Question

hi i am an SEO and i am in currently practicing android development of my own. i studied about database storing in android developers site and found an example code that to be in a notepad.

I tried using it in my project. In my project i have placed 2 edit boxes with a OK button, when the OK button is clicked the data in the edit box gets stored and it is shown in a new page.

the following is the code of my project’s main class file,

{

    b = (Button)findViewById(R.id.widget30);

    et1 = (EditText)findViewById(R.id.et1);
    et2 = (EditText)findViewById(R.id.et2);

    Bundle extras = getIntent().getExtras();
    if (extras != null) {
        String title = extras.getString(NotesDbAdapter.KEY_ET1);
        String body = extras.getString(NotesDbAdapter.KEY_ET2);
        mRowId = extras.getLong(NotesDbAdapter.KEY_ROWID);

        if (title != null) {
            et1.setText(title);
        }
        if (body != null) {
            et2.setText(body);
        }
    }

    b.setOnClickListener(new View.OnClickListener() 
    {
        @Override
        public void onClick(View v) 
        {
            if(et1.getText().toString().length() == 0 && et2.getText().toString().length() == 0)
            {
                et.setVisibility(View.VISIBLE);
                alertbox();
            }
            else
            {
            main.this.finish();
            Intent myIntent = new Intent(v.getContext(), T.class);
             startActivityForResult(myIntent, 0);
            }
        }               
    });
}


public void alertbox() 
{
    et = new TextView(this);
    Builder alert =new AlertDialog.Builder(main.this);
    alert.setTitle("Alert");
    alert.setMessage("Required all fields");
    alert.setPositiveButton("Ok", new DialogInterface.OnClickListener()
    {
         public void onClick(DialogInterface dialog, int whichButton)
         {
            dialog.cancel();
         }
    });
    AlertDialog alert1 = alert.create();
    alert1.show();
}

}

the following is the code of the DataBaseAdapter

public class NotesDbAdapter {

    public static final String KEY_ET1 = "a";
    public static final String KEY_ET2 = "b";
    public static final String KEY_ROWID = "_id";

    private static final String TAG = "NotesDbAdapter";
    private DatabaseHelper mDbHelper;
    private SQLiteDatabase mDb;
    private static final String DATABASE_CREATE =
        "create table notes (_id integer primary key autoincrement, "
        + "title text not null, body text not null);";

    private static final String DATABASE_NAME = "data";
    private static final String DATABASE_TABLE = "notes";
    private static final int DATABASE_VERSION = 2;

    private final Context mCtx;

    private static class DatabaseHelper extends SQLiteOpenHelper {

        DatabaseHelper(Context context) {
            super(context, DATABASE_NAME, null, DATABASE_VERSION);
        }

        @Override
        public void onCreate(SQLiteDatabase db) {

            db.execSQL(DATABASE_CREATE);
        }

        @Override
        public void onUpgrade(SQLiteDatabase db, int oldVersion, int newVersion) {
            Log.w(TAG, "Upgrading database from version " + oldVersion + " to "
                    + newVersion + ", which will destroy all old data");
            db.execSQL("DROP TABLE IF EXISTS notes");
            onCreate(db);
        }
    }


    public NotesDbAdapter(Context ctx) {
        this.mCtx = ctx;
    }


    public NotesDbAdapter open() throws SQLException {
        mDbHelper = new DatabaseHelper(mCtx);
        mDb = mDbHelper.getWritableDatabase();
        return this;
    }

    public void close() {
        mDbHelper.close();
    }



    public long createNote(String a, String b) {
        ContentValues initialValues = new ContentValues();
        initialValues.put(KEY_ET1, a);
        initialValues.put(KEY_ET2, b);

        return mDb.insert(DATABASE_TABLE, null, initialValues);
    }


    public boolean deleteNote(long rowId) {

        return mDb.delete(DATABASE_TABLE, KEY_ROWID + "=" + rowId, null) > 0;
    }


    public Cursor fetchAllNotes() {

        return mDb.query(DATABASE_TABLE, new String[] {KEY_ROWID, KEY_ET1,
                KEY_ET2}, null, null, null, null, null);
    }


    public Cursor fetchNote(long rowId) throws SQLException {

        Cursor mCursor =

            mDb.query(true, DATABASE_TABLE, new String[] {KEY_ROWID,
                    KEY_ET1, KEY_ET2}, KEY_ROWID + "=" + rowId, null,
                    null, null, null, null);
        if (mCursor != null) {
            mCursor.moveToFirst();
        }
        return mCursor;

    }


    public boolean updateNote(long rowId, String a, String b) {
        ContentValues args = new ContentValues();
        args.put(KEY_ET1, a);
        args.put(KEY_ET2, b);

        return mDb.update(DATABASE_TABLE, args, KEY_ROWID + "=" + rowId, null) > 0;
    }
}

when i run the project the new page is opening but the data’s entered is not shown there.

what is to be the error. pls teach me

Answer 1

You are going to need to get an instance of your database adapter

NotesDbAdapter adapter = new NotesDbAdapter(this); //pass activity context as a param

then you need to use the open method of the new database object to open the database

adapter.open();

now call the store method

String str = myEditText.getText().toString();
String str1 = "random other string";
adapter.createNote(str, str1);

I notice that your createNote method takes two params. I dont know where you want to get the other data from, so I just used ‘random other string’. Sub in the data you want to store as appropriate.

Finally you will need to close the database:

adapter.close();

And you have successfully stored the information. See this for help on how to use the console to view the data that you have entered into the database. (See specifically the sqlite3 portion of the page) Alternatively you could write some code to display it on the screen after retrieving it. You are going to need to read about cursors if you want to retrieve info. See here for some information on that.