How to send/open email attachments from android app?

I would like to somehow send a file from my app on one android device to my app on another device. This can be done any which way, and I'm open to suggestions if you can tell me how to send over network or something like that.

Currently, I'm looking at sending the fi开发者_开发技巧le as an email attachment, but I haven't found any good documentation on how to do it. I need two things to accomplish this, be able to send my file (stored on sd card or somewhere on device) as an attachment, and have my app recognized by android as the app to open an attachment with the file extention (.lst).

Any thoughts?

The files will all be fairly small xml text files if that makes a difference.

I would like to somehow send a file from my app on one android device to my app on another device. This can be done any which way, and I'm open to suggestions if you can tell me how to send over network or something like that.

Write a Web service. Or use Amazon SQS.

be able to send my file (stored on sd card or somewhere on device) as an attachment

As is written up here, you could try:

Intent sendIntent = new Intent(Intent.ACTION_SEND);

sendIntent.putExtra(Intent.EXTRA_SUBJECT, subject);
sendIntent.putExtra(Intent.EXTRA_STREAM, ...);
sendIntent.setType(...); 

where the first ellipsis is the path to your chosen file and the second ellipsis is a suitable MIME type.

and have my app recognized by android as the app to open an attachment with the file extention (.lst)

Never rely on file extensions. Use MIME types. You can set up an activity with an intent filter that offers ACTION_VIEW support for your MIME type.

I did this in order to process vcf files attached to mails and it worked. Here is the intent filer:

        <intent-filter>
            <category android:name="android.intent.category.DEFAULT" />
            <action android:name="android.intent.action.VIEW" />
            <data android:mimeType="text/x-vcard" />
        </intent-filter>

See the whole code in http://code.google.com/p/card-catcher.