Android——使用DatePicker和TimePicker显示当前日期和时间

1.DatePicker和TimePicker两种实现动态输入日期和时间的功能

2.DatePickerDialog和TimePickerDialog两种实现动态输入日期和时间的对话框

3.两组监测日期和时间改变的监听器

（1）OnDateChangedListener()和OnTimeChangedListener()

当用户更改了DatePicker里的年、月、日时，将触发OnDateChangedListener监听器的onDateChanged()事件

当用户更改了TimePicker里的时、分时，将触发OnTimeChangedListener监听器的onTimeChanged()事件

（2）OnDateSetListener()和OnTimeSetListener

当用户更改了DatePickerDialog里的年、月、日时，将触发OnDateSetListener监听器的onDateSet()事件

当用户更改了TimePickerDialog里的时、分时，将触发OnTimeSetListener监听器的onTimeSet()事件

activity_main.xml

<?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/datePicker"
android:layout_width="wrap_content"
android:layout_height="149dp"/>

<TimePicker
android:id="@+id/timePicker"
android:layout_width="wrap_content"
android:layout_height="wrap_content"/>

</LinearLayout>

MainActivity.java
import android.app.DatePickerDialog;
import android.app.TimePickerDialog;
import android.support.v7.app.AppCompatActivity;
import android.os.Bundle;
import android.widget.DatePicker;
import android.widget.TimePicker;

import java.util.Calendar;

public class MainActivity extends AppCompatActivity {

private TimePicker timePicker;
private DatePicker datePicker;
private Calendar calendar;
private int year;
private int month;
private int day;
private int hour;
private int minute;

@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);

//获取日历的一个对象
calendar = Calendar.getInstance();
//获取年月日时分的信息
year = calendar.get(Calendar.YEAR);
month = calendar.get(Calendar.MONTH)+1;
day = calendar.get(Calendar.DAY_OF_MONTH);
hour = calendar.get(Calendar.HOUR_OF_DAY);
minute = calendar.get(Calendar.MINUTE);
setTitle(year + "-" + month + "-" + day + "-" + hour + "-" + minute);

datePicker = (DatePicker) findViewById(R.id.datePicker);
timePicker = (TimePicker) findViewById(R.id.timePicker);

//datePicker初始化
datePicker.init(year, month-1, day, new DatePicker.OnDateChangedListener() {
@Override
public void onDateChanged(DatePicker view, int year, int monthOfYear, int dayOfMonth) {
setTitle(year + "-" + (monthOfYear+1) + "-" + dayOfMonth);
}
});

//timePicker
timePicker.setOnTimeChangedListener(new TimePicker.OnTimeChangedListener() {
@Override
public void onTimeChanged(TimePicker view, int hourOfDay, int minute) {
setTitle(hourOfDay + ":" + minute);
}
});

//DatePickerDialog
new DatePickerDialog(this, new DatePickerDialog.OnDateSetListener() {
@Override
public void onDateSet(DatePicker view, int year, int monthOfYear, int dayOfMonth) {
setTitle(year + "-" + (monthOfYear+1) + "-" + dayOfMonth);
}
},year, month-1, day).show();

//TimePickerDialog
new TimePickerDialog(this, new TimePickerDialog.OnTimeSetListener() {
@Override
public void onTimeSet(TimePicker view, int hourOfDay, int minute) {
setTitle(hourOfDay + ":" + minute);
}
},hour,minute,true).show();
}
}


4.注意：DatePciker对象以init()这个方法来指定DatePicker初始的年、月、日及OnDateChangedListener()的事件；而TimePicker对象则是直接以setOnTimeChangedListener()事件来处理时间改变时程序要做的操作。