GPS连接延迟Android

Question

，所以我基本上是一个应用程序项目，该项目必须扫描数据，并在我坐在东海岸的西海岸的位置。

这里的主要问题是，当我启动应用程序时，它要求允许打开"位置/GPS"。如果完成此操作，我启动扫描太快了，它将获得我的位置0.0 lat和0.0长的时间，这将使我在我和另一个位置之间的距离很疯狂，并且无休止地陷入困境（可能是循环的东西（可能是新秀的东西）我不知道如何退出，请参阅while loop futher down）。

• 我相信我几乎到处都在搜索，但我似乎找不到解决方案，我最好的答案是为其制作睡眠线程计时器，并在20秒后尝试获得正确的位置？
• 我能想到的另一件事是使用onstatuschange，尽管我不完全确定。

那里有什么想法？

while(mLat.equals("0.0") && mLon.equals("0.0")) {
            mLat = String.valueOf(gpsHelper.getLatitude());
            mLon = String.valueOf(gpsHelper.getLongitude());
            Location.distanceBetween(Double.valueOf(mLat), 
            Double.valueOf(mLon), Double.valueOf(lat), Double.valueOf(lon), dist);
            System.out.println("lat: " + lat + "nlong: " + lon + "nmLat: " + mLat + "nmLong: " + mLon + "n" + "nDist: " + Arrays.toString(dist));
        } 

所以这是gpshelper：

public final class GPSHelper implements LocationListener {
//**************************************************************************/
// VARIABLES
//**************************************************************************/
//region Variables
private String TAG = "GPSHelper";
// Context using GPS
private final Context mContext;
// Flag for GPS status
private boolean canGetLocation = false;
// Properties
private Location location;
private double latitude;
private double longitude;
private double speed;
// The minimum Distance to change Updates in meters
private static final long MIN_DISTANCE_CHANGE_FOR_UPDATES = 1; // 1 meter
// The minimum time between updates in milliseconds
private static final long MIN_TIME_BW_UPDATES = 1; // 1 millisecond
// Declaring a Location Manager
private LocationManager locationManager;
//endregion
//**************************************************************************/
// PROPERTIES
/***************************************************************************/
//region Properties
public Location getLocation() {
    return location;
}
private void setLocation(Location location) {
    this.location = location;
}
//endregion
//**************************************************************************/
// CONSTRUCTOR
/***************************************************************************/
//region Constructor
public GPSHelper(Context context) {
    this.mContext = context;
    connectToGPS();
}
//endregion
//**************************************************************************/
// FUNCTIONS
//**************************************************************************/
//region Functions
//***************************************************/
// Connect til GPS
//***************************************************/
public void connectToGPS() {
    try {
        locationManager = (LocationManager) mContext.getSystemService(Context.LOCATION_SERVICE);
        // Flag for GPS turned on
        boolean isGPSEnabled = locationManager.isProviderEnabled(LocationManager.GPS_PROVIDER);
        Log.i(TAG, "Enabled: " + isGPSEnabled);
        // Is GPS turned on
        if (isGPSEnabled) {
            this.canGetLocation = true;
            locationManager.requestLocationUpdates(
                    LocationManager.GPS_PROVIDER,
                    MIN_TIME_BW_UPDATES,
                    MIN_DISTANCE_CHANGE_FOR_UPDATES, this);
            updateLocation();
        } else {
            this.canGetLocation = false;
            this.setLocation(null);
        }
    } catch (SecurityException e) {
        e.printStackTrace();
    }

}
//***************************************************/
// Update location
//***************************************************/
private void updateLocation() throws SecurityException {
    // Get location
    if (locationManager != null) {
        if (getLocation() != null) {
            latitude = getLocation().getLatitude();
            longitude = getLocation().getLongitude();
            speed = getLocation().getSpeed();
        }
    }
}
//***************************************************/
// Stop use of GPS
//***************************************************/
public void disconnectFromGPS() {
    if (locationManager != null) {
        locationManager.removeUpdates(GPSHelper.this);
    }
}
//***************************************************/
// Get latitude/Breddegrad
//***************************************************/
public double getLatitude() {
    updateLocation();
    if (getLocation() != null) {
        return latitude;
    } else {
        return 0;
    }
}
//***************************************************/
// Get longitude/Længdegrad
//***************************************************/
public double getLongitude() {
    updateLocation();
    if (getLocation() != null) {
        return longitude;
    } else {
        return 0;
    }
}
//***************************************************/
// Get speed
//***************************************************/
public double getSpeed() {
    updateLocation();
    if (getLocation() != null) {
        double tempSpeed = speed / 3.6;
        //DecimalFormat  df = new DecimalFormat("#");
        //tempSpeed = Double.valueOf(df.format(tempSpeed));
        //tempSpeed = Math.round(tempSpeed);
        return tempSpeed;
    } else {
        return 0;
    }
}
//***************************************************/
// Check for connection to satellites
//***************************************************/
public boolean canGetLocation() {
    return this.canGetLocation;
}
//***************************************************/
// Ask user to turn on GPS
//***************************************************/
public void showSettingsAlert() {
    AlertDialog.Builder alertDialog = new AlertDialog.Builder(mContext);
    // Set title
    alertDialog.setTitle(mContext.getString(R.string.gps_helper_gps_status));
    // Set message
    alertDialog.setMessage(mContext.getString(R.string.gps_helper_gps_is_not_enabled));
    // "Ja" button
    alertDialog.setPositiveButton(mContext.getString(R.string.yes),
            (dialog, which) -> {
                Intent intent = new Intent(
                        Settings.ACTION_LOCATION_SOURCE_SETTINGS);
                mContext.startActivity(intent);
            });
    // "Nej" button
    alertDialog.setNegativeButton(mContext.getString(R.string.no),
            (dialog, which) -> dialog.cancel());
    // Show message
    alertDialog.show();
}
//endregion
//**************************************************************************/
// EVENTS
//**************************************************************************/
//region Events
@Override
public void onLocationChanged(Location location) {
    this.setLocation(location);
    latitude = location.getLatitude();
    longitude = location.getLongitude();
    speed = location.getSpeed();
}
@Override
public void onStatusChanged(String s, int i, Bundle bundle) {
}
@Override
public void onProviderEnabled(String s) {
}
@Override
public void onProviderDisabled(String s) {
}
//endregion}

Answer 1

我认为您在请求位置更新后不应该updateLocation()：

 if (isGPSEnabled) {
        this.canGetLocation = true;
    locationManager.requestLocationUpdates(
            LocationManager.GPS_PROVIDER,
            MIN_TIME_BW_UPDATES,
            MIN_DISTANCE_CHANGE_FOR_UPDATES, this);
    updateLocation();
}

在这里，在调用任何onLocationChanged()之前调用updateLocation()。我认为这就是为什么您的价值观为" 0"。您应该在onLocationChanged()中致电updateLocation()。

希望它有帮助