Question

（这是关于android中的LocationManager类）。

有没有办法使用requestLocationUpdates，但在某种程度上，它允许每次给我最佳活跃提供者的结果？我可以将getBestProvider的结果传递给它，但是它会始终从该提供程序返回结果，如果用户打开/关闭gps，它将无法正常工作。

我的代码在后台服务中。

Answer 1

有没有办法使用requestLocationUpdates，但在某种程度上允许它每次都为最佳活跃提供商提供结果？

不，尽管欢迎您为多个提供商注册单独的LocationListeners。

我可以将getBestProvider的结果传递给它，但是它总会返回该提供程序的结果，如果用户打开/关闭gps，它将无法正常工作。

启用和禁用其提供商时，会通知您LocationListener。如果您的当前提供程序已禁用，则可以向备份提供程序注册LocationListener。

Answer 2

这就是我的所作所为：

public class LocationActivity extends Activity implements LocationListener{

    private TextView latituteField;
    private TextView longitudeField;
    private LocationManager locationManager;
    private String provider;
    private TextView outputField;
    private Location location;
    private ScrollView scrollView;
    private Criteria criteria;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_location);

        latituteField = (TextView) findViewById(R.id.lat_textView);
        longitudeField = (TextView) findViewById(R.id.long_textView);
        outputField = (TextView) findViewById(R.id.output_textView);
        scrollView = (ScrollView) findViewById(R.id.scrollView1);

        locationManager = (LocationManager) getSystemService(Context.LOCATION_SERVICE);

        criteria = new Criteria();
        criteria.setAccuracy(Criteria.ACCURACY_FINE);

        List<String> providers = locationManager.getProviders(criteria, true);
        outputField.append("Providers available..." + "\n");
        for (String provider : providers) {
            outputField.append(provider + "\n");
            scrollView.fullScroll(ScrollView.FOCUS_DOWN);
        }

        provider = locationManager.getBestProvider(criteria, true);
        locationManager.requestLocationUpdates(provider, 400, 1, this);

        if (provider != null) {
            outputField.append("Provider " + provider + " has been selected." + "\n");
            scrollView.fullScroll(ScrollView.FOCUS_DOWN);

            if (location != null) {
                onLocationChanged(location);
            } else {
                latituteField.setText("Location not available");
                longitudeField.setText("Location not available");
            }
          } else {
            outputField.append("No provider selected" + "\n");
            scrollView.fullScroll(ScrollView.FOCUS_DOWN);
          }
    }

    @Override
      protected void onResume() {
        super.onResume();
        locationManager.requestLocationUpdates(provider, 400, 1, this);
      }

    protected void onPause() {
        super.onPause();
        locationManager.removeUpdates(this);
      }

    @Override
    public void onLocationChanged(Location location) {
        double lat =location.getLatitude();
        double lng =location.getLongitude();
        latituteField.setText(String.valueOf(lat));
        longitudeField.setText(String.valueOf(lng));
        outputField.append("New Location: " + String.valueOf(lat) + " " + String.valueOf(lng) + "\n");
        scrollView.fullScroll(ScrollView.FOCUS_DOWN);
    }

    @Override
    public void onProviderDisabled(String dProvider) {
        outputField.append("Provider " + dProvider + " has been disabled." + "\n");
        scrollView.fullScroll(ScrollView.FOCUS_DOWN);

        provider = locationManager.getBestProvider(criteria, true);
        locationManager.requestLocationUpdates(provider, 400, 1, this);

        if (provider != null) {
            outputField.append("Provider " + provider + " has been selected." + "\n");
            scrollView.fullScroll(ScrollView.FOCUS_DOWN);

            if (location != null) {
                onLocationChanged(location);
            } else {
                latituteField.setText("Location not available");
                longitudeField.setText("Location not available");
            }
          } else {
            outputField.append("No provider selected" + "\n");
            scrollView.fullScroll(ScrollView.FOCUS_DOWN);
          }
    }

    @Override
    public void onProviderEnabled(String eProvider) {
        outputField.append("Provider " + eProvider + " has been enabled." + "\n");
        scrollView.fullScroll(ScrollView.FOCUS_DOWN);

        provider = locationManager.getBestProvider(criteria, true);
        locationManager.requestLocationUpdates(provider, 400, 1, this);

        if (provider != null) {
            outputField.append("Provider " + provider + " has been selected." + "\n");
            scrollView.fullScroll(ScrollView.FOCUS_DOWN);

            if (location != null) {
                onLocationChanged(location);
            } else {
                latituteField.setText("Location not available");
                longitudeField.setText("Location not available");
            }
          } else {
            outputField.append("No provider selected" + "\n");
            scrollView.fullScroll(ScrollView.FOCUS_DOWN);
          }
    }

    @Override
    public void onStatusChanged(String provider, int status, Bundle extras) {
        outputField.append("Provider " + provider + " status changed to: " + Integer.toString(status) + "\n");
        scrollView.fullScroll(ScrollView.FOCUS_DOWN);
    }
}

Answer 3

从API级别9开始，可以使用此方法：

requestLocationUpdates(long minTime, float minDistance, Criteria criteria, PendingIntent intent);

See the documentation for more information on usage.

将requestLocationUpdates用于多个提供程序

3 个答案: