Develop Reference

LinearLayout suitable to another LinearLayout

I have two linear layout inside constrainLayout,
The bottom linear layout includes buttons and its height is wrap_content and must be wrap, because sometimes I keep only 1 button and sometimes 2 buttons.
I would like to set height of the top linearLayout to max but without covering the 2nd layout.
So I decided to set match_parent to the first, but after that it covers the 2nd layout.
I can't use weight/weightsum
<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">
<LinearLayout
android:layout_width="match_parent"
android:layout_height="match_parent"
android:orientation="vertical"
app:layout_constraintBottom_toTopOf="#+id/linearLayout"
app:layout_constraintEnd_toEndOf="parent"
app:layout_constraintHorizontal_bias="1.0"
app:layout_constraintStart_toStartOf="parent"
app:layout_constraintTop_toTopOf="parent">
</LinearLayout>
<LinearLayout
android:id="#+id/linearLayout"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:orientation="vertical"
android:padding="16dp"
app:layout_constraintBottom_toBottomOf="parent"
app:layout_constraintEnd_toEndOf="parent"
app:layout_constraintStart_toStartOf="parent">
<Button
android:id="#+id/button"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:text="Button1" />
<Button
android:id="#+id/button2"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:text="Button2"
android:visibility="gone" />
</LinearLayout>
</androidx.constraintlayout.widget.ConstraintLayout>

<?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">
<LinearLayout
android:layout_width="match_parent"
android:layout_height="match_parent"
android:weightSum="11"
android:orientation="vertical">
<LinearLayout
android:layout_width="match_parent"
android:layout_height="match_parent"
android:orientation="vertical"
android:layout_weight="9"
app:layout_constraintBottom_toTopOf="#+id/linearLayout"
app:layout_constraintEnd_toEndOf="parent"
app:layout_constraintHorizontal_bias="1.0"
app:layout_constraintStart_toStartOf="parent"
app:layout_constraintTop_toTopOf="parent">
</LinearLayout>
<LinearLayout
android:id="#+id/linearLayout"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:orientation="vertical"
android:layout_weight="1"
android:padding="16dp"
android:weightSum="2"
app:layout_constraintBottom_toBottomOf="parent"
app:layout_constraintEnd_toEndOf="parent"
app:layout_constraintStart_toStartOf="parent">
<Button
android:id="#+id/button"
android:layout_width="match_parent"
android:layout_weight="1"
android:layout_height="wrap_content"
android:text="Button1" />
<Button
android:id="#+id/button2"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:layout_weight="1"
android:text="Button2"
" />
</LinearLayout>
try this added weight sum and weight to make layout in prportion

Since you are using ConstraintLayout, you can set the height of the first LinearLayout to 0dp. The ConstraintLayout interprets it as "match constraints".
The next step would be to properly define the constraints of the first LinearLayout (which you did).
You can read more about ConstraintLayout here.
<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">
<LinearLayout
android:layout_width="match_parent"
android:layout_height="0dp"
android:orientation="vertical"
app:layout_constraintBottom_toTopOf="#+id/linearLayout"
app:layout_constraintEnd_toEndOf="parent"
app:layout_constraintHorizontal_bias="1.0"
app:layout_constraintStart_toStartOf="parent"
app:layout_constraintTop_toTopOf="parent">
</LinearLayout>
<LinearLayout
android:id="#+id/linearLayout"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:orientation="vertical"
android:padding="16dp"
app:layout_constraintBottom_toBottomOf="parent"
app:layout_constraintEnd_toEndOf="parent"
app:layout_constraintStart_toStartOf="parent">
<Button
android:id="#+id/button"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:text="Button1" />
<Button
android:id="#+id/button2"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:text="Button2"
android:visibility="gone" />
</LinearLayout>
</androidx.constraintlayout.widget.ConstraintLayout>

To do this you have to use a combination of linearlayout as parent and attribute layoutWeight ,If you use a constant value for layoutWeight for both top layout and button's container , then this will lead to some problem on different screen height devices , instead this solution make you able to set your buttons height as big as enough by setting its container's height to wrapContent and give all top area for the layout content .
You can also make the top linearLayout scrollable to get the best experience possible :
<?xml version="1.0" encoding="utf-8"?>
<LinearLayout
xmlns:android="http://schemas.android.com/apk/res/android" android:layout_width="match_parent"
android:layout_height="match_parent"
android:orientation="vertical">
<LinearLayout
android:id="#+id/this_layout_will_fil_all_space_except_the_bottom_layout_space"
android:layout_width="match_parent"
android:layout_height="0dp"
android:orientation="vertical"
android:background="#000000"
android:layout_weight="1">
</LinearLayout>
<LinearLayout
android:id="#+id/button_layout_at_bottom"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:orientation="horizontal"
android:gravity="center_horizontal"
android:padding="10dp">
<Button
android:id="#+id/button"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="Button1"
android:layout_marginEnd="50dp"/>
<Button
android:id="#+id/button2"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="Button2"
android:visibility="visible" />
</LinearLayout>
</LinearLayout>
For Buttons , you can set its width to wrapContent and add gravity attribute to its parent as above , in this way even if one buttons was gone , the other will fit perfectly in the center of the container .
Enjoy !

The main advantage of using ConstraintLayout is to avoid using any other nested ViewGroups, The more you add more hierarchy in layout, the less performance you'll have. You can check documentation for more.
So for performance wise it's better to add widgets/views directly within the ConstraintLayout.
So, here I removed the bottom LinearLayout, and kept only the buttons directly within the ConstraintLayout, you can do the same for the top LinearLayout, you can just add any underlying views directly to the ConstraintLayout
<?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">
<LinearLayout
android:layout_width="match_parent"
android:layout_height="0dp"
android:orientation="vertical"
app:layout_constraintBottom_toTopOf="#+id/button"
app:layout_constraintEnd_toEndOf="parent"
app:layout_constraintHorizontal_bias="1.0"
app:layout_constraintStart_toStartOf="parent"
app:layout_constraintTop_toTopOf="parent">
</LinearLayout>
<Button
android:id="#+id/button"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:layout_marginStart="16dp"
android:layout_marginTop="16dp"
android:layout_marginEnd="16dp"
android:text="Button1"
app:layout_constraintBottom_toTopOf="#id/button2"
app:layout_constraintEnd_toEndOf="parent"
app:layout_constraintStart_toStartOf="parent" />
<Button
android:id="#+id/button2"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:layout_marginStart="16dp"
android:layout_marginEnd="16dp"
android:layout_marginBottom="16dp"
android:text="Button2"
android:visibility="gone"
app:layout_constraintBottom_toBottomOf="parent"
app:layout_constraintEnd_toEndOf="parent"
app:layout_constraintStart_toStartOf="parent" />
</androidx.constraintlayout.widget.ConstraintLayout>

Constraint Layout - Set width of ImageView 1/4th the size of entire screen

How would I set the layout of an ImageView to be 1/4th the size of the parent layout using only XML.
I also want to avoid using a LinearLayout that is nested inside the parent ConstraintLayout to do this.
<androidx.constraintlayout.widget.ConstraintLayout xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:app="http://schemas.android.com/apk/res-auto"
android:orientation="vertical"
android:layout_width="match_parent"
android:layout_height="match_parent">
<ImageView
android:id="#+id/fragprofile_profile_picture"
android:layout_width="0dp"
android:layout_height="75dp"/>
</androidx.constraintlayout.widget.ConstraintLayout>

You can use GuideLine to do that,
<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:layout_width="match_parent"
android:layout_height="match_parent">
<android.support.constraint.Guideline
android:id="#+id/guideline"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:orientation="vertical"
app:layout_constraintGuide_percent="0.25" />
<ImageView
android:id="#+id/fragprofile_profile_picture"
android:layout_width="0dp"
android:layout_height="0dp"
android:layout_marginTop="16dp"
app:layout_constraintLeft_toLeftOf="parent"
app:layout_constraintRight_toLeftOf="#+id/guideline"
app:layout_constraintTop_toTopOf="parent"
app:layout_constraintBottom_toBottomOf="parent"/>
</android.support.constraint.ConstraintLayout>

