ribot’s Android Guidelines are a good example of standard naming conventions:
Naming convention for XML files:
activity_<ACTIVITY NAME>.xml - for all activities
dialog_<DIALOG NAME>.xml - for all custom dialogs
row_<LIST_NAME>.xml - for custom row for listview
fragment_<FRAGMENT_NAME>.xml - for all fragments
Naming convention for component/widget in xml files:
All components for X activity must start with the activity name
all component should have prefix or short name like btn for Button
For example,name for login activity component should be like following.
activity_login_btn_login
activity_login_et_username
activity_login_et_password
Short name of major components:
Button - btn
EditText - et
TextView - tv
ProgressBar - pb
Checkbox - chk
RadioButton - rb
ToggleButton - tb
Spinner - spn
Menu - mnu
ListView - lv
GalleryView - gv
LinearLayout -ll
RelativeLayout - rl