Start Activity with NFC in a specific task

Question

My app contains a number of activities. One of these activities responds to an NFC intent filter, as well as standard intents, however, this activity is launching in it's own task, and not in the same task as the app. The app is not necessarily running when the NFC intent is initiated but if it is, I want the activity to launch in the same task to ensure a seamless user experience. At the moment, the app is behaving as though there are 2 of them running.

Here is the manifest for my NFC activity:

<activity
        android:name="name.subname.app.activity.ItemSummaryActivity"
        android:label="@string/title_activity_item_summary" >
        <intent-filter>
            <action android:name="android.nfc.action.NDEF_DISCOVERED" />

            <data android:mimeType="application/vnd.name.nfcdemo" />

            <category android:name="android.intent.category.DEFAULT" />

            <data android:mimeType="text/plain" />
        </intent-filter>
    </activity>

Is it possible to launch the activity in the existing task, if it exists?

Add `android:launchMode="singleTask"` to activity tag, [ref.](https://developer.android.com/guide/topics/manifest/activity-element.html#lmode). Alternatively, you may supply `Intent.FLAG_ACTIVITY_BROUGHT_TO_FRONT` flag to your `startActivity()` intent — ozbek, Dec 08 '13 at 09:45
Are you talking about Host Card Emulation ? If Yes, then you can remove `` so that it doesn't start at a separate task. You can then register your service in the manifest so that it doesn't need to be run from activity. A will be able to handle it. — Shobhit Puri, Dec 08 '13 at 09:55

score 2 · Accepted Answer · edited May 23 '17 at 11:49

I see two options here:

1) Add android:launchMode="singleTask" to activity tag in the manifest:

<activity
        android:name="name.subname.app.activity.ItemSummaryActivity"
        android:label="@string/title_activity_item_summary"
        android:launchMode="singleTask" >

"singleTask":

The system creates the activity at the root of a new task and routes the intent to it. However, if an instance of the activity already exists, the system routes the intent to existing instance through a call to its onNewIntent() method, rather than creating a new one.

2) Supply Intent.FLAG_ACTIVITY_BROUGHT_TO_FRONT flag to startActivity() intent. But, if the activity is triggered by NFC (and using this option is not feasible) consider what @NFC guy has to say here.

Start Activity with NFC in a specific task

1 Answers1

Linked