关于DatePicker的理解（显示当前日期和时间）

关于DatePicker的布局，他就是两个控件，下面是效果图：

下面是LayOut里面的代码：

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:orientation="vertical" >
    
	<DatePicker
	    android:id="@+id/dataPicker"
	    android:layout_width="wrap_content"
	    android:layout_height="wrap_content" 
	    />
	<TimePicker
	    android:id="@+id/timePicker"
	    android:layout_width="wrap_content"
	    android:layout_height="wrap_content" 
	    />
</LinearLayout>

package com.example.datapicker;


import java.util.Calendar;

import com.example.tab.R;

import android.os.Bundle;
import android.support.v7.app.ActionBarActivity;
import android.widget.DatePicker;
import android.widget.DatePicker.OnDateChangedListener;
import android.widget.TimePicker;

public class datapicker1 extends ActionBarActivity{
	private DatePicker dataPicker;
	private TimePicker timePicker;
	private Calendar cal;
	private int year,month,day,hour,minute;
		@Override
		protected void onCreate(Bundle savedInstanceState) {
			// TODO Auto-generated method stub
			super.onCreate(savedInstanceState);
			setContentView(R.layout.datapicker);
			//获取一个日历对象
			cal = Calendar.getInstance();
			//获取年月日时分秒信息
			year = cal.get(Calendar.YEAR);
			month = cal.get(Calendar.MONTH)+1;
			day = cal.get(Calendar.DAY_OF_MONTH);
			hour = cal.get(Calendar.HOUR_OF_DAY);
			minute = cal.get(Calendar.MINUTE);
			
			//在App的标题栏设置时间
			setTitle(year+"-"+month+"-"+day+"-"+hour+":"+minute);
			
			
			dataPicker = (DatePicker) findViewById(R.id.dataPicker);
			timePicker = (TimePicker) findViewById(R.id.timePicker);
			
			//对日期进行点击事件，当在日历上进行点击是，会改变时间
			dataPicker.init(year, cal.get(Calendar.MONTH), day, new OnDateChangedListener() {
				
				@Override
				public void onDateChanged(DatePicker view, int year, int month, int day) {
					// TODO Auto-generated method stub
					setTitle(year+"-"+(month+1)+"-"+day);
				}
			});
			
			
		}

}