Получить текстовую строку из EditText?

Похоже, я не могу понять, как получить текстовую строку из EditText . Я хочу использовать текст из EditText при нажатии кнопки.

layout.xml:

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:id="@+id/popup_menu_root"
    android:background="#FFFFFF"
    android:orientation="vertical"
    android:layout_width="fill_parent"
    android:layout_height="fill_parent" >
    <Button android:id="@+id/popup_menu_button"
        android:text="ok"
        android:layout_width="fill_parent"
        android:layout_height="wrap_content" />
    <EditText
        android:id="@+id/edittext"
        android:layout_width="fill_parent"
        android:layout_height="wrap_content"/>
</LinearLayout>

My Activity:

public class MyClass extends Activity {

  public String txtCheckin = "???";
  private String txtDescription = "???";
  private PopupWindow pw;

  @Override
  public void onCreate(Bundle icicle) {
    super.onCreate(icicle);

    // get the instance of the LayoutInflater
    LayoutInflater inflater = (LayoutInflater) MyClass.this.getSystemService(Context.LAYOUT_INFLATER_SERVICE);
    // inflate our view from the corresponding XML file
    final View layout = inflater.inflate(R.layout.popuplayout, (ViewGroup)findViewById(R.id.popup_menu_root));
    // create a 100px width and 200px height popup window
    pw = new PopupWindow(layout, 100, 200, true);

    final EditText edittextDescription = (EditText) findViewById(R.id.edittext);

    // set actions to buttons we have in our popup
    Button button = (Button)layout.findViewById(R.id.popup_menu_button);
    button.setOnClickListener(new OnClickListener() {
        @Override
        public void onClick(View vv) {


        if (edittextDescription.getText() != null)
        {
            String newString = edittextDescription.getText().toString();
            transmitCheck("MANUAL", txtCheckin, "1", newString);
        }
        else
        {
            transmitCheck("MANUAL", txtCheckin, "1", "???");
        }


        finish();
        }
    });
}