我有一个需要，以获得最佳的位置迅速，从全球定位系统，网络或任何可用的一些Android的code。精度比速度更重要。

I have some Android code that needs to get the best available location QUICKLY, from GPS, network or whatever is available. Accuracy is less important than speed.

获取最好的位置肯定是一个非常标准的任务。然而，我无法找到任何code来证明它。 Android的位置code期待您指定的标准，注册更新，并等待 - 如果你有详细的标准，不介意等待周围是罚款。

Getting the best available location is surely a really standard task. Yet I can't find any code to demonstrate it. The Android location code expects you to specify criteria, register for updates, and wait - which is fine if you have detailed criteria and don't mind waiting around.

但我的应用程序需要工作多一点像地图应用确实当它第一次找到你 - 工作从任何可用的提供者，而只是检查的位置不疯狂过时或无效的

But my app needs to work a bit more like the Maps app does when it first locates you - work from any available provider, and just check the location isn't wildly out of date or null.

我已经尝试推出自己的code要做到这一点，但我有问题。 （这是一个IntentService，其中一个上传发生在里面，如果说有什么不同。我已经包括了所有的code的信息。）什么不对的code？

I've attempted to roll my own code to do this, but am having problems. (It's inside an IntentService where an upload happens, if that makes any difference. I've included all the code for info.) What's wrong with this code?

@Override
protected void onHandleIntent(Intent arg0) {
    testProviders();
    doUpload();
}
private boolean doUpload() {
       int j = 0;
       // check if we have accurate location data yet - wait up to 30 seconds
       while (j < 30) {
           if ((latString == "") || (lonString == "")) {
               Log.d(LOG_TAG, "latlng null");
               Thread.sleep(1000);
               j++;
       } else {
                Log.d(LOG_TAG, "found lat " + latString + " and lon " + lonString);
            break;
       }
       //do the upload here anyway, with or without location data
       //[code removed for brevity]
}
public boolean testProviders() {
    Log.e(LOG_TAG, "testProviders");
    String location_context = Context.LOCATION_SERVICE;
    locationmanager = (LocationManager) getSystemService(location_context);
    List<String> providers = locationmanager.getProviders(true);
    for (String provider : providers) {
        Log.e(LOG_TAG, "registering provider " + provider);
        listener = new LocationListener() {
            public void onLocationChanged(Location location) {
                // keep checking the location - until we have
                // what we need
                //if (!checkLoc(location)) {
                Log.e(LOG_TAG, "onLocationChanged");
                locationDetermined = checkLoc(location);
                //}
            }
            public void onProviderDisabled(String provider) {
            }
            public void onProviderEnabled(String provider) {
            }
            public void onStatusChanged(String provider, int status,
                    Bundle extras) {
            }
        };
        locationmanager.requestLocationUpdates(provider, 0,
                0, listener);
    }
    Log.e(LOG_TAG, "getting updates");
    return true;
}
private boolean checkLoc(Location location) {
    float tempAccuracy = location.getAccuracy();
    int locAccuracy = (int) tempAccuracy;
    Log.d(LOG_TAG, "locAccuracy = " + locAccuracy);
    if ((locAccuracy != 0) && (locAccuracy < LOCATION_ACCURACY)) {
        latitude = location.getLatitude();
        longitude = location.getLongitude();
        latString = latitude.toString();
        lonString = longitude.toString();
        return true;
    }
    return false;
}
public void removeListeners() {
    // Log.e(LOG_TAG, "removeListeners");
    if ((locationmanager != null) && (listener != null)) {
        locationmanager.removeUpdates(listener);
    }
    locationmanager = null;
    // Log.d(LOG_TAG, "Removed " + listener.toString());
}
@Override
public void onDestroy() {
    super.onDestroy();
    removeListeners();
}

不幸的是，这一发现的网络供应商，但永远只能输出经纬度空 30倍 - 这似乎从来没有得到一个位置都没有。我从来没有得到一个log语句 locationChanged 。

Unfortunately, this finds the network provider, but only ever outputs latlng null 30 times - it never seems to get a location at all. I never even get a log statement of locationChanged.

这很有趣，因为从DDMS我可以看到这样的输出：

It's funny, because from ddms I can see output like:

NetworkLocationProvider: onCellLocationChanged [305,8580]
NetworkLocationProvider: getNetworkLocation(): returning cache location with accuracy 75.0

似乎表明，网络供应商也有一些位置信息毕竟，我只是没有得到它。

seeming to suggest that the network provider does have some location info after all, I'm just not getting at it.

