1、SNTP.java文件是一个wifi时间更新Service(代码在后面) ,该Service如果没有成功获取网络时间则会每隔一段时间去程序获取网络时间,直到成功获取网络时间为止。
2、修改Settings\src\com\android\settings\DeviceInfoSettings.java,在onSharedPreferenceChanged函数中
public void onSharedPreferenceChanged(SharedPreferences preferences, String key) { if (key.equals(KEY_DATE_FORMAT)) { String format = preferences.getString(key, getResources().getString(R.string.default_date_format)); Settings.System.putString(getContentResolver(), Settings.System.DATE_FORMAT, format); updateTimeAndDateDisplay(); } else if (key.equals(KEY_AUTO_TIME)) { boolean autoEnabled = preferences.getBoolean(key, true); /* add at 2011.6.21 */ if( autoEnabled ){ Log.d("---------->"," startService !! " ); Intent intent = new Intent(DateTimeSettings.this,SNTP.class); intent.setFlags(Intent.FLAG_ACTIVITY_NEW_TASK); startService(intent); }else{ Log.d("---------->"," endService !! " ); Intent intent = new Intent(DateTimeSettings.this,SNTP.class); stopService(intent) ; } Settings.System.putInt(getContentResolver(), Settings.System.AUTO_TIME, autoEnabled ? 1 : 0); mTimePref.setEnabled(!autoEnabled); mDatePref.setEnabled(!autoEnabled); mTimeZone.setEnabled(!autoEnabled); } }
<service android:name=".sntp.SNTP" android:exported="true" android:process=":remote"> </service>
附上SNTP.java的代码:
package com.android.settings.sntp ; import java.net.DatagramPacket; import java.net.DatagramSocket; import java.net.InetAddress; import java.util.Calendar; import android.app.Activity; import android.content.Intent; import android.os.Bundle; import android.os.SystemClock; import android.text.format.DateFormat; import android.util.Log; import android.content.Context; import android.os.Handler; import android.app.Service; import android.os.IBinder; /** * {@hide} * * Simple SNTP client class for retrieving network time. * * Sample usage: * <pre> * SntpClient client = new SntpClient(); * if (client.requestTime("203.117.180.36")) { * long now = client.getNtpTime() + SystemClock.elapsedRealtime() - client.getNtpTimeReference(); * } * </pre> */ public class SNTP extends Service { private static final String TAG = "SNTP--->"; private static final boolean DBUG = true; private static Context mContext ; /*public static void SNTP( Context context ) { mContext = context ; }*/ @Override public IBinder onBind(Intent intent) { // TODO Auto-generated method stub return null; } @Override public void onDestroy() { mSntpHandler.removeCallbacks(mSntpTask); if(DBUG) Log.d(TAG," SNTP Service end !! " ); } @Override public void onStart(Intent intent, int startId){ super.onStart(intent, startId); if(DBUG) Log.d(TAG," start SNTP Service !! " ); startSyncSNTP(); } public void startSyncSNTP() { mSntpHandler.postDelayed(mSntpTask, 10); } private Handler mSntpHandler = new Handler(); private Runnable mSntpTask = new Runnable(){ public void run(){ mSntpHandler.removeCallbacks(mSntpTask); if( ! syncSNTP() ) { mSntpHandler.postDelayed(mSntpTask, 3000); } } }; public boolean syncSNTP( ) { SntpClient client = new SntpClient(); if(client.requestTime("203.117.180.36",3000)) { long now = client.getNtpTime() + SystemClock.elapsedRealtime() - client.getNtpTimeReference(); CharSequence ch=DateFormat.format("hh:mm:ss", now ); if(DBUG) Log.d(TAG,"ch="+ch); CharSequence date=DateFormat.format("yyyy MM dd", now); if(DBUG) Log.d(TAG,"date="+date); if( SystemClock.setCurrentTimeMillis(now) ){ if(DBUG) Log.d(TAG,"set Current Time ="+System.currentTimeMillis()); }else{ if(DBUG) Log.d(TAG," set Current Time false !" ); } }else{ if(DBUG) Log.d(TAG,"sntp request time false !!" ); return false ; } return true ; } public class SntpClient { private static final int NTP_PACKET_SIZE = 48 ; private static final int NTP_PORT = 123; private static final int NTP_MODE_CLIENT = 3; private static final int NTP_VERSION = 3; /* * Number of seconds between Jan 1, 1900 and Jan 1, 1970 * 70 years plus 17 leap days */ private static final long OFFSET_1900_TO_1970 = ((365L * 70L) + 17L) * 24L * 60L * 60L; private static final int TRANSMIT_TIME_OFFSET = 40; private static final int ORIGINATE_TIME_OFFSET = 24; private static final int RECEIVE_TIME_OFFSET = 32; // system time computed from NTP server response private long mNtpTime; // value of SystemClock.elapsedRealtime() corresponding to mNtpTime private long mNtpTimeReference; // round trip time in milliseconds private long mRoundTripTime; public boolean requestTime(String host, int timeout) { try { DatagramSocket socket = new DatagramSocket(); socket.setSoTimeout(timeout); InetAddress address = InetAddress.getByName(host); byte[] buffer = new byte[NTP_PACKET_SIZE]; DatagramPacket request = new DatagramPacket(buffer, buffer.length, address, NTP_PORT); /* * set mode = 3 (client) and version = 3 * mode is in low 3 bits of first byte * version is in bits 3-5 of first byte */ buffer[0] = NTP_MODE_CLIENT | (NTP_VERSION << 3); //get current time and write it to the request packet long requestTime = System.currentTimeMillis(); if(DBUG) Log.d(TAG, "System.currentTimeMillis(): " + requestTime + " ms"); long requestTicks = SystemClock.elapsedRealtime(); writeTimeStamp(buffer, TRANSMIT_TIME_OFFSET, requestTime); socket.send(request); // read the response DatagramPacket response = new DatagramPacket(buffer, buffer.length); socket.receive(response); long responseTicks = SystemClock.elapsedRealtime(); long responseTime = requestTime + (responseTicks - requestTicks); socket.close(); // extract the results long originateTime = readTimeStamp(buffer, ORIGINATE_TIME_OFFSET); long receiveTime = readTimeStamp(buffer, RECEIVE_TIME_OFFSET); long transmitTime = readTimeStamp(buffer, TRANSMIT_TIME_OFFSET); long roundTripTime = responseTicks - requestTicks - (transmitTime - receiveTime); long clockOffset = (receiveTime - originateTime) + (transmitTime - responseTime); if(DBUG) Log.d(TAG, "round trip: " + roundTripTime + " ms"); if(DBUG) Log.d(TAG, "clock offset: " + clockOffset + " ms"); // save our results mNtpTime = receiveTime;//requestTime + clockOffset; mNtpTimeReference = requestTicks; mRoundTripTime = roundTripTime; }catch (Exception e) { // TODO: handle exception if(DBUG) Log.d(TAG, "error: " + e); return false; } return true ; } /** * Returns the time computed from the NTP transaction. * * @return time value computed from NTP server response. */ public long getNtpTime() { return mNtpTime; } /** * Returns the reference clock value (value of SystemClock.elapsedRealtime()) * corresponding to the NTP time. * * @return reference clock corresponding to the NTP time. */ public long getNtpTimeReference() { return mNtpTimeReference; } /** * Returns the round trip time of the NTP transaction * * @return round trip time in milliseconds. */ public long getRoundTripTime() { return mRoundTripTime; } /** * Reads an unsigned 32 bit big endian number from the given offset in the buffer. */ private long read32(byte[] buffer, int offset) { byte b0 = buffer[offset]; byte b1 = buffer[offset+1]; byte b2 = buffer[offset+2]; byte b3 = buffer[offset+3]; // convert signed bytes to unsigned values int i0 = ((b0 & 0x80) == 0x80 ? (b0 & 0x7F) + 0x80 : b0); int i1 = ((b1 & 0x80) == 0x80 ? (b1 & 0x7F) + 0x80 : b1); int i2 = ((b2 & 0x80) == 0x80 ? (b2 & 0x7F) + 0x80 : b2); int i3 = ((b3 & 0x80) == 0x80 ? (b3 & 0x7F) + 0x80 : b3); return ((long)i0 << 24) + ((long)i1 << 16) + ((long)i2 << 8) + (long)i3; } /** * Reads the NTP time stamp at the given offset in the buffer and returns * it as a system time (milliseconds since January 1, 1970). */ private long readTimeStamp(byte[] buffer, int offset) { long seconds = read32(buffer, offset); long fraction = read32(buffer, offset + 4); return ((seconds - OFFSET_1900_TO_1970) * 1000) + ((fraction * 1000L) / 0x100000000L); } /** * Writes system time (milliseconds since January 1, 1970) as an NTP time stamp * at the given offset in the buffer. */ private void writeTimeStamp(byte[] buffer, int offset, long time) { long seconds = time / 1000L; long milliseconds = time - seconds * 1000L; seconds += OFFSET_1900_TO_1970; // write seconds in big endian format buffer[offset++] = (byte)(seconds >> 24); buffer[offset++] = (byte)(seconds >> 16); buffer[offset++] = (byte)(seconds >> 8); buffer[offset++] = (byte)(seconds >> 0); long fraction = milliseconds * 0x100000000L / 1000L; // write fraction in big endian format buffer[offset++] = (byte)(fraction >> 24); buffer[offset++] = (byte)(fraction >> 16); buffer[offset++] = (byte)(fraction >> 8); // low order bits should be random data buffer[offset++] = (byte)(Math.random() * 255.0); } }//class SntpClient }