Fatal编程技术网
  • java/
  • Java 如何从其他类（即活动类）中的（AsyncTask）获取列表值。。？

Java 如何从其他类（即活动类）中的（AsyncTask）获取列表值。。？

java android

Java 如何从其他类（即活动类）中的（AsyncTask）获取列表值。。？,java,android,android-asynctask,Java,Android,Android Asynctask,当我想从AsyncTask类中的全局变量获取值时，我遇到了一个问题。我想从另一个班级叫它 以下是我的AsyncTask类代码： public class PlacesDisplayTask extends AsyncTask<Object, Integer, List<HashMap<String, String>>> { List<NearbyPlaceModel> data_place = new ArrayList<>(

当我想从AsyncTask类中的全局变量获取值时，我遇到了一个问题。我想从另一个班级叫它

以下是我的AsyncTask类代码：

public class PlacesDisplayTask extends AsyncTask<Object, Integer, List<HashMap<String, String>>> {

    List<NearbyPlaceModel> data_place = new ArrayList<>();
    JSONObject googlePlacesJson;
    GoogleMap googleMap;

    @Override
    protected List<HashMap<String, String>> doInBackground(Object... inputObj) {

        List<HashMap<String, String>> googlePlacesList = null;
        Places placeJsonParser = new Places();

        try {
            googleMap = (GoogleMap) inputObj[0];
            googlePlacesJson = new JSONObject((String) inputObj[1]);
            googlePlacesList = placeJsonParser.parse(googlePlacesJson);
        } catch (Exception e) {
            Log.d("Exception", e.toString());
        }
        return googlePlacesList;
    }

    @Override
    protected void onPostExecute(List<HashMap<String, String>> list) {
        googleMap.clear();
        data_place.clear();
        for (int i = 0; i < list.size(); i++) {
            if(i < 10 ) {
                HashMap<String, String> googlePlace = list.get(i);
                double lat = Double.parseDouble(googlePlace.get("lat"));
                double lng = Double.parseDouble(googlePlace.get("lng"));
                String placeName = googlePlace.get("place_name");
                String vicinity = googlePlace.get("vicinity");
                LatLng latLng = new LatLng(lat, lng);
                markerOptions.icon(BitmapDescriptorFactory.fromBitmap(Configure.getBitmapFromURL(googlePlace.get("icon"))));
                markerOptions.title(placeName + " : " + vicinity);
                googleMap.addMarker(markerOptions);

                NearbyPlaceModel items = new NearbyPlaceModel();
                items.setVicinity(vicinity);
                items.setPlace_name(placeName);
                items.setLat(String.valueOf(lat));
                items.setLang(String.valueOf(lng));
                data_place.add(items);
            }
        }
    }

}
还是我的代码有问题？

如果我理解正确！在AsyncTask类中创建getter和setter方法。通过这种方式，您可以从活动中获取数据和设置数据

    public List<NearbyPlaceModel> getData_place() {
            return data_place;
        }

    public void setData_place(List<NearbyPlaceModel> data_place) {
            this.data_place = data_place;
        }

public List getData_place（）{
返回数据的位置；
}
公共作废设置数据位置（列出数据位置）{
this.data\u place=数据位置；
}
如果我理解正确！在AsyncTask类中创建getter和setter方法。通过这种方式，您可以从活动中获取数据和设置数据

    public List<NearbyPlaceModel> getData_place() {
            return data_place;
        }

    public void setData_place(List<NearbyPlaceModel> data_place) {
            this.data_place = data_place;
        }

public List getData_place（）{
返回数据的位置；
}
公共作废设置数据位置（列出数据位置）{
this.data\u place=数据位置；
}
您可以通过使用接口获得结果

  • 使用所需的回调方法创建接口
  • 在你的活动中实施它
  • 您将在回调方法中得到结果
    • 这里我给你一个基于你的代码的例子。 您的MainActivity类应该是这样的-

     public class MainActivity extends AppCompatActivity implements PlaceInterface{

     @Override
     protected void onCreate(Bundle savedInstanceState) {
         super.onCreate(savedInstanceState);
         setContentView(R.layout.activity_main);

         // your code...

