changed compileSdkVersion in build.gradle and changed RelativeLayout to LinearLaout
created two buttons and init them in Activity
added listeners to buttons
Created ArrayAdapterSimpleActivity
Created CustomAdapterActivity
Added Intents to go to other Activities, see that in AndroidManifest we have added them
Changed Activity to ListActivity
Added comments
Added ListView in layout with @android:id/list to make more easy the interaction with ListActivity
Created the items in String[] and added to ArrayAdapter using android.R.layout.simple_list_item_1
Added comments
ArrayAdapterSimpleActivity finished for now
Finished CustomAdapter with comments