Question

[！[在此处输入图片说明] [1]] [1]我所有遇到问题都可以告诉我如何解决这个问题，我想在片段类中使用构造函数：这是我的两个班级 AppLocationService：

public class AppLocationService extends Service implements LocationListener {

    protected LocationManager locationManager;
    Location location;

    private static final long MIN_DISTANCE_FOR_UPDATE = 10;
    private static final long MIN_TIME_FOR_UPDATE = 1000 * 60 * 2;

    public AppLocationService(Context context) {
        locationManager = (LocationManager) context
                .getSystemService(LOCATION_SERVICE);
    }

    public Location getLocation(String provider) {
        if (locationManager.isProviderEnabled(provider)) {
            locationManager.requestLocationUpdates(provider,
                    MIN_TIME_FOR_UPDATE, MIN_DISTANCE_FOR_UPDATE, this);
            if (locationManager != null) {
                location = locationManager.getLastKnownLocation(provider);
                return location;
            }
        }
        return null;
    }

    @Override
    public void onLocationChanged(Location location) {
    }

    @Override
    public void onProviderDisabled(String provider) {
    }

    @Override
    public void onProviderEnabled(String provider) {
    }

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

    @Override
    public IBinder onBind(Intent arg0) {
        return null;
    }

}

这里是片段：

public class AddressFragment extends Fragment {
    Button ShowAddress;
    TextView tvAddress;

    AppLocationService appLocationService;
    public AddressFragment(){

    }

    @Override
    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);

    }

    @Override
    public View onCreateView(LayoutInflater inflater, ViewGroup container,
                             Bundle savedInstanceState) {
        View rootView = inflater.inflate(R.layout.fragment_address, container, false);
        tvAddress = (TextView) rootView.findViewById(R.id.input_location);
        appLocationService = new AppLocationService(
                AddressFragment.this);


        ShowAddress = (Button) rootView.findViewById(R.id.btn_location);
        ShowAddress.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View arg0) {

                Location location = appLocationService
                        .getLocation(LocationManager.GPS_PROVIDER);

                //you can hard-code the lat & long if you have issues with getting it
                //remove the below if-condition and use the following couple of lines
                //double latitude = 37.422005;
                //double longitude = -122.084095

                if (location != null) {
                    double latitude = location.getLatitude();
                    double longitude = location.getLongitude();
                    LocationAddress locationAddress = new LocationAddress();
                    locationAddress.getAddressFromLocation(latitude, longitude,
                            getApplicationContext(), new GeocoderHandler());
                } else {
                    showSettingsAlert();
                }

            }
        });
        return rootView;
    }




    public void showSettingsAlert() {
        AlertDialog.Builder alertDialog = new AlertDialog.Builder(
                AddressFragment.this);
        alertDialog.setTitle("SETTINGS");
        alertDialog.setMessage("Enable Location Provider! Go to settings menu?");
        alertDialog.setPositiveButton("Settings",
                new DialogInterface.OnClickListener() {
                    public void onClick(DialogInterface dialog, int which) {
                        Intent intent = new Intent(
                                Settings.ACTION_LOCATION_SOURCE_SETTINGS);
                        AddressFragment.this.startActivity(intent);
                    }
                });
        alertDialog.setNegativeButton("Cancel",
                new DialogInterface.OnClickListener() {
                    public void onClick(DialogInterface dialog, int which) {
                        dialog.cancel();
                    }
                });
        alertDialog.show();
    }

    private class GeocoderHandler extends Handler {
        @Override
        public void handleMessage(Message message) {
            String locationAddress;
            switch (message.what) {
                case 1:
                    Bundle bundle = message.getData();
                    locationAddress = bundle.getString("address");
                    break;
                default:
                    locationAddress = null;
            }
            tvAddress.setText(locationAddress);
        }
    }




        // Inflate the layout for this fragment



    @Override
    public void onAttach(Activity activity) {
        super.onAttach(activity);
    }

    @Override
    public void onDetach() {
        super.onDetach();
    }
}

Answer 1

回答你的问题; Fragment不是来自Context。要让代码编译，您应该更改此

appLocationService = new AppLocationService(
            AddressFragment.this);

到此

appLocationService = new AppLocationService(getActivity());

但是，你永远不应该自己调用Service的构造函数。您应该使用Context#startService(Intent)（在您的情况下为getActivity().startService(new Intent(getActivity(), AppLocationService.class))）启动它。要为您的服务提供任何参数，请查看Intent#putExtra(String, String)

如何将java类的构造函数用于片段？

1 个答案: