Trouble shooting

android studio strouble shooting
https://docs.google.com/document/d/1w1Xn_hnSAODAAtdRDp7haYPBtEwX_l7Htpf8Wpgbu6w/pub?embedded=true

Linear layout

<?xml version="1.0" encoding="utf-8"?>
<RelativeLayout
	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:paddingBottom="@dimen/activity_vertical_margin"
	android:paddingLeft="@dimen/activity_horizontal_margin"
	android:paddingRight="@dimen/activity_horizontal_margin"
	android:paddingTop="@dimen/activity_vertical_margin"
	tools:context="com.xxx.myapplication.MainActivity">

	<TextView
		android:layout_width="wrap_content"
		android:layout_height="wrap_content"
		android:text="Hello world!" />
</RelativeLayout>