frameworks_base/docs/html/wear/preview/api-overview.jd

page.title=Preview API Overview
meta.tags="wear", "wear-preview"
page.tags="wear"
page.image=images/cards/card-n-apis_2x.png
@jd:body

<div id="qv-wrapper">
<div id="qv">
  <h2>Key developer features</h2>
  <ol>
      <ul style="list-style-type:none;">
        <li><a href="#ui">User Interface Improvements</a>
          <ol>
            <li><a href="#complications">Complications</a></li>
            <li><a href="#drawers">Navigation and Action Drawers</a></li>
            <li><a href="#wrv">Curved Layout</a></li>
          </ol>
        </li>

        <li><a href="#notify">Notifications and Input</a>
          <ol>
            <li><a href="#expanded">Expanded Notifications</a></li>
            <li><a href="#messaging">Messaging Style Notifications</a></li>
            <li><a href="#inline-action">Inline Action</a></li>
            <li><a href="#smart-replies">Smart Reply</a></li>
            <li><a href="#remote-input">Remote Input</a></li>
            <li><a href="#bridging">Bridging Mode</a></li>
            <li><a href="#imf">Input Method Framework</a></li>
            <li><a href="#wrist-gestures">Wrist Gestures</a></li>
          </ol>
        </li>

        <li><a href="#stand-alone">Standalone Devices</a>
          <ol>
            <li><a href="#wear-apk">Wear-Specific APKs</a></li>
            <li><a href="#network">Network Access</a></li>
            <li><a href="#auth">Authentication</a></li>
          </ol>
        </li>
      </ol>
</div>
</div>

    <p>
      Wear 2.0 is still in active development, but you can try it as part of
      the Wear 2.0 Developer Preview. The sections below highlight some of the
      new features for developers.
    </p>

    <h2 id="ui">
      User Interface Improvements
    </h2>

    <p>
      The preview introduces powerful additions to the user interface, opening
      up exciting possibilities to developers.
    </p>

    <h3 id="complications">
      Complications
    </h3>

    <img src="{@docRoot}wear/preview/images/complications-main-image.png"
    height="320" style="float:right;margin:10px 0 0 40px">
    <p>
      A <a href=
      "https://en.wikipedia.org/wiki/Complication_(horology)">complication</a>
      is a feature of a watch face that displays more than hours and minutes,
      such as a battery indicator or a step counter. The Complications API thus
      helps watch face developers create visual features and the data
      connections they require.
    </p>

    <p>
      Watch faces that use this API can display extra information without
      needing code for getting the underlying data. Data providers can supply
      data to any watch face using the API.
    </p>

    <p>
      For information about this API, see <a href=
      "{@docRoot}wear/preview/features/complications.html">Watch Face
      Complications</a>.
    </p>

    <h3 id="drawers">
      Navigation and Action Drawers
    </h3>

    <p>
      Wear 2.0 introduces two new widgets, navigation drawer and action drawer.
      These widgets give your users new ways to interact with your app. The
      navigation drawer appears at the top of the screen and allows users to
      navigate between app views. The action drawer appears at the bottom of
      the screen and allows users to choose from a list of actions associated
      with the current usage context. These drawers are accessible to users
      when they edge swipe from the top or bottom of the screen; they peek when
      users scroll in an opposite direction.
    </p>

    <div class="cols">
      <div class="col-2of6">
        <img src="{@docRoot}wear/preview/images/nav_drawer.gif" height="240"
        alt="" style="padding:.5em">
      </div>

      <div class="col-2of6">
        <img src="{@docRoot}wear/preview/images/action_drawer.gif" height="240"
        alt="" style="padding:.5em;">
      </div>
    </div>

    <p>
      To learn how to add these widgets to your app, see <a href=
      "{@docRoot}wear/preview/features/ui-nav-actions.html">Wear Navigation and
      Actions</a>.
    </p>

    <h3 id="wrv">
      Curved Layout
    </h3>

    <p>
      Wear 2.0 introduces the <code>WearableRecyclerView</code> class for
      displaying and manipulating a vertical list of items,
      optimized for round displays.
    </p>

    <p>
      The key features include the following:
    </p>

    <ul>
      <li>A curved layout on round devices
      </li>

      <li>A circular scrolling gesture, which can be toggled on and off
      </li>
    </ul>

    <p>
      To learn how to create a curved layout optimized for round devices, see
      <a href=
      "https://developer.android.com/wear/preview/features/wearable-recycler-view.html">
      Curved Layout</a>.
    </p>

    <h2 id="notify">
      Notifications and Input
    </h2>

    <p>
      In Wear 2.0, we’ve redesigned the key experiences on the watch to be even
      more intuitive and provide users new ways to respond to messages. Some of
      the highlights are below; for a complete list of changes, see <a href=
      "{@docRoot}wear/preview/features/notifications.html">Notification Changes
      in Wear 2.0</a>. <img src=
      "{@docRoot}wear/preview/images/expanded_diagram.png" height="340" style=
      "float:left;margin:10px 20px 0 0">
    </p>