         // calling the AsyncTask and send reference of the interface on it
         new PlacesDisplayTask(this).execute();  // something like this

     }


     @Override
     public void myPlaceList(ArrayList<NearbyPlaceModel>   nearbyPlaceModelArrayList) {
         ListView nearby_place = (ListView)  findViewById(R.id.itemListView);
         ListAdapter customAdapter = new ListAdapter(this, R.layout.nearby_place_listview, nearbyPlaceModelArrayList);
         nearby_place.setAdapter(customAdapter);
     }
}

     public class PlacesDisplayTask extends AsyncTask<Object, Integer, List<HashMap<String, String>>> {

     ArrayList<NearbyPlaceModel> data_place = new ArrayList<>();   // change
     JSONObject googlePlacesJson;
     GoogleMap googleMap;
     PlaceInterface placeInterface;    // change

     public PlacesDisplayTask(PlaceInterface placeInterface){   // change
         this.placeInterface = placeInterface;
     }

     @Override
     protected List<HashMap<String, String>> doInBackground(Object... inputObj) {

         List<HashMap<String, String>> googlePlacesList = null;
         Places placeJsonParser = new Places();

         try {
             googleMap = (GoogleMap) inputObj[0];
             googlePlacesJson = new JSONObject((String) inputObj[1]);
             googlePlacesList = placeJsonParser.parse(googlePlacesJson);
         } catch (Exception e) {
             Log.d("Exception", e.toString());
         }
         return googlePlacesList;
     }

     @Override
     protected void onPostExecute(List<HashMap<String, String>> list) {
         googleMap.clear();
         data_place.clear();
         for (int i = 0; i < list.size(); i++) {
             if(i < 10 ) {
                 HashMap<String, String> googlePlace = list.get(i);
                 double lat = Double.parseDouble(googlePlace.get("lat"));
                 double lng = Double.parseDouble(googlePlace.get("lng"));
                 String placeName = googlePlace.get("place_name");
                 String vicinity = googlePlace.get("vicinity");
                 LatLng latLng = new LatLng(lat, lng);
             markerOptions.icon(BitmapDescriptorFactory.fromBitmap(Configure.getBitmapFromURL(googlePlace.get("icon"))));
                 markerOptions.title(placeName + " : " + vicinity);
                 googleMap.addMarker(markerOptions);

                 NearbyPlaceModel items = new NearbyPlaceModel();
                 items.setVicinity(vicinity);
                 items.setPlace_name(placeName);
                 items.setLat(String.valueOf(lat));
                 items.setLang(String.valueOf(lng));
                 data_place.add(items);

                 placeInterface.myPlaceList(data_place);  // change
             }
         }
     }

 }

    public类MainActivity扩展AppCompatActivity实现PlaceInterface{
@凌驾
创建时受保护的void（Bundle savedInstanceState）{
super.onCreate（savedInstanceState）；
setContentView（R.layout.activity_main）；
//你的代码。。。
//调用AsyncTask并发送其上接口的引用
new PlacesDisplayTask（this）.execute（）；//类似这样的内容
}
@凌驾
public void myPlaceList（ArrayList nearbyPlaceModelArrayList）{
ListView附近的位置=（ListView）findViewById（R.id.itemListView）；
ListAdapter customAdapter=新的ListAdapter（这个，R.layout.nearear\u place\u listview，nearbyPlaceModelArrayList）；
附近的_place.setAdapter（customAdapter）；
}
}
    您的PlacesDisplayTask类应该是这样的-

     public class MainActivity extends AppCompatActivity implements PlaceInterface{

     @Override
     protected void onCreate(Bundle savedInstanceState) {
         super.onCreate(savedInstanceState);
         setContentView(R.layout.activity_main);

         // your code...

         // calling the AsyncTask and send reference of the interface on it
         new PlacesDisplayTask(this).execute();  // something like this

     }


     @Override
     public void myPlaceList(ArrayList<NearbyPlaceModel>   nearbyPlaceModelArrayList) {
         ListView nearby_place = (ListView)  findViewById(R.id.itemListView);
         ListAdapter customAdapter = new ListAdapter(this, R.layout.nearby_place_listview, nearbyPlaceModelArrayList);
         nearby_place.setAdapter(customAdapter);
     }
}

     public class PlacesDisplayTask extends AsyncTask<Object, Integer, List<HashMap<String, String>>> {

     ArrayList<NearbyPlaceModel> data_place = new ArrayList<>();   // change
     JSONObject googlePlacesJson;
     GoogleMap googleMap;
     PlaceInterface placeInterface;    // change

     public PlacesDisplayTask(PlaceInterface placeInterface){   // change
         this.placeInterface = placeInterface;
     }

     @Override
     protected List<HashMap<String, String>> doInBackground(Object... inputObj) {

         List<HashMap<String, String>> googlePlacesList = null;
         Places placeJsonParser = new Places();

         try {
             googleMap = (GoogleMap) inputObj[0];
             googlePlacesJson = new JSONObject((String) inputObj[1]);
             googlePlacesList = placeJsonParser.parse(googlePlacesJson);
         } catch (Exception e) {
             Log.d("Exception", e.toString());
         }
         return googlePlacesList;
     }

