1 <?xml version="1.0" encoding="utf-8"?>
2 <android.support.constraint.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">
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" />
18 </android.support.constraint.ConstraintLayout>