谁能帮助？我想工作的例子code会为Android /计算器社会有用的资源。

Can anyone help? I think working example code would be a useful resource for the Android/StackOverflow community.

推荐答案

您肯定是试图做到这一点的艰辛的道路。下面是一个新的应用程序，我工作的一些片段。它采用条件获得能够返回准确的罚款级别的所有供应商没有代价的。

You are definitely trying to do this the hard way. Here are some snippets from a new app I am working on. It uses Criteria to get all providers capable of returning a fine level of accuracy without a cost.

如果启用没有提供显示一个对话框，提示用户打开他们的位置设置。如果用户点击确定一个Intent实际发射发送他们在他们的电话的设置。如果存在提供者启用该应用需要的最新从任何已启用的提供者最后已知位置。对于我的程序，我只需要知道用户在什么一般地区，很可能是最后已知的位置是从他们的家乡地区。

If no providers are enabled a dialog is displayed that prompts the user to turn on their location settings. If the user hits ok an Intent is actually fired that sends them to the settings on their phone. If there are providers enabled the app takes the most recent last known location from any of the enabled providers. For my app I just need to know what general area the user is in and it's likely that the last known location is from their home area.

如果供应商启用了循环还要求位置更新尽快。这是理想的我的应用程序，但你可以改变这种以节省电池我修改参数的 requestLocationUpdates方法。

If providers are enabled the loop also requests location updates as quickly as possible. This is ideal for my app but you can change this to conserve battery my modifying the arguments to the requestLocationUpdates method.

这code具有对Android应用程序中的例子并不真正显示的优化是所有启用的提供商正在启动的同时的。所有的供应商将在返回单独的更新到 onLocationChanged方法。在我的应用程序我删除位置监听器的供应商之一返回一个足够好的准确位置后。

The optimization that this code has that the examples on the Android app don't really show is that all of the enabled providers are started simultaneously. All of the providers will return separate updates on to the onLocationChanged method. In my app I remove the location listener after one of the providers returns a location with a good enough accuracy.

启动位置更新：

void getCurrentLocation() {
    List<String> providers = locationManager.getProviders(criteria, true);
    if (providers != null) {
        Location newestLocation = null;
        for (String provider : providers) {
            Location location = locationManager.getLastKnownLocation(provider);
            if (location != null) {
                if (newestLocation == null) {
                    newestLocation = location;
                } else {
                    if (location.getTime() > newestLocation.getTime()) {
                        newestLocation = location;
                    }
                }
                locationManager.requestLocationUpdates(provider, 0, 0, this);
            }
        }
    } else {
        LocationDialogFragment dialog = new LocationDialogFragment();
        dialog.show(getSupportFragmentManager(),
            LocationDialogFragment.class.getName());
    }
}

接收位置更新：

Receive Location Update:

@Override
public void onLocationChanged(Location location) {
    float bestAccuracy = -1f;
    if (location.getAccuracy() != 0.0f
        && (location.getAccuracy() < bestAccuracy) || bestAccuracy == -1f) {
        if (location.getAccuracy() < Const.MIN_ACCURACY) {
            locationManager.removeUpdates(this);
        }
    }
    bestAccuracy = location.getAccuracy();
}

位置设置对话框：

Location Settings Dialog:

public class LocationDialogFragment extends DialogFragment {

    @Override
    public Dialog onCreateDialog(Bundle savedInstanceState) {
        AlertDialog.Builder builder = new AlertDialog.Builder(getActivity());
        builder.setMessage(R.string.location_dialog_message)
                .setPositiveButton(R.string.location_dialog_positive_button,
                    new OnClickListener() {

                        @Override
                        public void onClick(DialogInterface dialog, int which) {
                            Intent settingsIntent = new Intent(
                                    Settings.ACTION_LOCATION_SOURCE_SETTINGS);
                            startActivity(settingsIntent);
                        }
                    })
                .setNegativeButton(R.string.location_dialog_negative_button,
                    new OnClickListener() {

                        @Override
                        public void onClick(DialogInterface dialog, int which) {
                            Toast.makeText(getActivity(),
                                R.string.no_location_message, Toast.LENGTH_LONG)
                                    .show();
                        }
                    });
        return builder.create();
    }
}