How do I make a class to behave as an app?

Question

I made an image viewer that has 3 activities:

1) Main: where I search for files using regexp against filenames. The result is an ArrayList called 'files' that is sent using Extras to...

2) Thumbs: Through Extras it gets the filenames, and shows a grid with thumbnails (already stored locally). When you click a thumbnail, the position and 'files' is sent to...

3) Photo: It shows files(position) fullscreen.

Now, I want to make 'Photo' my default image viewer. I know how to call the class from another app. But is is possible to make 'Photo' the default viewer just by clicking an image, without calling the whole app?

Answer 1

In your manifest under your "Photo" image viewer activity add the following intent filter:

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

You'll need to get the URI of the image from within the intent to display it.