安卓定位管理器标准

Question

我需要从网络和GPS提供商那里接收位置变化。如果GPS提供商不可用或没有位置（卫星能见度差），我将从网络提供商接收位置，否则从GPS提供商接收位置。

是否可以根据我的需求使用标准选择提供商？

- Nik

---

如果您使用Criteria类来查找根据配置可用的最佳提供程序，则结果可能是GPS PROVIDER、NETWORK PROVIDER或PASSIVE中的任何一个。如果不使用Criteria类，则可以使用requestLocationUpdates来根据提供程序获取位置。 - ρяσѕρєя K

LocationManager无法在一个回调中同时通知我网络和GPS的位置信息吗？我需要使用两个具有不同回调的requestLocation()方法吗？ - Nik

要注册位置管理器以获取更新，您必须提供一个提供程序，从中获取更新。例如：mgr.requestLocationUpdates(LocationManager.NETWORK_PROVIDER, 10 * 1000, 50, this); - Archie.bpgc

Answer 1

实际上，Android开发者-使您的应用程序具备定位功能有一个很好的示例代码来满足您的需求。

在它的代码中，如果您同时使用GPS和网络提供商，它会进行比较：

...
} else if (mUseBoth) {
    // Get coarse and fine location updates.
    mFineProviderButton.setBackgroundResource(R.drawable.button_inactive);
    mBothProviderButton.setBackgroundResource(R.drawable.button_active);
    // Request updates from both fine (gps) and coarse (network) providers.
    gpsLocation = requestUpdatesFromProvider(
            LocationManager.GPS_PROVIDER, R.string.not_support_gps);
    networkLocation = requestUpdatesFromProvider(
            LocationManager.NETWORK_PROVIDER, R.string.not_support_network);

    // If both providers return last known locations, compare the two and use the better
    // one to update the UI.  If only one provider returns a location, use it.
    if (gpsLocation != null && networkLocation != null) {
        updateUILocation(getBetterLocation(gpsLocation, networkLocation));
    } else if (gpsLocation != null) {
        updateUILocation(gpsLocation);
    } else if (networkLocation != null) {
        updateUILocation(networkLocation);
    }
}
...

它实现了最佳位置提供者的思想（通过在指定时间内确定精度）

/** Determines whether one Location reading is better than the current Location fix.
  * Code taken from
  * http://developer.android.com/guide/topics/location/obtaining-user-location.html
  *
  * @param newLocation  The new Location that you want to evaluate
  * @param currentBestLocation  The current Location fix, to which you want to compare the new
  *        one
  * @return The better Location object based on recency and accuracy.
  */
protected Location getBetterLocation(Location newLocation, Location currentBestLocation) {
    if (currentBestLocation == null) {
        // A new location is always better than no location
        return newLocation;
    }

    // Check whether the new location fix is newer or older
    long timeDelta = newLocation.getTime() - currentBestLocation.getTime();
    boolean isSignificantlyNewer = timeDelta > TWO_MINUTES;
    boolean isSignificantlyOlder = timeDelta < -TWO_MINUTES;
    boolean isNewer = timeDelta > 0;

    // If it's been more than two minutes since the current location, use the new location
    // because the user has likely moved.
    if (isSignificantlyNewer) {
        return newLocation;
    // If the new location is more than two minutes older, it must be worse
    } else if (isSignificantlyOlder) {
        return currentBestLocation;
    }

    // Check whether the new location fix is more or less accurate
    int accuracyDelta = (int) (newLocation.getAccuracy() - currentBestLocation.getAccuracy());
    boolean isLessAccurate = accuracyDelta > 0;
    boolean isMoreAccurate = accuracyDelta < 0;
    boolean isSignificantlyLessAccurate = accuracyDelta > 200;

    // Check if the old and new location are from the same provider
    boolean isFromSameProvider = isSameProvider(newLocation.getProvider(),
            currentBestLocation.getProvider());

    // Determine location quality using a combination of timeliness and accuracy
    if (isMoreAccurate) {
        return newLocation;
    } else if (isNewer && !isLessAccurate) {
        return newLocation;
    } else if (isNewer && !isSignificantlyLessAccurate && isFromSameProvider) {
        return newLocation;
    }
    return currentBestLocation;
}

如果需要完整代码，请查看上面提供的链接。

- dumbfingers

Answer 2

要搜索最佳位置提供者，请使用以下代码： 请参考https://developer.android.com/reference/android/location/Criteria.html了解标准将如何工作？

public  String getProviderName() {
    LocationManager locationManager =(LocationManager)this.getSystemService(Context.LOCATION_SERVICE);
    Criteria criteria = new Criteria();
    criteria.setPowerRequirement(Criteria.POWER_LOW);
    criteria.setAccuracy(Criteria.ACCURACY_FINE);
    criteria.setSpeedRequired(true);
    criteria.setAltitudeRequired(false);
    criteria.setBearingRequired(false);
    criteria.setCostAllowed(false);
    return locationManager.getBestProvider(criteria, true);
}

- SandyPatel

Answer 3

不要给任何标准，尽量选择最好的供应商：

LocationManager mgr = (LocationManager) getSystemService(LOCATION_SERVICE);
Criteria criteria = new Criteria();
String best = mgr.getBestProvider(criteria, true);
//since you are using true as the second parameter, you will only get the best of providers which are enabled.
Location location = mgr.getLastKnownLocation(best);

- Archie.bpgc