:text="Show this screen to Store Staff to complete your purchase"/>
</android.support.constraint.ConstraintLayout>
</ViewFlipper>
<android.support.v7.widget.AppCompatButton
android:id="#+id/btn_close_cta"
fontPath="fonts/Medium-Extd.otf"
android:layout_width="match_parent"
android:layout_height="41dp"
android:background="#color/action_blue"
android:clickable="true"
android:elevation="4dp"
android:gravity="center"
android:text="#string/close"
android:textAlignment="center"
android:textColor="#ffffff"
android:textSize="14sp"
app:layout_constraintBottom_toBottomOf="parent"/>
</android.support.constraint.ConstraintLayout>
</android.support.v4.widget.NestedScrollView>
there is a viewflipper called switcher_cta i just want that to take up the remainder grey area of the screen. how can i stetch it ?

You have correctly set constraints to top and bottom, but in order for them to work the View's height must be set to 0dp.
Also avoid setting match parent in ConstraintLayout , since your view is aligned left and right to parent, setting width to 0dp will fill up the space.
<ViewFlipper
android:id="#+id/switcher_cta"
android:layout_width="0dp"
android:layout_height="0dp"
android:layout_marginTop="10dp"
android:background="#color/watermelon"
android:measureAllChildren="false"
app:layout_constraintBottom_toTopOf="#+id/btn_close_cta"
app:layout_constraintEnd_toEndOf="parent"
app:layout_constraintLeft_toLeftOf="parent"
app:layout_constraintRight_toRightOf="parent"
app:layout_constraintTop_toBottomOf="#+id/cvOne">