page.title=Creating and Running a Wearable App
page.tags=wear
helpoutsWidget=true
@jd:body
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<h2>This lesson teaches you to</h2>
<ol>
<li><a href="#UpdateSDK">Update Your SDK</a></li>
<li><a href="#SetupEmulator">Set Up an Android Wear Emulator or Device</a></li>
<li><a href="#CreateProject">Create a Project</a></li>
<li><a href="#Install">Install the Wearable App</a></li>
<li><a href="#Libraries">Include the Correct Libraries</a></li>
</ol>
</div>
</div>
<p>Wearable apps run directly on the wearable device, giving you access to low-level
hardware such as sensors, activities, services, and more, right
on the wearable.</p>
<p>A companion handheld app that contains the
wearable app is also required when you want to publish to the Google Play store.
Wearables don't support the Google Play store, so users download the companion handheld app,
which automatically pushes the wearable app to the wearable. The handheld app is also
useful for doing heavy processing, network actions, or other work and
sending the results to the wearable.
</p>
<p>This lesson goes over how to set up a device or emulator and create one project to contain
both your wearable and handheld apps.
</p>
<h2 id="UpdateSDK">Update Your SDK</h2>
<p>Before you begin building wearable apps, you must:</p>
<ul>
<li><strong>Update your SDK tools to version 23.0.0 or higher</strong>
<br>
The updated SDK tools enable you to build and test wearable apps.
</li>
<li><strong>Update your SDK with Android 4.4W.2 (API 20) or higher</strong>
<br>
The updated platform version provides new APIs for wearable apps.
</li>
</ul>
<p>To update your SDK with these components, see
<a href="{@docRoot}studio/intro/update.html#GetTools"> Get the latest SDK tools</a>.</p>
<p class="note"><strong>Note:</strong> If you plan to make your Wear apps available for China,
you must use the special release version 7.8.87 of the Google Play services client library to handle
communication between handset and wearable.
For information on how to configure Wear apps for China, see
<a href="{@docRoot}training/wearables/apps/creating-app-china.html"> Creating Android Wear Apps for
China</a>.</p>
<h2 id="SetupEmulator">Set Up an Android Wear Emulator or Device</h2>
<p>We recommend that you develop on real hardware so you can better
gauge the user experience. However, the emulator lets you test out different
types of screen shapes, which is useful for testing.</p>
<h3>Set up an Android Wear Virtual Device</h3>
<p>To set up an Android Wear virtual device:</p>
<ol>
<li>Click <b>Tools > Android > AVD Manager</b>.</li>
<li>Click <b>Create Virtual Device...</b>.</li>
<ol>
<li>Click <b>Wear</b> in the Category list:</li>
<li>Select Android Wear Square or Android Wear Round.</li>
<li>Click <b>Next</b>.</li>
<li>Select a release name (for example, KitKat Wear).</li>
<li>Click <b>Next</b>.</li>
<li>(Optional) Change any preferences for your virtual device.</li>
<li>Click <b>Finish</b>.</li>
</ol>
<li>Start the emulator:
<ol>
<li>Select the virtual device you just created.</li>
<li>Click the <b>Play</b> button.</li>
<li>Wait until the emulator initializes and shows the Android Wear home screen.</li>
</ol>
</li>
<li>Pair your handheld with the emulator:
<ol>
<li>On your handheld, install the Android Wear app from Google Play.</li>
<li>Connect the handheld to your machine through USB.</li>
<li>Forward the AVD's communication port to the connected handheld device (you must
do this every time the handheld is connected):
<pre>adb -d forward tcp:5601 tcp:5601</pre>
</li>
<li>Start the Android Wear app on your handheld device and connect to the emulator.</li>
<li>Tap the menu on the top right corner of the Android Wear app and select
<b>Demo Cards</b>.</li>
<li>The cards you select appear as notifications on the home screen of the emulator.</li>
</ol>
</li>
</ol>
<h3 id="SetupDevice">Set Up an Android Wear Device</h3>
<p>To set up an Android Wear device:</p>
<ol>
<li>Install the Android Wear app, available on Google Play, on your handheld.</li>
<li>Follow the app's instructions to pair your handheld with your wearable.
This allows you to test out synced handheld notifications, if you're building them.</li>
<li>Leave the Android Wear app open on your phone.</li>
<li>Enable adb debugging on the Android Wear device.</li>
<ol>
<li>Go to <strong>Settings > About</strong>.</li>
<li>Tap <strong>Build number</strong> seven times.</li>
<li>Swipe right to return to the Settings menu.</li>
<li>Go to <strong>Developer options</strong> at the bottom of the screen.
</li>
<li>Tap <strong>ADB Debugging</strong> to enable adb.</li>
</ol>
<li>Connect the wearable to your machine through USB, so you can install apps directly to it
as you develop. A message appears on both the wearable and the Android Wear app prompting you to
allow debugging.</li>
<p class="note"><strong>Note:</strong> If you can not connect your wearable
to your machine via USB, you can try
<a href="{@docRoot}training/wearables/apps/bt-debugging.html">connecting over Bluetooth</a>.
</p>
<li>On the Android Wear app, check <strong>Always allow from this computer</strong> and tap
<strong>OK</strong>.</li>
</ol>
<p>The <i>Android</i> tool window on Android Studio shows the system log from the
wearable. The wearable should also be listed when you run the <code>adb devices</code> command.</p>
<h2 id="CreateProject">Create a Project</h2>
<p>To begin development, create an app project that contains
wearable and handheld app modules. In Android Studio, click <b>File</b> >
<b>New Project</b> and follow the Project Wizard instructions, as described in
<a href="{@docRoot}studio/projects/create-project.html">Creating a
Project</a>. As you follow the wizard, enter the following information:</p>
<ol>
<li>In the <b>Configure your Project</b> window, enter a name for your app and a package
name.</li>
<li>In the <b>Form Factors</b> window:
<ul>
<li>Select <b>Phone and Tablet</b> and select <b>API 9: Android 2.3 (Gingerbread)</b>
under <b>Minimum SDK</b>.</li>
<li>Select <b>Wear</b> and select <b>API 20: Android 4.4 (KitKat Wear)</b>
under <b>Minimum SDK</b>.</li>
</ul>
</li>
<li>In the first <b>Add an Activity</b> window, add a blank activity for mobile.</li>
<li>In the second <b>Add an Activity</b> window, add a blank activity for Wear.</li>
</ol>
<p>When the wizard completes, Android Studio creates a new project with two modules, <b>mobile</b>
and <b>wear</b>. You now have a project for both your handheld and wearable apps for which you can
create activities, services, and custom layouts. The handheld app does most of
the heavy lifting, such as network communications, intensive processing, or tasks that require
long amounts of user interaction. When the app completes these operations, your app should
notify the wearable of the results through notifications or by syncing and sending data to
the wearable.</p>
<p class="note"><b>Note:</b> The <b>wear</b> module also contains a "Hello World" activity that
uses a
<a href="{@docRoot}reference/android/support/wearable/view/WatchViewStub.html"><code>WatchViewStub</code></a>.
This class inflates a layout based on whether the device's screen is round or square. The
<a href="{@docRoot}reference/android/support/wearable/view/WatchViewStub.html"><code>WatchViewStub</code></a>
class is one of the UI widgets that the
<a href="{@docRoot}training/wearables/apps/layouts.html#UiLibrary">wearable support library</a>
provides.
</p>
</li>
<h2 id="Install">Install the Wearable App</h2>
<p>When developing, you install apps directly to the wearable like with handheld apps. Use
either <code>adb install</code> or the <b>Play</b> button on Android Studio.</p>
<p>When you're ready to publish your app to users, you embed the wearable app inside of the
handheld app. When a user installs the handheld app from Google Play, a connected wearable
automatically receives the wearable app.</p>
<p class="note"><b>Note:</b> The automatic installation of wearable apps
does not work when you are signing apps with a debug key and only works with release keys. See
<a href="{@docRoot}training/wearables/apps/packaging.html">Packaging Wearable Apps</a> for
complete information on how to properly package wearable apps.</p>
<li>
To install the "Hello World" app to the wearable, select <b>wear</b> from the <b>Run/Debug
configuration</b> drop-down menu and click the <b>Play</b> button. The activity shows up on the
wearable and prints out "Hello world!"
</li></ol>
<h2 id="Libraries">Include the Correct Libraries</h2>
<p>As part of the Project Wizard, the correct
dependencies are imported for you in the appropriate module's <code>build.gradle</code> file.
However, these dependencies are not required, so read the following descriptions to find out if you
need them or not:</p>
<b>Notifications</b>
<p>The <a href="{@docRoot}tools/support-library/features.html#v4">Android
v4 support library</a> (or v13, which includes v4)
contains the APIs to extend your existing notifications on handhelds to support wearables.</p>
<p>For notifications that appear only on
the wearable (meaning, they are issued by an app that runs on the wearable), you can just use the
standard framework APIs (API Level 20) on the wearable and remove the support library
dependency in the <b>mobile</b> module of your project.
</p>
<b>Wearable Data Layer</b>
<p>To sync and send data between wearables and handhelds with the Wearable Data Layer APIs,
you need the latest version of
<a href="{@docRoot}google/play-services/setup.html">Google Play services</a>.
If you're not using these APIs, remove the dependency from both modules.</p>
<b>Wearable UI support library</b>
<p>This is an unofficial library that includes
<a href="{@docRoot}training/wearables/apps/layouts.html#UiLibrary">UI widgets designed for
wearables</a>. We encourage you to use them in your apps, because they exemplify best practices,
but they can still change at any time. However, if the libraries are updated, your apps won't
break since they are compiled into your app. To get new features from an updated library, you just
need to statically link the new version and update your app accordingly. This library is only
applicable if you create wearable apps.
</p>
<p>In the next lessons, you'll learn how to create layouts designed for wearables as well as how
to use the various voice actions that are supported by the platform.</p>