在android中用TimePicker和DatePicker或者TimePickerDialog和DatePickerDialog来动态调整时间和日期
首先是用TimePicker和DatePicker来实现动态调整时间和日期，举例如下：
import java.util.Calendar;
import android.app.Activity;
import android.os.Bundle;
import android.widget.DatePicker;
import android.widget.TextView;
import android.widget.TimePicker;
import android.widget.TimePicker.OnTimeChangedListener;
public class A02Activity extends Activity {
private int ayear,amonth,aday,ahour,aminute;
private TimePicker tp;
private DatePicker dp;
private TextView tv;
/** Called when the activity is first created. */
@Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.main);
Calendar c=Calendar.getInstance();
ayear=c.get(Calendar.YEAR);
amonth=c.get(Calendar.MONTH);
aday=c.get(Calendar.DAY_OF_MONTH);
ahour=c.get(Calendar.HOUR_OF_DAY);
aminute=c.get(Calendar.MINUTE);
tv=(TextView)findViewById(R.id.tv);
dp=(DatePicker)findViewById(R.id.dp);
dp.init(ayear, amonth, aday, new DatePicker.OnDateChangedListener() {
@Override
public void onDateChanged(DatePicker view, int year, int monthOfYear,
int dayOfMonth) {
// TODO Auto-generated method stub
ayear=year;
amonth=monthOfYear;
aday=dayOfMonth;
updateDisplay();
}
});
tp=(TimePicker)findViewById(R.id.tp);
tp.setIs24HourView(true);
tp.setOnTimeChangedListener(new OnTimeChangedListener(){
@Override
public void onTimeChanged(TimePicker view, int hourOfDay, int minute) {
// TODO Auto-generated method stub
ahour=hourOfDay;
aminute=minute;
updateDisplay();
}
});
}
public void updateDisplay(){
tv.setText(new StringBuilder().append(ayear).append("/")
.append(format(amonth+1)).append("/")
.append(format(aday)).append(" ")
.append(format(ahour)).append(":")
.append(format(aminute)));
}
public String format(int x){
String s=""+x;
if(s.length()==1){
s="0"+s;
}
return s;
}
}
其中res/layout/main.xml为：
<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:layout_width="fill_parent"
android:layout_height="fill_parent"
android:orientation="vertical" >
<TextView
android:id="@+id/tv"
android:layout_width="fill_parent"
android:layout_height="wrap_content"
android:text="@string/hello" />
<DatePicker
android:id="@+id/dp"
android:layout_width="fill_parent"
android:layout_height="wrap_content"
/>
<TimePicker
android:id="@+id/tp"
android:layout_width="fill_parent"
android:layout_height="wrap_content"
/>
</LinearLayout>
从上面的例子可以看出TimePicker的setOnTimeChangedListener()和DatePicker的setOnDateChangedListener()方法是不太一样的，TimePicker的是
直接以setOnTimeChangedListener()方法来处理时间动态改变时所要做的操作；而DatePicker是以init()方法来初始DatePicker的年、月、日和setOnDateChangedListener()处理日期动态改变时所要做的操作的。
在旧版本的Android SDK(1.0r2以前的SDK版本)中，DatePicker对象有提供setOnDateChangedListener()这个方法，但是在新版本的SDK（1.0r2），这个方法被删除了，，所以要实现OnDateChangedListener()时，必须以init()方式来重写OnDateChangedListener()；而TimePicker则直接以setOnTimeChangedListener()来实现即可。
用TimePickerDialog和DatePickerDialog来实现动态调整时间和日期例子如下所示：
import java.util.Calendar;
import android.app.Activity;
import android.app.DatePickerDialog;
import android.app.DatePickerDialog.OnDateSetListener;
import android.app.TimePickerDialog;
import android.app.TimePickerDialog.OnTimeSetListener;
import android.graphics.Color;
import android.os.Bundle;
import android.view.View;
import android.view.View.OnClickListener;
import android.widget.Button;
import android.widget.DatePicker;
import android.widget.TimePicker;
public class A03Activity extends Activity {
private Button b01,b02;
private int myear,mmonth,mday,mhour,mminute;
/** Called when the activity is first created. */
@Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.main);
b01=(Button)findViewById(R.id.b01);
b01.setText("设定时间");
b01.setBackgroundColor(Color.BLUE);
b02=(Button)findViewById(R.id.b02);
b02.setText("设定日期");
b02.setBackgroundColor(Color.GREEN);
Calendar c=Calendar.getInstance();
myear=c.get(Calendar.YEAR);
mmonth=c.get(Calendar.MONTH);
mday=c.get(Calendar.DAY_OF_MONTH);
mhour=c.get(Calendar.HOUR_OF_DAY);
mminute=c.get(Calendar.MINUTE);
b01.setOnClickListener(new OnClickListener(){
@Override
public void onClick(View v) {
// TODO Auto-generated method stub
new TimePickerDialog(A03Activity.this,new OnTimeSetListener(){
@Override
public void onTimeSet(TimePicker view, int hourOfDay,
int minute) {
// TODO Auto-generated method stub
mhour=hourOfDay;
mminute=minute;
}
},mhour,mminute,true).show();
}
});
b02.setOnClickListener(new OnClickListener(){
@Override
public void onClick(View v) {
// TODO Auto-generated method stub
new DatePickerDialog(A03Activity.this,new OnDateSetListener(){
@Override
public void onDateSet(DatePicker view, int year,
int monthOfYear, int dayOfMonth) {
// TODO Auto-generated method stub
myear=year;
mmonth=monthOfYear;
mday=dayOfMonth;
}
},myear,mmonth,mday).show();
}
});
}
}
其中res/layout/main.xml如下所示：
<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:layout_width="fill_parent"
android:layout_height="fill_parent"
android:orientation="vertical" >
<TextView
android:layout_width="fill_parent"
android:layout_height="wrap_content"
android:text="@string/hello" />
<Button
android:id="@+id/b01"
android:layout_width="fill_parent"
android:layout_height="wrap_content"
/>
<Button
android:id="@+id/b02"
android:layout_width="fill_parent"
android:layout_height="wrap_content"
/>
</LinearLayout>
DatePickerDialog和TimePickerDialog是Android提供的另外两种来实现动态修改日期时间的功能：DatePicker与TimePicker是直接显示在屏幕画面上，而DatePickerDialog与TimePickerDialog对象则是弹出Dialog的方式来显示。
这两种方式都可以实现动态修改日期时间的功能。