     @Override
     protected void onPostExecute(List<HashMap<String, String>> list) {
         googleMap.clear();
         data_place.clear();
         for (int i = 0; i < list.size(); i++) {
             if(i < 10 ) {
                 HashMap<String, String> googlePlace = list.get(i);
                 double lat = Double.parseDouble(googlePlace.get("lat"));
                 double lng = Double.parseDouble(googlePlace.get("lng"));
                 String placeName = googlePlace.get("place_name");
                 String vicinity = googlePlace.get("vicinity");
                 LatLng latLng = new LatLng(lat, lng);
             markerOptions.icon(BitmapDescriptorFactory.fromBitmap(Configure.getBitmapFromURL(googlePlace.get("icon"))));
                 markerOptions.title(placeName + " : " + vicinity);
                 googleMap.addMarker(markerOptions);

                 NearbyPlaceModel items = new NearbyPlaceModel();
                 items.setVicinity(vicinity);
                 items.setPlace_name(placeName);
                 items.setLat(String.valueOf(lat));
                 items.setLang(String.valueOf(lng));
                 data_place.add(items);

                 placeInterface.myPlaceList(data_place);  // change
             }
         }
     }

 }

    公共类位置显示任务扩展异步任务{
ArrayList data_place=新建ArrayList（）；//更改
JSONObject googlePlacesJson；
谷歌地图谷歌地图；
PlaceInterface PlaceInterface；//更改
公共场所显示任务（场所界面场所界面）{//change
this.placeInterface=placeInterface；
}
@凌驾
受保护列表doInBackground（对象…inputObj）{
列表googlePlacesList=null；
Places placeJsonParser=new Places（）；
试一试{
googleMap=（googleMap）inputObj[0]；
googlePlacesJson=新的JSONObject（（字符串）inputObject[1]）；
googlePlacesList=placeJsonParser.parse（googlePlacesJson）；
}捕获（例外e）{
Log.d（“异常”，例如toString（））；
}
返回谷歌PlacesList；
}
@凌驾
受保护的void onPostExecute（列表）{
googleMap.clear（）；
数据_place.clear（）；
对于（int i=0；i
    这就是界面-

     public interface PlaceInterface {
     void myPlaceList(ArrayList<NearbyPlaceModel> nearbyPlaceModelArrayList);
 }

    公共接口PlaceInterface{
作废我的PlaceList（ArrayList靠近PlaceModelArrayList）；
}
    希望这对您有所帮助。：）

    您可以使用接口获得结果

  • 使用所需的回调方法创建接口
  • 在你的活动中实施它
  • 您将在回调方法中得到结果
    • 这里我给你一个基于你的代码的例子。 您的MainActivity类应该是这样的-

     public class MainActivity extends AppCompatActivity implements PlaceInterface{

     @Override
     protected void onCreate(Bundle savedInstanceState) {
         super.onCreate(savedInstanceState);
         setContentView(R.layout.activity_main);

         // your code...

         // calling the AsyncTask and send reference of the interface on it
         new PlacesDisplayTask(this).execute();  // something like this

     }


     @Override
     public void myPlaceList(ArrayList<NearbyPlaceModel>   nearbyPlaceModelArrayList) {
         ListView nearby_place = (ListView)  findViewById(R.id.itemListView);
         ListAdapter customAdapter = new ListAdapter(this, R.layout.nearby_place_listview, nearbyPlaceModelArrayList);
         nearby_place.setAdapter(customAdapter);
     }
}

     public class PlacesDisplayTask extends AsyncTask<Object, Integer, List<HashMap<String, String>>> {

     ArrayList<NearbyPlaceModel> data_place = new ArrayList<>();   // change
     JSONObject googlePlacesJson;
     GoogleMap googleMap;
     PlaceInterface placeInterface;    // change

     public PlacesDisplayTask(PlaceInterface placeInterface){   // change
         this.placeInterface = placeInterface;
     }

     @Override
     protected List<HashMap<String, String>> doInBackground(Object... inputObj) {

         List<HashMap<String, String>> googlePlacesList = null;
         Places placeJsonParser = new Places();

         try {
             googleMap = (GoogleMap) inputObj[0];
             googlePlacesJson = new JSONObject((String) inputObj[1]);
             googlePlacesList = placeJsonParser.parse(googlePlacesJson);
         } catch (Exception e) {
             Log.d("Exception", e.toString());
         }
         return googlePlacesList;
     }

     @Override
     protected void onPostExecute(List<HashMap<String, String>> list) {
         googleMap.clear();
         data_place.clear();
         for (int i = 0; i < list.size(); i++) {
             if(i < 10 ) {
                 HashMap<String, String> googlePlace = list.get(i);
                 double lat = Double.parseDouble(googlePlace.get("lat"));
                 double lng = Double.parseDouble(googlePlace.get("lng"));
                 String placeName = googlePlace.get("place_name");
                 String vicinity = googlePlace.get("vicinity");
                 LatLng latLng = new LatLng(lat, lng);
             markerOptions.icon(BitmapDescriptorFactory.fromBitmap(Configure.getBitmapFromURL(googlePlace.get("icon"))));
                 markerOptions.title(placeName + " : " + vicinity);
                 googleMap.addMarker(markerOptions);