You can use Guideline.
Vertical guideline.
<androidx.constraintlayout.widget.Guideline
android:id="#+id/start_guide_line"
android:layout_width="0dp"
android:layout_height="0dp"
android:orientation="vertical"
app:layout_constraintGuide_percent="0.25"
/>
Horizontal Guideline
<androidx.constraintlayout.widget.Guideline
android:id="#+id/top_guide_line"
android:layout_width="0dp"
android:layout_height="0dp"
android:orientation="horizontal"
app:layout_constraintGuide_percent="0.25"
/>

Put two views in the center of the screen

I have two views (com.github.mikephil.charting.charts.BarChart and LinearLayout), the content inside one view is approx 600 dp high, the other once has 500 dp. Width of both views is fill_parent.
I would like to position them both into the center of the screen (so they overlaps).
Unfortunately, Android's layout alignment is very unintuitive and hit or miss for me and I'm not able to achieve that.
Can you please help?
<RelativeLayout
android:layout_width="fill_parent"
android:layout_height="fill_parent"
android:gravity="center"
android:orientation="vertical"
android:background="#11FFFFFF">
<com.github.mikephil.charting.charts.BarChart
android:id="#+id/chart"
android:layout_width="match_parent"
android:layout_height="500dp"
/>
<LinearLayout
android:layout_width="match_parent"
android:layout_height="match_parent"
android:orientation="horizontal"
android:gravity="center">
<LinearLayout
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_marginRight="50dp"
android:orientation="vertical"
android:gravity="center">
<TextView
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:textColor="#FFFFFF"
android:textSize="150dp"
android:includeFontPadding="false"/>
<TextView
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_marginTop="10dp"
android:text="HITS"
android:textAppearance="?android:attr/textAppearanceLarge"/>
</LinearLayout>
<LinearLayout
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_marginLeft="50dp"
android:orientation="vertical"
android:gravity="center">
<TextView
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:textColor="#FFFFFF"
android:textSize="150dp"
android:includeFontPadding="false"/>
<TextView
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_marginTop="10dp"
android:text="MISSED"
android:textAppearance="?android:attr/textAppearanceLarge"/>
</LinearLayout>
</LinearLayout>
</RelativeLayout>
I want to position both Views inside this RelativeLayout in the center of the screen, overlapping

Put in the 2 views you wanna to place in center inside a RelativeLayout, then add android:layout_centerInParent="true" into the 2 views.
For example it look like this:
<RelativeLayout
android:layout_width="match_parent"
android:layout_height="match_parent">
<com.github.mikephil.charting.charts.BarChart
....all other stuff
android:layout_centerInParent="true" > //..add this
<LinearLayout
..... all other stuff
android:layout_centerInParent="true" > //..add this
</LinearLayout>
</RelativeLayout>

Define your main layout as ConstraintLayout and then constraint all sides of both elements to their parent.
Something like this:
<?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:layout_width="match_parent"
android:layout_height="match_parent">
<LinearLayout
android:layout_width="600dp"
android:layout_height="600dp"
app:layout_constraintBottom_toBottomOf="parent"
app:layout_constraintEnd_toEndOf="parent"
app:layout_constraintStart_toStartOf="parent"
app:layout_constraintTop_toTopOf="parent">
</LinearLayout>
<com.github.mikephil.charting.charts.BarChart
android:layout_width="500dp"
android:layout_height="500dp"
app:layout_constraintBottom_toBottomOf="parent"
app:layout_constraintEnd_toEndOf="parent"
app:layout_constraintStart_toStartOf="parent"
app:layout_constraintTop_toTopOf="parent">
</com.github.mikephil.charting.charts.BarChart>
</android.support.constraint.ConstraintLayout>
With this code your BarChart is above your LinearLayout.

In my experience it's most of the times best practice to use the lightest container possible, which in this case is probably a FrameLayout, so I would use that instead of RelativeLayout and use android:layout_gravity="center" in the subviews like this for example:
<FrameLayout
android:layout_width="match_parent"
android:layout_height="match_parent">
<com.github.mikephil.charting.charts.BarChart
android:layout_gravity="center" >
<LinearLayout
android:layout_gravity="center" >
</LinearLayout>
</FrameLayout>

CardView: Let child item overlap

I have a problem with my RecyclerView.
I want to design some CardViews that looks like this:
Therefore I need the ImageView on the top left to overlap the CardView. I already know the usage of negative margins but my problem mainly is
Overlaps in Cardviews get cropped of even when clipToPadding is set to false
Does anyone have a solution for this problem?

