# MGLForegroundStyleLayer

    @interface MGLForegroundStyleLayer : MGLStyleLayer

`MGLForegroundStyleLayer` is an abstract superclass for style layers whose content is defined by an `MGLSource` object.

Create instances of `MGLRasterStyleLayer`, `MGLHillshadeStyleLayer`, and the concrete subclasses of `MGLVectorStyleLayer` in order to use `MGLForegroundStyleLayer`‘s methods. Do not create instances of `MGLForegroundStyleLayer` directly, and do not create your own subclasses of this class.

### Specifying a Style Layer’s Content

- `sourceIdentifier`

  Identifier of the source from which the receiver obtains the data to style.

  #### Declaration

  Objective-C

      @property (readonly, nonatomic, nullable) NSString *sourceIdentifier;

  Swift

      var sourceIdentifier: String? { get }

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