# Class yii\base\Theme

Inheritance | yii\base\Theme » yii\base\Component » yii\base\BaseObject
Implements | yii\base\Configurable
Available since version | 2.0
Source Code | https://github.com/yiisoft/yii2/blob/master/framework/base/Theme.php

Theme represents an application theme.

When yii\base\View renders a view file, it will check the active theme to see if there is a themed version of the view file exists. If so, the themed version will be rendered instead.

A theme is a directory consisting of view files which are meant to replace their non-themed counterparts.

Theme uses $pathMap to achieve the view file replacement:

1. It first looks for a key in $pathMap that is a substring of the given view file path;
2. If such a key exists, the corresponding value will be used to replace the corresponding part in the view file path;
3. It will then check if the updated view file exists or not. If so, that file will be used to replace the original view file.
4. If Step 2 or 3 fails, the original view file will be used.

For example, if $pathMap is `['@app/views' => '@app/themes/basic']`, then the themed version for a view file `@app/views/site/index.php` will be `@app/themes/basic/site/index.php`.

It is possible to map a single path to multiple paths. For example,

    'pathMap' => [
        '@app/views' => [
            '@app/themes/christmas',
            '@app/themes/basic',
        ],
    ]

In this case, the themed version could be either `@app/themes/christmas/site/index.php` or `@app/themes/basic/site/index.php`. The former has precedence over the latter if both files exist.

To use a theme, you should configure the theme property of the "view" application component like the following:

    'view' => [
        'theme' => [
            'basePath' => '@app/themes/basic',
            'baseUrl' => '@web/themes/basic',
        ],
    ],

The above configuration specifies a theme located under the "themes/basic" directory of the Web folder that contains the entry script of the application. If your theme is designed to handle modules, you may configure the $pathMap property like described above.

For more details and usage information on Theme, see the guide article on theming.

## Public Properties

Hide inherited properties

Property | Type | Description | Defined By
--- | --- | --- | ---
$basePath | string | The root path of this theme. All resources of this theme are located under this directory. | yii\base\Theme
$baseUrl | string | The base URL (without ending slash) for this theme. All resources of this theme are considered to be under this base URL. | yii\base\Theme
$behaviors | yii\base\Behavior[] | List of behaviors attached to this component. This property is read-only. | yii\base\Component
$pathMap | array | The mapping between view directories and their corresponding themed versions. | yii\base\Theme

## Public Methods

Hide inherited methods

Method | Description | Defined By
--- | --- | ---
__call() | Calls the named method which is not a class method. | yii\base\Component
__clone() | This method is called after the object is created by cloning an existing one. | yii\base\Component
__construct() | Constructor. | yii\base\BaseObject
__get() | Returns the value of a component property. | yii\base\Component
__isset() | Checks if a property is set, i.e. defined and not null. | yii\base\Component
__set() | Sets the value of a component property. | yii\base\Component
__unset() | Sets a component property to be null. | yii\base\Component
applyTo() | Converts a file to a themed file if possible. | yii\base\Theme
attachBehavior() | Attaches a behavior to this component. | yii\base\Component
attachBehaviors() | Attaches a list of behaviors to the component. | yii\base\Component
behaviors() | Returns a list of behaviors that this component should behave as. | yii\base\Component
canGetProperty() | Returns a value indicating whether a property can be read. | yii\base\Component
canSetProperty() | Returns a value indicating whether a property can be set. | yii\base\Component
className() | Returns the fully qualified name of this class. | yii\base\BaseObject
detachBehavior() | Detaches a behavior from the component. | yii\base\Component
detachBehaviors() | Detaches all behaviors from the component. | yii\base\Component
ensureBehaviors() | Makes sure that the behaviors declared in behaviors() are attached to this component. | yii\base\Component
getBasePath() |  | yii\base\Theme
getBaseUrl() |  | yii\base\Theme
getBehavior() | Returns the named behavior object. | yii\base\Component
getBehaviors() | Returns all behaviors attached to this component. | yii\base\Component
getPath() | Converts a relative file path into an absolute one using $basePath. | yii\base\Theme
getUrl() | Converts a relative URL into an absolute URL using $baseUrl. | yii\base\Theme
hasEventHandlers() | Returns a value indicating whether there is any handler attached to the named event. | yii\base\Component
hasMethod() | Returns a value indicating whether a method is defined. | yii\base\Component
hasProperty() | Returns a value indicating whether a property is defined for this component. | yii\base\Component
init() | Initializes the object. | yii\base\BaseObject
off() | Detaches an existing event handler from this component. | yii\base\Component
on() | Attaches an event handler to an event. | yii\base\Component
setBasePath() |  | yii\base\Theme
setBaseUrl() |  | yii\base\Theme
trigger() | Triggers an event. | yii\base\Component

## Property Details

$basePath public property

The root path of this theme. All resources of this theme are located under this directory.

public string $basePath = null
$baseUrl public property

The base URL (without ending slash) for this theme. All resources of this theme are considered to be under this base URL.

public string $baseUrl = null
$pathMap public property

The mapping between view directories and their corresponding themed versions. This property is used by applyTo() when a view is trying to apply the theme. Path aliases can be used when specifying directories. If this property is empty or not set, a mapping yii\base\Application::$basePath to $basePath will be used.

public array $pathMap = null

## Method Details

applyTo() public method

Converts a file to a themed file if possible.

If there is no corresponding themed file, the original file will be returned.

public string applyTo ( $path )
$path | string | The file to be themed
return | string | The themed file, or the original file if the themed version is not available.
throws | yii\base\InvalidConfigException | if $basePath is not set

getBasePath() public method

See also $pathMap.

public string getBasePath ( )
return | string | The root path of this theme. All resources of this theme are located under this directory.

getBaseUrl() public method

public string getBaseUrl ( )
return | string | The base URL (without ending slash) for this theme. All resources of this theme are considered to be under this base URL.

getPath() public method

Converts a relative file path into an absolute one using $basePath.

public string getPath ( $path )
$path | string | The relative file path to be converted.
return | string | The absolute file path
throws | yii\base\InvalidConfigException | if $basePath is not set

getUrl() public method

Converts a relative URL into an absolute URL using $baseUrl.

public string getUrl ( $url )
$url | string | The relative URL to be converted.
return | string | The absolute URL
throws | yii\base\InvalidConfigException | if $baseUrl is not set

setBasePath() public method

See also $pathMap.

public void setBasePath ( $path )
$path | string | The root path or path alias of this theme. All resources of this theme are located under this directory.

setBaseUrl() public method

public void setBaseUrl ( $url )
$url | string | The base URL or path alias for this theme. All resources of this theme are considered to be under this base URL.