Preventing main activity from being launched if running already

Question

I have an application that is launched via an intent-filter action. The problem is that every time the event/ action occurs, Android displays a dialog asking to launch the app even if it is already started.

I want the behavior to be as follows:

• User asked to launch the app if app is not open.
• Dialog does not display if app is running in the foreground.

Is there a way to achieve both of these goals? I am targeting Android 4.0.

edit

Here is my intent filter:

        <intent-filter>
            <action android:name="android.intent.action.MAIN" />
            <category android:name="android.intent.category.LAUNCHER" />
        </intent-filter>
        <intent-filter>
            <action android:name="android.hardware.usb.action.USB_DEVICE_ATTACHED" />
        </intent-filter>

       <intent-filter>
            <action android:name="android.hardware.usb.action.USB_DEVICE_DETACHED" />
        </intent-filter>

       <meta-data
            android:name="android.hardware.usb.action.USB_DEVICE_DETACHED"
            android:resource="@xml/device_filter" />

Answer 1

You need to set the Activity's launchMode to singleTask. You can do this by adding the activity attribute in your Android Manifest:

android:launchMode="singleTask"

See the documentation for more details.