android - 如何在 GPS 和网络提供商之间切换？

Question

在我的应用中，我想同时使用这两个位置提供程序。

这意味着，如果禁用了 gps，我希望我的应用程序切换到网络，并在启用 gps 时切换回它。

我正在使用两个 LocationListener 来处理这两个请求。

public void onStatusChanged(String provider, int status,Bundle extras) 
    switch (status) {
        case LocationProvider.TEMPORARILY_UNAVAILABLE:
             ......
            break;
        case LocationProvider.OUT_OF_SERVICE
             .....
            break;
        case LocationProvider.AVAILABLE
             .....
            break;   
}

在每个监听器中，我在 onStatusChanged() 中检测到这些状态。原来，这个方法会在第一次更改(禁用网络)时使用，但是当我再次启用网络时，它什么也没有显示，这是为什么？监听器不会一直检测状态？？

请帮助我，最好在代码中发布您的解决方案...谢谢!

Answer 1

这是我的做法:

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);
    }
}