NullPointerException on findViewById() in android

Question

In the following code i get a NullPointerException on lines 9/10 with findViewById().
In my main class I just instantiated an object from this class, to use .getFrom()

public class UserInteraction extends Activity {
EditText etFrom;
int from;
EditText etTill;
int till;

public UserInteraction(){
    etFrom = (EditText)findViewById(R.id.et_from);
    etTill = (EditText)findViewById(R.id.et_till);
}

public int getFrom() {
    String s = etFrom.getText().toString();
    int i = Integer.parseInt(s);
    return i;
}

public int getTill() {
    String s = etTill.getText().toString();
    int i = Integer.parseInt(s);
    return i;
}

Is it that the contentView is set in my main class ..? What could be the cause ?

Answer 1

The setContentView method should be called with appropriate layout before calling findViewById. It is usually called in onCreate(Bundle savedInstance) method.