package com.example.user_000.appname;

EditText username = (EditText)findViewById(R.id.username);
EditText password = (EditText)findViewById(R.id.password);

public void login(View view){
    if(username.getText().toString().equals("admin") && password.getText().toString().equals("admin")){

        //correcct password
    }else {
        //wrong password
    }