Develop Reference

Align textviews in left and right side of a linear layout?

I currently doing one of the project from "Google Android Dev". I am facing a problem in my layout design. Kindly help me how to align one textview in left side and right side of a linear layout.
<?xml version="1.0" encoding="utf-8"?>
<androidx.constraintlayout.widget.ConstraintLayout
android:layout_width="match_parent"
android:layout_height="wrap_content">
<ImageView
android:id="#+id/imageView"
android:layout_width="match_parent"
android:layout_height="194dp"
android:layout_marginBottom="8dp"
android:scaleType="centerCrop"
app:layout_constraintBottom_toTopOf="#+id/textAppearanceHeadline6"
app:layout_constraintEnd_toEndOf="parent"
app:layout_constraintHorizontal_bias="1.0"
app:layout_constraintStart_toStartOf="parent"
app:layout_constraintTop_toTopOf="parent"
tools:srcCompat="#drawable/faye" />
<TextView
android:id="#+id/textAppearanceHeadline6"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_marginStart="8dp"
android:layout_marginTop="8dp"
android:text="Faye"
android:textColor="#android:color/black"
android:textSize="16sp"
android:textStyle="bold"
app:layout_constraintStart_toStartOf="#+id/imageView"
app:layout_constraintTop_toBottomOf="#+id/imageView" />
<LinearLayout
android:id="#+id/textAppearanceBody1"
android:layout_width="0dp"
android:layout_height="wrap_content"
android:layout_marginTop="16dp"
app:layout_constraintBottom_toBottomOf="parent"
app:layout_constraintEnd_toEndOf="parent"
app:layout_constraintStart_toStartOf="#+id/textAppearanceHeadline6"
app:layout_constraintTop_toBottomOf="#+id/textAppearanceHeadline6">
<TextView
android:id="#+id/textView2"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_marginTop="16dp"
android:layout_marginBottom="8dp"
android:text="Age : 7"/>
<TextView
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_gravity="start|right"
android:layout_marginEnd="8dp"
android:layout_marginBottom="8dp"
android:text="Hobbies: Sunbathing"
android:textColor="#5A5656" />
</LinearLayout>
</androidx.constraintlayout.widget.ConstraintLayout>
I am new to android so you are most welcome for code review.

Try to change your layout like this:
<?xml version="1.0" encoding="utf-8"?>
<androidx.constraintlayout.widget.ConstraintLayout
android:layout_width="match_parent"
android:layout_height="wrap_content">
<ImageView
android:id="#+id/imageView"
android:layout_width="match_parent"
android:layout_height="194dp"
android:layout_marginBottom="8dp"
android:scaleType="centerCrop"
app:layout_constraintBottom_toTopOf="#+id/textAppearanceHeadline6"
app:layout_constraintEnd_toEndOf="parent"
app:layout_constraintHorizontal_bias="1.0"
app:layout_constraintStart_toStartOf="parent"
app:layout_constraintTop_toTopOf="parent"
tools:srcCompat="#drawable/faye" />
<TextView
android:id="#+id/textAppearanceHeadline6"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_margin="8dp"
android:text="Faye"
android:textColor="#android:color/black"
android:textSize="16sp"
android:textStyle="bold"
app:layout_constraintStart_toStartOf="#+id/imageView"
app:layout_constraintTop_toBottomOf="#+id/imageView" />
<LinearLayout
android:id="#+id/textAppearanceBody1"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:layout_margin="8dp"
android:orientation="horizontal"
app:layout_constraintBottom_toBottomOf="parent"
app:layout_constraintEnd_toEndOf="parent"
app:layout_constraintStart_toStartOf="#+id/textAppearanceHeadline6"
app:layout_constraintTop_toBottomOf="#+id/textAppearanceHeadline6">
<TextView
android:id="#+id/textView2"
android:layout_width="0dp"
android:layout_height="wrap_content"
android:layout_weight="1"
android:gravity="center|start"
android:text="Age : 7"/>
<TextView
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="Hobbies: Sunbathing"
android:gravity="center"
android:textColor="#5A5656" />
</LinearLayout>
</androidx.constraintlayout.widget.ConstraintLayout>

