Converting strings to Calendar Dates and finding the Difference Between them

Converting strings to Calendar Dates and finding the Difference Between them

I'm new to android and trying to develope a simple application which in
the user will enter two dates and by clicking a button he will recevie the
difference between them in days. here is my code,unfurtunat÷ly the output
is always 0.Thanks for your help!
package il.ac.hit.datetodate;
import java.text.ParseException;
import java.text.SimpleDateFormat;
import java.util.Calendar;
import android.os.Bundle;
import android.app.Activity;
import android.view.View;
import android.widget.Button;
import android.widget.EditText;
import android.widget.TextView;
public class MainActivity extends Activity {
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
final EditText ed1 = (EditText) findViewById(R.id.editText1);
final EditText ed2 = (EditText) findViewById(R.id.editText2);
final TextView tv = (TextView) findViewById(R.id.textView2);
final Button bt = (Button) findViewById(R.id.button1);
bt.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View v) {
Calendar cal1 = Calendar.getInstance();
Calendar cal2 = Calendar.getInstance();
SimpleDateFormat sdf1 = new SimpleDateFormat("MMM dd yyyy");
SimpleDateFormat sdf2 = new SimpleDateFormat("MMM dd yyyy");
try {
cal1.setTime(sdf1.parse(ed1.getText().toString()));
} catch (ParseException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
try {
cal2.setTime(sdf2.parse(ed2.getText().toString()));
} catch (ParseException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
long days1 = cal1.getTimeInMillis();
long days2 = cal2.getTimeInMillis();
long diff = (days2 - days1)/(1000*60*60*24);
tv.setText(String.valueOf(diff));
}
});
}
}