Tashachan

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:tools="http://schemas.android.com/tools"
    android:background="@color/colorBack"
    tools:context="com.example.android.helloandroid.MainActivity"
    tools:ignore="ExtraText"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:orientation="vertical" >

Tashachan

<?xml version="1.0" encoding="utf-8"?>
<android.support.constraint.ConstraintLayout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:tools="http://schemas.android.com/tools"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:background="#2b2b2b"
    tools:context="com.example.android.helloandroid.MainActivity">
<LinearLayout
    android:layout_width="match_parent"
    android:layout_height="match_parent"