Copy the contents of other in to this object, but only where fields are not defined by this object. For purposes of a field being defined, the following pieces of data in the Intent are considered to be separate fields:

• action, as set by Intent.SetAction(string).
• data Uri and MIME type, as set by Intent.SetData(Android.Net.Uri), Intent.SetType(string), or Intent.SetDataAndType(Android.Net.Uri, System.String).
• categories, as set by Intent.AddCategory(string).
• package, as set by Intent.SetPackage(string).
• component, as set by Intent.SetComponent(ComponentName) or related methods.
• source bounds, as set by Intent.SourceBounds.
• selector, as set by Intent.Selector.
• clip data, as set by Intent.ClipData.
• each top-level name in the associated extras.

In addition, you can use the Intent.FILL_IN_ACTION, Intent.FILL_IN_DATA, Intent.FILL_IN_CATEGORIES, Intent.FILL_IN_PACKAGE, Intent.FILL_IN_COMPONENT, Intent.FILL_IN_SOURCE_BOUNDS, Intent.FILL_IN_SELECTOR, and Intent.FILL_IN_CLIP_DATA to override the restriction where the corresponding field will not be replaced if it is already set.

Note: The component field will only be copied if Intent.FILL_IN_COMPONENT is explicitly specified. The selector will only be copied if Intent.FILL_IN_SELECTOR is explicitly specified.

For example, consider Intent A with {data="foo", categories="bar"} and Intent B with {action="gotit", data-type="some/thing", categories="one","two"}.

Calling A.fillIn(B, Intent.FILL_IN_DATA) will result in A now containing: {action="gotit", data-type="some/thing", categories="bar"}.

[Android Documentation]