android send mail with attachment, without write file to external memory

android-mail.java

//based on http://stephendnicholas.com/archives/974

package it.my.app;

import android.content.ContentProvider;
import java.io.File;
import java.io.FileNotFoundException;
import android.content.ContentProvider;
import android.content.ContentValues;
import android.content.UriMatcher;
import android.database.Cursor;
import android.net.Uri;
import android.os.ParcelFileDescriptor;
import android.util.Log;

public class LogFileProvider extends ContentProvider {

    private static final String CLASS_NAME = "LogFileProvider";

    // The authority is the symbolic name for the provider class
    public static final String AUTHORITY = "it.my.app.LogFileProvider";

    // UriMatcher used to match against incoming requests
    private UriMatcher uriMatcher;

    @Override
    public boolean onCreate() {
        uriMatcher = new UriMatcher(UriMatcher.NO_MATCH);

        // Add a URI to the matcher which will match against the form
        // 'content://it.my.app.LogFileProvider/*'
        // and return 1 in the case that the incoming Uri matches this pattern
        uriMatcher.addURI(AUTHORITY, "*", 1);

        return true;
    }

    @Override
    public ParcelFileDescriptor openFile(Uri uri, String mode)
            throws FileNotFoundException {

        String LOG_TAG = CLASS_NAME + " - openFile";

        Log.v(LOG_TAG,
                "Called with uri: '" + uri + "'." + uri.getLastPathSegment());

        // Check incoming Uri against the matcher
        switch (uriMatcher.match(uri)) {

            // If it returns 1 - then it matches the Uri defined in onCreate
            case 1:

                // The desired file name is specified by the last segment of the
                // path
                // E.g.
                // 'content://it.my.app.LogFileProvider/Test.txt'
                // Take this and build the path to the file
                String fileLocation = getContext().getCacheDir() + File.separator
                        + uri.getLastPathSegment();

                // Create & return a ParcelFileDescriptor pointing to the file
                // Note: I don't care what mode they ask for - they're only getting
                // read only
                ParcelFileDescriptor pfd = ParcelFileDescriptor.open(new File(
                        fileLocation), ParcelFileDescriptor.MODE_READ_ONLY);
                return pfd;

            // Otherwise unrecognised Uri
            default:
                Log.v(LOG_TAG, "Unsupported uri: '" + uri + "'.");
                throw new FileNotFoundException("Unsupported uri: "
                        + uri.toString());
        }
    }

    // //////////////////////////////////////////////////////////////
    // Not supported / used / required for this example
    // //////////////////////////////////////////////////////////////

    @Override
    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;
    }
}


// add in manifest, inside <application></application>
<provider android:name="LogFileProvider" 
    android:authorities="it.my.app.LogFileProvider"
    android:enabled="true"
    android:exported="false"
    android:grantUriPermissions="true"></provider>

// file creator
public static void createCachedFile(Context context, String fileName,
                                        String content) throws IOException {
  File cacheFile = new File(context.getCacheDir() + File.separator
          + fileName);
  cacheFile.createNewFile();

  FileOutputStream fos = new FileOutputStream(cacheFile);
  OutputStreamWriter osw = new OutputStreamWriter(fos, "UTF8");
  PrintWriter pw = new PrintWriter(osw);

  pw.println(content);

  pw.flush();
  pw.close();
}

// create intent to send email
public static Intent getSendEmailIntent(Context context, String email,
                                        String subject, String body, String fileName) {

  final Intent emailIntent = new Intent(
          android.content.Intent.ACTION_SEND);

  //Explicitly only use Gmail to send
  emailIntent.setClassName("com.google.android.gm","com.google.android.gm.ComposeActivityGmail");

  emailIntent.setType("plain/text");

  //Add the recipients
  emailIntent.putExtra(android.content.Intent.EXTRA_EMAIL,
          new String[] { email });

  emailIntent.putExtra(android.content.Intent.EXTRA_SUBJECT, subject);

  emailIntent.putExtra(android.content.Intent.EXTRA_TEXT, body);

  //Add the attachment by specifying a reference to our custom ContentProvider
  //and the specific file of interest
  emailIntent.putExtra(
          Intent.EXTRA_STREAM,
          Uri.parse("content://" + LogFileProvider.AUTHORITY + "/"
                  + fileName));

  return emailIntent;
}

// send email with attachment
Utils.createCachedFile(YourActivity.this,"Test.txt", "This is a test");
startActivity(Utils.getSendEmailIntent(YourActivity.this, "<YOUR_EMAIL_HERE>@<YOUR_DOMAIN>.com", "Test", "See attached", "Test.txt"));

It is great. but it has a small issue!
I have changed android:exported="false" to android:exported="true" and it works!
Good Job!