Android Code Style Rules

Package structure

Package structure should be categorized by features.

main
    java
        login
            LoginActivity.java
            LoginFragment.java
            LoginRequest.java
        
        utils

Class Member Ordering

imports

class name

variables
    constants
    public
    protected
    no-access modifier
    private

constructors

methods
    static methods

    lifecycle methods arranged by lifecycle order

    overriden methods

    others
        public
        protected
        private

inner classes

Resource File Basics

File Naming

Layout file names should use the following pattern:

${layout_name}_${feature_name}

Activities:
```
activity_login              // CORRECT
```
Fragments:
```
fragment_register           // CORRECT
```
Items:
```
recycler_item_bulletin      // CORRECT
```
Components:
```
view_event_item             // CORRECT
```
Dialogs: Dialogs names should contain dialog_ prefix
```
dialog_login.xml
```
Drawables:
```
ic_launcher.png        // CORRECT
```
For custom drawables such as shape, layerlist, following pattern should be used: ${componentName}_${detail}
```
circle_red.xml
circle_blue.xml
rectangle_lightblue.xml
```
Selectors

Selector names should contain selector_ prefix and next word should be a clear identifier. There is no need to add "color" or "drawable" word into the file name since they can be accessed by R.color or R.drawable. It will be better to find a good name to identify what exactly selector does.
```
selector_blue_button.xml              // CORRECT
```
Others: `layout prefix still can be used for general purpose such as layout.
```
layout_circle.xml
```

Resource Identification

Dimens: Any dimensions used in the layout should be written directly in xml. Only the common dimensions should be added to the dimens.xml file.
```
toolbar_height
space_default
avatar_icon_size
```
Strings: Strings files must be separated by feature
```
strings_login.xml
```

Naming

Classes: Class names should contain type as suffix
```
LoginActivity
LoginFragment
```

Fields:

String nameAnotherWords;          // CORRECT

Constants: Constant names use CONSTANT_CASE: all uppercase letters, with words separated by underscores, declared static final.
```
static final int NUMBER_CODE = 5;
```
Parameters: One-character parameter names should be avoided.
```
public void setName(String name) {...}      // CORRECT
```
Packages: Package names are all lowercase, with consecutive words simply concatenated together (no underscores).
```
com.kaloglu.boiler_plate.boilerplate            // CORRECT
```
Identifier: Camelcase pattern should be used: @+id/${viewType}${logicalName}
```
@+id/textViewName
@+id/buttonSubmit
```

Import statements

Wildcard imports, static or otherwise, are not used.

import com.example.test:     // CORRECT
import com.example.*;        // WRONG

Import statements are not line-wrapped.

import com.example.test;      // CORRECT
import com.example            // WRONG
                    .test;

In AndroidManifest.xml file Activity name attribute should use "." operator.

<activity
       android:name=".ui.register.LoginActivity"/>                 // CORRECT

Formatting

When defining classes, interfaces, functions that take more than one parameter, each parameter must be defined on the new line.

listener.onItemSelected(
    context,
    instalmentViewPager.getCurrentItem(),
    numberPickerInstallment.getCurrentItem(),
    installmentOptions.getIndex()
);

listener.onItemSelected(
    new Foo(
        installmentText,
        installmentName
    ),
    installmentViewPager.getCurrentItem(),
    numberPickerInstallment.getCurrentItem(),
    installmentOptions.getIndex()
);

class MyClass(                                                                                              // CORRECT
        fooList: ArrayList<Foo>,
        private val bar: Bar,
        private val callBack: Callback
) : ParentClass() {

Note: You can use ALT+ENTER shortcut to put parameters on separate lines.

Comments

When writing multi-line comments, use the /* ... */ style

/*
* Use this for comments                          // Use this for comments up to two lines
* that are more than two-lines.
*/

kaloglu/CleanWithMultiModule