Just set ImageView (Twitter icon) elevation more higher than CardView elevation.
Set android:elevation="10dp" to ImageView and set card_view:cardElevation="2dp" to CardView.
Here is an example:
<?xml version="1.0" encoding="utf-8"?>
<RelativeLayout
xmlns:card_view="http://schemas.android.com/apk/res-auto"
xmlns:android="http://schemas.android.com/apk/res/android"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:padding="16dp">
<RelativeLayout
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:layout_centerVertical="true">
<android.support.v7.widget.CardView
android:id="#+id/card_view"
android:layout_width="match_parent"
android:layout_height="200dp"
android:layout_marginTop="20dp"
card_view:cardElevation="2dp"
card_view:cardCornerRadius="4dp"
card_view:cardUseCompatPadding="false"
card_view:cardPreventCornerOverlap="false">
<RelativeLayout
android:layout_width="match_parent"
android:layout_height="wrap_content">
<ImageView
android:id="#+id/image"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:layout_alignParentStart="true"
android:layout_alignParentTop="true"
android:scaleType="centerCrop"
android:src="#drawable/sample_1" />
<TextView
android:id="#+id/title"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:layout_alignBottom="#+id/image"
android:padding="8dp"
android:background="#CCFFFFFF"
android:text="This is simple title"
android:textColor="#000000" />
</RelativeLayout>
</android.support.v7.widget.CardView>
<ImageView
android:id="#+id/icon_play"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_alignParentTop="true"
android:layout_alignParentLeft="true"
android:layout_marginLeft="10dp"
android:elevation="10dp"
android:src="#mipmap/ic_launcher"/>
</RelativeLayout>
</RelativeLayout>
OUTPUT:
Hope this will help~

Child which have to Overlap CardView add this attribute to the child
Note : The child elevation must be greater than CardView elevation
android:elevation="10dp"

Instead of negative margin (which can be unpredictable) on the image, you can try to create another layout in the CardView to be the main content bubble, and add margin top to that instead.
<CardView>
<FrameLayout
background="bubble"
marginTop="15dp">
<!-- stuff here -->
</FrameLayout>
<ImageView ... />
</CardView>

In Constraint layout..... I have done left side you can change according to your requirement.
<?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=".SecondActivity">
<androidx.constraintlayout.widget.ConstraintLayout
android:layout_width="match_parent"
android:layout_height="wrap_content"
app:layout_constraintTop_toTopOf="parent">
<androidx.cardview.widget.CardView
android:id="#+id/card"
android:layout_width="200dp"
android:layout_height="200dp"
android:layout_margin="20dp"
app:cardCornerRadius="100dp"
app:layout_constraintStart_toStartOf="parent"
app:layout_constraintTop_toTopOf="parent">
<androidx.constraintlayout.widget.ConstraintLayout
android:layout_width="match_parent"
android:layout_height="wrap_content">
<ImageView
android:layout_width="150dp"
android:layout_height="150dp"
android:layout_margin="20dp"
android:src="#drawable/ic_box"
app:layout_constraintStart_toStartOf="parent"
app:layout_constraintTop_toTopOf="parent"
/>
</androidx.constraintlayout.widget.ConstraintLayout>
</androidx.cardview.widget.CardView>
</androidx.constraintlayout.widget.ConstraintLayout>
<ImageView
android:layout_width="20dp"
android:layout_height="30dp"
android:layout_marginStart="170dp"
android:layout_marginLeft="170dp"
android:layout_marginTop="25dp"
android:src="#drawable/ic_box"
app:layout_constraintStart_toStartOf="parent"
app:layout_constraintTop_toTopOf="parent" />
</androidx.constraintlayout.widget.ConstraintLayout>

