Android Studio Begineer Project

ActivityMain.xml <? xml version ="1.0" encoding ="utf-8" ?> <LinearLayout xmlns: android ="http://schemas.android.com/apk/res/android" xmlns: app ="http://schemas.android.com/apk/res-auto" xmlns: tools ="http://schemas.android.com/tools" android :layout_width ="match_parent" android :layout_height ="match_parent" tools :context =".MainActivity" android :orientation ="vertical" > <TextView android :layout_width ="match_parent" android :layout_height ="wrap_content" android :gravity ="center" android :text ="@string/cursit_price" android :textSize ="20sp" /> <TextView android :layout_width ="match_parent" android :layout_height ="wrap_content" android :text ="@string/buyingPrice" android :gravity