Question

我刚刚开始使用android studio并希望创建一个显示我当前位置的地图。我有一个＆＃34; Map类＆＃34;和＆＃34;获取位置＆＃34;类。我想要＆＃34;获取位置＆＃34;运行并将经度和纬度数据存储在静态变量中的类，以便我可以从＆＃34; map类＆＃34;中访问它们。我怎么做？我如何获得＆＃34;获取位置＆＃34;在map类之前运行的类？

这是我的代码：

地图类

import android.content.Intent;
import android.support.v4.app.FragmentActivity;
import android.os.Bundle;

import com.google.android.gms.maps.CameraUpdateFactory;
import com.google.android.gms.maps.GoogleMap;
import com.google.android.gms.maps.OnMapReadyCallback;
import com.google.android.gms.maps.SupportMapFragment;
import com.google.android.gms.maps.model.LatLng;
import com.google.android.gms.maps.model.MarkerOptions;

public class MapsActivity extends FragmentActivity implements OnMapReadyCallback {

private GoogleMap mMap;


@Override
protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_maps);
    // Obtain the SupportMapFragment and get notified when the map is ready to be used.
    SupportMapFragment mapFragment = (SupportMapFragment) getSupportFragmentManager()
            .findFragmentById(R.id.map);
    mapFragment.getMapAsync(this);
}


/**
 * Manipulates the map once available.
 * This callback is triggered when the map is ready to be used.
 * This is where we can add markers or lines, add listeners or move the camera. In this case,
 * we just add a marker near Sydney, Australia.
 * If Google Play services is not installed on the device, the user will be prompted to install
 * it inside the SupportMapFragment. This method will only be triggered once the user has
 * installed Google Play services and returned to the app.
 */
@Override
public void onMapReady(GoogleMap googleMap) {
    mMap = googleMap;


    // Add a marker in Sydney and move the camera
    LatLng sydney = new LatLng(GetLocation.latitude,GetLocation.longitude);
    mMap.addMarker(new MarkerOptions().position(sydney).title("Marker in Sydney"));
    mMap.moveCamera(CameraUpdateFactory.newLatLng(sydney));
}


}

GetLocation类：

public class GetLocation extends AppCompatActivity {

private Button button;
private TextView textView;
private LocationManager locationManager;
private LocationListener locationListener;
static double latitude;
static double longitude;


@Override
protected void onCreate(Bundle savedInstanceState) {

    super.onCreate(savedInstanceState);

    locationManager = (LocationManager) getSystemService(LOCATION_SERVICE);
    locationListener = new LocationListener() {
        @Override
        public void onLocationChanged(Location location) {
            latitude = location.getLatitude();
            longitude = location.getLongitude();
            Log.d("ADebugTag", "Value: " + Double.toString(latitude));


        }

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

        }

        @Override
        public void onProviderEnabled(String provider) {

        }

        @Override
        public void onProviderDisabled(String provider) {
            Intent intent = new Intent(Settings.ACTION_LOCATION_SOURCE_SETTINGS);
            startActivity(intent);
        }
    };
    if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.M) {
        if (checkSelfPermission(Manifest.permission.ACCESS_FINE_LOCATION) != PackageManager.PERMISSION_GRANTED && ActivityCompat.checkSelfPermission(this, Manifest.permission.ACCESS_COARSE_LOCATION) != PackageManager.PERMISSION_GRANTED) {
            requestPermissions(new String[]{
                    Manifest.permission.ACCESS_FINE_LOCATION, Manifest.permission.ACCESS_COARSE_LOCATION,
                    Manifest.permission.INTERNET
            }, 10 );
        }
        return;

    }else{
        configureButton();
    }
}

@Override
public void onRequestPermissionsResult(int requestCode, @NonNull String[] permissions, @NonNull int[] grantResults) {
    switch (requestCode){
        case 10:
            if (grantResults.length>0 && grantResults[0] == PackageManager.PERMISSION_GRANTED)
                configureButton();
            return;
    }
}

private void configureButton() {
}

@Override
protected void onResume() {
    super.onResume();
    locationManager.requestLocationUpdates(
            LocationManager.NETWORK_PROVIDER, 5000, 0,
            locationListener);

}

}

正如您所看到的，我正在尝试访问纬度和经度，但它们只是0.但是当我单独运行getLocation类时，它们会返回正确的位置。

Answer 1

您需要创建函数并返回值，然后调用该函数。在“获取位置”类中，您可以执行一个函数并返回值纬度和经度。在“Map类”类中，您可以调用该函数来获取纬度和经度的值。

希望它会对你有所帮助。

Answer 2

您需要一个辅助类来设置并获得所需的值：

public class GlobalVariables {


private static GlobalVariables instance = new GlobalVariables();

// Getter-Setters
public static GlobalVariables getInstance() {
    return instance;
}

public static void setInstance(GlobalVariables instance) {
    GlobalVariables.instance = instance;
}

private String notification_index;


private GlobalVariables() {

}


public String getValue() {
    return notification_index;
}


public void setValue(String notification_index) {
    this.notification_index = notification_index;
}

}

如何在另一个类中访问变量？

2 个答案: