The document provides information about deep linking on Android. It discusses how to configure an Android app manifest to handle deep links, add intent filters to specify supported URI schemes and paths. It also covers best practices for implementing deep links, including testing links and providing a good user experience when links are opened. The document recommends ways to annotate deep links on a website, such as using HTML <link> tags or XML sitemaps. It provides guidelines for using the App Indexing API to surface app content in Google search.

1. Android
Deep Linking
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3. Find the right app for you
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5. Example
Here's an intent that launches the Zxing barcode scanner app. It
follows the syntax thus:
intent:
//scan/
#Intent;
package=com.google.zxing.client.android;
scheme=zxing;
end;
To launch the Zxing barcode scanner app, you encode your href on
the anchor as follows:
<a
href="intent://scan/#Intent;scheme=zxing;package=com.google.zxi
ng.client.android;end"> Take a QR code </a> www.letsnurture.com

6. What is App Indexing?
App Indexing allows you to connect pages from
your website with specific content within your
smartphone app.
This enables smartphone users who have your
app installed to open it directly from relevant
mobile search results on Google.
For example, imagine you run a recipe website
and have an app that can also show your recipe.
Thanks to the app indexing feature, when a
Google searcher on a mobile device is shown one
of your recipes as a search result, they will now be
able to open that result directly in your app if they
have it installed.
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7. Here is how to specify a deep link to your app content:
• In your Android manifest file, add one or
more <intent-filter> elements for the activities that
should be launchable from Google Search results.
• Add an <action> tag that specifies
the ACTION_VIEW intent action.
• Add a <data> tag for each data URI format the
activity accepts. This is the primary mechanism to
declare the format for your deep links.
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8. • Add a <category> for
both BROWSABLE and DEFAULT intent categories.
– BROWSABLE is required in order for the intent to be executable from a
web browser. Without it, clicking a link in a browser cannot resolve to
your app and only the current web browser will respond to the URL.
– DEFAULT is not required if your only interest is providing deep links to
your app from Google Search results. However, the DEFAULT category
is required if you want your Android app to respond when users click
links from any other web page that points to your web site. The
distinction is that the intent used from Google search results includes
the identity of your app, so the intent explicitly points to your app as
the recipient — other links to your site do not know your app identity,
so the DEFAULT category declares your app can accept an implicit
intent.
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9. <activity
android:name="com.example.android.GizmosActivity"
android:label="@string/title_gizmos" > <intent-filter
android:label="@string/filter_title_viewgizmos"> <action
android:name="android.intent.action.VIEW" /> <!--
Accepts URIs that begin with
"http://example.com/gizmos” -->
<data android:scheme="http"
android:host="example.com"
android:pathPrefix="/gizmos" /> <category
android:name="android.intent.category.DEFAULT" />
<category
android:name="android.intent.category.BROWSABLE" />
</intent-filter>
</activity>
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10. In this example, your app would respond to
deep links such as
http://example.com/gizmos?1234,
http://example.com/gizmos/1234,
http://example.com/gizmos/toys/1234, etc.
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11. <activity android:name="com.example.android.GizmosActivity"
android:label="@string/title_gizmos" >
<intent-filter android:label="@string/filter_title_viewgizmos"> <action
android:name="android.intent.action.VIEW" /> <category
android:name="android.intent.category.DEFAULT" /> <category
android:name="android.intent.category.BROWSABLE" /> <!-- Accepts
URIs that begin with "example://gizmos” -->
<data android:scheme="example" android:host="gizmos" /> </intent-filter>
<intent-filter android:label="@string/filter_title_viewgizmos">
<action android:name="android.intent.action.VIEW" /> <category
android:name="android.intent.category.DEFAULT" /> <category
android:name="android.intent.category.BROWSABLE" /> <!-- Accepts
URIs that begin with "http://example.com/gizmos” --> <data
android:scheme="http" android:host="example.com"
android:pathPrefix="/gizmos" />
</intent-filter>
</activity>
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12. • You can test your deep links using the Android Debug Bridge:
adb shell am start -a android.intent.action.VIEW-d
"http://example.com/gizmos" com.example.android
adb shell am start -a android.intent.action.VIEW -d "example://gizmos"
com.example.android
Make sure to test this on a fresh install of your app as well.
