Android : android Parse.com get specific data

here is my screenshot

in my activity.java

email = (EditText) findViewById(R.id.txtemail);
emailsave = email.getText().toString();

btnLogin.setOnClickListener(new OnClickListener() {

    public void onClick(View arg0) {


      //parse condition and so on.....


       //this is where i paste it.

       firstname.setText("");
       lastname.setText("");
   }
}

I want to retrieve specific data according to email that I put in my edittext.