Java / Kotlin code naming conventions

Strictly follow camelCase for Java/Kotlin names. I prefer simple readability and fluidity of code. Prefixing variables with m or s breaks that fluidity. I prefer not prefix my variables with m or s. If you really want to differentiate between parameters and local variables, prefer prefixing them with this. instead of m and Class. instead of s.

Logging tags should be named TAG and prefer static. No need to prefix TAG with Class.TAG.

private static final String TAG = <CurrentClass>.class.getSimpleName();

XML naming conventions

Strictly follow snake_case for XML names.

Avoid adding view in the name, unless a few exceptions discussed below.

Layout files

Activity layout files start with activity_ e.g. activity_main.xml

Fragment layout files start with fragment_ e.g. fragment_main.xml

Content placeholder files start with content_ e.g. content_main.xml

Item layout files start with item_ e.g. item_todo.xml. This item could be used in ListView or RecyclerView.

XML id naming conventions

This table will be expanded as needed.

Widget	XML id prefix	XML examle	Java / Kotlin variable prefix	Java / Kotlin example
TextView *	text_	text_empty_view	text	textEmptyView
TextView	text_	text_firstname	text	textFirstname
EditText	edit_	edit_firstname	edit	editFirstname
Button	button_	button_ok	button	buttonOk
FloatingActionButton	fab_	fab_add_new	fab	fabAddNew
ImageButton	imgbutton_	imgbutton_show	imgbutton	imgButtonShow
ImageView	image_	image_user_avatar	image	imageUserAvatar
RecyclerView	recycler_<item>s	recycler_todos	recycler	recyclerTodos
CardView	card_<item>	card_todo	card	cardTodo
Layouts **	layout_<name>	layout_detail	layout	layoutDetail
BottomNavigationView	bottom_nav_<name>	bottom_nav_main	bottomNav	bottomNavMain
ListView	list_<item>s	list_todos	list	listTodos
Menu	menu_	menu_main	menu	menuMain
MenuItem	menu_item_	menu_item_settings	menuItem	menuItemSettings
CheckBox ***	check_	check_done	check	checkDone
RadioButton ***	radio_	radio_home	radio	radioHome
Switch ***	switch_	switch_vibrate	switch	switchVibrate
Slider	slide_	slide_color_tone	slide	slideColorTone
SnackBar	snack_	snack_undo	snack	snackUndo
Toast	toast_	toast_message	toast	toastMessage
Toolbar	toolbar_	toolbar_main	toolbar	toolbarMain
ActionBar	actionbar_	actionbar_main	actionbar	actionbarMain
NavigationView	nav_	nav_main	nav	navMain

* This is an exception for empty view. Usually do not include the word view in the name of the view.

** Only have id for layout if they are referenced in code. Never include type of layout in name e.g. do NOT use layout_linear_detail or layout_constraint_detail, just include the name with layout_ prefix. This keeps flexibility to change the type of layout without needing to refactor code.

*** Never include the state of widget in the name e.g. do NOT use check_power_on or switch_vibrate_off, just include the name with widget specific prefix.

If using Kotlin Android Extensions, the name of the widgets in code will be same as their names from XML is snake case. It is okay to keep them snake case in Kotlin code in that case.