java - 如何将类返回到 onPostExecute？

Question

更新，请见下文。

如何将我的类 LocationData 和我的 ArrayList listOfObjects 返回到 onPostExecute()？我想在我的 UI 中使用它，现在它在 AsyncTask 的后台。我还想添加标记:

mMap.addMarker(new MarkerOptions()
    .position(new LatLng(lati, longi))
    .title(name));

这样我就可以在每次循环后将每个新位置添加到 map 中。

我是否在返回 LocationData 类后将上面的内容放在 onPostExecute 中？

    try {

        String apples = endpoint.listContactInfo().execute().toString();

        JSONObject jObject = new JSONObject(apples);

        JSONArray jsonArr = jObject.getJSONArray("items");

        for (int i = 0; i < jsonArr.length(); i++) {
            JSONObject jsonObj1 = jsonArr.getJSONObject(i);

            // Storing each json item in variable
            String id = jsonObj1.getString(TAG_ID);
            String nameFirst1 = jsonObj1.getString(TAG_FIRSTNAME);
            String nameLast1 = jsonObj1.getString(TAG_LASTNAME);
            String emailAddress1 = jsonObj1.getString(TAG_EMAIL);
            String streetAddress1 = jsonObj1.getString(TAG_ADDRESS);
            String phone1 = jsonObj1.getString(TAG_PHONE);

            // test to see if made it to string
            Log.d("YOUR_TAG", "First Name: " + nameFirst1 + " Last Name: "
                    + nameLast1);

            address = coder.getFromLocationName(streetAddress1, 5);

            Address location1 = address.get(0);

            // SET LAT LNG VALUES FOR MARKER POINT

            lati = location1.getLatitude();
            longi = location1.getLongitude();

            Log.d("Location", "Location:" + lati + " " + longi);

            class LocationData {
                private double lat;
                private double longitude;
                private String name;

                public LocationData(double lat, double longitude,
                        String name) {
                    this.lat = lat;
                    this.longitude = longitude;
                    this.name = name;
                }

                public void setLat(double lat) {
                    this.lat = lat;
                }

                public void setLongitude(double longitude) {
                    this.longitude = longitude;
                }

                public double getLat() {
                    return lat;
                }

                public double getLongitude() {
                    return longitude;
                }

                public void setName(String name) {
                    this.name = name;
                }

                public String getName() {
                    return name;
                }

            }

            ArrayList<LocationData> listOfObjects = new ArrayList<LocationData>();

            listOfObjects.add(new LocationData(lati, longi, nameFirst1));

        }

    } catch (IOException e) {
        e.printStackTrace();
    } catch (JSONException e) {
        // TODO Auto-generated catch block
        e.printStackTrace();
    }
    return (long) 0;

}

// WHAT DO I PUT HERE TO RETURN LocationData Class here
// ADD MARKER TO MAP UI
protected void onPostExecute() {

    // mMap.addMarker(new MarkerOptions()
    // .position(new LatLng(lati, longi))
    // .title("Hello world"));

这看起来很简单，但我已经创建了这个方法: 公共(public) ArrayList getLocationData() {

                                 ArrayList<LocationData> listOfObjects = new ArrayList<LocationData>();

                                 listOfObjects.add(new LocationData(lati, longi, nameFirst1));

                                 return listOfObjects;
                             }

在我的 LocationData 类中。然后我放置 LocationData.getLocationData();使用 onPostExecute，我得到 LocationData 无法解析。目前的代码看起来像这样:

 try {

    String apples = endpoint.listContactInfo().execute().toString();

    JSONObject jObject = new JSONObject(apples);

    JSONArray jsonArr = jObject.getJSONArray("items");

     for(int i =0 ; i<jsonArr.length() ;i++ ){
         JSONObject jsonObj1 = jsonArr.getJSONObject(i);


                    // Storing each json item in variable
                    String id = jsonObj1.getString(TAG_ID);
                    final String nameFirst1 = jsonObj1.getString(TAG_FIRSTNAME);
                    String nameLast1 = jsonObj1.getString(TAG_LASTNAME);
                    String emailAddress1 = jsonObj1.getString(TAG_EMAIL);
                    String streetAddress1 = jsonObj1.getString(TAG_ADDRESS);
                    String phone1 = jsonObj1.getString(TAG_PHONE);

                    //test to see if made it to string
                    Log.d("YOUR_TAG", "First Name: " + nameFirst1 + " Last Name: " + nameLast1);

                       address = coder.getFromLocationName(streetAddress1,5);

                        Address location1 = address.get(0);

                        // SET LAT LNG VALUES FOR MARKER POINT

                     lati = location1.getLatitude();
                         longi = location1.getLongitude();

                         Log.d("Location", "Location:" + lati + " " +  longi);


                       class LocationData {
                             private double lat;
                             private double longitude;
                             private String name;

                             public LocationData(double lat, double longitude, String name) {
                                 this.lat = lat;
                                 this.longitude = longitude;
                                 this.name = name;
                             }

                             public void setLat(double lat) {
                                 this.lat = lat;
                             }

                             public void setLongitude(double longitude) {
                                 this.longitude = longitude;
                             }

                             public double getLat() {
                                 return lat;
                             }

                             public double getLongitude() {
                                 return longitude;
                             }

                             public void setName(String name) {
                                   this.name = name;
                                }

                             public String getName() {
                                 return name;



                                }

                             public ArrayList<LocationData> getLocationData() {

                                 ArrayList<LocationData> listOfObjects = new ArrayList<LocationData>();

                                 listOfObjects.add(new LocationData(lati, longi, nameFirst1));

                                 return listOfObjects;
                             }

                             }

     }

    } catch (IOException e) {
    e.printStackTrace();
  } catch (JSONException e) {
    // TODO Auto-generated catch block
    e.printStackTrace();
}
      return (long) 0;


    }
    //WHAT DO I PUT HERE TO RETURN LocationData Class here
         // ADD MARKER TO MAP UI
    protected void onPostExecute(Long result ) {

                  //CANT BE RESOLVED
        LocationData.getLocationData();

        //mMap.addMarker(new MarkerOptions()
        //.position(new LatLng(lati, longi))
        // .title("Hello world"));

这是我根据@Sustain 的建议所做的更改。我现在似乎没有得到任何 map 标记。有人看到了什么吗？

public class FinderActivity extends Activity implements LocationListener  {


GoogleMap mMap;
Location myLocation;
EditText length;
String lengthString;
LocationManager locationmanager;
double lati;
double longi;
String nameFirst1;
//Spinner s;

   List<Address> address;
   Geocoder coder = new Geocoder(this);
private static final String TAG_ID = "id";
private static final String TAG_FIRSTNAME = "nameFirst";
private static final String TAG_LASTNAME = "nameLast";
private static final String TAG_EMAIL = "emailAddress";
private static final String TAG_ADDRESS = "streetAddress";
private static final String TAG_STATE = "state";

private static final String TAG_PHONE = "phone";
JSONArray contacts = null;


private static class LocationData {
     private double lat;
     private double longitude;
     private String name;

     public LocationData(double lat, double longitude, String name) {
         this.lat = lat;
         this.longitude = longitude;
         this.name = name;
     }

     public void setLat(double lat) {
         this.lat = lat;
     }

     public void setLongitude(double longitude) {
         this.longitude = longitude;
     }

     public double getLat() {
         return lat;
     }

     public double getLongitude() {
         return longitude;
     }

     public void setName(String name) {
           this.name = name;
        }

     public String getName() {
         return name;

        }

     }

@SuppressLint("NewApi")
@Override
public void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.maps);
    mMap = ((MapFragment) getFragmentManager().findFragmentById(R.id.map)).getMap();
    if (mMap!= null) {

        mMap.setMapType(GoogleMap.MAP_TYPE_NORMAL);


        mMap.setMyLocationEnabled(true);
        mMap.animateCamera(CameraUpdateFactory.zoomBy(17));

        }

    LocationManager locationmanager = (LocationManager) getSystemService(LOCATION_SERVICE);
    Criteria cr = new Criteria();
    String provider = locationmanager.getBestProvider(cr, true);

    Location location = locationmanager.getLastKnownLocation(provider);

    locationmanager.requestLocationUpdates(provider, 20, 0, (LocationListener) this);

    mMap.moveCamera(CameraUpdateFactory.newLatLng((new LatLng(location.getLatitude(), location.getLongitude()))));


    new EndpointsTask().execute(getApplicationContext());

}

public class EndpointsTask extends AsyncTask<Context, LocationData, Long> {

    private List<LocationData> locationList = new ArrayList<LocationData>();

    public Long doInBackground(Context... contexts) {

      Contactinfoendpoint.Builder endpointBuilder = new Contactinfoendpoint.Builder(
          AndroidHttp.newCompatibleTransport(),
          new JacksonFactory(),
          new HttpRequestInitializer() {
          public void initialize(HttpRequest httpRequest) { }
          });
  Contactinfoendpoint endpoint = CloudEndpointUtils.updateBuilder(
  endpointBuilder).build();

  try {

    String apples = endpoint.listContactInfo().execute().toString();

    JSONObject jObject = new JSONObject(apples);

    JSONArray jsonArr = jObject.getJSONArray("items");

     for(int i =0 ; i<jsonArr.length() ;i++ ){
         JSONObject jsonObj1 = jsonArr.getJSONObject(i);


                    // Storing each json item in variable
                    String id = jsonObj1.getString(TAG_ID);
                    String nameFirst1 = jsonObj1.getString(TAG_FIRSTNAME);
                    String nameLast1 = jsonObj1.getString(TAG_LASTNAME);
                    String emailAddress1 = jsonObj1.getString(TAG_EMAIL);
                    String streetAddress1 = jsonObj1.getString(TAG_ADDRESS);
                    String phone1 = jsonObj1.getString(TAG_PHONE);

                    //test to see if made it to string
                    Log.d("YOUR_TAG", "First Name: " + nameFirst1 + " Last Name: " + nameLast1);

                       address = coder.getFromLocationName(streetAddress1,5);

                        Address location1 = address.get(0);

                        // SET LAT LNG VALUES FOR MARKER POINT

                     lati = location1.getLatitude();
                         longi = location1.getLongitude();

                         Log.d("Location", "Location:" + lati + " " +  longi);

                         LocationData data = new LocationData(lati, longi, nameFirst1);
                         locationList.add(data);
                         publishProgress(data);

     }

    } catch (IOException e) {
    e.printStackTrace();
  } catch (JSONException e) {
    // TODO Auto-generated catch block
    e.printStackTrace();
}
      return (long) 0;

    }

    protected void onProgressUpdate(LocationData data) {
        // Add Marker on Map using data. This is called by
        // publishProgress(LocationData) on the UI Thread.
        mMap.addMarker(new MarkerOptions()
        .position(new LatLng(lati, longi))
         .title(nameFirst1));

        Log.d("bananas", lati + longi + nameFirst1);
    }

    //WHAT DO I PUT HERE TO RETURN LocationData Class here
         // ADD MARKER TO MAP UI
    protected void onPostExecute() {

    }

    }

Answer 1

LocationData 类定义在一个无法访问的范围内。相反，在它自己的 .java 文件中定义它，如下所示:

class LocationData {
    // final Fields
    // Constructor
    // Getters
}

或者如果您不在其他任何地方使用它，则作为最外层类的私有(private)静态类。

然后对于你的 AsyncTask 子类你可以有类似的东西:

private class AsyncJsonTask extends AsyncTask<Param, LocationData, Void>
{
    private List<LocationData> locationList = new ArrayList<LocationData>();
    // ...
    protected void doInBackground(Param) {
        // ...
        for (int i = 0; i < jsonArr.length(); i++) {
            // Do your stuff with JSon Objects
            // ...
            // Instanciate a new LocationData and pass it as progress:
            LocationData data = new LocationData(latitude, longitude, name);
            locationList.add(data);
            publishProgress(data);
        }
    }

    protected void onProgressUpdate(LocationData data) {
        // Add Marker on Map using data. This is called by
        // publishProgress(LocationData) on the UI Thread.
        mMap.addMarker(/* marker */);
    }

    protected void onPostExecute() {
        // Assign outer class member field the value of the builded list
        // for future reference.
        mLocationList = locationList;
    }
}

这样，您可以在获取下一个标记之前在 map 上单独发布每个标记。

作为旁注，您应该研究静态方法和字段的含义；您对 LocationData.getLocationData() 的调用将无效。