preview/features/complications.jd

page.title=Watch Face Complications
meta.keywords="wear-preview"
page.tags="wear-preview"
page.image=/wear/preview/images/complications-main-image.png
@jd:body

    <div id="qv-wrapper">
      <div id="qv">
    <h2>In this document</h2>
      <ol>
          <li>
            <a href="#adding_complications_to_a_watch_face">Adding
            Complications to a Watch Face</a>
          </li>
          <li>
            <a href="#exposing_data_to_complications">Exposing Data to
            Complications</a>
          </li>
          <li>
            <a href="#using_complication_types">Using Complication Types</a>
          </li>
          <li>
            <a href="#using_fields_for_complication_data">Using Fields for
            Complication Data</a>
          </li>
          <li>
            <a href="#api_additions">API Additions</a>
          </li>
      </ol>
    <h2>See Also</h2>
      <ol>
        <li><a class="external-link"
          href="https://github.com/googlesamples/android-WatchFace">Watch
          Face sample app with complications</a></li>
      </ol>
      </div>
    </div>

    <p>
      A complication is any feature in a watch face that displays <a href=
      "https://en.wikipedia.org/wiki/Complication_(horology)">more than hours and
      minutes</a>. For example, a battery indicator is a complication. The
      Complications API is for both watch faces and data provider apps.
    </p>

    <div class="col-4of10">
      <img src="../images/complications-main-image.png" alt="Complications"
      id="img-split-screen">
    </div>

    <p>
      Watch faces can display extra information without needing code for
      getting the underlying data. Data providers can supply data (such as
      battery level, weather, or step-count data) to any watch face using the
      API.
    </p>

    <p>
      Along with reviewing this page, download the Android Wear 2.0 Preview
      Reference (see the Complications API <a href=
      "#api_additions">additions</a>) and review the Javadoc for complications.
    </p>

    <p>
      Apps that provide data to watch faces for complications are called
      "complication data providers." These apps are not responsible for controlling
      how their data is rendered on the watch face.
      This allows a watch face to integrate the data naturally with the
      watch face design.
      The consuming watch faces are responsible for drawing
      the complications.
    </p>

    <p>
      Watch faces can receive complication data of
      <a href="#using_complication_types">various types</a> (e.g. small text
      data or icon data) and then display it.
    </p>

    <p>
      As indicated in the diagram below, Android Wear mediates the flow of data
      from providers to watch faces.
    </p>

    <img src="../images/complications-data-flow.png" width="" alt=
    "Complications data flow" title="Complications data flow">

    <p>
      For creating or modifying watch faces, see <a href=
      "#adding_complications_to_a_watch_face">Adding complications to a watch
      face</a>.
    </p>

    <p>
      For writing apps that provide data to watch faces, see <a href=
      "#exposing_data_to_complications">Exposing data to complications</a>.
    </p>

    <h2 id="adding_complications_to_a_watch_face">
      Adding Complications to a Watch Face
    </h2>

    <p>
      Watch face developers can receive complication data and enable users to
      select providers for that data. Additionally, Android Wear provides a
      <a href="#allowing_users_to_choose_data_providers">user interface for
      data source selection</a>.
    </p>

    <h3 id="receiving_data_and_rendering_complications">
      Receiving data and rendering complications
    </h3>

    <p>
      To start receiving complication data, a watch face calls
      <code>setActiveComplications</code> within the
      <code>WatchFaceService.Engine</code> class with a list of watch face
      complication IDs. A watch face creates these IDs to uniquely identify
      slots on the watch face where complications can appear, and passes them
      to the <code>createProviderChooserIntent</code> method (of the
      <code>ProviderChooserIntent</code> class) to allow the user to decide
      which complication should go in which slot.
    </p>

    <p>
      Complication data is delivered via the
      <code>onComplicationDataUpdate</code> (of
      <code>WatchFaceService.Engine</code>) callback.
    </p>

    <p>
      The watch face may render the data as desired as long as the expected
      fields are represented; the required fields should always be included and
      the data should be represented in some way. Depending on the type, some
      of the optional fields should also be included (see the Notes column in
      the <a href="#types_and_fields">table</a> below).
    </p>

    <p>
      We provide design guidelines for our style, as a suggestion for standard
      complications, but developers can use their own styles or incorporate the
      data into the watch face in different ways.
    </p>

    <h3 id="allowing_users_to_choose_data_providers">
      Allowing users to choose data providers
    </h3>

    <p>
      Android Wear provides a user interface (via an Activity) that enables
      users to choose providers for a particular complication. Watch faces can
      call the <code>createProviderChooserIntent</code> method to obtain an
      intent that can be used to show the chooser interface.
    </p>

    <p>
      This intent must be used with <code>startActivityForResult</code>. When a
      watch face calls <code>createProviderChooserIntent</code>, the watch face
      supplies a watch face complication ID and a list of supported types. The
      types should be listed in order of preference, usually with types
      offering more information, such as ranged value, given higher preference.
    </p>

    <p>
      When the user selects a data provider, the configuration is saved
      automatically; nothing more is required from the watch face.
    </p>

    <h3 id="user_interactions_with_complications">
      User interactions with complications
    </h3>

    <p>
      Providers can specify an action that occurs if the user taps on a
      complication, so it should be possible for most complications to be
      tappable. This action will be specified as a <code>PendingIntent</code>
      included in the <code>ComplicationData</code> object. The watch face is
      responsible for detecting taps on complications, and should fire the
      pending intent when a tap occurs.
    </p>

    <p>
      It may be infeasible to make some complications tappable (e.g., in the
      case of a complication that fills the entire background of the watch
      face), but it is expected that watch faces accept taps on complications
      where possible.
    </p>

    <h2 id="exposing_data_to_complications">
      Exposing Data to Complications
    </h2>

    <p>
      A complication data provider is a service that extends
      <code>ComplicationProviderService</code>. To respond to update requests
      from the system, your data provider must implement the
      <code>onComplicationUpdate</code> method of the
      <code>ComplicationProviderService</code> class. This method will be
      called when the system wants data from your provider - this could be when
      a complication using your provider becomes active, or when a fixed amount
      of time has passed. A <code>ComplicationManager</code> object is passed
      as a parameter to the <code>onComplicationUpdate</code> method, and can
      be used to send data back to the system.
    </p>

    <p>
      In your app's manifest, declare the service and add an intent filter for
      the following:
    </p>

    <pre>
android.support.wearable.complications.ACTION_COMPLICATION_UPDATE_REQUEST
</pre>
    <p>
      The service's manifest entry should also include an
      <code>android:icon</code> attribute. The provided icon should be a
      single-color white icon. Vector drawables are recommended for the icons.
      An icon should represent the provider and will be shown in the provider
      chooser.
    </p>

    <p>
      Include metadata to specify the supported types, update period, and
      configuration action, if required; for details, download the Android Wear
      2.0 Preview Reference and see the keys listed for the
      <code>ComplicationProviderService</code> class (in the Javadoc; see
      <a href="#api_additions">API Additions</a>).
    </p>

    <h3 id="update_period">
      Update period
    </h3>

    <p>
      Your provider can specify an update period using the following metadata
      key in the manifest:
    </p>

    <pre>
android.support.wearable.complications.UPDATE_PERIOD_SECONDS
</pre>
    <p>
      This should be set to as long a time as possible, as updating too
      frequently may impact battery life. Note that update requests are not
      guaranteed to be sent with this frequency. The system does apply a
      minimum update period, and in particular, updates requests may come less
      often when the device is in ambient mode or is not being worn.
    </p>

    <p>
      You can alternatively use a "push style" to send updates, rather than
      requesting updates on a fixed schedule. To do so, you can set the update
      period to 0 so scheduled update requests do not occur (or set it to a
      non-zero value) and use a <code>ProviderUpdateRequester</code> to trigger
      calls to <code>onComplicationUpdate</code> as required.
    </p>

