Code Style Guidelines

Code Style Guidelines for Quiz-app

Our code style guidelines are based on the official AOSP Java Code Style for Contributors.

Important guidelines

Indentation

Use 4 spaces per indentation level and no tabs.

Comments

Use in-line commenting to help the next developer who might be editing your code, even if it seems obvious now. Inline comments should appear on the line above the code you are commenting. Comment XML View elements using <!-- Comment -->. Use block style comments for classes and functions. Every class, method and constant should have a javadoc style comment. Wherever the code is complex, explain using multi-line comments.

Resources

All the resources like strings, dimensions, colors should be taken from their respective files. For eg, if a color is not present, add it to the colors.xml file and then use it.

File naming

Class files

Class names are written in UpperCamelCase.

For classes that extend an Android component, the name of the class should end with the name of the component; for example: SignInActivity, SignInFragment, ImageUploaderService, ChangePasswordDialog.

Resources files

Resources file names are written in lowercase_underscore.

Drawable files

Naming conventions for drawables:

Asset Type	Prefix	Example
Action bar	ab_	ab_stacked.9.png
Button	btn_	btn_send_pressed.9.png
Dialog	dialog_	dialog_top.9.png
Divider	divider_	divider_horizontal.9.png
Icon	ic_	ic_star.png
Menu	menu_	menu_submenu_bg.9.png
Notification	notification_	notification_bg.9.png
Tabs	tab_	tab_pressed.9.png

Naming conventions for icons (taken from Android iconography guidelines):

Asset Type	Prefix	Example
Icons	ic_	ic_star.png
Launcher icons	ic_launcher	ic_launcher_calendar.png
Menu icons and Action Bar icons	ic_menu	ic_menu_archive.png
Status bar icons	ic_stat_notify	ic_stat_notify_msg.png
Tab icons	ic_tab	ic_tab_recent.png
Dialog icons	ic_dialog	ic_dialog_info.png

Naming conventions for selector states:

State	Suffix	Example
Normal	_normal	btn_order_normal.9.png
Pressed	_pressed	btn_order_pressed.9.png
Focused	_focused	btn_order_focused.9.png
Disabled	_disabled	btn_order_disabled.9.png
Selected	_selected	btn_order_selected.9.png

Layout files

Layout files should match the name of the Android components that they are intended for but move the top level component name to the beginning. For example, if we are creating a layout for the SignInActivity, the name of the layout file should be activity_sign_in.xml.

Id names

Layout resource ids should use the following naming convention where possible: <layout name>_<object type>_<object name>

Example

home_listview_quizzes

Follow Field Naming Conventions

• Non-public, non-static field names start with m.
• Other fields start with a lower case letter.
• Static final fields (constants) are ALL_CAPS_WITH_UNDERSCORES.

Example

public class MyClass {
    public static final int SOME_CONSTANT = 42;
    public int publicField;
    int mPackagePrivate;
    private int mPrivate;
    protected int mProtected;
}

Loop variables should be declared in the for statement itself unless there is a compelling reason to do otherwise:

for (int i = 0; i < n; i++) {
    doSomething(i);
}

Use standard brace style

Braces do not go on their own line; they go on the same line as the code before them:

Example

class MyClass {
    int func() {
        if (something) {
            // ...
        } else if (somethingElse) {
            // ...
        } else {
            // ...
        }
    }
}