Android sending email with attachments doesn't always work

Question

I am sending an email with attachments using a ContentProvider.

1. Firstly, I write the files into the cache dir.
2. Then I create the email with a url for each file to be found in by the content provider
3. Then I start a new activity with the ACTION_SEND_MULTIPLE intent.
4. I choose gmail and then hit the send button.

This sometimes works, it seems to work the first time in a while, but not working after subsequent tries... but it is not always like that.

When it doesn't work the email is stuck in sending in gmail. This happens on 2.3.3 and 4.0.1, opening the mail in the gmail client and hitting send button so often causes the message to be delivered almost instantly, but not every time.

Opening the Intent with Google Drive has the same behaviour as gmail.

Opening the Intent with the built in exchange mail client always works so far.

Here is the code for sending the email:

            Intent sendIntent = new Intent(Intent.ACTION_SEND_MULTIPLE);
            sendIntent.putExtra(Intent.EXTRA_EMAIL, exportParams.emailAddresses);
            sendIntent.putExtra(Intent.EXTRA_SUBJECT, "Leader Activity Report");
            sendIntent.putExtra(Intent.EXTRA_TEXT, "Leader Activity Report, see attached file.");
            Uri fileUri = CachedFileProvider.createFileUri(result.fileName);
            if (L.dbg())
                L.dbg("Using uri:" + fileUri.toString());
            ArrayList<Uri> uris = new ArrayList<Uri>();
            uris.add(fileUri);
            Uri fileUri2 = CachedFileProvider.createFileUri(result.fileNameDayByDay);
            uris.add(fileUri2);
            if (L.dbg())
                L.dbg("Using uri2:" + fileUri2.toString());
            sendIntent.putParcelableArrayListExtra(Intent.EXTRA_STREAM, uris);
            sendIntent.setType("text/plain");
            parent.startActivity(sendIntent);

Here is the Content Provider

public class CachedFileProvider extends ContentProvider {

private static final String CLASS_NAME = "CachedFileProvider";
public static final String AUTHORITY = "com.josh.lll.file.provider";

private UriMatcher uriMatcher;

@Override
public boolean onCreate() {
    uriMatcher = new UriMatcher(UriMatcher.NO_MATCH);
    uriMatcher.addURI(AUTHORITY, "*", 1);
    return true;
}


@Override
public ParcelFileDescriptor openFile(Uri uri, String mode)
        throws FileNotFoundException {
    try {
        String LOG_TAG = CLASS_NAME + " - openFile";
        Log.v(LOG_TAG,
                "Called with uri: '" + uri + "' - " + uri.getLastPathSegment());
        switch (uriMatcher.match(uri)) {
        case 1:
            String fileLocation = getContext().getCacheDir() + File.separator
                    + uri.getLastPathSegment();
            Log.i(CLASS_NAME,"Returning file :"+fileLocation);
            ParcelFileDescriptor pfd = ParcelFileDescriptor.open(new File(
                    fileLocation), ParcelFileDescriptor.MODE_READ_ONLY);
            return pfd;
        default:
            Log.v(LOG_TAG, "Unsupported uri: '" + uri + "'.");
            throw new FileNotFoundException("Unsupported uri: "
                    + uri.toString());
        }
    } catch (FileNotFoundException t) {
        Bug.major(this, t, "Could not return file descriptor");
        throw t;
    } catch (RuntimeException t) {
        Bug.major(this, t, "Could not return file descriptor");
        throw t;
    } catch (Error t) {
        Bug.major(this, t, "Could not return file descriptor");
        throw t;
    }
}

public static String createFullyQualifiedFileName(Context c, String fileNamePart) {
    File cacheDir = c.getCacheDir();
    Log.i(CLASS_NAME,"Using cache dir:"+cacheDir);
    return cacheDir + File.separator + fileNamePart;
}

public static Uri createFileUri(String fileNamePart) {
    return Uri.parse("content://" + AUTHORITY + "/"+ fileNamePart);
}

public int update(Uri uri, ContentValues contentvalues, String s,
        String[] as) {
    return 0;
}

@Override
public int delete(Uri uri, String s, String[] as) {
    return 0;
}

@Override
public Uri insert(Uri uri, ContentValues contentvalues) {
    return null;
}

@Override
public String getType(Uri uri) {
    return null;
}

@Override
public Cursor query(Uri uri, String[] projection, String s, String[] as1,
        String s1) {
    return null;
}

}

For both successful and 'stalled' email sends the following log message is printed by gmail:

04-03 22:17:35.027: I/Gmail(13206): >>>>> Attachment uri: content://com.josh.lll.file.provider/report_20100401_20130402_LeadetJosh_3_1364980653516.csv
04-03 22:17:35.035: I/Gmail(13206): >>>>>           type: text/plain
04-03 22:17:35.035: I/Gmail(13206): >>>>>           size: 0
04-03 22:17:35.054: I/Gmail(13206): >>>>> Attachment uri:  content://com.josh.lll.file.provider/backup_20100401_20130402_LeadetJosh_3_1364980653516_day_by_day.lll
04-03 22:17:35.054: I/Gmail(13206): >>>>>           type: text/plain
04-03 22:17:35.054: I/Gmail(13206): >>>>>           size: 0

Answer 1

it happens for files stored in system folders like /data/app or /system.

Workaround for this is: Copy those files into sdcard location and attach/use them from there.