Use it like this
<TextView
android:id="#+id/textView2"
android:layout_width="0dp"
android:layout_gravity="center_vertical"
android:weight="1"
android:layout_height="wrap_content"
android:text="Age : 7"/>
<TextView
android:layout_width="0dp"
android:layout_height="wrap_content"
android:layout_gravity="center_vertical"
android:text="Hobbies: Sunbathing"
android:textColor="#5A5656" />
weight here will allow the first textview to take all the space and will leave the required space for the hobby textview.
Use it as per your requirement.

Problem placing TextView on ImageView using ConstraintLayout

I am using Constraintlayout and I want to place my Textview on my Imageview, it is supposed to look like this after I'm done: https://i.stack.imgur.com/mYAws.png but each time I add constraints to the texts(Vertically and horizontally), the texts disorganizes and goes totally from how I want it to be,
Sometimes even shifting my images. I have tried severally to adjust it well to no avail
My layout.xml:
<?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"
android:fillViewport="true">
<androidx.constraintlayout.widget.ConstraintLayout
android:layout_width="match_parent"
android:layout_height="match_parent"
tools:context=".FirstFragment">
<!-- TODO: Update blank fragment layout -->
<TextView
android:id="#+id/textView3"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_marginTop="16dp"
android:text="Current"
android:textColor="#FF3D19"
android:textSize="24sp"
app:layout_constraintEnd_toEndOf="parent"
app:layout_constraintStart_toStartOf="parent"
app:layout_constraintTop_toTopOf="parent" />
<ImageView
android:id="#+id/imageView3"
android:layout_width="358dp"
android:layout_height="337dp"
app:layout_constraintEnd_toEndOf="parent"
app:layout_constraintStart_toStartOf="parent"
app:layout_constraintTop_toBottomOf="#+id/textView3"
app:srcCompat="#drawable/orange_panel" />
<ImageView
android:id="#+id/imageView4"
android:layout_width="146dp"
android:layout_height="151dp"
android:layout_marginStart="45dp"
android:layout_marginTop="7dp"
app:layout_constraintStart_toStartOf="parent"
app:layout_constraintTop_toBottomOf="#+id/imageView3"
app:srcCompat="#drawable/green_panel" />
<ImageView
android:id="#+id/imageView5"
android:layout_width="146dp"
android:layout_height="151dp"
android:layout_marginTop="6dp"
android:layout_marginEnd="44dp"
app:layout_constraintEnd_toEndOf="parent"
app:layout_constraintTop_toBottomOf="#+id/imageView3"
app:srcCompat="#drawable/pink_panel" />
<TextView
android:id="#+id/textView3"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="Tonight"
android:textColor="#FFFFFF"
android:textSize="18sp"
tools:layout_editor_absoluteX="89dp"
tools:layout_editor_absoluteY="415dp" />
<TextView
android:id="#+id/textView4"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="Tomorrow"
android:textColor="#FFFFFF"
android:textSize="18sp"
tools:layout_editor_absoluteX="254dp"
tools:layout_editor_absoluteY="415dp" />
</androidx.constraintlayout.widget.ConstraintLayout>
</androidx.core.widget.NestedScrollView>

The answer is pretty straightforward. First you should delete this lines from both text views.
tools:layout_editor_absoluteX="254dp"
tools:layout_editor_absoluteY="415dp"
Then all you need to do is add constraints like this. Below are constraints for your image
app:layout_constraintEnd_toEndOf="parent"
app:layout_constraintStart_toStartOf="parent"
app:layout_constraintTop_toTopOf="parent"
And the constraints for your text view would be like this.
app:layout_constraintEnd_toEndOf="#+id/image_view"
app:layout_constraintStart_toStartOf="#+id/image_view"
app:layout_constraintTop_toTopOf="#+id/image_view"
Of course you can add different constraints for the image because i do not know how do you want to position the image view in the app. But if you want a text view to be inside the image like in the link you sent then the constraints for the text view will be always like this.