    <h3 id="provider_configuration">
      Provider configuration
    </h3>

    <p>
      If required, a provider can include a configuration activity that is
      shown to the user when the user chooses a data provider. To include the
      configuration activity, include a metadata item in the provider service
      declaration in the manifest with a key of the following:
    </p>

    <p>
      <code>android.support.wearable.complications.PROVIDER_CONFIG_ACTION</code>
    </p>

    <p>
      The value can be an action of your choice.
    </p>

    <p>
      Then create the configuration activity with an intent filter for that
      action. The configuration activity must reside in the same package as the
      provider. The configuration activity must return <code>RESULT_OK</code> or
      <code>RESULT_CANCELED</code>, to tell the system whether the provider
      should be set.
    </p>

    <p>
      The configuration activity may also be used as an opportunity to request
      any permissions required by the provider.
    </p>

    <p>
      For details, download the Android Wear 2.0 Preview Reference (see
      <a href="#api_additions">API Additions</a>), containing the Javadoc, and
      see the following in the <code>ComplicationProviderService</code> class:
    </p>

    <pre>
METADATA_KEY_PROVIDER_CONFIG_ACTION
    </pre>

    <h2 id="using_complication_types">
      Using Complication Types
    </h2>

    <p>
      Complication types determine the kinds of data shown in a complication.
      For example, the <code>SHORT_TEXT</code> type is available when the key
      data is a short string. In the example of the <code>SHORT_TEXT</code>
      type, optional data are an icon and a short title.
    </p>

    <p>
      Data providers use these complication types differently from the way
      watch face providers use these types:
    </p>

    <ul>
      <li>A data provider chooses the types of complication data to supply. For
      example, a step count provider might support the
      <code>RANGED_VALUE</code> and <code>SHORT_TEXT</code> types, whereas a
      "next meeting" provider might support the <code>SHORT_TEXT</code> and
      <code>LONG_TEXT</code> types. The data provider also chooses which
      optional fields of those types to include.
      </li>

      <li>A watch face provider chooses how many complication types to support.
      For example, a round complication on a watch face might support the
      <code>SHORT_TEXT</code>, <code>ICON</code> and <code>RANGED_VALUE</code>
      types, whereas a gauge on the watch face might support only the
      <code>RANGED_VALUE</code> type.
      </li>
    </ul>

    <p>
      A <code>ComplicationData</code> object will always have a single
      complication type. Each complication type has required and optional
      fields. Generally, a required field represents the primary piece of data;
      most types take their name from the required field.
    </p>

    <p>
      A given type may include different sets of fields. For example,
      <code>SHORT_TEXT</code> may be just a single piece of text, or a title
      and text, or an icon and text. A complication that supports a given type
      must be able to display all the expected variants. However, some optional
      fields do not need to be displayed (see the <em>Notes</em> column of the
      table below). For example, the Short title field of the
      <code>RANGED_VALUE</code> type is not required so that, for example,
      gauges can be shown without including text.
    </p>

    <h3 id="examples_of_complication_types">
      Examples of Complication Types
    </h3>

    <p>
      The following shows examples of complication types:
    </p>
    <img src="../images/complication-type-exs.png" width="" alt=
    "Complication types" title="Complications types - examples">


    <h3 id="types_and_fields">
      Types and fields
    </h3>

    <p>
      The following table describes the types and fields of the
      <code>ComplicationData</code> object.
    </p>

    <table>
      <tr>
        <th style="width:175px">
          Type
        </th>
        <th style="width:175px">
          Required fields
        </th>
        <th style="width:175px">
          Optional fields
        </th>
        <th>
          Notes
        </th>
      </tr>

      <tr>
        <td>
          SHORT_TEXT
        </td>
        <td>
          Short text
        </td>
        <td>
          Icon<br>
          Short title
        </td>
        <td>
          Exactly one of Icon/Short title is expected to be shown if either or
          both are provided.
        </td>
      </tr>

      <tr>
        <td>
          ICON
        </td>
        <td>
          Icon
        </td>
        <td>
        </td>
        <td>
          Used when text is not needed.The icon is expected to be single-color,
          and may be tinted by the watch face.
        </td>
      </tr>

