Android LocationManager标准

我需要从网络和GPS提供商处接收位置更改.

如果GPS提供商不可用或没有位置(卫星可见性差)我会从网络提供商处获得GPS提供商的位置.

是否有可能根据我的需要选择使用标准？

解决方法

实际上 Android Developers – Making Your App Location Aware有一个很好的示例代码来满足您的需求.

在其代码中,如果您使用两个提供商(来自GPS和网络),它将进行比较：

...
} 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想法(通过确定在指定时间段内的准确性,如：

/** 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;
}

有关完整代码,请查看上面提供的链接.