Question

我正在使用android studio创建一个应用程序，并在一个欢迎的弹出对话框中，我希望应用程序获得用户的位置，所以我编写了代码，但为什么它找不到我的位置。为什么？！？我正在努力工作几天。这是我的代码

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


@Override
public void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_main);
    latituteField = (TextView) findViewById(R.id.TextView02);
    longitudeField = (TextView) findViewById(R.id.TextView04);
    addressField = (TextView) findViewById(R.id.TextView05);


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

    Criteria criteria = new Criteria();
    provider = locationManager.getBestProvider(criteria, true);
    Log.d("SomeTag", provider);
    Log.d("SomeTag", String.valueOf(locationManager.isProviderEnabled(provider)));
    Location location = locationManager.getLastKnownLocation(provider);


    if (location != null) {
        System.out.println("Provider " + provider + " has been selected.");
        onLocationChanged(location);
    } else {
        latituteField.setText("Please wait for location update...");
        longitudeField.setText("Please wait for location update...");
        addressField.setText("Please wait for location update...");
    }
}


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


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

@Override
public void onLocationChanged(Location location) {

    double lat = location.getLatitude();
    double lng = location.getLongitude();

    Geocoder geoCoder = new Geocoder(this, Locale.getDefault());
    StringBuilder builder = new StringBuilder();
    try {
        List<Address> address = geoCoder.getFromLocation(lat, lng, 1);
        int maxLines = address.get(0).getMaxAddressLineIndex();
        for (int i=0; i<maxLines; i++) {
            String addressStr = address.get(0).getAddressLine(i);
            builder.append(addressStr);
            builder.append(" ");
        }

        String fnialAddress = builder.toString(); 

        latituteField.setText(String.valueOf(lat));
        longitudeField.setText(String.valueOf(lng));
        addressField.setText(fnialAddress); 

    } catch (IOException e) {}
    catch (NullPointerException e) {}
}

@Override
public void onStatusChanged(String provider, int status, Bundle extras) {


}

@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();
}
}

你可以帮我找出什么问题吗？即使它更简单，我只需要应用程序知道我居住的地方（我的意思是城市）

Answer 1

你是否写了许可

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

并使用真实手机

或者通过ddms为模拟器设置gps位置

Answer 2

阅读有关位置策略的Android文档here。您需要为位置更新添加侦听器。 getLastKnownLocation()应该仍然有用，但你不能依赖它。另外，您是否在模拟器上进行测试？如果你没有使用开发工具设置位置，那么你经常得到null。

为什么我无法获得我的职位？

2 个答案: