Navigation components : Deeplink using uri depending buildType

Question

Any way to read a constant depending buildType ${deepLinkHost}?

debug -> deepLinkUri = http://link.debug/
staging -> deepLinkUri = http://link.staging/
release ->  deepLinkUri=  http://link/

<?xml version="1.0" encoding="utf-8"?>
<navigation xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:app="http://schemas.android.com/apk/res-auto"
    xmlns:tools="http://schemas.android.com/tools"
    android:id="@+id/navigation_home"
    app:startDestination="@id/fragment_home">

    <fragment
        android:id="@+id/fragment_home"
        android:name="..."
        tools:layout="@layout/fragment_home">
        <argument
            android:name="token"
            android:defaultValue="@null"
            app:argType="string"
            app:nullable="true" />
        <deepLink app:uri="${deepLinkUri}/?code={token}" />
</fragment>

This was manage before with manifestPlaceholders.deepLinkHost on build.gradle and deeplinks by activity in the AndroidManifest, but once google uses 1 Activity to N Fragments, how can we manage it with navigation components?

Answer 1

It looks like it's not currently supported out of the box, but there is a pretty simple workaround. Normally registering a deep link requires two steps:

1. Add deepLink to the navigation graph. Since we can't specify any substitution or a @string resource as the uri, let's just define the host name as a variable: <deepLink app:uri="http://{deepLinkHost}/?code={token}" />. This link will match any host and pass deepLinkHost as a parameter.
2. Register an intent-filter in the AndroidManifest.xml, so our activity actually reacts on the deep link. The recommended approach for the latest android studio is to add <nav-graph android:value="@navigation/nav_graph" /> to the manifest, so it generates necessary intent-filter automatically. It will, however, register our activity to accept links with any host, which is probably not what we want. So instead of doing this, let's go with the standard approach. Basically here we define the intent-filter manually instead of auto-generating it from navigation graph. So we can use manifest substitutions just as we would normally do.

Example

• debug -> http://link.debug/identification?code=123
• staging -> http://link.staging/identification?code=123
• release -> http://link/identification?code=123

and

• debug -> http://link.debug/banner?id=123
• staging -> http://link.staging/banner?id=123
• release -> http://link/banner?id=123

build.gradle

buildTypes {

        debug {
            manifestPlaceholders.deepLinkUri = "http://link.debug"
        }

        staging {
           manifestPlaceholders.deepLinkUri = "http://link.staging"
        }

        release {
           manifestPlaceholders.deepLinkUri = "http://link"
        }
    }

AndroidManifest.xml

 <activity
     android:name=".HomeActivity">
     <intent-filter>
       <action android:name="android.intent.action.MAIN" />
        <category android:name="android.intent.category.LAUNCHER" />
     </intent-filter>
     <intent-filter>
        <action android:name="android.intent.action.VIEW" />
         <category android:name="android.intent.category.DEFAULT" />
         <category android:name="android.intent.category.BROWSABLE" />
    
         <data
            android:host="${deepLinkUri}"
            android:scheme="https" />
    </intent-filter>   
 </activity>

navigation_main.xml

<?xml version="1.0" encoding="utf-8"?>
<navigation xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:app="http://schemas.android.com/apk/res-auto"
    xmlns:tools="http://schemas.android.com/tools"
    android:id="@+id/navigation_home"
    app:startDestination="@id/fragment_home">

    <fragment
        android:id="@+id/fragment_home"
        android:name="..."
        tools:layout="@layout/fragment_home">
        <argument
            android:name="deepLinkUri"
            android:defaultValue="@null"
            app:argType="string"
            app:nullable="true" />
        <argument
            android:name="token"
            android:defaultValue="@null"
            app:argType="string"
            app:nullable="true" />
        <deepLink app:uri="{deepLinkUri}/identification?code={token}" />
</fragment>

    <fragment
        android:id="@+id/fragment_marketing"
        android:name="..."
        tools:layout="@layout/fragment_marketing">
        <argument
            android:name="deepLinkUri"
            android:defaultValue="@null"
            app:argType="string"
            app:nullable="true" />
        <argument
            android:name="id"
            app:argType="integer"
            app:nullable="true" />
        <deepLink app:uri="{deepLinkUri}/banner?id={id}" />
</fragment>

---

22.05.2020 Update: Starting with the gradle plugin version 3.6 the deep link uri cannot contain parameters in scheme and host parts, it will result in Improper use of wildcards and/or placeholders in deeplink URI host error.

Fortunately one can use a wildcard, so to make the approach work again just change the deepLink definition in your nav graph file:

<deepLink app:uri="{deepLinkUri}/banner?id={id}" /> to <deepLink app:uri=".*/banner?id={id}" />