                 NearbyPlaceModel items = new NearbyPlaceModel();
                 items.setVicinity(vicinity);
                 items.setPlace_name(placeName);
                 items.setLat(String.valueOf(lat));
                 items.setLang(String.valueOf(lng));
                 data_place.add(items);

                 placeInterface.myPlaceList(data_place);  // change
             }
         }
     }

 }

    public类MainActivity扩展AppCompatActivity实现PlaceInterface{
@凌驾
创建时受保护的void（Bundle savedInstanceState）{
super.onCreate（savedInstanceState）；
setContentView（R.layout.activity_main）；
//你的代码。。。
//调用AsyncTask并发送其上接口的引用
new PlacesDisplayTask（this）.execute（）；//类似这样的内容
}
@凌驾
public void myPlaceList（ArrayList nearbyPlaceModelArrayList）{
ListView附近的位置=（ListView）findViewById（R.id.itemListView）；
ListAdapter customAdapter=新的ListAdapter（这个，R.layout.nearear\u place\u listview，nearbyPlaceModelArrayList）；
附近的_place.setAdapter（customAdapter）；
}
}
    您的PlacesDisplayTask类应该是这样的-

     public class MainActivity extends AppCompatActivity implements PlaceInterface{

     @Override
     protected void onCreate(Bundle savedInstanceState) {
         super.onCreate(savedInstanceState);
         setContentView(R.layout.activity_main);

         // your code...

         // calling the AsyncTask and send reference of the interface on it
         new PlacesDisplayTask(this).execute();  // something like this

     }


     @Override
     public void myPlaceList(ArrayList<NearbyPlaceModel>   nearbyPlaceModelArrayList) {
         ListView nearby_place = (ListView)  findViewById(R.id.itemListView);
         ListAdapter customAdapter = new ListAdapter(this, R.layout.nearby_place_listview, nearbyPlaceModelArrayList);
         nearby_place.setAdapter(customAdapter);
     }
}

     public class PlacesDisplayTask extends AsyncTask<Object, Integer, List<HashMap<String, String>>> {

     ArrayList<NearbyPlaceModel> data_place = new ArrayList<>();   // change
     JSONObject googlePlacesJson;
     GoogleMap googleMap;
     PlaceInterface placeInterface;    // change

     public PlacesDisplayTask(PlaceInterface placeInterface){   // change
         this.placeInterface = placeInterface;
     }

     @Override
     protected List<HashMap<String, String>> doInBackground(Object... inputObj) {

         List<HashMap<String, String>> googlePlacesList = null;
         Places placeJsonParser = new Places();

         try {
             googleMap = (GoogleMap) inputObj[0];
             googlePlacesJson = new JSONObject((String) inputObj[1]);
             googlePlacesList = placeJsonParser.parse(googlePlacesJson);
         } catch (Exception e) {
             Log.d("Exception", e.toString());
         }
         return googlePlacesList;
     }

     @Override
     protected void onPostExecute(List<HashMap<String, String>> list) {
         googleMap.clear();
         data_place.clear();
         for (int i = 0; i < list.size(); i++) {
             if(i < 10 ) {
                 HashMap<String, String> googlePlace = list.get(i);
                 double lat = Double.parseDouble(googlePlace.get("lat"));
                 double lng = Double.parseDouble(googlePlace.get("lng"));
                 String placeName = googlePlace.get("place_name");
                 String vicinity = googlePlace.get("vicinity");
                 LatLng latLng = new LatLng(lat, lng);
             markerOptions.icon(BitmapDescriptorFactory.fromBitmap(Configure.getBitmapFromURL(googlePlace.get("icon"))));
                 markerOptions.title(placeName + " : " + vicinity);
                 googleMap.addMarker(markerOptions);

                 NearbyPlaceModel items = new NearbyPlaceModel();
                 items.setVicinity(vicinity);
                 items.setPlace_name(placeName);
                 items.setLat(String.valueOf(lat));
                 items.setLang(String.valueOf(lng));
                 data_place.add(items);

                 placeInterface.myPlaceList(data_place);  // change
             }
         }
     }

 }

    公共类位置显示任务扩展异步任务{
ArrayList data_place=新建ArrayList（）；//更改
JSONObject googlePlacesJson；
谷歌地图谷歌地图；
PlaceInterface PlaceInterface；//更改
公共场所显示任务（场所界面场所界面）{//change
this.placeInterface=placeInterface；
}
@凌驾
受保护列表背景（O）