Android Style Guide

Follow a standard coding style in android, it will be easier for you and also for others to understand your code easily.

Nabil Mosharraf Hossain
3 min readOct 25, 2018


We made this specifically for our organisation Greentech Apps Foundation

1. Package Structure

A feature based package structure:

  • Clearer feature dependency and interface boundaries.
  • Easier to understand the components that define the feature.
  • Reduces risk of unknowingly modifying unrelated or shared code.
  • Simpler navigation: most related classes will be in the one package.
  • Easier to remove a feature.

The alternative approach of defining your packages by how a feature is built (by placing related Activities, Fragments, Adapters etc in separate packages) can lead to a fragmented code base with less implementation flexibility. Most importantly, it hinders your ability to comprehend your code base in terms of its primary role: to provide features for your app.

  • - contain all feature packages
  • - contain all db related classes
  • - contain all models
  • - contain utility/misc classes
  • - contain extended/custom views

2. Naming conventions

Layout Files

  • activity_<ACTIVITY NAME>.xml - for all activities
  • dialog_<DIALOG NAME>.xml - for all dialogs
  • item_<LIST_NAME>.xml - for custom item for listview/recyclerview
  • fragment_<FRAGMENT_NAME>.xml - for all fragments


Consider prefixing with layout name or sections, so that we know which sections it belong to

Use namespaces. Eg. global_ or error_, etc.


<string name="network_error">Network error</string>
<string name="call_failed">Call failed</string>
<string name="map_failed">Map loading failed</string>


<string name="error_message_network">Network error</string>
<string name="error_message_call">Call failed</string>
<string name="error_message_map">Map loading failed</string>

Write string values in normal conventions (do not capitalize all characters, use textAllCaps on a TextView).


<string name="error_message_call">CALL FAILED</string>


<string name="error_message_call">Call failed</string>


  • Treat colors.xml as palette of colors. Instead of defining color per elements, define a few color theme to be used in the application.


<color name="button_foreground">#FFFFFF</color>
<color name="button_background">#2A91BD</color>


<!-- grayscale -->
<color name="white">#FFFFFF</color>

<!-- basic colors -->
<color name="blue">#2A91BD</color>


  • You should also define a “palette” of typical spacing and font sizes, for basically the same purposes as for colors. A good example of a dimens file:
<resources><!-- font sizes -->
<dimen name="font_22sp">22sp</dimen>
<dimen name="font_18sp">18sp</dimen>
<dimen name="font_15sp">15sp</dimen>
<dimen name="font_12sp">12sp</dimen>
<!-- typical spacing between two views -->
<dimen name="spacing_40dp">40dp</dimen>
<dimen name="spacing_24dp">24dp</dimen>
<dimen name="spacing_14dp">14dp</dimen>
<dimen name="spacing_10dp">10dp</dimen>
<dimen name="spacing_4dp">4dp</dimen>
<!-- typical sizes of views -->
<dimen name="btn_height_60dp">60dp</dimen>
<dimen name="btn_height_40dp">40dp</dimen>
<dimen name="btn_height_32dp">32dp</dimen>

You should use the spacing_**** dimensions for layouting, in margins and paddings, instead of hard-coded values, much like strings are normally treated. This will give a consistent look-and-feel, while making it easier to organize and change styles and layouts.

Resource IDs

Use camelCase convention and preprend the viewType before the actual function

  • Button — btn
  • EditText — et
  • TextView — tv
  • Checkbox — cb
  • RadioButton — rb
  • ToggleButton — tb
  • Spinner — spn
  • Menu — mnu
  • ListView — lv
  • RecyclerView — rv
  • LinearLayout -ll
  • RelativeLayout — rl





Drawable Files

Naming convention for Drawable files

Classes & Interfaces

Written in UpperCamelCase


interface onClickListener


interface OnClickListener

Methods & Variables

Written in lowerCamelCase


public void SetValue(){
public int mPublicFielD;
public int public_field;


public void setValue(){
public int publicField;
  • Static final fields should be written in UPPERCASE, with an underscore separating words
public static final int THE_ANSWER = 42;

TODO comments

Use TODO temporary codes. Add a date.


// TODO: Remove this code after all production mixers understand.
// TODO: Change this to use a flag instead of a constant. 22 jun 18
// TODO: Remove this code after the UrlTable has been checked in. 22.10.18

Feel free to submit any type of suggestions for improving the coding standard

Happy Coding!!!

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