Create a deep link for a destination

In Android, a deep link is a link that takes you directly to a specific destination within an app.

The Navigation component lets you create two different types of deep links: explicit and implicit.

Create an explicit deep link

An explicit deep link is a single instance of a deep link that uses a PendingIntent to take users to a specific location within your app. You might surface an explicit deep link as part of a notification or an app widget, for example.

When a user opens your app via an explicit deep link, the task back stack is cleared and replaced with the deep link destination. When nesting graphs, the start destination from each level of nesting—that is, the start destination from each <navigation> element in the hierarchy—is also added to the stack. This means that when a user presses the Back button from a deep link destination, they navigate back up the navigation stack just as though they entered your app from its entry point.

You can use the NavDeepLinkBuilder class to construct a PendingIntent, as shown in the example below. Note that if the provided context is not an Activity, the constructor uses PackageManager.getLaunchIntentForPackage() as the default activity to launch, if available.

val pendingIntent = NavDeepLinkBuilder(context)
    .setGraph(R.navigation.nav_graph)
    .setDestination(R.id.android)
    .setArguments(args)
    .createPendingIntent()

PendingIntent pendingIntent = new NavDeepLinkBuilder(context)
    .setGraph(R.navigation.nav_graph)
    .setDestination(R.id.android)
    .setArguments(args)
    .createPendingIntent();

By default, NavDeepLinkBuilder launches your explicit deep link into the default launch Activity that is declared in your app's manifest. If your NavHost is in another activity, you must specify its component name when creating the deep link builder:

val pendingIntent = NavDeepLinkBuilder(context)
    .setGraph(R.navigation.nav_graph)
    .setDestination(R.id.android)
    .setArguments(args)
    .setComponentName(DestinationActivity::class.java)
    .createPendingIntent()

PendingIntent pendingIntent = new NavDeepLinkBuilder(context)
        .setGraph(R.navigation.nav_graph)
        .setDestination(R.id.android)
        .setArguments(args)
        .setComponentName(DestinationActivity.class)
        .createPendingIntent();

If you have a ComponentName, you can pass it directly to the builder:

val componentName = ...

val pendingIntent = NavDeepLinkBuilder(context)
    .setGraph(R.navigation.nav_graph)
    .setDestination(R.id.android)
    .setArguments(args)
    .setComponentName(componentName)
    .createPendingIntent()

ComponentName componentName = ...;

PendingIntent pendingIntent = new NavDeepLinkBuilder(context)
        .setGraph(R.navigation.nav_graph)
        .setDestination(R.id.android)
        .setArguments(args)
        .setComponentName(componentName)
        .createPendingIntent();

If you have an existing NavController, you can also create a deep link by using NavController.createDeepLink().

Create an implicit deep link

An implicit deep link refers to a specific destination in an app. When the deep link is invoked—for example, when a user clicks a link—Android can then open your app to the corresponding destination.

Deep links can be matched by URI, intent actions, and MIME types. You can specify multiple match types for a single deep link, but note that URI argument matching is prioritized first, followed by action, and then MIME type.

Here's an example deep link that contains a URI, an action, and a MIME type:

<fragment android:id="@+id/a"
          android:name="com.example.myapplication.FragmentA"
          tools:layout="@layout/a">
        <deepLink app:uri="www.example.com"
                app:action="android.intent.action.MY_ACTION"
                app:mimeType="type/subtype"/>
</fragment>

You can also use the Navigation Editor to create an implicit deep link to a destination as follows:

1. In the Design tab of the Navigation Editor, select the destination for the deep link.
2. Click + in the Deep Links section of the Attributes panel.

3. In the Add Deep Link dialog that appears, enter the info for your deep link.

   Note the following:

   • URIs without a scheme are assumed as either http or https. For example, www.google.com matches both http://www.google.com and https://www.google.com.
   • Path parameter placeholders in the form of {placeholder_name} match one or more characters. For example, http://www.example.com/users/{id} matches http://www.example.com/users/4. The Navigation component attempts to parse the placeholder values into appropriate types by matching placeholder names to the defined arguments that are defined for the deep link destination. If no argument with the same name is defined, a default String type is used for the argument value. You can use the .* wildcard to match 0 or more characters.
   • Query parameter placeholders can be used instead of or in conjunction with path parameters. For example, http://www.example.com/users/{id}?myarg={myarg} matches http://www.example.com/users/4?myarg=28.
   • Query parameter placeholders for variables defined with default or nullable values are not required to match. For example, http://www.example.com/users/{id}?arg1={arg1}&arg2={arg2} matches http://www.example.com/users/4?arg2=28 or http://www.example.com/users/4?arg1=7. This is not the case with path parameters. For example, http://www.example.com/users?arg1=7&arg2=28 does not match the above pattern because the required path parameter is not supplied.
   • Extraneous query parameters do not affect deep link URI matching. For example, http://www.example.com/users/{id} matches http://www.example.com/users/4?extraneousParam=7, even though extraneousParam is not defined in the URI pattern.

4. (optional) Check Auto Verify to require Google to verify that you are the owner of the URI. For more information, see Verify Android App Links.

5. Click Add. A link icon appears above the selected destination to indicate that destination has a deep link.

6. Click the Code tab to toggle to the XML view. A nested <deepLink> element has been added to the destination:

   <deepLink app:uri="https://www.google.com" />
   

To enable implicit deep linking, you must also make additions to your app's manifest.xml file. Add a single <nav-graph> element to an activity that points to an existing navigation graph, as shown in the following example:

<?xml version="1.0" encoding="utf-8"?>
<manifest xmlns:android="http://schemas.android.com/apk/res/android"
    package="com.example.myapplication">

    <application ... >

        <activity name=".MainActivity" ...>
            ...

            <nav-graph android:value="@navigation/nav_graph" />

            ...

        </activity>
    </application>
</manifest>

When building your project, the Navigation component replaces the <nav-graph> element with generated <intent-filter> elements to match all of the deep links in the navigation graph.

When triggering an implicit deep link, the state of the back stack depends on whether the implicit Intent was launched with the Intent.FLAG_ACTIVITY_NEW_TASK flag:

• If the flag is set, the task back stack is cleared and replaced with the deep link destination. As with explicit deep linking, when nesting graphs, the start destination from each level of nesting—that is, the start destination from each <navigation> element in the hierarchy—is also added to the stack. This means that when a user presses the Back button from a deep link destination, they navigate back up the navigation stack just as though they entered your app from its entry point.
• If the flag is not set, you remain on the task stack of the previous app where the implicit deep link was triggered. In this case, the Back button takes you back to the previous app, while the Up button starts your app's task on the hierarchical parent destination within your navigation graph.

Handling deep links

It is strongly recommended to always use the default launchMode of standard when using Navigation. When using standard launch mode, Navigation automatically handles deep links by calling handleDeepLink() to process any explicit or implicit deep links within the Intent. However, this does not happen automatically if the Activity is re-used when using an alternate launchMode such as singleTop. In this case, it is necessary to manually call handleDeepLink() in onNewIntent(), as shown in the following example:

override fun onNewIntent(intent: Intent?) {
    super.onNewIntent(intent)
    navController.handleDeepLink(intent)
}

@Override
protected void onNewIntent(Intent intent) {
    super.onNewIntent(intent);
    navController.handleDeepLink(intent);
}

Additional resources

To learn more about navigation, see the following resources.

Samples

• Android Architecture Components Navigation Basic Sample

Codelabs

• Navigation codelab

Videos

• Android Jetpack: manage UI navigation with Navigation Controller (Google I/O '18)