    <h3 id="expanded">
      Expanded Notifications
    </h3>

    <p>
      When a user taps on a notification that is bridged from the phone to the
      watch or that lacks a <a href=
      "{@docRoot}reference/android/support/v4/app/NotificationCompat.Builder.html#setContentIntent(android.app.PendingIntent)">
      {@code contentIntent}</a>, the user will be taken to the expanded view of
      that notification. When you <a href=
      "{@docRoot}training/wearables/notifications/pages.html">specify
      additional content pages</a> and actions for a notification, those are
      available to the user within the expanded notification. Each expanded
      notification follows <a href=
      "https://google.com/design/spec-wear">Material Design for Android
      Wear</a>, so the user gets an app-like experience.
    </p>

    <h3 id="messaging">
      Messaging Style Notifications
    </h3>

    <p>
      If you have a chat messaging app, your notifications should use {@code
      Notification.MessagingStyle}, which is new in Android 6.0. Wear 2.0 uses
      the chat messages included in a <a href=
      "{@docRoot}preview/features/notification-updates.html#style">{@code
      MessagingStyle}</a> notification (see {@code addMessage()}) to provide a
      rich chat, app-like experience in the expanded notification.
    </p>

    <h3 id="inline-action">
      Inline Action
    </h3>

    <p>
      Wear 2.0 enables you to add an inline action within the notification
      stream so that users can quickly take an action on a notification.
      Examples of good use cases for an inline action within a notification stream
      include replying to a text message, stopping a fitness activity, or
      archiving an email message.
    </p>

    <p>
      To learn how to add an inline action to your notification stream, see
      <a href=
      "https://developer.android.com/wear/preview/features/notifications.html#inline">
      Inline Action</a>.
    </p>

    <h3 id="smart-replies">
      Smart Reply
    </h3>

    <p>
      Android Wear 2.0 introduces support for Smart Reply in <a href=
      "{@docRoot}wear/preview/features/notifications.html#messaging">{@code
      MessagingStyle}</a> notifications. Smart Reply provides the user with
      contextually relevant, touchable choices in the expanded notification and
      in <a href="{@docRoot}reference/android/app/RemoteInput.html">{@code
      RemoteInput}</a>.
    </p>

    <p>
      By enabling Smart Reply for your {@code MessagingStyle} notifications,
      you provide users a fast (single tap), discreet (no speaking aloud), and
      reliable way to respond to chat messages they receive.
    </p>

    <img src="{@docRoot}wear/preview/images/remoteinput.png" height="350"
    style="float:right;margin:10px 0 0 40px">

    <h3 id="remote-input">
      Remote Input
    </h3>

    <p>
      Wear 2.0 users can choose between various input options from <a href=
      "{@docRoot}reference/android/app/RemoteInput.html">Remote Input</a>.
      These options include:
    </p>

    <ul>
      <li>Dictation
      </li>

      <li>Emoji
      </li>

      <li>Canned responses
      </li>

      <li>Smart Reply
      </li>

      <li>Default IME
      </li>
    </ul>

    <p>
      For messaging notifications with Smart Reply, the system-generated Smart
      Reply appears within <a href=
      "{@docRoot}reference/android/app/RemoteInput.html">{@code
      RemoteInput}</a> above the developer-provided list of canned responses.
      You can also use the <a href=
      "{@docRoot}reference/android/app/RemoteInput.Builder.html#setChoices(java.lang.CharSequence[])">
      setChoices()</a> method in the {@code RemoteInput} API to enable users to
      select from a list of canned responses.
    </p>

    <h3 id="bridging">
      Bridging Mode
    </h3>

    <p>
      By default, notifications are <a href=
      "{@docRoot}training/wearables/notifications/index.html">bridged</a>
      (shared) from an app on a companion phone to the watch. Since a phone app
      and a standalone watch app may be sources of the same notifications, the
      Android Wear 2.0 Preview includes a Bridging mode feature.
    </p>

    <p>
      For information about this feature, see <a href=
      "{@docRoot}wear/preview/features/bridger.html">Bridging Mode for
      Notifications</a>.
    </p>

    <h3 id="imf">
      Input Method Framework
    </h3>

    <p>
      Wear 2.0 extends the Android input method framework (IMF) to Android
      Wear. This allows users to enter text on Wear using the system default
      IME or third party IMEs. The Wear IME lets the user enter text via
      gesture typing as well as tapping individual keys. The IMF APIs used for
      Wear devices are the same as other form factors, though usage is slightly
      different due to limited screen real estate.
    </p>

    <p>
      Wear provides user settings on the watch that let the user:
    </p>

    <ul>
      <li>Enable multiple IMEs from the list of installed IMEs.
      </li>

      <li>Set a single default IME from the list of enabled IMEs.
      </li>

      <li>Change languages for various IMEs.
      </li>
    </ul>

    <p>
      To learn how to create an IME for Wear, see <a href=
      "{@docRoot}wear/preview/features/ime.html">Input Method Framework</a>.
    </p>

    <h3 id="wrist-gestures">
      Wrist Gestures
    </h3>

    <p>
      Wrist gestures can enable quick, one-handed interactions with your app
      when use of a touch screen is inconvenient. The following <a href=
      "https://support.google.com/androidwear/answer/6312406">wrist
      gestures</a> are available for use by apps:
    </p>

    <ul>
      <li>Flick wrist out
      </li>

      <li>Flick wrist in
      </li>
    </ul>

    <p>
      For more information, see <a href=
      "{@docRoot}wear/preview/features/gestures.html">Wrist Gestures</a>.
    </p>

    <h2 id="stand-alone">
      Standalone Devices
    </h2>

    <p>
      Standalone watches enable Android Wear apps to work independently of
      phone apps. This means your app can continue to offer full functionality
      even if the paired phone is far away or turned off.
    </p>

    <h3 id="wear-apk">
      Wear-Specific APKs
    </h3>

    <p>
      For delivery to a watch, an Android Wear app is currently embedded in its
      corresponding phone app. This delivery method can result in an increased
      download size for users, regardless of whether they have an Android Wear
      device.
    </p>

    <p>
      For information about planning and building your standalone app
      for Wear 2.0, see <a href=
      "https://developer.android.com/wear/preview/features/standalone-apps.html">
      Standalone Apps</a>.
    </p>

    <p>
      For information about distributing your app, see <a href=
      "https://developer.android.com/wear/preview/features/app-distribution.html">
      App Distribution</a>.
    </p>

    <h3 id="network">
      Network Access
    </h3>

    <p>
      Since Android Wear apps will work independently of phone apps, Android
      Wear's network access will no longer require the <a href=
      "{@docRoot}training/wearables/data-layer/index.html">Wearable Data Layer
      API</a>. Android Wear apps will have the ability to make their own
      network requests. Additionally, they will be able to directly use Google
      Cloud Messaging. For more information, see
      <a href=
      "https://developer.android.com/wear/preview/features/standalone-apps.html#network_access">
      Network Access and Cloud Messaging</a>.
    </p>

    <p>
      No APIs for network access or GCM are specific to Android Wear; refer to
      the existing documentation about <a href=
      "{@docRoot}training/basics/network-ops/connecting.html">Connecting to the
      Network</a> and <a href=
      "https://developers.google.com/cloud-messaging/">Cloud Messaging</a>.
    </p>

    <p>
      We recommend using the following libraries:
    </p>

    <ul>
      <li>
        <a href=
        "{@docRoot}reference/android/app/job/JobScheduler.html">JobScheduler</a>
        for asynchronous jobs, including polling at regular intervals
      </li>

      <li>Multi-networking APIs, to connect to specific network
      types; see <a href=
      "{@docRoot}about/versions/android-5.0.html#Wireless">Multiple Network
      Connections</a>
      </li>
    </ul>

    <p>
      The <a href=
      "{@docRoot}training/wearables/data-layer/index.html">Wearable Data Layer
      API</a> is available to communicate with a phone app.
      However, use of this API to connect to a network will be discouraged.
    </p>

    <h3 id="auth">
      Authentication
    </h3>

    <p>
      Since Android Wear apps will work independently of phone apps, Android
      Wear's authentication capabilities will be more powerful; apps will have
      new ways to authenticate.
    </p>

    <h4>
      Users can enter a username and password on a watch
    </h4>

    <p>
      Google Keyboard will be standard on Android Wear, allowing for direct
      text entry. This feature will work as expected with standard <a href=
      "{@docRoot}reference/android/widget/EditText.html">EditText widgets</a>.
      For passwords, the {@code textPassword} attribute will be used.
    </p>

    <h4>
      Utilizing Account Manager
    </h4>

    <p>
      Android Wear will include the <a href=
      "{@docRoot}reference/android/accounts/AccountManager.html">AccountManager</a>,
      which will be accessible for syncing and storing account data, as it is
      on an Android phone.
    </p>

    <h4>
      Authentication tokens can be passed over the Wearable Data Layer
    </h4>

    <p>
      For Android-paired watches (only), a phone securely transfers
      authentication credentials to a watch app via the <a href=
      "{@docRoot}training/wearables/data-layer/index.html">Wearable Data Layer
      API</a>. The credentials can be transferred as messages or data items.
    </p>

    <p>
      If your watch app needs to determine if your phone app is installed, you
      can advertise a capability on the phone app and retrieve the capability
      on the watch. For more information, see the following sections of
      <a href="{@docRoot}training/wearables/data-layer/messages.html">Sending
      and Receiving Messages</a>:
    </p>

    <ul>
      <li>Advertise Capabilities
      </li>

      <li>Retrieve the Nodes with the Required Capabilities
      </li>
    </ul>