android - 访问 GPS 不工作。应用程序使用网络获取位置

Question

我的应用不想使用 GPS 而是使用网络来获取位置。我通过分析纬度和经度来检查，它们有点随机(比如网络位置)。

如果我使用另一个使用 GPS 的应用程序(例如 Endomondo Sports tracker)，我会看到特征标记，这意味着 GPS 当前正在工作:

当我启动我的应用程序时，根本没有任何标记。

我正在使用以下代码(Lars Vogella 的代码，来源:http://www.vogella.com/articles/AndroidLocationAPI/article.html):

import android.app.Activity;
import android.content.Context;
import android.location.Criteria;
import android.location.Location;
import android.location.LocationListener;
import android.location.LocationManager;
import android.os.Bundle;
import android.widget.TextView;
import android.widget.Toast;

public class ShowLocationActivity extends Activity implements LocationListener {
  private TextView latituteField;
  private TextView longitudeField;
  private LocationManager locationManager;
  private String provider;


/** Called when the activity is first created. */

  @Override
  public void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.main);
    latituteField = (TextView) findViewById(R.id.TextView02);
    longitudeField = (TextView) findViewById(R.id.TextView04);

    // Get the location manager
    locationManager = (LocationManager) getSystemService(Context.LOCATION_SERVICE);
    // Define the criteria how to select the locatioin provider -> use
    // default
    Criteria criteria = new Criteria();
    provider = locationManager.getBestProvider(criteria, false);
    Location location = locationManager.getLastKnownLocation(provider);

    // Initialize the location fields
    if (location != null) {
      System.out.println("Provider " + provider + " has been selected.");
      onLocationChanged(location);
    } else {
      latituteField.setText("Location not available");
      longitudeField.setText("Location not available");
    }
  }

  /* Request updates at startup */
  @Override
  protected void onResume() {
    super.onResume();
    locationManager.requestLocationUpdates(provider, 400, 1, this);
  }

  /* Remove the locationlistener updates when Activity is paused */
  @Override
  protected void onPause() {
    super.onPause();
    locationManager.removeUpdates(this);
  }

  @Override
  public void onLocationChanged(Location location) {
    int lat = (int) (location.getLatitude());
    int lng = (int) (location.getLongitude());
    latituteField.setText(String.valueOf(lat));
    longitudeField.setText(String.valueOf(lng));
  }

  @Override
  public void onStatusChanged(String provider, int status, Bundle extras) {
    // TODO Auto-generated method stub

  }

  @Override
  public void onProviderEnabled(String provider) {
    Toast.makeText(this, "Enabled new provider " + provider,
        Toast.LENGTH_SHORT).show();

  }

  @Override
  public void onProviderDisabled(String provider) {
    Toast.makeText(this, "Disabled provider " + provider,
        Toast.LENGTH_SHORT).show();
  }
} 

当然我在AndroidManifest.xml文件中添加了权限:

<uses-permission android:name="android.permission.ACCESS_COARSE_LOCATION" />
<uses-permission android:name="android.permission.ACCESS_FINE_LOCATION" />
<uses-permission android:name="android.permission.INTERNET" />

有什么想法吗？

Answer 1

解决方案:您可以使用 GPS 而不是通过决定标准来选择最佳提供商。

示例，替换:

locationManager.requestLocationUpdates(provider, 400, 1, this);

与:

locationManager.requestLocationUpdates(LocationManager.GPS_PROVIDER, 400, 1, this);

解释:

根据您的应用程序的用例，您必须选择特定的位置提供程序即 LocationManager.GPS_PROVIDER 或 LocationManager.NETWORK_PROVIDER

或者，您可以提供一些输入标准，例如准确性、功率要求、货币成本等，让 Android 决定最接近的匹配位置提供者

    // Retrieve a list of location providers that have fine accuracy, no monetary cost, etc
Criteria criteria = new Criteria();
criteria.setAccuracy(Criteria.ACCURACY_FINE);
criteria.setCostAllowed(false);
String providerName = locManager.getBestProvider(criteria, true);
//and then you can make location update request with selected best provider
locationManager.requestLocationUpdates(provider, 400, 1, this); 

看看how to use locationmanager , how to specify Criteria和 how getBestProvider method works供引用