Android增加SNTP网络时间同步功能

因为android的网络时间同步只支持NITZ协议 可能是国外的运营商这些都是肯定有的 所以在中国这个网络时间同步就显得很不足 因为国内很多基站都不支持NITZ 我们如果要让这个网络时间同步功能能够和他的名字对等 就得加上补救措施 用SNTP来补充做时间校对。

1.监听网络是不是连接上了
packages/apps/Settings/AndroidManifest.xml
        <receiver android:name=".widget.SettingsAppWidgetProvider"
                android:label="@string/gadget_title" android:exported="false">
            <intent-filter>
                <action android:name="android.appwidget.action.APPWIDGET_UPDATE" />
                <action android:name="android.net.wifi.WIFI_STATE_CHANGED" />
                <action android:name="android.net.conn.BACKGROUND_DATA_SETTING_CHANGED" />
                <action android:name="android.bluetooth.adapter.action.STATE_CHANGED" />
                <action android:name="android.location.PROVIDERS_CHANGED" />
                <action android:name="com.android.sync.SYNC_CONN_STATUS_CHANGED" />
                <action android:name="android.net.conn.CONNECTIVITY_CHANGE"/>
            </intent-filter>
            <meta-data android:name="android.appwidget.provider" android:resource="@xml/appwidget_info" />
        </receiver>
    <service android:name=".SNTP" android:exported="true" android:process=":remote"></service>

添加SNTP service

<service android:name=".SNTP"
        android:exported="true" 
        android:process=":remote">
</service>

packages/apps/Settings/src/com/android/settings/widget/SettingsAppWidgetProvider.java

796     private boolean getAutoState(Context context) {
797         try {
798             return Settings.System.getInt(context.getContentResolver(),
799                 Settings.System.AUTO_TIME) > 0;
800         } catch (SettingNotFoundException snfe) {
801 //            return true;
802             // moon
803             return false;
804         }
805     }


847         }else if (action.equals(ConnectivityManager.CONNECTIVITY_ACTION)) {
848             ConnectivityManager connManager = (ConnectivityManager) context.getSystemService(Context.                        CONNECTIVITY_SERVICE);
849             if (null != connManager && null != connManager.getActiveNetworkInfo()) {
850                 State state = connManager.getActiveNetworkInfo().getState();
851                 Log.i("tag", "state===============" + state);
852                 if (State.CONNECTED == state) {
853                     if(getAutoState(context))
854                     context.startService(new Intent(context, SNTP.class));
855                     }
856                 }
857         }else {


2. 在网络时间同步的那个checkbox refrence点击事件里加上(防止开始没有点开同步 但是连上网了 那么不应该进行校时 要等这个时候才可以校时)
packages/apps/Settings/src/com/android/settings/DateTimeSettings.java
} else if (key.equals(KEY_AUTO_TIME)) {
250             boolean autoEnabled = preferences.getBoolean(key, false);
251             //xxw
252             if( autoEnabled ){
253                 Intent intent = new Intent(DateTimeSettings.this,SNTP.class);
254                 intent.setFlags(Intent.FLAG_ACTIVITY_NEW_TASK);
255                 startService(intent);
256             }else{
257                 Intent intent = new Intent(DateTimeSettings.this,SNTP.class);
258                 stopService(intent) ;
259             }
260             //xxw .

最后SNTP.java

package com.android.settings;

import java.net.DatagramPacket;
import java.net.DatagramSocket;
import java.net.InetAddress;
import java.util.Calendar;
import java.util.TimeZone;

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(&quot;203.117.180.36&quot;)) {
 *     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);
//            }
            syncSNTP();
        }
    };

    public boolean syncSNTP() {
        SntpClient client = new SntpClient();
        if (client.requestTime("203.117.180.36", 3000)) {

            long now = client.getNtpTime() + SystemClock.elapsedRealtime()
                    - client.getNtpTimeReference();
//            Calendar ca = Calendar.getInstance(TimeZone.getDefault());
//            ca.getTimeInMillis();
           
            if(now - System.currentTimeMillis()<5000) return false;
           
            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

}

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