It's all about tools:layout_editor_absoluteX and tools:layout_editor_absoluteY for yours textView3 and textView4. Also i think you do not know for what namespace tools exist.

Check the example below; it shows you what constraints can be used to get in the direction of your layout goals.
<?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">
<androidx.constraintlayout.widget.ConstraintLayout
android:layout_width="match_parent"
android:layout_height="wrap_content">
<TextView
android:id="#+id/textView1"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_marginTop="16dp"
android:text="Current"
android:textColor="#FF3D19"
android:textSize="24sp"
app:layout_constraintEnd_toEndOf="parent"
app:layout_constraintStart_toStartOf="parent"
app:layout_constraintTop_toTopOf="parent" />
<ImageView
android:id="#+id/imageView1"
android:layout_width="300dp"
android:layout_height="300dp"
android:layout_marginTop="16dp"
android:background="#00FF00"
android:textColor="#FFFFFF"
app:layout_constraintEnd_toEndOf="parent"
app:layout_constraintStart_toStartOf="parent"
app:layout_constraintTop_toBottomOf="#+id/textView1" />
<ImageView
android:id="#+id/imageView2"
android:layout_width="120dp"
android:layout_height="120dp"
android:layout_marginTop="16dp"
android:background="#0000FF"
app:layout_constraintStart_toStartOf="#+id/imageView1"
app:layout_constraintTop_toBottomOf="#+id/imageView1" />
<ImageView
android:id="#+id/imageView3"
android:layout_width="120dp"
android:layout_height="120dp"
android:layout_marginTop="16dp"
android:background="#FF0000"
app:layout_constraintEnd_toEndOf="#+id/imageView1"
app:layout_constraintTop_toBottomOf="#+id/imageView1" />
<TextView
android:id="#+id/textView2"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="Tonight"
android:textColor="#FFFFFF"
android:textSize="18sp"
app:layout_constraintBottom_toBottomOf="#+id/imageView2"
app:layout_constraintEnd_toEndOf="#+id/imageView2"
app:layout_constraintStart_toStartOf="#+id/imageView2"
app:layout_constraintTop_toTopOf="#+id/imageView2" />
<TextView
android:id="#+id/textView3"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="Tomorrow"
android:textColor="#FFFFFF"
android:textSize="18sp"
app:layout_constraintBottom_toBottomOf="#+id/imageView3"
app:layout_constraintEnd_toEndOf="#+id/imageView3"
app:layout_constraintStart_toStartOf="#+id/imageView3"
app:layout_constraintTop_toTopOf="#+id/imageView3" />
</androidx.constraintlayout.widget.ConstraintLayout>
</androidx.core.widget.NestedScrollView>
See how this example looks: screenshot.

How to create layout which support different screen size? [duplicate]

