Application hangs while fetching records from a pre existing database Android

Question

I have a DatabaseHelper class like this :

public class DataBaseHelper extends SQLiteOpenHelper
{

// The Android's default system path of your application database.
private static String DB_PATH = android.os.Environment.getExternalStorageDirectory() + "/FitnessData/";

private static String DB_NAME = "OFSDb.db";

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;
}

/**
 * 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
    String myPath = DB_PATH + DB_NAME;
    myDataBase = SQLiteDatabase.openDatabase(myPath, null, SQLiteDatabase.OPEN_READONLY);

}

@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)
{

}

// Add your public helper methods to access and get content from the
// database.
// You could return cursors by doing "return myDataBase.query(....)" so it'd
// be easy
// to you to create adapters for your views.

public VehicleData getInfo(String regno)
{
    VehicleData vData = new VehicleData();
    String selectQuery = "SELECT  * FROM" + DB_NAME + " WHERE FIT_REF_NO = " + regno;
    SQLiteDatabase db = this.getWritableDatabase();
    Cursor cursor = db.rawQuery(selectQuery, null);

    // looping through all rows and adding to list
    if (cursor.moveToFirst())
    {
        do
        {

            vData.regno = cursor.getString(1);
            vData.ownername = cursor.getString(2);
            vData.makername = cursor.getString(3);
            vData.makermodel = cursor.getString(4);
        }
        while (cursor.moveToNext());

    }

    return vData;

}

}

The class VehicleData is like :

public class VehicleData
{
public String regno;
public String ownername;
public String makername;
public String makermodel;
public String picsnum;
public String status;

}

The Class where I'm trying to use the methods from Database Helper goes like this :

public class Reference extends Activity
{
public static String rslt = "";
public static String picsNumber = "";
public static String ipAdress;
Button bproceed;
Button bSendRef;
TextView regno;
TextView ownername;
TextView vmake;
TextView vmodel;
DataBaseHelper controller;

@Override
protected void onCreate(Bundle savedInstanceState)
{

    super.onCreate(savedInstanceState);
    setContentView(R.layout.reference);
    // set color for fields
    regno = ((TextView) findViewById(R.id.regnum));
    regno.setTextColor(Color.parseColor("#34afdd"));
    ownername = (TextView) findViewById(R.id.ownername);
    ownername.setTextColor(Color.parseColor("#34afdd"));
    vmake = ((TextView) findViewById(R.id.vmake));
    vmake.setTextColor(Color.parseColor("#34afdd"));
    vmodel = ((TextView) findViewById(R.id.vmodel));
    vmodel.setTextColor(Color.parseColor("#34afdd"));
    HideStaticTexts();
    final TextView tvNotif = (TextView) findViewById(R.id.tvNotif);
    tvNotif.setVisibility(View.INVISIBLE);
    // disable proceed button until data recieved from web service
    bproceed = (Button) findViewById(R.id.bproceed);
    bSendRef = (Button) findViewById(R.id.bSendRef);
    bproceed.setEnabled(false);
    bproceed.setClickable(false);
    /* Get data Against Ref Number using button Submit */


    DataBaseHelper myDbHelper = new DataBaseHelper(this);


    try
    {

        myDbHelper.createDataBase();

    }
    catch (IOException ioe)
    {

        throw new Error("Unable to create database");

    }

    try
    {

        myDbHelper.openDataBase();

    }
    catch (SQLException sqle)
    {

        throw sqle;

    }

    // handling send from keyboard
    final EditText edt = (EditText) findViewById(R.id.editText1);
    edt.setOnEditorActionListener(new OnEditorActionListener()
    {
        @Override
        public boolean onEditorAction(TextView v, int actionId, KeyEvent event)
        {
            boolean handled = false;
            if (actionId == EditorInfo.IME_ACTION_SEND)
            {
                bSendRef.callOnClick();
                handled = true;
            }
            return handled;
        }
    });

    ((Button) findViewById(R.id.bSendRef)).setOnClickListener(new View.OnClickListener()
    {

        @Override
        public void onClick(View v)
        {
            // TODO Auto-generated method stub
            String searchUser = edt.getText().toString();
            VehicleData response = controller.getInfo(searchUser);

            ShowStaticTexts();

            ((TextView) findViewById(R.id.regnumval)).setText(response.regno); /*
                                                                                 * Regn
                                                                                 * No
                                                                                 */
            ((TextView) findViewById(R.id.ownerNameVal)).setText(response.ownername); /*
                                                                                     * Owner
                                                                                     * name
                                                                                     */
            ((TextView) findViewById(R.id.vehicleMakeVal)).setText(response.makername); /*
                                                                                         * Manufacturer
                                                                                         * Name
                                                                                         */
            ((TextView) findViewById(R.id.vehicleModelVal)).setText(response.makermodel); /*
                                                                                         * Maker
                                                                                         * Name
                                                                                         */
            picsNumber = response.picsnum;
            Toast.makeText(Reference.this.getApplicationContext(), picsNumber + " images will be clicked", Toast.LENGTH_LONG).show();
            tvNotif.setVisibility(View.VISIBLE);
            tvNotif.setText(picsNumber + " IMAGES WILL BE CLICKED ");
            bproceed.setEnabled(true);
            bproceed.setClickable(true);

