a)         调用Activity的onCreateDialog()方法创建对话框

b)        分别在OnDateSetListener的onDateSet()方法和OnTimeSetListener的onTimeSet()事件方法中更改日期和时间。

c)         调用Activity的 showDialog()方法显示对话框

public class MainActivity extends Activity {   private Button b1,b2;   private TextView tv1,tv2;   private Calendar c;   private int m_year,m_month,m_day;   private int m_hour,m_minute;    public void onCreate(Bundle savedInstanceState) {        super.onCreate(savedInstanceState);        setContentView(R.layout.main);        b1 = (Button)findViewById(R.id.Button01);        b2 = (Button)findViewById(R.id.Button02);        c = Calendar.getInstance();        m_year = c.get(Calendar.YEAR);        m_month = c.get(Calendar.MONTH);        m_day = c.get(Calendar.DAY_OF_MONTH);        m_hour = c.get(Calendar.HOUR);        m_minute = c.get(Calendar.MINUTE);        tv1 = (TextView)findViewById(R.id.TextView01);        tv1.setText(m_year+":"+(m_month+1)+":"+m_day);        tv2 = (TextView)findViewById(R.id.TextView02);        tv2.setText(m_hour+":"+m_minute);        b1.setOnClickListener(new OnClickListener() {                 public void onClick(View v) {                        showDialog(0);                 }          });        b2.setOnClickListener(new OnClickListener() {                 public void onClick(View v) {                        showDialog(1);                 }          });    }    protected Dialog onCreateDialog(int id) {       if(id==0)              return new DatePickerDialog(this,l1,m_year, m_month, m_day);       else              return new TimePickerDialog(this,l2, m_hour, m_minute, false);    }    private OnDateSetListener  l1 = new OnDateSetListener() {          public void onDateSet(DatePicker view, int year, int monthOfYear,                        int dayOfMonth) {                 m_year = year;                 m_month = monthOfYear;                 m_day = dayOfMonth;                 tv1.setText(m_year+":"+(m_month+1)+":"+m_day);          }   };   private OnTimeSetListener  l2 = new OnTimeSetListener() {          public void onTimeSet(TimePicker view, int hourOfDay, int minute) {                 m_hour = hourOfDay;                 m_minute = minute;                 tv2.setText(m_hour+":"+m_minute);          }   };}