How to create kotlin login with sqlite?

Question

how can I create a login in koltin using sqlite.

User register

 bt_204.setOnClickListener {
            val admin = AdminSQliteOpenHelper(this, "administracion",null,1)
            val bd = admin.writableDatabase
            val registro = ContentValues()
            registro.put("nombre_usuario", et_nombre_201.text.toString())
            registro.put("clave1", et_pasword_204.text.toString())
            registro.put("clave2",et_paword_203.text.toString() )
            bd.insert("usuario", null , registro)
            bd.close()
            et_nombre_201.setText("")
            et_paword_203.setText("")
            et_pasword_204.setText("")
            Toast.makeText(this,"Usuarios registrado correctamente", Toast.LENGTH_SHORT).show()
            val intent = Intent (this,MainActivity::class.java)
            startActivity(intent)
        }

main activity

try this but the app is destroyed(I am a beginner)

   bt_ingresar_04.setOnClickListener {
            val admin = AdminSQliteOpenHelper(this, "administracion", null, 1)
            val bd = admin.writableDatabase
            val fila = bd.rawQuery(
                "select nombre_usuario,clave1 from usuario where nombre_usuario=${et_02.text} &&    ${etp_03.text}"
                null
            )
            if (fila.moveToFirst()) {
                val intent = Intent(this, MainActivity_03::class.java)
                startActivity(intent)
            } else {
                Toast.makeText(this, "Usuario no registrado", Toast.LENGTH_SHORT).show()
            }

        }

Answer 1

&& is the logical operator for Java but not for sql. You must use AND.

Also in the where clause of the query you must specify all the needed column names, but you don't. You specify only the column nombre_usuario.

Also the parameters et_02.text and etp_03.text should be properly quoted, so the final result is something like:

where column1 = 'value1' and column2 = 'value2'

But the proper way of doing this is by using ? placholders and pass the parameters in the 2nd argument of rawQuery() as an array of strings.

So change to this:

val fila = bd.rawQuery(
    "select nombre_usuario, clave1 from usuario where nombre_usuario = ? and column_password = ?",
    arrayOf(et_02.text, etp_03.text)
)

Replace column_password with the name of the column where you store the password.

Also, in bt_204.setOnClickListener, in this line:

registro.put("clave2",et_paword_203.text.toString() )

maybe there is a typo for et_paword_203.