Intent filter to download attachment from gmail apps on Android

I have android application with intent filter (ACTION_VIEW) to open file and import it into my application. I wish to download file attachment from gmail app into my application. Some of file type (i.e. jpg, png, txt) are saved correctly, but some are not (i.e doc, xls, ppt). I believe I have the correct intent filter for my activity since it works from other app (i.e. dropbox), but not gmail app. Is there any solution for this ?

I was able to make the download and preview buttons pop up on Android in GMail by removing the scheme data filter in my intent (delete the scheme line and give it a try):

<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="file" />
<data android:mimeType="*/*" />
<data android:pathPattern=".*\\.ext" />
<data android:host="*" />
</intent-filter>

However, as per the Android documentation, "If a scheme is not specified for the intent filter, all the other URI attributes are ignored." With the scheme and URI attributes removed, the only other way to filter the intents is using Mime type, and we all know that custom file extensions do not have registered mime types.

For reference, URI are of the form:

• scheme://host:port/path
• pathPrefix
• pathPattern

So without a scheme, all of that drops. After discovering the above, I tried the obvious -- use a " * " for the scheme, and even tried " .* ". Neither of those worked. I hope someone else can build off my trials. But I believe it has to do with selecting the correct scheme. Unfortunately, the only schemes I know of are http https content and file, and none of the above are the magic bullet.

EDIT::::::::

I solved this yesterday. Please see my solution:

<intent-filter>
<action android:name="android.intent.action.VIEW" />
<category android:name="android.intent.category.DEFAULT" />
<data android:mimeType="application/*" host="*" android:pathPattern=".*.ext" android:scheme="content" />
</intent-filter>

This intent will cause gmail to display the Download / Preview buttons. In fact, this will also cause your app to open when .ext files are sent as attachments to the regular email client as well.