putting multiple date and time wedgets in single activity

 I have a solution that allows for an unlimited number of date fields 
without adding new dialog types. When the user clicks one of the 
buttons, I register which TextView and Calendar is currently being 
modified before launching the DatePickerDialog. The dialog's 
OnDateSetListener then updates the registered TextView and Calendar.

import java.util.Calendar;
import android.app.Activity;
import android.app.DatePickerDialog;
import android.app.Dialog;
import android.app.DatePickerDialog.OnDateSetListener;
import android.os.Bundle;
import android.view.View;
import android.widget.Button;
import android.widget.DatePicker;
import android.widget.TextView;
public class MultiDatePickerActivity extends Activity {

    private TextView startDateDisplay;
    private TextView endDateDisplay;
    private Button startPickDate;
    private Button endPickDate;
    private Calendar startDate;
    private Calendar endDate;

    static final int DATE_DIALOG_ID = 0;

    private TextView activeDateDisplay;
    private Calendar activeDate;

    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.multidatepicker);

        /*  capture our View elements for the start date function   */
        startDateDisplay = (TextView) findViewById(R.id.startDateDisplay);
        startPickDate = (Button) findViewById(R.id.startPickDate);

        /* get the current date */
        startDate = Calendar.getInstance();

        /* add a click listener to the button   */
        startPickDate.setOnClickListener(new View.OnClickListener() {
            public void onClick(View v) {
                showDateDialog(startDateDisplay, startDate);
            }
        });

        /* capture our View elements for the end date function */
        endDateDisplay = (TextView) findViewById(R.id.endDateDisplay);
        endPickDate = (Button) findViewById(R.id.endPickDate);

        /* get the current date */
        endDate = Calendar.getInstance();

        /* add a click listener to the button   */
        endPickDate.setOnClickListener(new View.OnClickListener() {
            public void onClick(View v) {
                showDateDialog(endDateDisplay, endDate);
            }
        });

        /* display the current date (this method is below)  */
        updateDisplay(startDateDisplay, startDate);
        updateDisplay(endDateDisplay, endDate);
    }

    private void updateDisplay(TextView dateDisplay, Calendar date) {
        dateDisplay.setText(
                new StringBuilder()
                    // Month is 0 based so add 1
                    .append(date.get(Calendar.MONTH) + 1).append("-")
                    .append(date.get(Calendar.DAY_OF_MONTH)).append("-")
                    .append(date.get(Calendar.YEAR)).append(" "));

    }

    public void showDateDialog(TextView dateDisplay, Calendar date) {
        activeDateDisplay = dateDisplay;
        activeDate = date;
        showDialog(DATE_DIALOG_ID);
    }

    private OnDateSetListener dateSetListener = new OnDateSetListener() {
        @Override
        public void onDateSet(DatePicker view, int year, int monthOfYear, int dayOfMonth) {
            activeDate.set(Calendar.YEAR, year);
            activeDate.set(Calendar.MONTH, monthOfYear);
            activeDate.set(Calendar.DAY_OF_MONTH, dayOfMonth);
            updateDisplay(activeDateDisplay, activeDate);
            unregisterDateDisplay();
        }
    };

    private void unregisterDateDisplay() {
        activeDateDisplay = null;
        activeDate = null;
    }

    @Override
    protected Dialog onCreateDialog(int id) {
        switch (id) {
            case DATE_DIALOG_ID:
                return new DatePickerDialog(this, dateSetListener, activeDate.get(Calendar.YEAR), activeDate.get(Calendar.MONTH), activeDate.get(Calendar.DAY_OF_MONTH));
        }
        return null;
    }

    @Override
    protected void onPrepareDialog(int id, Dialog dialog) {
        super.onPrepareDialog(id, dialog);
        switch (id) {
            case DATE_DIALOG_ID:
                ((DatePickerDialog) dialog).updateDate(activeDate.get(Calendar.YEAR), activeDate.get(Calendar.MONTH), activeDate.get(Calendar.DAY_OF_MONTH));
                break;
        }
    }
}