        }

    });
    /* Start Camera Using Proceed Button */
    bproceed.setOnClickListener(new View.OnClickListener()
    {

        @Override
        public void onClick(View v)
        {
            // TODO Auto-generated method stub
            if (picsNumber.equals("4"))
            {
                Intent intent = new Intent(Reference.this, Camera.class);
                // ---use putExtra() to add new key/value pairs---
                intent.putExtra("refnum", ((EditText) findViewById(R.id.editText1)).getText().toString());
                intent.putExtra("regno", ((TextView) findViewById(R.id.regnumval)).getText().toString());
                intent.putExtra("picnum", picsNumber);
                startActivity(intent);
                finish();
            }
            else
            {
                Intent intent = new Intent(Reference.this, Camera2.class);
                // ---use putExtra() to add new key/value pairs---
                intent.putExtra("refnum", ((EditText) findViewById(R.id.editText1)).getText().toString());
                intent.putExtra("regno", ((TextView) findViewById(R.id.regnumval)).getText().toString());
                intent.putExtra("picnum", picsNumber);
                startActivity(intent);
                finish();

            }

        }
    });
    /* Clear form using Clear Button */
    ((Button) findViewById(R.id.bclear)).setOnLongClickListener(new OnLongClickListener()
    {
        @Override
        public boolean onLongClick(View v)
        {
            // TODO Auto-generated method stub
            Intent intent = new Intent(Reference.this, Settings.class);
            String reset = "RESET";
            intent.putExtra("reSet", reset);
            startActivity(intent);
            return true;
        }
    });

    /* Clear All Controls Using Clear Button */
    ((Button) findViewById(R.id.bclear)).setOnClickListener(new View.OnClickListener()
    {

        @Override
        public void onClick(View v)
        {
            ((EditText) findViewById(R.id.editText1)).setText("");
            clearAllControls();
            // force keyboard to show up when reset is called
            edt.requestFocus();
            InputMethodManager imm = (InputMethodManager) getSystemService(Context.INPUT_METHOD_SERVICE);
            imm.showSoftInput(edt, InputMethodManager.SHOW_IMPLICIT);
            tvNotif.setVisibility(View.INVISIBLE);
            HideStaticTexts();

        }

    });
}

private void HideStaticTexts()
{
    // TODO Auto-generated method stub
    regno.setVisibility(View.INVISIBLE);
    ownername.setVisibility(View.INVISIBLE);
    vmake.setVisibility(View.INVISIBLE);
    vmodel.setVisibility(View.INVISIBLE);
}

private void ShowStaticTexts()
{
    // TODO Auto-generated method stub
    regno.setVisibility(View.VISIBLE);
    ownername.setVisibility(View.VISIBLE);
    vmake.setVisibility(View.VISIBLE);
    vmodel.setVisibility(View.VISIBLE);
}

public void clearAllControls()
{
    ((TextView) findViewById(R.id.regnumval)).setText("");
    ((TextView) findViewById(R.id.ownerNameVal)).setText("");
    ((TextView) findViewById(R.id.vehicleMakeVal)).setText("");
    ((TextView) findViewById(R.id.vehicleModelVal)).setText("");

}

public static void hideSoftKeyboard(Activity activity, View view)
{
    InputMethodManager imm = (InputMethodManager)        activity.getSystemService(Context.INPUT_METHOD_SERVICE);
    imm.hideSoftInputFromWindow(view.getApplicationWindowToken(), 0);
}

}

When I input a string in the editText and press the button the application hangs. Can't even read LogCat. Please help me?

Answer 1

"SELECT * FROM" + DB_NAME + " WHERE FIT_REF_NO = " + regno; ... CRASH!!

1 - You miss a space after FROM
2 - DB_NAME should be YOUR_TABLE_NAME

Try:

"SELECT  * FROM " + YOUR_TABLE_NAME + " WHERE FIT_REF_NO = " + regno;

Also note that columns are 0 based . I hope there's another column with index 0 you are not retrieving:

if (cursor.moveToFirst())
{
    do
    {
        //vData.XYX = cursor.getString(0);
        vData.regno = cursor.getString(1);
        vData.ownername = cursor.getString(2);
        vData.makername = cursor.getString(3);
        vData.makermodel = cursor.getString(4);
    }
    while (cursor.moveToNext());

However, retrieving column values by index is not a good thing, especially if you used star (*) in place of specifying your field names (you are never guaranteed that a column is always extracted at a certain position in the column set).
You can alternatively or both:

1 - Specify all column names insetad of *, so that you are sure you get them in that order.
2 - Use cursor.getString(cursor.getColumnIndex("columnName"));

Moreover, if regno is a string , you should surround its value by single quotes , as in:

"SELECT  * FROM " + YOUR_TABLE_NAME + " WHERE FIT_REF_NO = '" + regno + "'";

But it would be much better if you bind the parameter , as in:

"SELECT  * FROM " + YOUR_TABLE_NAME + " WHERE FIT_REF_NO = ?";
//...
Cursor cursor = db.rawQuery(selectQuery, new String[]{regno});

I hope I helped.

[EDIT]

It's never a good idea to specify a database path.
Android handles databases automatically in its default path:

/data/data/your.app.name/databases/your.db