app/src/main/res/layout/activity_main.xml

   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">
   8
   9     <TextView
  10         android:layout_width="wrap_content"
  11         android:layout_height="wrap_content"
  12         android:text="@string/app_name"
  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 </android.support.constraint.ConstraintLayout>