SQL Lite android app login

Question

I am working on a game at the moment and all I want is my login screen to be able to check that the username and password I have already stored in my database is correct an

Answer 1

You can try below way.

Create class called DBAdapter.java and add following code.

public class DBAdapter {
    private static final String DATABASE_NAME         = "Your database name"; 
    private static final String DATABASE_CREATE_USERS = "create table TABLE_NAME (
    UserID integer primary key autoincrement, " + "Username text, Password text);" ; 

    private static final String DATABASE_SELECT_USERS = "users";
    public static final String USER_ID       = "UserID";
    public static final String USER_NAME     = "Username";
    public static final String USER_PASSWORD = "Password ";

    private final Context context;
    private DatabaseHelper DBHelper;
    private SQLiteDatabase db;  

    DBAdapter(Contex ctx) {
        this.context = ctx;
        DBHelper     = new DatabaseHelper(context);
    }

    private static class DatabaseHelper extends SQLiteOpenHelper {
        DatabaseHelper(Context context) {
            super(context, DATABASE_NAME, null, DATABASE_VERSION);
        }

        public void onCreate(SQLiteDatabase db) {
            System.out.println("Creating table");
            db.execSQL(DATABASE_CREATE_USERS);
        }

        public void onUpgrade(SQLiteDatabase arg0, int arg1, int arg2) {

        }
    }   

    public DBAdapter open() throws SQLException {
        db = DBHelper.getWritableDatabase();
        return this;
    }

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

    public Cursor fetchUser(String username, String password) {  
        Cursor myCursor = db.query(DATABASE_SELECT_USERS,   
        new String[] { USER_ID, USER_NAME, USER_PASSWORD },   
                         USER_NAME + "='" + username + "' AND " +   
                         USER_PASSWORD + "='" + password + "'", null, null, null, null);  

        if (myCursor != null) {  
            myCursor.moveToFirst();  
        }  
        return myCursor;  
    }  

    public void InsertData(String username, String password) {
        String sql = "INSERT INTO users (Username,Password) VALUES('"+username+"','"+password+"')";
        db.execSQL(sql);
    }
}

and then create your Java file

Login.java

public class Login extends Activity 
{

    public void onCreate(Bundle savedInstanceState) 
    {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.main);

        final EditText txt_username = (EditText) findViewById(R.id.editText1);
        final EditText txt_psw      = (EditText) findViewById(R.id.editText2);

        Button btn_signin = (Button) findViewById(R.id.button1);

        // Inner class to implement Button Listener when button is clicked.
        btn_signin.setOnClickListener(new OnClickListener() {
            public void onClick(View v) {                   
                DBAdapter db = new DBAdapter(getBaseContext());
                db.open();                              
                db.InsertData("Chao", "1234");              
                Log.v("LoginDetails", txt_username.getText().toString()+"../.."
                      +txt_psw.getText().toString());

                // Accessing user using the fetchUser method we created in DBAdapter
                Cursor cur = db.fetchUser( txt_username.getText().toString(), 
                                           txt_psw.getText().toString());

                // Use this line if you want to see the number of users with these login details
                System.out.println("cur.getCount()   "+cur.getCount());

                if(cur.getCount()!=0) {
                    String usn=cur.getString(1);
                    if(usn.equals("Chao")) {   

                    }
                    else { 

                    }

                    System.out.println("Query succedded");
                    Toast.makeText(getBaseContext(), "Success! Valid User name and password", Toast.LENGTH_LONG).show();

                    db.close();
                }
                else
                    Toast.makeText(getBaseContext(), "Please enter Valid User name and password", Toast.LENGTH_LONG).show();
            } //Closes the onClick method
        }); //Closes the onClickListener
    }
}