I have created layout for different screen size and this is my xml code for default layout
but so any one please tell me what I should do to support my layout for any screen size android devices.
do I need to change my xml code?
or
just I need to modify my xml code ?
please tell me so I can solve my problem
xlm
<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">
<LinearLayout
android:layout_width="match_parent"
android:layout_height="match_parent"
android:padding="5dp"
android:orientation="vertical">
<TextView
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="#string/Login"
android:textSize="40sp"
android:layout_marginTop="40dp"
android:fontFamily="sans-serif-black"
android:layout_gravity="center"/>
<TextView
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="#string/nice"
android:layout_marginTop="40dp"
android:textSize="30sp"/>
<com.google.android.material.textfield.TextInputLayout
android:id="#+id/textInputLayoutUsername"
android:layout_width="match_parent"
android:layout_height="wrap_content"
app:errorEnabled="true"
app:errorTextAppearance="#style/ErrorStyleNormal"
android:padding="5dp"
android:layout_marginTop="30dp"
app:hintTextAppearance="#style/ErrorStyleNormal">
<com.google.android.material.textfield.TextInputEditText
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:textSize="25sp"
android:hint="Username"
/>
</com.google.android.material.textfield.TextInputLayout>
<com.google.android.material.textfield.TextInputLayout
android:id="#+id/textInputLayoutPassword"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:padding="5dp"
app:errorEnabled="true"
app:passwordToggleEnabled="true"
app:errorTextAppearance="#style/ErrorStyleNormal"
android:layout_marginTop="20dp"
app:hintTextAppearance="#style/ErrorStyleNormal"
app:counterTextAppearance="#style/CounterStyleNormal">
<com.google.android.material.textfield.TextInputEditText
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:hint="Password"
android:textSize="25sp"
android:inputType="textPassword"/>
</com.google.android.material.textfield.TextInputLayout>
<TextView
android:id="#+id/textViewForgotPassword"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_gravity="end"
android:layout_marginEnd="15dp"
android:layout_marginRight="15dp"
android:text="#string/ForgotPassword"
android:textSize="15sp" />
<androidx.cardview.widget.CardView
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_gravity="center"
app:cardCornerRadius="25dp"
android:elevation="5dp"
android:padding="10dp"
android:layout_marginTop="30dp">
<RelativeLayout
android:layout_width="match_parent"
android:layout_height="match_parent"
android:padding="5dp">
<ImageView
android:id="#+id/image"
android:layout_width="60dp"
android:layout_height="60dp"
android:src="#drawable/ic_arrow_forward"/>
<TextView
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="#string/Login"
android:layout_toEndOf="#+id/image"
android:layout_centerVertical="true"
android:textSize="25sp"
android:layout_marginRight="10dp"
android:layout_marginEnd="10dp"
android:fontFamily="sans-serif-black"
android:layout_toRightOf="#+id/image" />
</RelativeLayout>
</androidx.cardview.widget.CardView>
<TextView
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:textSize="20sp"
android:text="#string/To_Join_With"
android:layout_gravity="center"
android:layout_marginTop="20dp"
android:textColor="#android:color/black"/>
<TextView
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:textSize="20sp"
android:text="#string/Click_here"
android:layout_gravity="center"
android:textColor="#android:color/holo_blue_bright"/>
</LinearLayout>
</androidx.constraintlayout.widget.ConstraintLayout>

If you want to support different screen sizes, then use https://developer.android.com/reference/android/support/annotation/Dimension for different sizes of elements for different screens. If you need a different layout of elements on different screens, then you can create different xml files for different screen sizes Android layouts for different screen sizes