Bottom of ScrollView clipped when using ConstraintLayout

I have an issue using a ScrollView inside ConstraintLayout (constraint-layout:1.0.0-beta3)
The content of my ScrollView isn't showed entirely.
Here is my layout:
<android.support.constraint.ConstraintLayout
xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:app="http://schemas.android.com/apk/res-auto"
android:id="#+id/activity_test"
android:layout_width="match_parent"
android:layout_height="match_parent">
<LinearLayout
android:id="#+id/header"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:orientation="horizontal"
app:layout_constraintRight_toRightOf="parent"
app:layout_constraintLeft_toLeftOf="parent"
app:layout_constraintTop_toTopOf="parent"
android:background="#212121">
<TextView
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="Constraint Layout"
android:textSize="45sp"/>
</LinearLayout>
<ScrollView
android:layout_width="match_parent"
android:layout_height="wrap_content"
app:layout_constraintTop_toBottomOf="#+id/header"
app:layout_constraintLeft_toLeftOf="parent"
app:layout_constraintRight_toRightOf="parent">
<LinearLayout
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:orientation="vertical">
<Button
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:text="BUTTON"
android:layout_marginTop="800dp"/>
</LinearLayout>
</ScrollView>
</android.support.constraint.ConstraintLayout>
And here is the result
As you can see the button isn't visible and I reached the bottom of my ScrollView.
It seems to works well with LinearLayout with layout below
<LinearLayout
xmlns:android="http://schemas.android.com/apk/res/android"
android:id="#+id/activity_test"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:orientation="vertical">
<LinearLayout
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:orientation="horizontal"
android:background="#212121">
<TextView
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="Linear Layout"
android:textSize="45sp"/>
</LinearLayout>
<ScrollView
android:layout_width="match_parent"
android:layout_height="wrap_content">
<LinearLayout
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:orientation="vertical">
<Button
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:text="BUTTON"
android:layout_marginTop="800dp"/>
</LinearLayout>
</ScrollView>
</LinearLayout>
And result is
With LinearLayout end of ScrollView is reachable.
Is there a bug with ConstraintLayout or do I made something wrong?

The way I would have done it is:
<android.support.constraint.ConstraintLayout
xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:app="http://schemas.android.com/apk/res-auto"
android:id="#+id/activity_test"
android:layout_width="match_parent"
android:layout_height="match_parent">
<TextView
android:id="#+id/header"
android:layout_width="0dp"
android:layout_height="wrap_content"
android:background="#212121"
android:text="Constraint Layout"
android:textSize="45sp"
app:layout_constraintLeft_toLeftOf="parent"
app:layout_constraintRight_toRightOf="parent"
app:layout_constraintTop_toTopOf="parent" />
<ScrollView
android:layout_width="0dp"
android:layout_height="0dp"
android:fillViewport="true"
app:layout_constraintBottom_toBottomOf="parent"
app:layout_constraintLeft_toLeftOf="parent"
app:layout_constraintRight_toRightOf="parent"
app:layout_constraintTop_toBottomOf="#+id/header">
<android.support.constraint.ConstraintLayout
android:layout_width="match_parent"
android:layout_height="match_parent">
<Button
android:layout_width="0dp"
android:layout_height="wrap_content"
android:layout_gravity="bottom"
android:text="BUTTON"
app:layout_constraintBottom_toBottomOf="parent"
app:layout_constraintLeft_toLeftOf="parent"
app:layout_constraintRight_toRightOf="parent" />
</android.support.constraint.ConstraintLayout>
</ScrollView>
</android.support.constraint.ConstraintLayout>
Which gives:
A few things to keep in mind:
you don't need a linearlayout for the header, you can just use the textview directly.
don't use match_parent, it might seem to work, but is undefined. Use 0dp instead with the correct constraints to stretch the view as you want.
clearly, don't use a 800dp margin. It might look ok on your particular screen, but won't give you what you want on different devices.
scrollview by default will wrap its content -- the fillViewport attribute is here to make it takes the indicated space
you can use nested ConstraintLayout when it makes sense. In the future, we might also take advantage of it to do some performance improvements

I changed the height of the ScrollView to match_parent and added a bottom constraint. This seemed to make it work correctly.
<ScrollView
android:layout_width="match_parent"
android:layout_height="match_parent"
app:layout_constraintBottom_toBottomOf="parent"
app:layout_constraintTop_toBottomOf="#+id/header"
app:layout_constraintLeft_toLeftOf="parent"
app:layout_constraintRight_toRightOf="parent">
Note: Having a height of wrap_content on a vertically scrolling view usually doesn't end well, in any layout.