• Use our deep link test tool to test your app behavior with deep links
on your phone. Alternatively, you can test your app's behavior in a
browser by creating an HTML page with an intent:// link in it:
<a
href="intent://example.com/gizmos#Intent;scheme=http;package=com.exam
ple.android;end;"> http://example.com/gizmos</a> <a
href="intent://gizmos#Intent;scheme=example;package=com.example.androi
d;end;">example://gizmos</a>
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13. Restricting access to parts of your app content
res/xml/noindex.xml
<?xml version="1.0" encoding="utf-8"?>
<search-engine
xmlns:android="http://schemas.android.com/ap
k/res/android"> <noindex
uri="http://example.com/gizmos/hidden_uri"/>
<noindex
uriPrefix="http://example.com/gizmos/hidden_p
refix"/> <noindex uri="gizmos://hidden_path"/>
<noindex uriPrefix="gizmos://hidden_prefix"/>
</search-engine>
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14. <?xml version="1.0" encoding="utf-8"?> <manifest
xmlns:android="http://schemas.android.com/apk/res/an
droid" package="com.example.android.Gizmos">
<application>
<activity
android:name="com.example.android.GizmosActivity"
android:label="@string/title_gizmos" > <intent-filter
android:label="@string/filter_title_viewgizmos"> <action
android:name="android.intent.action.VIEW"/> ...
</activity>
<meta-data android:name="search-engine"
android:resource="@xml/noindex"/>
</application> <uses-permission
android:name="android.permission.INTERNET"/>
</manifest>
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15. Connect your app to your website
• In order for Google to recognize your app as the official
application for your website, you must connect your app to
your website through the Google Play Console and
Webmaster Tools. Please follow the steps listed here.
• After your app and your website are connected, if your app
is using an HTTP scheme for handling deep links, Google
will automatically start indexing the content of your app
using URLs that Google has discovered through web
indexing and that match the intent-filter patterns in
yourAndroidManifest.xml file.
• After your app content is indexed without errors, deep links
can appear in Google mobile search results automatically.
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16. • If your app is using a custom URI scheme,
you can still participate in App Indexing by
specifying which deep links corresponds to
your web pages using sitemaps, web
annotations or the App Indexing API.
• Regardless of whether your web content is
indexed automatically or not, we still
recommend that you publish your deep links
using sitemaps, web annotations or the App
Indexing API as we will discuss next.
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17. Add app deep links on your website
• Each page on your site can specify whether its
contents should be loaded in your app. We offer
several ways to tell Google about the relationship
between a web page and a deep link to your app:
• Using a <link> element in the the <head> section of a
page.
• Using an <xhtml:link> element in the Sitemap <url>
element specifying the page.
• Using Schema.org markup for the ViewAction potential
action.
• Using the App Indexing API.
• Using the App Indexing API can also surface your
app's history in the Google app query
autocompletions.
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18. Format of the app URIs
• This <link> element specifies an alternate URI (specified in
the href attribute) that can be used to open the content in your
app. The format of the app URI is:
• android-app://{package_id}/{scheme}/{host_path}
Where:
• package_id: application ID as specified in the Android Play
Store.
• scheme: the scheme to pass to the application. Can be http,
or a custom scheme.
• host_path: identifies the specific content within your
application.
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19. Deep link App URI
http://example.com/gizmos?1234 android-app://
com.example.android/http/example.com/
gizmos?1234
http://example.com/gizmos/1234 android-app://
com.example.android/http/example.com/
gizmos/1234
http://example.com/gizmos/toys/1234 android-app://
com.example.android/http/example.com/
gizmos/toys/1234
example://gizmos?1234 android-app://
com.example.android/example/gizmos?1
234
example://gizmos/1234 android-app://
com.example.android/example/gizmos/1
234
example://gizmos/toys/1234 android-app://
com.example.android/example/gizmos/to
ys/1234
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20. Link rel=alternate elements in HTML
In the HTML of the page http://example.com/gizmos, you add a <link>
element as follows for the deep link http://example.com/gizmos:
<html> <head> ... <link rel="alternate" href="android-app://
com.example.android/http/example.com/gizmos" /> ... </head> <body> …
</body>
Or, if you're using a non-HTTP scheme (e.g., example://gizmo), you
would add the following:
<html> <head> ... <link rel="alternate" href="android-app://
com.example.android/example/gizmos" /> ... </head> <body> … </body>
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21. Update robots.txt
• When Google indexes content from your app, your app will
need to make any HTTP request that it usually makes under
normal operation.