I edited you XML so it may be a good start for learning how to use ConstraintLayout. Check a tutorial for ConstraintLayout (constraintlayout.com)
Don't use match_parent with ConstraintLayout we only have 0dp (match_constraint) and wrap_conent
Don't mess up the XML with unneccessary nested ViewGroups (LinearLayout)
When using margin or padding best to use numbers based on 8 (8 - 16 - 24 - 32 - ...)
Using a CardView for button is wrong, check MaterialButton documents at material.io
<?xml version="1.0" encoding="utf-8"?>
<androidx.core.widget.NestedScrollView
xmlns:android="http://schemas.android.com/apk/res/android"
android:layout_width="match_parent"
android:layout_height="match_parent">
<androidx.constraintlayout.widget.ConstraintLayout xmlns:app="http://schemas.android.com/apk/res-auto"
android:layout_width="match_parent"
android:layout_height="match_parent">
<TextView
android:id="#+id/textView"
android:layout_width="0dp"
android:layout_height="wrap_content"
android:gravity="center"
android:text="#string/Login"
android:textSize="40sp"
app:layout_constraintEnd_toEndOf="parent"
app:layout_constraintStart_toStartOf="parent"
app:layout_constraintTop_toTopOf="parent" />
<TextView
android:id="#+id/textView_loginMessage"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_marginTop="32dp"
android:text="#string/nice"
android:textSize="32sp"
app:layout_constraintStart_toStartOf="parent"
app:layout_constraintTop_toBottomOf="#+id/textView" />
<com.google.android.material.textfield.TextInputLayout
android:id="#+id/textInputLayoutUsername"
android:layout_width="0dp"
android:layout_height="wrap_content"
android:layout_marginTop="24dp"
android:padding="5dp"
app:errorEnabled="true"
app:errorTextAppearance="#style/ErrorStyleNormal"
app:hintTextAppearance="#style/ErrorStyleNormal"
app:layout_constraintEnd_toEndOf="parent"
app:layout_constraintStart_toStartOf="parent"
app:layout_constraintTop_toBottomOf="#id/textView_loginMessage">
<com.google.android.material.textfield.TextInputEditText
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:hint="Username"
android:textSize="25sp" />
</com.google.android.material.textfield.TextInputLayout>
<com.google.android.material.textfield.TextInputLayout
android:id="#+id/textInputLayoutPassword"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:layout_marginTop="24dp"
android:padding="5dp"
app:counterTextAppearance="#style/CounterStyleNormal"
app:errorEnabled="true"
app:errorTextAppearance="#style/ErrorStyleNormal"
app:hintTextAppearance="#style/ErrorStyleNormal"
app:layout_constraintEnd_toEndOf="parent"
app:layout_constraintStart_toStartOf="parent"
app:layout_constraintTop_toBottomOf="#id/textInputLayoutUsername"
app:passwordToggleEnabled="true">
<com.google.android.material.textfield.TextInputEditText
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:hint="Password"
android:inputType="textPassword"
android:textSize="25sp" />
</com.google.android.material.textfield.TextInputLayout>
<TextView
android:id="#+id/textViewForgotPassword"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_gravity="end"
android:layout_marginTop="24dp"
android:layout_marginEnd="16dp"
android:text="#string/ForgotPassword"
android:textSize="15sp"
app:layout_constraintEnd_toEndOf="parent"
app:layout_constraintTop_toBottomOf="#+id/textInputLayoutPassword" />
<com.google.android.material.button.MaterialButton
android:id="#+id/materialButton"
style="#style/Widget.MaterialComponents.Button.TextButton.Icon"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_marginTop="32dp"
app:icon="#color/yourArrowIcon"
app:iconGravity="start"
android:text="yourText"
app:layout_constraintEnd_toEndOf="parent"
app:layout_constraintStart_toStartOf="parent"
app:layout_constraintTop_toBottomOf="#+id/textViewForgotPassword" />
<TextView
android:id="#+id/textView_join"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_gravity="center"
android:layout_marginTop="16dp"
android:text="#string/To_Join_With"
android:textColor="#android:color/black"
android:textSize="20sp"
app:layout_constraintEnd_toEndOf="parent"
app:layout_constraintStart_toStartOf="parent"
app:layout_constraintTop_toBottomOf="#id/materialButton" />
<TextView
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_gravity="center"
android:layout_marginTop="16dp"
android:text="#string/Click_here"
android:textColor="#android:color/holo_blue_bright"
android:textSize="20sp"
app:layout_constraintEnd_toEndOf="parent"
app:layout_constraintStart_toStartOf="parent"
app:layout_constraintTop_toBottomOf="#id/textView_join" />
</androidx.constraintlayout.widget.ConstraintLayout>
</androidx.core.widget.NestedScrollView>

