Android deep link does not work if the app is opened by deep link already

In the manifest file of your project, you need to add the following to your main activity.

android:launchMode="singleTask"

So, in the manifest, you would have something similar to the below:

<activity android:name="some.package.name.LaunchActivity" 
      android:launchMode="singleTask"
      android:screenOrientation="portrait"
      android:theme="@style/Theme.SomeTheme">
          <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:scheme="dlscheme" android:host="dlhost" />
          </intent-filter>
 </activity>

Basically what this does is create a new task and a new instance will be pushed to the task as the root one. However, if any activity instance exists in any tasks, the system routes the intent to that activity instance through the onNewIntent() method call. In this mode, activity instances can be pushed to the same task. And if the user clicks the BACK key from the current activity, the system will return the user to the previous activity.

On the other hand, in singleTop if an instance of activity already exists at the top of the current task and system routes intent to this activity, no new instance will be created because it will fire off an onNewIntent() method instead of creating a new object.

More information can be found here.

Hope this helps 🙂