Sqlite get from assets folder in android?

Question

It's working fine

This is code for accessing external DB from assets folder. In android We can create sqlite database by using SQLite Database Browser. Now the question is how to access this database in source code. The answer is very simple. Store the database in assets folder that is placed in project folder.Please below see that answer.

Please created assets folder -> "your" means database name

1) DatabaseHelper.class

public class DatabaseHelper extends SQLiteOpenHelper{

    //The Android's default system path of your application database.
    String DB_PATH =null;

    private static String DB_NAME = "your";
    private SQLiteDatabase myDataBase; 
    private final Context myContext;

    /**
     * Constructor
     * Takes and keeps a reference of the passed context in order to access to the application assets and resources.
     * @param context
     */
    public DatabaseHelper(Context context) {
        super(context, DB_NAME, null, 1);
        this.myContext = context;
        DB_PATH="/data/data/"+context.getPackageName()+"/"+"databases/";
    }   

  /**
     * Creates a empty database on the system and rewrites it with your own database.
     * */
    public void createDataBase() throws IOException{

        boolean dbExist = checkDataBase();

        if(dbExist){
            //do nothing - database already exist
        } else {

            //By calling this method and empty database will be created into the default system path
             //of your application so we are gonna be able to overwrite that database with our database.
            this.getReadableDatabase();

            try {
                copyDataBase();

            } catch (IOException e) {
                throw new Error("Error copying database");
            }
        }

    }

    /**
     * Check if the database already exist to avoid re-copying the file each time you open the application.
     * @return true if it exists, false if it doesn't
     */
    private boolean checkDataBase(){

        SQLiteDatabase checkDB = null;

        try{
            String myPath = DB_PATH + DB_NAME;
            checkDB = SQLiteDatabase.openDatabase(myPath, null, SQLiteDatabase.OPEN_READONLY);

        } catch (SQLiteException e){

            //database does't exist yet.

        }

        if(checkDB != null){
            checkDB.close();
        }

        return checkDB != null ? true : false;
    }

    /**
     * Copies your database from your local assets-folder to the just created empty database in the
     * system folder, from where it can be accessed and handled.
     * This is done by transfering bytestream.
     * */
    private void copyDataBase() throws IOException{

        //Open your local db as the input stream
        InputStream myInput = myContext.getAssets().open(DB_NAME);

        // Path to the just created empty db
        String outFileName = DB_PATH + DB_NAME;

        //Open the empty db as the output stream
        OutputStream myOutput = new FileOutputStream(outFileName);

        //transfer bytes from the inputfile to the outputfile
        byte[] buffer = new byte[1024];
        int length;
        while ((length = myInput.read(buffer)) > 0){
            myOutput.write(buffer, 0, length);
        }

        //Close the streams
        myOutput.flush();
        myOutput.close();
        myInput.close();
    }

    public void openDataBase() throws SQLException{

        //Open the database
        try {
            String myPath = DB_PATH + DB_NAME;
            myDataBase = SQLiteDatabase.openDatabase(myPath, null, SQLiteDatabase.OPEN_READONLY+SQLiteDatabase.NO_LOCALIZED_COLLATORS);
        } catch (Exception e) {
            // TODO: handle exception
        }
    }     

    @Override
    public synchronized void close() {
            if(myDataBase != null)
                myDataBase.close();

            super.close();
    } 

    @Override
    public void onCreate(SQLiteDatabase db) {
    }

    @Override
    public void onUpgrade(SQLiteDatabase db, int oldVersion, int newVersion) {
    }

    //return cursor
    public Cursor query(String table,String[] columns, String selection,String[] selectionArgs,String groupBy,String having,String orderBy){
        return myDataBase.query("cities", null, null, null, null, null, null);
    }
}

2) CopyDbActivity.class

public class CopyDbActivity extends Activity {
    /** Called when the activity is first created. */
    Cursor c=null;
    @Override
    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.main);

        ((Button)findViewById(R.id.button01)).setOnClickListener(new View.OnClickListener(){
            @Override
            public void onClick(View v) {

                 DatabaseHelper myDbHelper = new DatabaseHelper(CopyDbActivity.this);
                 try {
                    myDbHelper.createDataBase();

            } catch (IOException ioe) {
                throw new Error("Unable to create database");
            }

            try {
                myDbHelper.openDataBase();

