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

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

However, if I open the app not by triggering a deeplink, like clicking the app icon to open the app. Then triggering deeplink afterward would always work.

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Here come the details:

So I have my activity set up like this in AndroidManifest, namely LaunchActivity.

<activity
    android:name="some.package.name.LaunchActivity"
    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>

And in LaunchActivity, I would print a log in onCreate() to indicate that it have been there.

I used

adb shell am start -W -a android.intent.action.VIEW -d "dlscheme://dlhost/param" some.package.name

to test the deep link.

With the app killed, I used the above command. It can open the app and route to the correct activity, no problem. And have the following log.

adb shell am start -W -a android.intent.action.VIEW -d "dlscheme://dlhost/param" some.package.name
Starting: Intent { act=android.intent.action.VIEW dat=dlscheme://dlhost/param pkg=some.package.name }
Status: ok
Activity: some.package.name/.activity.LaunchActivity
ThisTime: 898
TotalTime: 898
WaitTime: 919
Complete

However, if I enter the same command again, without killing the app. It would only open the app, but it will not open the correct activity, and produce the following log.

adb shell am start -W -a android.intent.action.VIEW -d "dlscheme://dlhost/param" some.package.name
Starting: Intent { act=android.intent.action.VIEW dat=dlscheme://dlhost/param pkg=some.package.name }
Warning: Activity not started, its current task has been brought to the front
Status: ok
Activity: some.package.name/.activity.LaunchActivity
ThisTime: 0
TotalTime: 0
WaitTime: 6
Complete

with this extra line

Warning: Activity not started, its current task has been brought to the front

I actually also tried this with a website, using this chrome intent:

intent://dlhost/param#Intent;scheme=dlscheme;package=some.package.name;end

and it would behave the same.

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 :)

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

android:launchMode="singleTask"

And handle the deeplink inside onNewIntent()

@Override
protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_recipe);
    onNewIntent(getIntent());
}

protected void onNewIntent(Intent intent) {
    String action = intent.getAction();
    String data = intent.getDataString();
    if (Intent.ACTION_VIEW.equals(action) && data != null) {
        String recipeId = data.substring(data.lastIndexOf("/") + 1);
        Uri contentUri = RecipeContentProvider.CONTENT_URI.buildUpon()
                .appendPath(recipeId).build();
        showRecipe(contentUri);
    }
}

Add android:launchMode="singleTop" in manifest in your LaunchActivity activity tags

I found that adding android:launchMode="singleTask" works. singleTop did not work for me.

The Mainefest file looks like this sample

<activity
                    android:name=".user.HomeActivity"
                    android:screenOrientation="portrait"
                    android:exported="true"
                    android:launchMode="singleTop"
                    android:windowSoftInputMode="stateAlwaysHidden"
                    android:theme="@style/AppTheme.NoActionBar" >
                    <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="example"/>
                        <data android:host="example.com"
                            android:pathPrefix="/deeplink"/>
                        <action android:name="android.intent.action.MAIN" />
                    </intent-filter>
                </activity>

HomeActivity

@Override
            protected void onNewIntent(Intent intent) {
                super.onNewIntent(intent);
                Uri data = intent.getData();
                if (data != null)
                    callDeep(data);
                setIntent(intent);
                Log.d("DeepLinking", "new intent value==>" + data + "==== value===>");
            }
        //or in on create 
        @Override
            protected void onCreate(Bundle savedInstanceState) {
                super.onCreate(savedInstanceState);
                setContentView(R.layout.activity_home);
          Uri data = intent.getData();
                Log.d("DeepLinking", "intent value==>" + data + "==== value===>" + bundle + "===action==>" + action);
        }
        
    

   

Add android:launchMode="singleTop" in manifest with your activity

> if your launch mode is default then this warning comes " Warning: Activity not started, its current task has been brought to the front " because every time it's creating new instance of your activity while if you use Single Top launch mode then onNewIntent() method called instead of creating a new object

From the logs its said "Warning: Activity not started, its current task has been brought to the front", so a new instance of the activity is not created. In such cases the new intent will redirected to onNewIntent(Intent intent) of the activity.

In your case I suspect you haven't overridden this method and will be extracting info from the onCreate() mehtod of the activity.

Instead create a method something like extractDataFromIntentAndProcess(Intent intent) and invoke it from oncreate method (extractDataFromIntentAndProcess(getIntent())) & also from onNewIntent method (extractDataFromIntentAndProcess(intent)) of your activity.

I was facing similar issue with NavigationUI and AppLink integration. I am following single activity architecture so if the app was already present in the task stack and I wanted to open separate fragment using AppLink it wouldn't work with launchMode="singleTask". I even tried finishOnTaskLaunch but none seems to work.

Then going through the documentation (which i should have done in the first place), I came to know that in the above case the intent is received in onNewIntent() of the activity class and to redirect the intent from current fragment to required fragment we need to call:

// get the instance of navController for activity class, then

navController.handleDeepLink(intent)

This solved my problem of opening the required fragment via AppLink/DeepLink when already other fragment is in the task.

Hope I was able to help.