Using ListView inside Recycleriew

I am using listview inside a RecyclerView. For RecyclerView Item layout, I am using Constraint layout. If set constraint layout height to match_parent, then there is extra space below listview.
If I set constraint layout height to wrap_content, then only one item is displayed in listview. I am so confused. Anybody help me to solve this.
Below is my layout
<?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:id="#+id/linearLayout3"
android:layout_width="match_parent"
android:layout_height="match_parent">
<TextView
android:id="#+id/world_credits_description"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_marginTop="20dp"
android:textColor="#color/black"
android:textSize="20sp"
app:layout_constraintStart_toStartOf="parent"
app:layout_constraintEnd_toEndOf="parent"
app:layout_constraintTop_toTopOf="parent"/>
<TextView
android:id="#+id/description_1_text_view"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:textSize="16sp"
android:textColor="#color/black"
android:layout_marginTop="20dp"
app:layout_constraintTop_toBottomOf="#id/world_credits_description"
app:layout_constraintStart_toStartOf="parent"
app:layout_constraintEnd_toEndOf="parent"/>
<TextView
android:id="#+id/description_2_text_view"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_marginTop="20dp"
android:textColor="#color/black"
android:textSize="15sp"
app:layout_constraintStart_toStartOf="parent"
app:layout_constraintEnd_toEndOf="parent"
app:layout_constraintTop_toBottomOf="#id/description_1_text_view"/>
<Button
android:id="#+id/cost_1_button"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_marginTop="20dp"
app:layout_constraintEnd_toEndOf="parent"
app:layout_constraintHorizontal_bias="0.226"
app:layout_constraintHorizontal_chainStyle="spread"
app:layout_constraintStart_toStartOf="parent"
app:layout_constraintTop_toBottomOf="#id/description_2_text_view" />
<Button
android:id="#+id/cost_2_button"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_marginTop="20dp"
app:layout_constraintStart_toEndOf="#id/cost_1_button"
app:layout_constraintTop_toBottomOf="#id/description_2_text_view"/>
<Button
android:id="#+id/cost_3_button"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_marginTop="20dp"
app:layout_constraintStart_toEndOf="#id/cost_2_button"
app:layout_constraintTop_toBottomOf="#id/description_2_text_view"/>
<Button
android:id="#+id/button"
android:layout_marginTop="20dp"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:textAllCaps="false"
app:layout_constraintTop_toBottomOf="#id/cost_1_button"
app:layout_constraintStart_toStartOf="parent"
app:layout_constraintEnd_toEndOf="parent"/>
<ListView
android:id="#+id/details_list_view"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:divider="#null"
app:layout_constraintBottom_toBottomOf="parent"
app:layout_constraintEnd_toEndOf="parent"
app:layout_constraintTop_toBottomOf="#id/button"
app:layout_constraintVertical_bias="0.103" />
</androidx.constraintlayout.widget.ConstraintLayout>
Thanks in Advance

Why do the buttons goes up?

So I programmed a simple app with android studio and the layout that is shown in the app when I run it is different than the xml file I designed.
Here is a link of an image of the problem.
https://imgur.com/6JIHSQ7
<?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">
<Button
android:id="#+id/subBtn"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="#string/subBtn"
android:textSize="30sp"
app:layout_constraintBaseline_toBaselineOf="#+id/addBtn"
app:layout_constraintStart_toStartOf="#+id/divBtn" />
<Button
android:id="#+id/addBtn"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_marginStart="36dp"
android:layout_marginLeft="36dp"
android:layout_marginBottom="42dp"
android:text="#string/addBtn"
android:textSize="30sp"
app:layout_constraintBottom_toTopOf="#+id/multBtn"
app:layout_constraintStart_toEndOf="#+id/subBtn" />
<EditText
android:id="#+id/n1EditText"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_marginTop="56dp"
android:ems="10"
android:hint="#string/number1"
android:inputType="textPersonName"
app:layout_constraintEnd_toEndOf="parent"
app:layout_constraintHorizontal_bias="0.444"
app:layout_constraintStart_toStartOf="parent"
app:layout_constraintTop_toTopOf="parent" />
<EditText
android:id="#+id/n2EditText"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_marginTop="39dp"
android:ems="10"
android:hint="#string/number2"
android:inputType="textPersonName"
app:layout_constraintStart_toStartOf="#+id/n1EditText"
app:layout_constraintTop_toBottomOf="#+id/n1EditText" />
<Button
android:id="#+id/multBtn"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_marginEnd="108dp"
android:layout_marginRight="108dp"
android:layout_marginBottom="336dp"
android:text="#string/multBtn"
android:textSize="30sp"
app:layout_constraintBottom_toBottomOf="parent"
app:layout_constraintEnd_toEndOf="parent" />
<Button
android:id="#+id/divBtn"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_marginStart="88dp"
android:layout_marginLeft="88dp"
android:layout_marginBottom="336dp"
android:text="#string/divBtn"
android:textSize="30sp"
app:layout_constraintBottom_toBottomOf="parent"
app:layout_constraintStart_toStartOf="parent" />
<TextView
android:id="#+id/resultTextView"
android:layout_width="174dp"
android:layout_height="73dp"
android:layout_marginTop="8dp"
android:layout_marginBottom="8dp"
android:background="#color/colorPrimaryDark"
android:text="#string/resultView"
android:textColor="#color/colorPrimary"
android:textSize="50sp"
app:layout_constraintBottom_toBottomOf="parent"
app:layout_constraintEnd_toEndOf="parent"
app:layout_constraintHorizontal_bias="0.455"
app:layout_constraintStart_toStartOf="parent"
app:layout_constraintTop_toBottomOf="#+id/n2EditText"
app:layout_constraintVertical_bias="0.637" />
</androidx.constraintlayout.widget.ConstraintLayout>
I think it might be related to the virtual device i'm using but I don't know if that's the problem.

