Android位置管理器标准

Question

我需要从网络和GPS提供商接收位置更改。

如果GPS提供商不能提供或没有位置（卫星可见度差），我会从GPS提供商的其他网络提供商处获得位置。

是否可以根据我的需要选择使用标准的提供商？

Answer 1

其实Android Developers - Making Your App Location Aware有一个很好的例子代码，以满足您的需求。

在其代码，如果你同时使用供应商（根据GPS和网络），它会做一个比较：

... 
} 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); 
    } 
} 
... 

它实施最佳位置提供的想法（通过在指定期间内判断的准确像时间：

/** 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，请看看上面提供的链接

Answer 2

只要不放弃任何的标准，并设法得到最好提供商：

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); 

Answer 3

对于搜索最佳位置提供商请用户belowe℃。 ode： 请参阅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); 
}