      <tr>
        <td>
          RANGED_VALUE
        </td>
        <td>
          Value<br>
          Min value<br>
          Max value
        </td>
        <td>
          Icon<br>
          Short text<br>
          Short title
        </td>
        <td>
          Optional fields are not guaranteed to be displayed.
        </td>
      </tr>

      <tr>
        <td>
          LONG_TEXT
        </td>
        <td>
          Long text
        </td>
        <td>
          Long title<br>
          Icon<br>
          Small image
        </td>
        <td>
          Title is expected to be shown if provided.
        </td>
      </tr>

      <tr>
        <td>
          SMALL_IMAGE
        </td>
        <td>
          Small image
        </td>
        <td>
        </td>
        <td>
          A small image has one of two styles: <em>photo style</em> or <em>icon
          style</em>. Photo style means it should fill the space and can be
          cropped; icon style means it should not be cropped and may be padded.
        </td>
      </tr>

      <tr>
        <td>
          LARGE_IMAGE
        </td>
        <td>
          Large image
        </td>
        <td>
        </td>
        <td>
          This image is expected to be large enough to fill the watch face.
        </td>
      </tr>
    </table>

    <p>
      In addition, the following two types have no fields. These two types may
      be sent for any complication slot and do not need to be included in a
      list of supported types:
    </p>

    <table>
      <tr>
        <th style="width:175px">
          Type
        </th>
        <th style="width:175px">
          Required fields
        </th>
        <th style="width:175px">
          Optional fields
        </th>
        <th>
          Notes
        </th>
      </tr>

      <tr>
        <td>
          NOT_CONFIGURED
        </td>
        <td>
          None
        </td>
        <td>
          None
        </td>
        <td>
          Sent when a provider has not yet been chosen for a complication.
        </td>
      </tr>

      <tr>
        <td>
          EMPTY
        </td>
        <td>
          None
        </td>
        <td>
          None
        </td>
        <td>
          Sent by a provider when there is no data to display in a
          complication, or sent by the system when nothing should be shown in a
          complication.
        </td>
      </tr>
    </table>

    <h2 id="using_fields_for_complication_data">
      Using Fields for Complication Data
    </h2>

    <p>
      The fields of a <code>ComplicationData</code> object have different
      functions. For example, a text field contains the primary data while a
      title field is descriptive; a step count complication might have a text
      field value of "2,543" with a title field value of "steps."
    </p>

    <p>
      The following table contains descriptions of the fields in a
      <code>ComplicationData</code> object. The fields may or may not be
      populated, depending on the complication type.
    </p>

    <table>
      <tr>
        <th style="width:175px">
          Field
        </th>
        <th>
          Description
        </th>
      </tr>

      <tr>
        <td>
          Short text
        </td>
        <td>
          Primary text field for small complications. Should not exceed 7
          characters.
        </td>
      </tr>

      <tr>
        <td>
          Icon
        </td>
        <td>
          A single-color image representing the data or the source of the data.
          Must be tintable. Vector drawables are recommended for this field.
        </td>
      </tr>

      <tr>
        <td>
          Short title
        </td>
        <td>
          Descriptive field for small complications. Should not exceed 7
          characters. May only be meaningful in combination with <em>Short
          text</em>.
        </td>
      </tr>

      <tr>
        <td>
          Long text
        </td>
        <td>
          Primary data field for large, text-based complications.
        </td>
      </tr>

      <tr>
        <td>
          Long title
        </td>
        <td>
          Descriptive field for large, text-based complications. May only be
          meaningful in combination with <em>Long text</em>.
        </td>
      </tr>

      <tr>
        <td>
          Value
        </td>
        <td>
          A numerical (float) representation of the data. Expected to be
          depicted relative to the bounds the <em>Min value</em> and <em>Max
          value</em> fields (but not required to be between those bounds).
        </td>
      </tr>