The problem is, your addBtn and subBtn are not aware of the n2EditText. The addBtn depends on the divBtn and the divBtn is placed 336dp above the bottom edge of the screen.
If you need the addBtn to appear below the n2EditText then you need to add a vertical constraint connecting to the n2EditText. Once your buttons are connected to their immediate top elements, you don't need to add the bottom constraint to the bottom edge of the screen.
Imagine a ConstraintLayout as a collection of widgets hanging down from the top of the screen, each tied to the immediately top elements with the chains called "constraints". You don't need to tie the bottom widget to the ground unless it is required by design.
Here is the modified layout:
<?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">
<Button
android:id="#+id/subBtn"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="-"
android:textSize="30sp"
android:layout_marginTop="16dp"
app:layout_constraintTop_toBottomOf="#+id/n2EditText"
app:layout_constraintStart_toStartOf="#+id/n2EditText"/>
<Button
android:id="#+id/addBtn"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="+"
android:textSize="30sp"
app:layout_constraintStart_toEndOf="#+id/subBtn"
app:layout_constraintTop_toTopOf="#+id/subBtn"
android:layout_marginStart="16dp"/>
<EditText
android:id="#+id/n1EditText"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_marginTop="56dp"
android:ems="10"
android:hint="n1"
android:inputType="textPersonName"
app:layout_constraintEnd_toEndOf="parent"
app:layout_constraintStart_toStartOf="parent"
app:layout_constraintTop_toTopOf="parent" />
<EditText
android:id="#+id/n2EditText"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_marginTop="16dp"
android:ems="10"
android:hint="n2"
android:inputType="textPersonName"
app:layout_constraintStart_toStartOf="#+id/n1EditText"
app:layout_constraintTop_toBottomOf="#+id/n1EditText"/>
<Button
android:id="#+id/multBtn"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="*"
android:textSize="30sp"
app:layout_constraintStart_toEndOf="#+id/divBtn"
android:layout_marginStart="16dp"
app:layout_constraintTop_toTopOf="#+id/divBtn"/>
<Button
android:id="#+id/divBtn"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="/"
android:textSize="30sp"
app:layout_constraintStart_toStartOf="#+id/subBtn"
android:layout_marginTop="8dp"
app:layout_constraintTop_toBottomOf="#+id/subBtn"/>
<TextView
android:id="#+id/resultTextView"
android:layout_width="174dp"
android:layout_height="73dp"
android:layout_marginBottom="8dp"
android:background="#color/colorPrimaryDark"
android:text="res"
android:textColor="#color/colorPrimary"
android:textSize="50sp"
app:layout_constraintBottom_toBottomOf="parent"
app:layout_constraintEnd_toEndOf="parent"
app:layout_constraintStart_toStartOf="parent"
android:layout_marginTop="8dp" app:layout_constraintTop_toBottomOf="#+id/divBtn"/>
</androidx.constraintlayout.widget.ConstraintLayout>
Anyway, when you have a lot of widgets, you may have to use a ScrollView to accommodate them all.

