我正在编写一个基于位置的Android应用程序，其中我正在应用位置监听器来捕获GPS坐标，速度和距离。问题是我的＆＃34; onLocationChanged＆＃34;每个时间间隔都会调用两次回调函数，导致将值加2次而不是1.这是我的onLocationChanged代码：
`@Override
public void onLocationChanged(Location location) {
/* currentLatitude = location.getLatitude();
currentLongitude = location.getLongitude();
driverLoc.setDriver_latitude(currentLatitude);
driverLoc.setDriver_longitude(currentLongitude);
Toast.makeText(this, currentLatitude + " WORKS " + currentLongitude + "" + (location.getSpeed() * 3.6f), Toast.LENGTH_LONG).show();
*/
latitude = location.getLatitude();
longitude = location.getLongitude();
driverLoc.setDriver_latitude(latitude);
driverLoc.setDriver_longitude(longitude);
long elapsedMillis = SystemClock.elapsedRealtime();
//Toast.makeText(JourneyStartActivity.this, "Elapsed milliseconds: " + (elapsedMillis/1000),
// Toast.LENGTH_SHORT).show();
long Milis = previousMiliSecs;
previousMiliSecs = elapsedMillis;
int hours = (int) (elapsedMillis / 3600000);
int minutes = (int) (elapsedMillis - hours * 3600000) / 60000;
long secs = TimeUnit.MILLISECONDS.toSeconds((previousMiliSecs - Milis));
long currentMilis = previousMiliSecs - Milis;
if( location.getAccuracy() <=10 && (previousMiliSecs - Milis) >= 10000) {
Location temp = mCurrentLocation;
mCurrentLocation = location;
float[] fArr;
fArr = new float[3];
double distance = mCurrentLocation.distanceTo(temp);
//location.distanceBetween(temp.getLatitude(), temp.getLongitude(), mCurrentLocation.getLatitude(), mCurrentLocation.getLongitude(), fArr);
//double distance = getDistanceFromLatLonInKm(temp.getLatitude(), temp.getLongitude(), mCurrentLocation.getLatitude(), mCurrentLocation.getLongitude());
//double distance = fArr[0];
float journeySpeed = (location.getSpeed() * 3.6f);
//float journeySpeed = (float) ((distance / 10.0f) * 3.6f);
//journeySpeed *= 3.6f;
if (GPSTracker.inJourney) {
journey.setTotalDistanceCovered(distance);
journey.setJourneySpeedIntervals(journeySpeed);
}
/*
TextView txt = (TextView) ((Activity) mContext).findViewById(R.id.textView38);
txt.setText(String.valueOf(journey.getTotalDistanceCovered()));
*/
//Log.e("Home GPS Update","Lat: " + latitude + " Long: " + longitude + " Speed: " + journeySpeed + " Distance: " + journey.getTotalDistanceCovered());
Log.e("Home GPS Update", "Lat: " + latitude + " Long: " + longitude + " Speed: " + journeySpeed + " Distance: " + journey.getTotalDistanceCovered() + " Accuracy: " + location.getAccuracy() + " Seconds: " + secs);
}
}`
Please help me out here as i am stuck on it since last 3 days...
以下是我的代码，即设置Google API客户端：
@Override
public void onConnected(Bundle bundle) {
if (ActivityCompat.checkSelfPermission(this, android.Manifest.permission.ACCESS_FINE_LOCATION) != PackageManager.PERMISSION_GRANTED && ActivityCompat.checkSelfPermission(this, android.Manifest.permission.ACCESS_COARSE_LOCATION) != PackageManager.PERMISSION_GRANTED) {
// TODO: Consider calling
// ActivityCompat#requestPermissions
// here to request the missing permissions, and then overriding
// public void onRequestPermissionsResult(int requestCode, String[] permissions,
// int[] grantResults)
// to handle the case where the user grants the permission. See the documentation
// for ActivityCompat#requestPermissions for more details.
return;
}
mLocationRequest = LocationRequest.create();
mLocationRequest.setPriority(LocationRequest.PRIORITY_HIGH_ACCURACY);
mLocationRequest.setSmallestDisplacement(0);
mLocationRequest.setInterval(1 * 10000); // 10 seconds, in milliseconds
mLocationRequest.setFastestInterval(1 * 10000); // 10 second, in milliseconds
LocationServices.FusedLocationApi.requestLocationUpdates(mGoogleApiClient, mLocationRequest, this);
Location location = LocationServices.FusedLocationApi.getLastLocation(mGoogleApiClient);
if (location == null) {
LocationServices.FusedLocationApi.requestLocationUpdates(mGoogleApiClient, mLocationRequest, this);
} else {
//If everything went fine lets get latitude and longitude
currentLatitude = location.getLatitude();
currentLongitude = location.getLongitude();
driverLoc.setDriverLocation(location);
driverLoc.setDriver_latitude(currentLatitude);
driverLoc.setDriver_longitude(currentLongitude);
//Toast.makeText(this, "Latitude: "+driverLoc.getDriver_latitude() + " Longitude: "+driverLoc.getDriver_longitude(), Toast.LENGTH_LONG).show();
}
}
10-31 15:38:07.854 21996-21996/amidtech.android.optimusdrive E/Home GPS Update: Lat: 24.833515 Long: 67.0378417 Speed: 0.0 Distance: 0.0 Accuracy: 4.8 Seconds: 14
10-31 15:38:07.855 21996-21996/amidtech.android.optimusdrive E/Home GPS Update: Lat: 24.833515 Long: 67.0378417 Speed: 0.0 Distance: 0.0 Accuracy: 4.8 Seconds: 14
10-31 15:38:17.856 21996-21996/amidtech.android.optimusdrive E/Home GPS Update: Lat: 24.833515 Long: 67.0378417 Speed: 0.0 Distance: 0.0 Accuracy: 4.8 Seconds: 10
10-31 15:38:17.858 21996-21996/amidtech.android.optimusdrive E/Home GPS Update: Lat: 24.833515 Long: 67.0378417 Speed: 0.0 Distance: 0.0 Accuracy: 4.8 Seconds: 10
10-31 15:38:32.853 21996-21996/amidtech.android.optimusdrive E/Home GPS Update: Lat: 24.833515 Long: 67.0378417 Speed: 0.0 Distance: 0.0 Accuracy: 4.9 Seconds: 14
10-31 15:38:32.854 21996-21996/amidtech.android.optimusdrive E/Home GPS Update: Lat: 24.833515 Long: 67.0378417 Speed: 0.0 Distance: 0.0 Accuracy: 4.9 Seconds: 14
答案 0 :(得分：1)
检查您是否注册了两次相同的回调，这可能就是问题所在。 您添加了两次相同的侦听器：
LocationServices.FusedLocationApi.requestLocationUpdates(mGoogleApiClient, mLocationRequest, this);
Location location = LocationServices.FusedLocationApi.getLastLocation(mGoogleApiClient);
if (location == null) {
LocationServices.FusedLocationApi.requestLocationUpdates(mGoogleApiClient, mLocationRequest, this);
} else { ...
位置管理器没有缓存值，第一次返回null。此时，您再次注册相同的侦听器。你应该忽略第一个空值