Views

A View occupies a rectangular area on the screen and is responsible for drawing and event handling.The View class is a superclass for all GUI components in Android.

Commonly used Views are :

• EditText
• ImageView
• TextView
• Button
• ImageButton
• CheckBox

… read more – views section

ViewGroup (+layouts)

A ViewGroup is a special view that can contain other views (called children.) The view group is the base class for layouts and views containers. This class also defines the ViewGroup.

Android contains the following commonly used ViewGroupsubclasses:

• LinearLayout
• RelativeLayout
• FrameLayout
• ScrollView

… read more – view-group section

TableLayout

A layout that arranges its children into rows and columns. A TableLayout consists of a number of TableRow objects, each defining a row (actually, you can have other children, which will be explained below). TableLayout containers do not display border lines for their rows, columns, or cells. Each row has zero or more cells; each cell can hold one View object. The table has as many columns as the row with the most cells. A table can leave cells empty. Cells can span columns, as they can in HTML.

… full example

Activity implements OnClickListener

… full example

Log + Logcat

Generally, you should use the Log.v(), Log.d(), Log.i(), Log.w(), and Log.e() methods to write logs. You can then view the logs in logcat (android studio).

… full article

developer.android.com

here you can find all the documentation about android (by google)

Link to site

Links:

• Class code: basics and logs
• Class code: layouts
• Lesson Summary Video!