      <tr>
        <td>
          Min value
        </td>
        <td>
          The lower bound for the range within which <em>Value</em> should be
          depicted. Only meaningful in combination with <em>Value</em> and
          <em>Max value</em>.
        </td>
      </tr>

      <tr>
        <td>
          Max value
        </td>
        <td>
          The upper bound for the range within which <em>value</em> should be
          depicted. Only meaningful in combination with <em>Value</em> and
          <em>Min value</em>.
        </td>
      </tr>

      <tr>
        <td>
          Small image
        </td>
        <td>
          A small image to represent the data or the source of the data. May be
          full color. Not expected to fill the entire watch face.
        </td>
      </tr>

      <tr>
        <td>
          Large image
        </td>
        <td>
          An image with sufficient resolution to fill the watch face. May be
          full color.
        </td>
      </tr>
    </table>

    <h3 id="providing_time-dependent_values">
      Providing time-dependent values
    </h3>

    <p>
      Some complications need to display a value that relates to the current
      time. Examples include the current date, the time until the next meeting,
      or the time in another time zone.
    </p>

    <p>
      Providers of such data should not need to update a complication every
      second/minute to keep those values up to date. Instead, they can specify
      the values as relative to the current date or time.
    </p>

    <p>
      Providers can use the builders in the <code>ComplicationText</code> class
      to create these time-dependent values.
    </p>

    <h2 id="api_additions">
      API Additions
    </h2>

    <p>
      The Complications API includes new classes in the Wearable Support
      Library. For more information, download the <a href=
      "{@docRoot}wear/preview/start.html#get_the_preview_reference_documentation">
      Android Wear 2.0 Preview Reference</a>.
    </p>

    <ul>
      <li>
        <code>ComplicationData</code>
        <ul>
          <li>Parcelable (using a Bundle internally); immutable
          </li>

          <li>Represents all types of complication data
          </li>

          <li>Includes a Builder for instance creation
          </li>
        </ul>
      </li>

      <li>
        <code>ComplicationText</code>
        <ul>
          <li>Used to supply text-based values in a
          <code>ComplicationData</code> object
          </li>

          <li>Includes options for time-dependent values, whose text value
          depends on the current time
          </li>
        </ul>
      </li>

      <li>
        <code>ComplicationProviderService</code>
        <ul>
          <li>Extends <code>Service</code> and includes callback methods to
          respond to the complication system
          </li>

          <li>Callback methods are all called on the main thread
          </li>
        </ul>
      </li>

      <li>
        <code>ComplicationManager</code>
        <ul>
          <li>A wrapper for the complication manager service, for use by
          providers
          </li>

          <li>Allows providers to send complication data to the system
          </li>
        </ul>
      </li>

      <li>
        <code>ProviderChooserIntent</code>
        <ul>
          <li>Non-instantiable utility class
          </li>

          <li>Includes a method that a watch face can call for starting a
          provider chooser (to allow a user to configure complications)
          </li>
        </ul>
      </li>

      <li>
        <code>ProviderInfoRetriever</code>
        <ul>
          <li>Can be used (by watch face configuration activities) to retrieve
          the current data provider information (app, provider name, icon) for
          all complications belonging to a watch face
          </li>
        </ul>
      </li>

      <li>
        <code>ProviderUpdateRequester</code>
        <ul>
          <li>Can be used by data provider apps to trigger calls to
          <code>onComplicationUpdated</code> in their provider service, to
          enable the push of updates
          </li>
        </ul>
      </li>
    </ul>

    <p>
      Additionally, the <code>WatchFaceService.Engine</code> class contains the
      following new methods:
    </p>

    <ul>
      <li>
        <code>setActiveComplications</code>
        <ul>
          <li>Should be called by the watch face to tell the
          <code>ComplicationManager</code> object what complication slots are
          available and what types are supported
          </li>
        </ul>
      </li>

      <li>
        <code>onComplicationDataUpdate</code>
        <ul>
          <li>Called by the <code>ComplicationManager</code> object to send
          complication data to the watch face
          </li>
        </ul>
      </li>
    </ul>