Preventing Multiple Instance of Application/Activity When Opening Files

Issue

I have one activity which forms the basis of my application. Here is the problem.

• I create an activity instance called Instance1.
• My activity is then sent to the background by navigating back to the home menu. onPause and onStop are called on Instance1.
• I then navigate to Gmail and open an emails attachment.
• This creates a new instance of my activity 'Instance2` (I know this because I log what the instance is). Anything I do now within my activity is within this new instance.
• If I then navigate out and to gmail, onDestroy is called on Instance2 then if I open my application by touching the icon the original Instance1 onRestart is called.

Here is my intent filter inside my manifest.xml

<intent-filter>
                <action android:name="android.intent.action.VIEW" />
                <category android:name="android.intent.category.DEFAULT" />
                <data android:mimeType="*/*" />
                <data android:pathPattern=".*\\.dog" />
</intent-filter>

I have also added the following to my Applications tag in the manifest file but it has no effect.

android:launchMode="singleTask"

Question

Why can't it realise there is an instance running and open that?

ADDITION

I used singleInstance and moved it into my Activity tag. However, now I can't get my email attachments data? Previously I used the following.

Intent intent = getIntent();

        if (intent != null) {
            Log.d("MainActivity","Intent not null");
            Uri u = intent.getData();
            if (u != null) {
                Log.d("MainActivity","URI not null");

Solution

The launchMode tag is part of the <activity> element, not the application element.

You should use singleTop to re-use the existing activity.

Answered By - David Snabel-Caunt