package com.stephendnicholas.gmailattach;

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 CachedFileProvider extends ContentProvider {

  private static final String CLASS_NAME = "CachedFileProvider";

  // The authority is the symbolic name for the provider class
  public static final String AUTHORITY = "com.stephendnicholas.gmailattach.provider";

  // UriMatcher used to match against incoming requests<br /> 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://com.stephendnicholas.gmailattach.provider/*'
    // 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://com.stephendnicholas.gmailattach.provider/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; }
}

<provider android:name="CachedFileProvider" android:authorities="com.stephendnicholas.gmailattach.provider"></provider>

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();
}

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://" + CachedFileProvider.AUTHORITY + "/" + fileName));

  return emailIntent;
}

Button button = (Button) findViewById(R.id.dostuff);

button.setOnClickListener(new OnClickListener() {
  @Override
  public void onClick(View v) {
    try {
      Utils.createCachedFile(GmailAttacherActivity.this, "Test.txt", "This is a test");

      startActivity(Utils.getSendEmailIntent( GmailAttacherActivity.this, "<YOUR_EMAIL_HERE>@<YOUR_DOMAIN>.com", "Test", "See attached", "Test.txt"));
    } catch (IOException e) {
      e.printStackTrace();
    } catch (ActivityNotFoundException e) {
      Toast.makeText(GmailAttacherActivity.this, "Gmail is not available on this device.", Toast.LENGTH_SHORT).show();
    }
  }
});