New to android development, main activity widgets appear randomly on equator compared to design view

Question

So I just started android development and I arranged a few buttons and textViews in the xml design mode and when I ran it in an emulator and on my phone, the widgets seem to automatically move to the top left except the widget that was already there (like the TextView with hello world). I was following this video tutorial and I think the widgets are supposed to align themselves with some parent object by default but it wasn't doing that for me. Can someone help me with this?

Here's my xml code :

<?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"
tools:context="com.example.danishdua.testapp.MainActivity">

<TextView
    android:layout_width="wrap_content"
    android:layout_height="wrap_content"
    android:text="Hello World!"
    app:layout_constraintBottom_toBottomOf="parent"
    app:layout_constraintLeft_toLeftOf="parent"
    app:layout_constraintRight_toRightOf="parent"
    app:layout_constraintTop_toTopOf="parent"
    app:layout_constraintVertical_bias="0.032" />

<Button
    android:id="@+id/button"
    android:layout_width="wrap_content"
    android:layout_height="wrap_content"
    android:text="Test"
    tools:layout_editor_absoluteX="5dp"
    tools:layout_editor_absoluteY="230dp" />

<Button
    android:id="@+id/button2"
    android:layout_width="wrap_content"
    android:layout_height="wrap_content"
    android:text="Test"
    tools:layout_editor_absoluteX="278dp"
    tools:layout_editor_absoluteY="230dp" />

<TextView
    android:id="@+id/textView"
    android:layout_width="wrap_content"
    android:layout_height="wrap_content"
    android:text="Just a textView"
    tools:layout_editor_absoluteX="163dp"
    tools:layout_editor_absoluteY="478dp" />

Basically, what I see on android studio is this:Android Studio

And what I see on emulator is: Android emulator

Thanks!