public class MainActivity extends Activity {
 private Button buttonDate;
 private Button buttonTime;
 @Override
 protected void onCreate(Bundle savedInstanceState) {
  super.onCreate(savedInstanceState);
  setContentView(R.layout.activity_main);
  buttonDate = (Button) findViewById(R.id.dataBn);
  buttonTime = (Button) findViewById(R.id.timeBn);
  iniClick();//Binding the listeners for you program
 }
 public void iniClick(){
  //set listener for your Date button
  buttonDate.setOnClickListener(new View.OnClickListener() {
   @Override
   public void onClick(View v) {
    Calendar calendar = Calendar.getInstance();
    //create a datePickerDialog and then shoe it on your screen
    new DatePickerDialog(MainActivity.this,//binding the listener for your DatePickerDialog
      new DatePickerDialog.OnDateSetListener() {
       @Override
       public void onDateSet(DatePicker view, int year, int month, int dayOfMonth) {
        Toast.makeText(MainActivity.this,"Year:" + year + " Month:" + month + " Day:" + dayOfMonth,Toast.LENGTH_SHORT).show();
       }
      }
      , calendar.get(Calendar.YEAR)
      , calendar.get(Calendar.MONTH)
      , calendar.get(Calendar.DAY_OF_MONTH)).show();
   }
  });
  //set listener for your Time button
  buttonTime.setOnClickListener(new View.OnClickListener() {
   @Override
   public void onClick(View v) {
    Calendar calendar = Calendar.getInstance();
    //create a datePickerDialog and then shoe it on your screen
    new TimePickerDialog(MainActivity.this,
      new TimePickerDialog.OnTimeSetListener() {
       @Override
       public void onTimeSet(TimePicker view, int hourOfDay, int minute) {
        Toast.makeText(MainActivity.this,"Hour:" + hourOfDay + " Minute:" + minute ,Toast.LENGTH_SHORT).show();
       }
      }
      , calendar.get(Calendar.HOUR_OF_DAY)
      , calendar.get(Calendar.MINUTE)
      , true).show();
   }
  });
 }
}

<?xml version="1.0" encoding="utf-8" ?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
 android:id="@+id/idtatabHost"
 android:layout_width="match_parent"
 android:layout_height="match_parent"
 android:orientation="horizontal"
 android:layout_weight="1">
 <Button
  android:id="@+id/dataBn"
  android:text="點我一下 挑日期"
  android:layout_width="0dp"
  android:layout_weight="1"
  android:layout_height="wrap_content" />
 <Button
  android:id="@+id/timeBn"
  android:text="點我一下 挑時間 。。。"
  android:layout_width="0dp"
  android:layout_weight="1"
  android:layout_height="wrap_content" />
</LinearLayout>