我们的应用程序之一正在Sunmi的T1和T2 mini上运行。应用程序使用下面的LocationUtil类发送回设备的位置数据：
public class LocationUtil
{
private static final String TAG = LocationUtil.class.getSimpleName();
private final long UPDATE_INTERVAL_IN_MILLISECONDS = 20000;
private final long FASTEST_UPDATE_INTERVAL_IN_MILLISECONDS = 10000;
private final int REQUEST_CHECK_SETTINGS = 100;
private FusedLocationProviderClient mFusedLocationClient;
private SettingsClient mSettingsClient;
private LocationRequest mLocationRequest;
private LocationSettingsRequest mLocationSettingsRequest;
private LocationCallback mLocationCallback;
private Location mCurrentLocation;
private LocationReceived locReceiveListener;
private boolean gettingUpdatesStarted;
private Context context;
public LocationUtil(){
}
public LocationUtil(Context context)
{
this.context = context;
}
public interface LocationReceived {
void onReceive(Location location);
void onError(String message);
}
private Activity actContext = null;
public void initialise(Activity context) {
this.actContext = context;
mFusedLocationClient = LocationServices.getFusedLocationProviderClient(context);
mSettingsClient = LocationServices.getSettingsClient(context);
mLocationRequest = new LocationRequest();
mLocationRequest.setInterval(UPDATE_INTERVAL_IN_MILLISECONDS);
mLocationRequest.setFastestInterval(FASTEST_UPDATE_INTERVAL_IN_MILLISECONDS);
mLocationRequest.setPriority(LocationRequest.PRIORITY_HIGH_ACCURACY);
LocationSettingsRequest.Builder builder = new LocationSettingsRequest.Builder();
builder.addLocationRequest(mLocationRequest);
mLocationSettingsRequest = builder.build();
if (mLocationCallback == null)
{
mLocationCallback = new LocationCallback()
{
@Override
public void onLocationResult(LocationResult locationResult)
{
super.onLocationResult(locationResult);
// location is received
mCurrentLocation = locationResult.getLastLocation();
locReceiveListener.onReceive(mCurrentLocation);
}
@Override
public void onLocationAvailability(LocationAvailability locationAvailability)
{
super.onLocationAvailability(locationAvailability);
}
};
}
}
public void StartLocationUpdater(LocationReceived locReceiveListenerIn){
locReceiveListener = locReceiveListenerIn;
if (!gettingUpdatesStarted)
{
gettingUpdatesStarted = true;
mSettingsClient.checkLocationSettings(mLocationSettingsRequest)
.addOnSuccessListener(new OnSuccessListener<LocationSettingsResponse>()
{
@SuppressLint("MissingPermission")
@Override
public void onSuccess(LocationSettingsResponse locationSettingsResponse)
{
Log.i(TAG, "All location settings are satisfied.");
mFusedLocationClient.requestLocationUpdates(mLocationRequest,
mLocationCallback, Looper.myLooper());
}
})
.addOnFailureListener(new OnFailureListener()
{
@Override
public void onFailure(@NonNull Exception e)
{
int statusCode = ((ApiException) e).getStatusCode();
gettingUpdatesStarted = false;
switch (statusCode)
{
case LocationSettingsStatusCodes.RESOLUTION_REQUIRED:
Log.i(TAG, "Location settings are not satisfied. Attempting to upgrade " +
"location settings ");
try {
// Show the dialog by calling startResolutionForResult(), and check the
// result in onActivityResult().
ResolvableApiException rae = (ResolvableApiException) e;
rae.startResolutionForResult((Activity) actContext, REQUEST_CHECK_SETTINGS);
} catch (IntentSender.SendIntentException sie) {
Log.i(TAG, "PendingIntent unable to execute request.");
}
break;
case LocationSettingsStatusCodes.SETTINGS_CHANGE_UNAVAILABLE:
String errorMessage = "Location settings are inadequate, and cannot be " +
"fixed here. Fix in Settings.";
Log.e(TAG, errorMessage);
}
}
});
}
}
public void getLastLocation(LocationReceived locReceiveListenerIn) {
locReceiveListener = locReceiveListenerIn;
mFusedLocationClient = LocationServices.getFusedLocationProviderClient(context);
mFusedLocationClient.getLastLocation()
.addOnSuccessListener( new OnSuccessListener<Location>() {
@Override
public void onSuccess(Location location) {
// Got last known location. In some rare situations this can be null.
if (location != null) {
mCurrentLocation = location;
locReceiveListener.onReceive(mCurrentLocation);
}
else{
locReceiveListener.onError("No location received");
}
}
});
}
public void stopLocationUpdates() {
// Removing location updates
mFusedLocationClient
.removeLocationUpdates(mLocationCallback)
.addOnCompleteListener(new OnCompleteListener<Void>() {
@Override
public void onComplete(@NonNull Task<Void> task) {
gettingUpdatesStarted = false;
}
});
}
}
但是，似乎只有先将设备连接到WIFI，然后再切换回3G和4G时，应用程序才能获取位置数据。首次连接3G或4G网络时，该设备不会发送任何位置数据。经过测试，发现以下内容：
结果是3G初始定位可以成功，但速度很慢。该代码使用了GMS的融合定位方案。当设备通过登录询问位置信息时，设备很快就会获得基站的位置信息。 GMS使用基站的位置信息来分析设备的经度和纬度。但是三分钟后，GMS进程打印了没有位置的日志，并且您的应用程序仍然没有位置信息。但是一段时间后，该应用程序能够从4G网络获取信息。根据当前可用的信息，怀疑GMS将位置返回给应用程序有问题
即使使用最新的Google Play服务，也无法提供位置信息
进一步的调查表明，第一个问题是该设备的Google Play服务版本已过时。 Google Play服务未更新的原因是由于SIM卡限制。