Question

 public class Breakfast extends Activity implements OnItemClickListener {

DBOpener dbopener;

@Override
protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);

    //for fullscreen view
    requestWindowFeature(Window.FEATURE_NO_TITLE);
    getWindow().setFlags(WindowManager.LayoutParams.FLAG_FULLSCREEN,WindowManager.LayoutParams.FLAG_FULLSCREEN);
    setContentView(R.layout.dinner);

    dbopener = new DBOpener(this);
}

// Open the DB, query all subject codes and refresh the listview when app resumes
@Override
protected void onResume() {
    super.onResume();

    // Configure the listview
    ArrayList<String> mealNames = new ArrayList<String>();
    ListView lstDine = (ListView)this.findViewById(R.id.dine);
    lstDine.setAdapter(new ArrayAdapter<String>(this,android.R.layout.simple_list_item_1, mealNames));

    // Open/create the DB
    try
    {
      dbopener.createDatabase(); // Create DB if necessary
      dbopener.openDatabase(); // Open the DB

      Cursor dinners = dbopener.getBreakfastNames();
      while (dinners.moveToNext()) {
          mealNames.add(dinners.getString(0)); // Get the Lunch Name & adds to list                                                 
      }
      dinners.close();

      // Update the listview
      ArrayAdapter<String> ad = (ArrayAdapter<String>)lstDine.getAdapter();
      ad.notifyDataSetChanged();     
      lstDine.setOnItemClickListener(this);
    }
    catch (Exception e)
    {
        Toast.makeText(this, "Could not open DB", //Display when Database Cannot be opened
        Toast.LENGTH_LONG).show();
    }
}

//Close the DB when app pauses
@Override
protected void onPause() {
    super.onPause();        
    dbopener.close();
}

// When user clicks on an item
public void onItemClick(AdapterView<?> parent, View v, int pos, long id) {

    switch(pos)
    {

        case 0 :
        Intent event1 = new Intent("com.edu.tp.iit.mns.Display");
        //event1.putExtra("name" , ???);
        //event1.putExtra("nutrition" , ???);
        //event1.putExtra("rating" , ???);
        startActivity(event1);
        break;

this is only part of the code. i want to know what should i put inside the (???). its a list view item..so for case 0 i want the name nutrition and rating to be displayed in Display class. and this is my database done using SQLite Database browser.

   public class DBOpener extends SQLiteOpenHelper {

    private static String DB_PATH = 
   "/data/data/com.edu.tp.iit.mns/databases/"; //path of our database
    private static String DB_NAME ="finals"; // Database name
    private final Context myContext;
    private SQLiteDatabase db;



@Override
public void onCreate(SQLiteDatabase db) {
    // TODO Auto-generated method stub

}

@Override
public void onUpgrade(SQLiteDatabase db, int oldVersion, int newVersion) {
    // TODO Auto-generated method stub

}

public DBOpener(Context context) {
    super(context, DB_NAME, null, 1);
    myContext = context;
}

public void createDatabase() throws IOException {
    boolean dbExists = checkDatabase();
    if (dbExists) {
        // Do nothing, DB already exists
        Log.d("DBOpener", "DB exists");
    } else {
        // By calling this method an empty database will be created
            // in the default system path of your application, which we
            // will overwrite with our own database.
        Log.d("DBOpener", "DB does not exit - copying from assets");
        this.getReadableDatabase();
        copyDatabase();
        }
}


private boolean checkDatabase() {
    SQLiteDatabase checkDB = null;
    try {
        // Try opening the database
        String path = DB_PATH + DB_NAME;
        checkDB = SQLiteDatabase.openDatabase(path, null, 
            SQLiteDatabase.OPEN_READONLY);
    } catch (SQLiteException e) {
        // If it fails, DB does not exist
    }
    if (checkDB != null)
        checkDB.close(); // Close the DB; we don’t need it now
    return checkDB != null;
}

private void copyDatabase() throws IOException {
    InputStream istream = myContext.getAssets().open(DB_NAME);
    OutputStream ostream = new FileOutputStream(DB_PATH + DB_NAME);
    // Transfer bytes from istream to ostream
    byte[] buffer = new byte[1024];
    int length;
    while ((length = istream.read(buffer)) > 0) {
        ostream.write(buffer, 0, length);
    }
    // Close streams
    istream.close();
    ostream.flush();
    ostream.close();
}

public void openDatabase() throws SQLiteException {
    db = SQLiteDatabase.openDatabase(DB_PATH + DB_NAME, null, 
        SQLiteDatabase.OPEN_READWRITE);
}

@Override
public synchronized void close() {
    if (db != null)
        db.close();
    super.close();
}

// Retrieve all subject codes
public Cursor getDinnerNames() {
    if (db == null)
        return null;
    return db.query("dinner", new String[] {"name"},
        null, null, null, null, null);
}


// Get details of specific subject
public Cursor getDinnerDetails(String name) {
    if (db == null)
        return null;
    return db.query("dinner", new String[] {"name", "nutrition", "rating"},
        "name = ?", new String[] {name}, null, null, null);
}

// Retrieve all subject codes
public Cursor getLunchNames() {
    if (db == null)
        return null;
    return db.query("lunch", new String[] {"name"},
        null, null, null, null, null);
}

// Get details of specific subject
    public Cursor getLunchDetails(String name) {
        if (db == null)
            return null;
        return db.query("dinner", new String[] {"name", "nutrition", "rating"},
            "name = ?", new String[] {name}, null, null, null);
    }

    // Retrieve all subject codes
    public Cursor getBreakfastNames() {
        if (db == null)
            return null;
        return db.query("breakfast", new String[] {"name"},
            null, null, null, null, null);
    }

    // Get details of specific subject
    public Cursor getBreakfastDetails(String name) {
        if (db == null)
            return null;
        return db.query("breakfast", new String[] {"name", "nutrition", "rating"},
            "name = ?", new String[] {name}, null, null, null);
    }
 }

Answer 1

So putExtra() method add extended data to the intent. So you use it when you want to pass data through Activities, you can put all primitive types like float, integer, short or also reference types like String. You can add Bundle object with method putExtras() also other Objects. So you add to intent datatypes you need to.

See this:

Example of add Object to Intent:

Intent intent = new Intent(DownloadingActivity.this, DownloadService.class);
                        intent.putExtra("url", "http://dl.dropbox.com/u/67617541/DOR0023.rar");
                        intent.putExtra("receiver", new DownloadReceiver(new Handler()));

You should read something about Intent here

So you created ArrayAdapter of Strings and you use getBreakfastNames() that return only name of breakfast so you can add to intent only

String name = (String) parent.getItemAtPosition(pos);
event1.putExtra("name", name);

but i recommend to you create class that extend from for example SimpleCursorAdapter and use design pattern Holder to full control over your data in ListView. It’s cleaner, faster.