A very general question. Then here is the general answer: addTextChangedListener your listener on your EditText via addTextChangedListener . In the afterTextChanged method afterTextChanged listener implements the search you need by the current EditText value. Search logic at your discretion. This can be either a direct database request or a complex caching system.
Further simple example, but in this form can not be used. It is necessary to screen characters so that the malicious hacker will not destroy your database.
//Connection con = получение конекшена к базе данных. Statement stmt = con.createStatement(); ResultSet rs = stmt.executeQuery("SELECT * FROM YOUR_TABLE WHERE your_field = '" + yourEditText.getText() + "'"); if (rs.next()) { // действия с результатом запроса. } rs.close();