• However, these requests will appear to your servers as
originating from Googlebot.
• Therefore, your server's robots.txt file must be configured
properly to allow these requests. For example, your robots.txt
file could include the following:
User-Agent: Googlebot Allow: /
• The app's behavior should not change because it or your
server detects Googlebot. Consider network calls made from
your app with Googlebot to be from a valid user.
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22. AndroidManifest.xml
<application ... <meta-data
android:name="com.google.android.gms.version"
android:value="@integer/google_play_services_ver
sion" /> ... </application>
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23. Once your project is configured to use Google Play Services API, follow these
steps for any activity that supports deep links:
• Create an instance of GoogleApiClient in the onCreate() method of your
activity.
• Notify Google each time a new activity is viewed using
the AppIndexApi.view() method. This can be called in
the onStart() method of each activity.
• The view() should report the content that the user is currently looking at
in your app. When that content changes, and the user is looking at
something else, the app should call viewEnd() on the exiting content and
then view() for the new content that is shown.
• The usual way this works is with onStart() and onStop() but it need not in
the case of fragments or other scrolling-type UIs, for example.
• Disconnect your client in your onStop() method.
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24. Best Practices
• Only call the AppIndexApi.view() method once
each time the user explicitly chooses to view some
content.
• There should be an existing deep link in the app
for each API call.
• Use an accurate and descriptive title in
your AppIndexApi.view() call. The text defined in
this title may be used in the Google app query
autocompletions.
• We recommend that you inform your users that
links visited in the app may be shared with Google
to improve the search experience.
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25. Quality Guidelines
• Google may take corrective action (e.g., demoting or removing your app
deep links from Google Search results and query autocompletions) in
cases where we see abuse, deception, or other actions that hurt the
search experience for our users. In particular, you should avoid:
• Calling the API on content the user is not viewing.
• Calling the API more than once per user view.
• Calling the API with a title that is misleading or incorrect.
• Note that Google may react to other misleading practices not listed here.
The examples above are not exhaustive. Google may take action on other
practices or techniques that hurt the search experience.
• Finally, once you have done everything in the launch checklist, Google will
be able to start indexing your app. You can check for any issues that arise
in Webmaster Tools.
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26. App Indexing Checklist
Android app
• App supports deep linking and the manifest file describes an intent
filter with the action android.intent.action.VIEW, and has the
categories android.intent.category.BROWSABLE and
android.intent.category.DEFAULT.
• App deep link implementation has been tested by running the
command "adb shell am start [deep link]" or by using the deep link
test tool on a fresh app install with an Android device.
• Tapping the BACK button after opening a deep link leads you back
to the previous screen.
• After opening a deep link, relevant content is visible without further
action required; app provides the "first click free" experience even
on a freshly installed app.
• App supports a deep link that opens the home screen.
• App implements the App Indexing API to surface app's history in
Google app query autocompletions. (Optional)
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27. Website and server
• Deep link annotations have been added to
sitemaps or to web pages.
• None of the domains or subdomains the app
needs resources from have robots.txt that
blocks Googlebot from those resources.
• Official website(s) for your app have been
verified in your app's Play Console.
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28. Test your deep links
• To test android-app:// URIs on your phone,
enter a deep link URI in the text box below. It
will generate a QR code that can be scanned
using a barcode scanner app on your Android
phone (e.g. Barcode Scanner), which should
open a browser page with a link. When you
click on the link on your phone, it should open
the deep link you have entered in the text box.
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29. Featured Apps
https://developers.google.com/app-indexing/apps
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