• Intent extras
• Async task
• SQLite database
  
• Active Android

• A Bundle of  any additional information
• Used to provide extended information

Intent intent = new Intent(MainActivity.this, ReadFromDbActivity.class);
intent.putExtra("key", "value");
startActivity(intent);
getIntent().getExtras().get("key");

• Android uses SQLite database
• Android stores your database in private disk space that's associated with you application
• Define Schema and Contract
• Add
• Read
• Delete
• Update

DbHelper mDbHelper = new DbHelper(Context);SQLiteDatabase db = mDbHelper.getWritableDatabase();

ContentValues values = new ContentValues();
              values.put(DBExampleContract.DBEntry.COLUMN_USER_NAME,           name.getText().toString());
              values.put(DBExampleContract.DBEntry.COLUMN_USER_SURNAME,           surname.getText().toString());
              values.put(DBExampleContract.DBEntry.USER_DESCRIPTION,           description.getText().toString()); 
db.insert(DBExampleContract.DBEntry.TABLE_NAME, null,values);

 SQLiteDatabase db = mDbHelper.getReadableDatabase();        //Which columns from the database will be used
        String[] projection = {
               DBExampleContract.DBEntry.COLUMN_USER_NAME,
               DBExampleContract.DBEntry.COLUMN_USER_SURNAME,
               DBExampleContract.DBEntry.USER_DESCRIPTION
        };
 Cursor cursor = db.query(
 DBExampleContract.DBEntry.TABLE_NAME, // The table to query
         projection, // The columns to return
         null, // The columns for the WHERE clause
         null, // The values for the WHERE clause         null, // don't group the rows
         null, // don't filter by row groups
         null // The sort order
        );
 cursor.moveToFirst();
 while (cursor.moveToNext()) {     cursor.getString(cursor.getColumnIndex     (DBExampleContract.DBEntry.COLUMN_USER_NAME));}

 // Where part of query
String selection = DBExampleContract.DBEntry.COLUMN_USER_NAME                   + " LIKE ?";

String[] selectionArgs =   { String.valueOf(userName.getText().toString())};db.delete(DBExampleContract.DBEntry.TABLE_NAME, selection, selectionArgs);

• We are lazy and we do not want to write so much code
• This is hard to read
• Adds a lot of boilerplate code 
• There is a solution for this and it's called Object-relational mapping (ORM) 

• Realm - Relatively new 
• GreenDao - Fast but generates it's own models
• Active Android   - Great solution for smaller apps

• Download jar file from here http://www.activeandroid.com/ or here

• Add jar file as a dependency in build gradle 

dependencies { 
     compile files('libs/activeandroid.jar')}

• Initialize ActiveAndroid in Application class

public class OfcaApplication extends Applicaton {
           @Override
    public void onCreate() {
        super.onCreate();
       
        ActiveAndroid.initialize(this);
    }
}

• Create your model, extend Model class and add anotations
• Your model can have multiple constructors but you will have to declare empty constructor in that case

• Save data downloaded from weather service to database

• Application https://github.com/sjugc/TVZMc2-Android-4
  

• http://developer.android.com/training/basics/data-storage/databases.html
  
• http://www.activeandroid.com/
  
• https://github.com/infinum/dbview