Try this
<?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">
<Button
android:id="#+id/subBtn"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_marginStart="16dp"
android:layout_marginLeft="16dp"
android:layout_marginTop="52dp"
android:layout_marginEnd="25dp"
android:layout_marginRight="25dp"
android:text="submit"
android:textSize="30sp"
app:layout_constraintEnd_toStartOf="#+id/addBtn"
app:layout_constraintHorizontal_chainStyle="packed"
app:layout_constraintStart_toStartOf="parent"
app:layout_constraintTop_toBottomOf="#+id/n2EditText" />
<Button
android:id="#+id/addBtn"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_marginTop="52dp"
android:text="add"
android:textSize="30sp"
app:layout_constraintEnd_toEndOf="parent"
app:layout_constraintStart_toEndOf="#+id/subBtn"
app:layout_constraintTop_toBottomOf="#+id/n2EditText" />
<EditText
android:id="#+id/n1EditText"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_marginStart="8dp"
android:layout_marginLeft="8dp"
android:layout_marginTop="52dp"
android:layout_marginEnd="8dp"
android:layout_marginRight="8dp"
android:ems="10"
android:hint="1"
android:inputType="textPersonName"
app:layout_constraintEnd_toEndOf="parent"
app:layout_constraintHorizontal_bias="0.439"
app:layout_constraintStart_toStartOf="parent"
app:layout_constraintTop_toTopOf="parent" />
<EditText
android:id="#+id/n2EditText"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_marginStart="2dp"
android:layout_marginLeft="2dp"
android:layout_marginTop="36dp"
android:ems="10"
android:hint="2"
android:inputType="textPersonName"
app:layout_constraintStart_toStartOf="#+id/n1EditText"
app:layout_constraintTop_toBottomOf="#+id/n1EditText" />
<Button
android:id="#+id/multBtn"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_marginTop="44dp"
android:text="mult"
android:textSize="30sp"
app:layout_constraintStart_toEndOf="#+id/subBtn"
app:layout_constraintTop_toBottomOf="#+id/addBtn" />
<Button
android:id="#+id/divBtn"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_marginTop="44dp"
android:layout_marginEnd="48dp"
android:layout_marginRight="48dp"
android:text="div"
android:textSize="30sp"
app:layout_constraintEnd_toEndOf="#+id/subBtn"
app:layout_constraintTop_toBottomOf="#+id/subBtn" />
<TextView
android:id="#+id/resultTextView"
android:layout_width="174dp"
android:layout_height="73dp"
android:layout_marginStart="8dp"
android:layout_marginLeft="8dp"
android:layout_marginTop="48dp"
android:layout_marginEnd="8dp"
android:layout_marginRight="8dp"
android:background="#color/colorPrimaryDark"
android:text="resultView"
android:textColor="#color/colorPrimary"
android:textSize="50sp"
app:layout_constraintEnd_toEndOf="parent"
app:layout_constraintHorizontal_bias="0.547"
app:layout_constraintStart_toStartOf="parent"
app:layout_constraintTop_toBottomOf="#+id/divBtn" />
</androidx.constraintlayout.widget.ConstraintLayout>

Probably on your layout editor and phone screen sizes are different. Use ConstraintLayout or some other add constraints to views

I cannot say definitly just looking at image but i think you are using facing problem because of your layout. Use LinearLayout to fix it.
<?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"
xmlns:app="http://schemas.android.com/apk/res-auto"
android:orientation="vertical" />
<!-- EditText: number1 -->
<!-- EditText Number2 -->
<LinearLayout
android:orientation="horizontal"
android:layout_width="match_parent"
android:layout_height="wrap_content" />
<!-- 2 Buttons here -->
<LinearLayout
android:orientation="horizontal"
android:layout_width="match_parent"
android:layout_height="wrap_content" />
<!-- 2 Buttons here -->
</LinearLayout>
</LinearLayout>

Some general tips that can help:
Check the constraints if you're using ConstraintLayout or relatives between view if you're using RelativeLayout;
Check the values and the units of views;
Check the screen resolution of your "Preview" pane and Emulator.
If it's possible to provide some additional information about the layout that is used, if these tips didn't help.
In preview pane you can find info about resolutions here:
In the emulator pane you can simple see the sizes in the column: