问题
I have the Galaxy tab GT-P1000 7 inch with firmware version 2.3.3 and Phones running Android 2.2. In both versions when ever I am trying to get the time from GPS, its showing 1 day advance from 1st jan 2012. Same code is working fine on Samsung, LG and Motorola Phones.
The Sample code for the App is,
package com.vxceed.dateTime;
import java.util.Calendar;
import android.app.Activity;
import android.content.Context;
import android.location.Location;
import android.location.LocationListener;
import android.location.LocationManager;
import android.os.Bundle;
import android.view.View;
import android.widget.TextView;
import android.widget.Toast;
public class SampleDateTimeActivity extends Activity {
private LocationManager locationManager;
private TextView tv;
String varTime="";
/**
* Location Listener
*/
LocationListener locationListener = new LocationListener() {
@Override
public void onStatusChanged(String provider, int status, Bundle extras) {
}
@Override
public void onProviderEnabled(String provider) {
locationManager.requestLocationUpdates(LocationManager.GPS_PROVIDER, 0, 0, locationListener);
}
@Override
public void onProviderDisabled(String provider) {
Toast.makeText(SampleDateTimeActivity.this,"GPS off", Toast.LENGTH_SHORT).show();
}
@Override
public void onLocationChanged(Location location) {
setCurrentLocation(location);
}
};
private void setCurrentLocation(Location location) {
varTime=String.valueOf(location.getTime());
}
/** Called when the activity is first created. */
@Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.main);
locationManager=(LocationManager) this.getSystemService(Context.LOCATION_SERVICE);
locationManager.requestLocationUpdates(LocationManager.GPS_PROVIDER, 0,0, locationListener);
tv=(TextView)findViewById(R.id.textView1);
}
public void refreshTime(View v)
{
String currentGPSTime="";
currentGPSTime=varTime;
if(currentGPSTime.compareTo("")==0)
{
tv.setText("Time Not Available");
}
else
{
Calendar cal=Calendar.getInstance();
cal.setTimeInMillis(new Long(currentGPSTime));
long currentDeviceTime=Calendar.getInstance().getTimeInMillis();
Calendar cal2=Calendar.getInstance();
cal2.set(cal.get(Calendar.YEAR), cal.get(Calendar.MONTH), cal.get(Calendar.DATE)-1,cal.get(Calendar.HOUR_OF_DAY),cal.get(Calendar.MINUTE));
long currentGPSTime_less_one_Day=cal2.getTimeInMillis();
tv.setText( "GPSTIME:"+cal.getTime().toString() +" \n GPS_TIME_in_Millis:"+varTime+"\nDevice_Time_in_millis:"+String.valueOf(currentDeviceTime) +"\nGPS Time -1 day:"+String.valueOf(currentGPSTime_less_one_Day));
}
}
@Override
protected void onDestroy() {
// TODO Auto-generated method stub
super.onDestroy();
if (locationManager != null && locationListener != null){
locationManager.removeUpdates(locationListener);
locationManager = null;
}
}
}
I have searched the Google and then referring the NMEA official document I figure out How to Use the NMEA data. Here is the Working Code for the NMEA listener:
NmeaListener nmeaListener = new NmeaListener() {
@Override
public void onNmeaReceived(long timestamp, String nmea) {
parse(nmea);
}
};
private boolean parse(String strNMEA) {
// Discard the sentence if its checksum does not match our calculated
// checksum
boolean bStatus = false;
try {
if (!IsValid(strNMEA)) {
return false;
}
String[] sArrNMEA = strNMEA.split(",");
String strNMEAType = sArrNMEA[0];
if (strNMEAType.equals("$GPRMC")) {
bStatus = ParseGPRMC(sArrNMEA);
} else {
bStatus = false;
}
sArrNMEA = null;
} catch (Exception e) {
}
return bStatus;
}
private boolean ParseGPRMC(String[] sArrNMEA) {
boolean result = false;
try {
if (sArrNMEA.length > 9) {
int Hr = 0;
int Mins = 0;
int Secs = 0;
if (!sArrNMEA[1].equals("")) {
Hr = Integer.parseInt(sArrNMEA[1].substring(0, 2));
Mins = Integer.parseInt(sArrNMEA[1].substring(2, 4));
if (sArrNMEA[1].length() > 6) {
Secs = Integer.parseInt(sArrNMEA[1].substring(4, 6));
} else {
Secs = Integer.parseInt(sArrNMEA[1].substring(4));
}
}
if (!sArrNMEA[9].equals("")) {
int Day = Integer.parseInt(sArrNMEA[9].substring(0, 2));
int Month = Integer.parseInt(sArrNMEA[9].substring(2, 4));
if (Month > 0) {
Month = Month - 1;
}
int Year = Integer.parseInt(sArrNMEA[9].substring(4));
Year = 2000 + Year;
if (!sArrNMEA[1].equals("")) {
Calendar cal = Calendar.getInstance(TimeZone
.getTimeZone("UTC"));
cal.set(Year, Month, Day, Hr, Mins, Secs);
nmeaTime = String.valueOf(cal.getTimeInMillis());
}
}
result = true;
}
} catch (Exception e) {
}
return result;
}
private boolean IsValid(String strNMEA) {
// Compare the characters after the asterisk to the calculation
strNMEA = strNMEA.replace("\r", "");
strNMEA = strNMEA.replace("\n", "");
return strNMEA.substring(0, strNMEA.length())
.substring(strNMEA.indexOf("*") + 1)
.equalsIgnoreCase(GetChecksum(strNMEA));
}
private String GetChecksum(String strNMEA) {
// Loop through all chars to get a checksum
int Checksum = 0;
try {
char ch = '\0';
for (int i = 0; i < strNMEA.length(); i++) {
ch = strNMEA.charAt(i);
if (ch == '$') {
// Ignore the dollar sign
} else if (ch == '*') {
// Stop processing before the asterisk
break;
} else {
// Is this the first value for the checksum?
if (Checksum == 0) {
// Yes. Set the checksum to the value
Checksum = (byte) ch;
} else {
// No. XOR the checksum with this character's value
Checksum = Checksum ^ (byte) ch;
}
}
}
} catch (Exception e) {
}
// Return the checksum formatted as a two-character hexadecimal
return Integer.toHexString(Checksum);
}
回答1:
This seems to be affecting all stock Samsung firmwares, i am logging a concern with Samsung about this. It seems to be isolated to Samsung devices. So if you can test on another device, or install custom firmware. both of those have worked for me. and your code looks good, nothing wrong there, this is a firmware issue
EDIT: I have contacted the Korean Engineers - they have said they weren't aware of the problem but have patched and it should be fixed in the latest update for the SGS and other affected products. (unless of course that device hasn't had an update for a while - so not sure about the SGT) They have said the problem lies with the devices using Broadcomm chips...so yeah
Use the above code. it seems to work for me will have to check it on a few other devices but yeah
回答2:
I suspect that Samsung were hoping that it was a leap year issue which would just go away after March 1st, 2012.
Sorry to disappoint - but it hasn't! We have been seeing this problem with the app PhoneTrack installed on Samsung phones since January 1st and it is still there today.
Hopefully, Samsung will now act responsibly and issue updates for all devices affected by this GPS driver bug.
回答3:
I hit this bug on my Nexus S running Android 4.0.3 (annoyingly causing a whole bunch of data to be incorrectly timestamped).
I was upgraded to 4.0.4 yesterday and this seems to have fixed the issue. Not sure if there is a plan to issue fixes to previous Android versions.
A real howler of a bug though...
回答4:
It worked for me and I replaced IsValid(String strNMEA) method with this function:
private boolean checksum(String strNMEA)
{
int checksum = 0;
strNMEA = strNMEA.replace("\r", "");
strNMEA = strNMEA.replace("\n", "");
String strChecksum = strNMEA.substring(strNMEA.indexOf("*") + 1);
String str = strNMEA.substring(1, strNMEA.indexOf("*"));
for (int i = 0; i < str.length(); i++) {
checksum = checksum ^ str.charAt(i);
}
return checksum == Integer.valueOf(strChecksum, 16);
}
来源：https://stackoverflow.com/questions/8708695/android-samsung-galaxy-tabs-and-android-2-2-devices-showing-gps-date-1-day-adv