            }catch(SQLException sqle){
                throw sqle;
            }
            Toast.makeText(CopyDbActivity.this, "Success", Toast.LENGTH_SHORT).show();

            c=myDbHelper.query("cities", null, null, null, null,null, null);
            if(c.moveToFirst())
            {
                do {
                    /*Toast.makeText(CopyDbActivity.this,
                            "_id: " + c.getString(0) + "\n" +
                            "E_NAME: " + c.getString(1) + "\n" +
                            "E_AGE: " + c.getString(2) + "\n" +
                            "E_DEPT:  " + c.getString(3),
                            Toast.LENGTH_LONG).show();*/
               } while (c.moveToNext());
           }

            }
        });}
}

3) XML file

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:orientation="vertical"
    android:layout_width="fill_parent"
    android:layout_height="fill_parent"
    >

<Button android:id="@+id/button01"
     android:layout_width="wrap_content" 
     android:layout_height="wrap_content"
     android:text="Copy Database">
        </Button>

</LinearLayout>

Answer 1

Use this

 private static String DB_NAME = "your.db";

Or

 private static String DB_NAME = "your.sqlite";

Instead of

private static String DB_NAME = "your";

Answer 2

public class DatabaseOpenHelper extends OpenHelper {

    private Context context;

    private SQLiteDatabase sqliteDatabase;

    private static String DB_PATH;

    private static String DB_NAME;

    public DatabaseOpenHelper(Context context, String name, CursorFactory factory) {
        super(context, name, factory);
        this.context = context;
        this.DB_NAME = name;
        this.DB_PATH = context.getString(R.string.DB_PATH);
        try {
            createDataBase();
        } catch (Exception ioe) {
            throw new Error("Unable to create database");
        }
    }

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

    }

    /** Open Database for Use */
    public void openDatabase() {
        String databasePath = DB_PATH + DB_NAME;
        sqliteDatabase = SQLiteDatabase.openDatabase(databasePath, null,
                (SQLiteDatabase.OPEN_READWRITE));
    }

    /** Close Database after use */
    @Override
    public synchronized void close() {
        if ((sqliteDatabase != null) && sqliteDatabase.isOpen()) {
            sqliteDatabase.close();
        }
        super.close();
    }

    /** Get database instance for use */
    public SQLiteDatabase getSqliteDatabase() {
        return sqliteDatabase;
    }

    /** Create new database if not present */
    public void createDataBase() {
        SQLiteDatabase sqliteDatabase = null;

        if (databaseExists()) {
            /* Check for Upgrade */
        } else {
            /* Database does not exists create blank database */
            sqliteDatabase = this.getReadableDatabase();
            sqliteDatabase.close();

            copyDataBase();
        }
    }

    /** Check Database if it exists */
    private boolean databaseExists() {
        SQLiteDatabase sqliteDatabase = null;
        try {
            String databasePath = DB_PATH + DB_NAME;
            sqliteDatabase = SQLiteDatabase.openDatabase(databasePath, null,
                    SQLiteDatabase.OPEN_READONLY);
        } catch (SQLiteException e) {
            e.printStackTrace();
        }

        if (sqliteDatabase != null) {
            sqliteDatabase.close();
        }
        return sqliteDatabase != null ? true : false;
    }

    /**
     * Copy existing database file in system
     */
    public void copyDataBase() {

        int length;
        byte[] buffer = new byte[1024];
        String databasePath = DB_PATH + DB_NAME;

        try {
            InputStream databaseInputFile = this.context.getAssets().open(DB_NAME+".sqlite");
            OutputStream databaseOutputFile = new FileOutputStream(databasePath);

            while ((length = databaseInputFile.read(buffer)) > 0) {
                databaseOutputFile.write(buffer, 0, length);
                databaseOutputFile.flush();
            }
            databaseInputFile.close();
            databaseOutputFile.close();

        } catch (FileNotFoundException e) {
            e.printStackTrace();
        } catch (IOException e) {
            e.printStackTrace();
        }

    }
}

Answer 3

I suggest using my library https://github.com/mavstuff/sqlite_android which is able to read a sqlite database from the Assets without the need of copying .

There is an *.AAR file in Releases you can use in your projects.

Of course the database can be used in the read-only mode as there is no way to write back to Assets.