Code in text

In ordinary text sentences (as opposed to, say, code samples), use code font to mark up most things that have anything to do with code.

  • In HTML, use the <code> element.
  • In Markdown, use backticks (`).

This page explains how to format code in ordinary text sentences. For more information about formatting placeholders, command-line syntax, and code samples, see the following links:

Some specific items to put in code font

The following list includes items that should be in code font, but it's not an exhaustive list.

  • Attribute names and values
  • Class names
  • Command-line utility names
  • Data types
  • Defined (constant) values for an element or attribute
  • DNS record types
  • Enum (enumerator) names
  • Environment variable names

  • Element names (XML and HTML)

    Place angle brackets (<>) around the element name; you might have to escape the angle brackets to make them appear in the document.

  • Filenames, filename extensions (if used), and paths
  • Folders and directories
  • HTTP verbs
  • HTTP status codes
  • HTTP content-type values
  • Language keywords
  • Method and function names
  • Namespace aliases
  • Placeholder variables
  • Query parameter names and values
  • Text input

  • UI elements that are rendered based on previously entered text input

    For example, if a user was instructed in a procedure to enter an instance name as my-instance, when you tell them to click the instance name, use code font and bold: Click my-instance.

Generally, don't put quotation marks around code unless the quotation marks are part of the code.

Items to put in ordinary (non-code) font

The following list includes items that should not be in code font, but it's not an exhaustive list.

  • Email addresses

  • URLs

    However, often it's a good idea to put URLs on a separate line, enclosed in a <pre> element, which renders them in code font, or else to turn them into links. For more information, see link text.

  • Names of products, services, and organizations

    Often, command-line utility names are spelled the same as the software project or product with which they are associated, with only differences in capitalization. In such cases, use code font for the command and ordinary font for the name of the project or product.

    Recommended:

    • Invoke the GCC 8.3 compiler using gcc for C programs or g++ for C++ programs.
    • To send the file over FTP with IPv6, use ftp -6.
    • The options for the curl command are explained on the curl project website.

Method names

When you refer to a method name in text, omit the class name except where including it would prevent ambiguity.

Recommended: To retrieve the zebra's metadata, call its get() method.

Not recommended: To retrieve the zebra's metadata, call its animal.get() method.

Put an empty pair of parentheses after a method name to indicate that it's a method.

HTTP status codes

To refer to a single status code, use the following formatting and phrasing:

an HTTP 400 Bad Request status code

In particular, call it a status code instead of a response code or error code, and put the number and the name in code font. If the HTTP is implicit from context, you can leave it out.

To refer to a range of codes, use the following form:

an HTTP 2xx or 400 status code

In particular, use Nxx (with a specific digit in place of N) to indicate anything in the N00-N99 range, and put the status code number in code font even if you're leaving out the code's name.

If you prefer to specify an exact range, you can do so:

an HTTP status code in the 200-299 range

Here, too, put the numbers in code font.

Coding style guides

The following Google coding-style guides are available on GitHub:

Some open source projects have their own overriding style guides. For example, Java code in the Android Open Source Project follows the AOSP Java Code Style for Contributors guide.

Keywords

In general, don't use technical keywords as if they were English verbs or nouns. If in some rare cases you do, then don't try to inflect them. Don't form plurals from keywords and don't make keywords possessive. It's okay to use lowercase, plain text string in a general discussion of the STRING data type.

Recommended Not recommended
To add the data, send a POST request. POST the data.
To retrieve the data, send a GET request. Retrieve information by GETting the data.

You can't close the file before opening it.

You can't call the close() method for a file before you call open().

 Close()ing the file requires you to have open()ed it first.

Takes an array of extended ASCII code points (an array of INT64 values) and returns BYTES values.

For STRING arguments, returns the original string with all alphabetic characters in uppercase.

 Takes an array of extended ASCII code points (ARRAY of INT64) and returns BYTES.

Exception: When documenting a Java API, it's common to leave out words like object or instance and instead use the class name as a noun: store the MyClass you got from the ClassFactory. If you need to pluralize such nouns, then add object or instance: store the MyClass objects you got from the ClassFactory instances.

Linking API terms in Android

When you're writing code comments that you'll turn into generated reference documentation, link to all elements of Android APIs, such as classes, methods, constants, and XML attributes. Use code font and regular HTML <a> elements to link to this reference material.

Link AndroidManifest.xml elements and attributes to the API guide pages. Link the attribute for a particular widget or layout to its Javadoc in the widget or layout's API reference entry.

Recommended:

<a href="/guide/topics/manifest/data-element.html">data</a>

Very common classes such as Activity and Intent don't need to be linked every time. If you use a term as a concept rather than a class, then don't put it in code font and don't capitalize it. Here are some objects that do not always require Javadoc links or capitalization:

  • activity, activities
  • service
  • fragment
  • view
  • loader
  • action bar
  • intent
  • content provider
  • broadcast receiver
  • app widget

If you use one of these terms in the context of referring to an actual instance, use the formal class name and link to its reference page. Here are two examples:

Recommended: An Activity is an app component that provides a screen with which users can interact...

Recommended: The user interface for an activity is provided by a hierarchy of views—objects derived from the View class.

To link to a class or method:

  • To link to a class, use the class name as link text—for example:

    <a href="/reference/android/widget/TextView">TextView</a>

  • To link to a method, use the method name as a fragment identifier. If you're linking to a static method, also include the class name in the link text. If you need to distinguish between overloaded versions of a particular method, consider showing the full signature—for example:

    <a href="/reference/android/app/Activity.html#onCreate(android.os.Bundle)">onCreate(Bundle)</a>

  • To link the attribute for a particular widget or layout to its Javadoc in the widget or layout's API reference entry, use the URL for the page, and then add the fragment identifier #attr_android:ATTRIBUTE_NAME. For example, to link to the XML attribute android:inputType for the TextView widget, add the following:

    <a href="/reference/android/widget/TextView.html#attr_android:inputType>inputType</a>