Code Style. Kotlin

Use this page to configure formatting options for Kotlin files. When you change these settings, the Preview pane shows how this will affect your code.

Tabs and Indents

Item	Description
Use tab character	If this checkbox is selected, tab characters are used: On pressing the `Tab` key For indentation For code reformatting When the checkbox is cleared, IntelliJ IDEA uses spaces instead of tabs.
Smart tabs	If this checkbox is selected, the part of indentation defined by the nesting of code blocks, is made of the tabs and (if necessary) spaces, while the part of indentation defined by the alignment is made only of spaces. If this checkbox is cleared, only tabs are used. This means that a group of spaces that fits the specified tab size is automatically replaced with a tab, which may result in breaking fine alignment. The Smart tabs checkbox is available if the Use tab character checkbox is selected.
Tab size	In this field, specify the number of spaces included in a tab.
Indent	In this field, specify the number of spaces to be inserted for each indent level.
Continuation indent	In this field, specify the number of spaces to be inserted between the elements of an array, in expressions, method declarations and method calls.
Keep indents on empty lines	If this checkbox is selected, IntelliJ IDEA will keep indents on the empty lines as if they contained some code. If this checkbox is cleared, IntelliJ IDEA will delete the tab characters and spaces.

Spaces

Use this tab to specify where you want spaces in your code. To have IntelliJ IDEA automatically insert a space at a location, select the checkbox next to this location in the list. The results are displayed in the preview pane.

Wrapping and Braces

In this tab, customize the code style options, which IntelliJ IDEA will apply on reformatting the source code. The left-hand pane contains the list of exceptions (Keep when reformatting), and placement and alignment options for the various code constructs (lists, statements, operations, annotations, and so on) The right-hand pane shows the preview.

Alignment takes precedence over indentation options.

Hard wrap at

Use the Hard wrap at field to specify a margin space required on the right side of an element. If you select the Default option, then a value of the right margin from the global settings is used.

Wrap on typing

Use the Wrap on typing settings to specify how the edited text is fitted in the specified Hard wrap at:

Default: in this case IntelliJ IDEA uses the Wrap on typing option that is specified in the global settings.
Yes: in this case IntelliJ IDEA uses the value specified in the Right Margin field.
No: in this case this option is switched off and a line can exceed the value specified in the right margin.

Visual guides

Use the Visual guides field to specify multiple right margins. You can leave a default value or enter the number of spaces for your margin. If you want to specify several margins, enter numbers separated by comma.

Keep when reformatting

Use the checkboxes to configure exceptions that IntelliJ IDEA will make when reformatting the source code. For example, by default, the Line breaks checkbox is selected. If your code contains lines that are shorter than a standard convention, you can convert them by disabling the Line breaks checkbox before you reformat the source code.

Wrapping options

The wrapping style applies to the various code constructs, specified in the left-hand pane (for example, method call arguments, method declaration parameters, or assignment statements).

Item	Description
Wrapping style	From this list, select the desired wrapping style: Do not wrap: when this option is selected, no special wrapping style is applied. With this option selected, the nested alignment and braces settings are ignored. Wrap if long: select this option to have lines going beyond the right margin wrapped with proper indentation. Wrap always: select this option to have all elements in lists wrapped, so that there is one element per line with proper indentation. Chop down if long: select this option to have elements in lists that go beyond the right margin wrapped, so that there is one element per line with proper indentation.

Item

Description

Wrapping style

From this list, select the desired wrapping style:

Do not wrap: when this option is selected, no special wrapping style is applied.
With this option selected, the nested alignment and braces settings are ignored.
Wrap if long: select this option to have lines going beyond the right margin wrapped with proper indentation.
Wrap always: select this option to have all elements in lists wrapped, so that there is one element per line with proper indentation.
Chop down if long: select this option to have elements in lists that go beyond the right margin wrapped, so that there is one element per line with proper indentation.

Alignment options

Item	Description
Align when multiline	If this checkbox is selected, a code construct starts at the same column on each next line. Otherwise, the position of a code construct is determined by the current indentation level.

