activity main xml 28bydefault 29

1<?xml version="1.0" encoding="utf-8"?>
2<androidx.constraintlayout.widget.ConstraintLayout xmlns:android="http://schemas.android.com/apk/res/android"
3    xmlns:app="http://schemas.android.com/apk/res-auto"
4    xmlns:tools="http://schemas.android.com/tools"
5    android:layout_width="match_parent"
6    android:layout_height="match_parent"
7    tools:context=".MainActivity">
8
9    <TextView
10        android:layout_width="wrap_content"
11        android:layout_height="wrap_content"
12        android:text="Hello World!"
13        app:layout_constraintBottom_toBottomOf="parent"
14        app:layout_constraintLeft_toLeftOf="parent"
15        app:layout_constraintRight_toRightOf="parent"
16        app:layout_constraintTop_toTopOf="parent" />
17
18</androidx.constraintlayout.widget.ConstraintLayout>