deep-link.md

Deep link

• is an intent filter
  • https://developer.android.com/training/app-links/verify-site-associations#the-difference
• associate a URL with the activity you want to open.
  • https://developer.android.com/codelabs/android-navigation#10

Explicit deep link

• specifies a destination ID.
• uses a PendingIntent.
  • PendingIntent is a wrapper of an Intent, which lets another application run the Intent.
• clears the back stack, and pushes the following destinations in sequence:
  • the startDestination of the navigation graph
  • parent activity destinations
    • https://developer.android.com/codelabs/android-navigation#9
  • other startDestination(s) if navigation graphs are nested
  • the specified destination (goal)
• is a notification or an app widget, for example.

Implicit deep link

• specifies a URI.
• A URI without a scheme matches both http and https.
  • e.g. www.example.com/foo matches both https://www.example.com/foo and http://www.example.com/foo.
  • .* matches 0 or more characters.
  • Placefolders like http://www.example.com/users/{id}?myarg={myarg} are available.
  • {id} can be got as arguments?.getString("id"), or as arguments?.getInt("id") if SafeArgs is used as follows.

<fragment>
  <deepLink
    android:id="@+id/deepLink"
    app:uri="example.com/users/{id}" />
    <argument
      android:name="id"
      app:argType="integer" />
</fragment>

• clears the back stack like explicit deep linking if the implicit Intent was launched with the Intent.FLAG_ACTIVITY_NEW_TASK flag.
• does NOT clear the back stack unlike explicit deep linking unless the implicit Intent was launched with the Intent.FLAG_ACTIVITY_NEW_TASK flag. <nav-graph> in <activity> in AndroidManifest.xml is required to enable implicit deep linking from outside the app.
  • At compile time, <nav-graph> generates <intent-filter> elements for all the deep links.