Blank lines

Use this tab to define where and how many blank lines you want IntelliJ IDEA to retain and insert in your code after reformatting. For each type of location, specify the number of blank lines to be inserted. The results are displayed in the preview pane.

Item	Description
Keep maximum blank lines	In this area, specify the number of blank lines to be kept after reformatting in the specified locations.
Minimum blank lines	In this area, specify the number of blank lines to be present in the specified locations. These settings do not influence the number of blank lines before the first and after the last item.

Imports

Item	Description
Top-level Symbols	Use this area to define how the top-level symbols are imported. The possible options are: Use single name import: if this option is selected, only a particular declaration from a package during code generation or import optimization is imported. Use import with '': if this option is selected, a statement importing an entire package is inserted. Use import with '' if at least <n> names used: if this option is selected, specify the number of declarations to be imported from a single package, until all the statements importing a single declaration are substituted with a statement importing an entire package.
Java Statics and Enum Members	Use this area to define how Java statics and enums are imported.
Other	Use this area to define how the other symbols are imported. Insert imports for nested classes: If this checkbox is selected, IntelliJ IDEA creates imports for the nested classes referenced in your code. If this option is not selected, IntelliJ IDEA generates import for the top-level class and qualifies the name of the nested class with the name of its top-level class.
Packages to Use Import with '*'	Use the table as follows: Package: In the text fields of this column, specify the packages to be imported. With Subpackages: Select this checkbox to have IntelliJ IDEA import all the subpackages of the selected package.

Other

Item	Description
Use trailing comma	Add a comma symbol after the last item of a series of elements. class Person( val firstName: String, val lastName: String, val age: Int, // trailing comma ) The Kotlin style guide encourages the use of trailing commas at the declaration site and leaves it at your discretion for the call site. For more information, refer to Kotlin coding conventions.

Item

Description

Use trailing comma

Add a comma symbol after the last item of a series of elements.

                        class Person(
                            val firstName: String,
                            val lastName: String,
                            val age: Int, // trailing comma
                        )
                    

The Kotlin style guide encourages the use of trailing commas at the declaration site and leaves it at your discretion for the call site. For more information, refer to Kotlin coding conventions.

Code Generation

Item	Description
Comment Code	Use this area to configure code style for generated comments (line `Ctrl+/` and block `Ctrl+Shift+/`): Line comment at first column: start line comments (`Ctrl+/`) at the first column. If you disable the option, the comments will be aligned with your code. Add a space at comment start: insert a space between the line comment character and the first character of the commented line. Enforce on reformat: insert a space between a line comment character and the first character of a commented line in existing comments when you're reformatting your code. Note that the first character has to be an alphanumeric symbol, otherwise the space won't be inserted. For example, the `//&Lorem ipsum` comment will be ignored by the reformatter. This option becomes available when Add a space at comment start is enabled. Block comment at first column: start block comments (`Ctrl+Shift+/`) at the first column. If you disable the option, the comments will be aligned with your code. Add spaces around block comments: insert a space between the block comment character and the first character of the commented text.

Item

Description

Comment Code

Use this area to configure code style for generated comments (line Ctrl+/ and block Ctrl+Shift+/):

Line comment at first column: start line comments (Ctrl+/) at the first column. If you disable the option, the comments will be aligned with your code.
Add a space at comment start: insert a space between the line comment character and the first character of the commented line.
Enforce on reformat: insert a space between a line comment character and the first character of a commented line in existing comments when you're reformatting your code. Note that the first character has to be an alphanumeric symbol, otherwise the space won't be inserted. For example, the //&Lorem ipsum comment will be ignored by the reformatter.
This option becomes available when Add a space at comment start is enabled.
Block comment at first column: start block comments (Ctrl+Shift+/) at the first column. If you disable the option, the comments will be aligned with your code.
Add spaces around block comments: insert a space between the block comment character and the first character of the commented text.

Set from...

Click this link to reveal the list of languages to be used as the base for the current language code style. Only the settings that are applicable to the current language are taken. All the other settings are not affected.

This link appears in the upper-right corner of the language-specific code style page, when applicable.

Click Reset to discard changes and return to the initial set of code style settings.

Last modified: 11 February 2024