如何访问填写的AsyncTask，从另一个类的ListView？ [英] How to access a listview that filled in asynctask, from another class?

问题描述

我开发使用服务的Andr​​oid应用程序。我正在从服务信息和保持JSON数据到ArrayList中它是好的，但我从另一个类需要这些数据。我试图访问该数组列表，但它给空每次我试图。这里是我的code：

 公共类AllVehicles扩展android.app.Fragment {
公众的ArrayList＆LT;汽车与GT; vehicleList =新的ArrayList＆LT;车辆与GT;（）;
公共AllVehicles（）{}@覆盖
公共无效的onCreate（捆绑savedInstanceState）{
    super.onCreate（savedInstanceState）;
    GetAllVehicles getAllVehicles =新GetAllVehicles（）;
    getAllVehicles.execute（TR101，member.getAuthToken（）的toString（），将String.valueOf（member.getMemberId（）），将String.valueOf（member.getFirmId（））。）;
}
异步任务// onPostExecute
 保护无效onPostExecute（长效）{
            尝试{
                JSONObject的jsonObj =新的JSONObject（response_vehicles）;
                JSONArray jsonArray = jsonObj.getJSONArray（VehicleOnlineList）;
                的for（int i = 0; I＆LT; jsonArray.length（）;我++）{
                    车辆=新车（）;
                    vehicle_report =新车（）;
                    JSONArray jsonArr = jsonArray.getJSONArray（ⅰ）;
                    vehicle.setVehicleId（jsonArr.isNull（0）？0：jsonArr.getInt（0））;
                    vehicle.setDeviceId（jsonArr.isNull（1）？0：jsonArr.getInt（1））;
                    vehicle.setPlate（jsonArr.isNull（2），：jsonArr.getString（2））;
                    vehicle.setVehicleName（jsonArr.isNull（3），：jsonArr.getString（3））;
                    vehicleList.add（车辆）;
                }
//调用vehicleList的方法：
公众的ArrayList＆LT;汽车与GT; getVehicleReportList（）{
        返回vehicleList;
    }
 

这是我想打电话给该列表中的类：

 公共类ReportActivity扩展android.app.Fragment {
    车辆的车辆;
    AllVehicles allVehicles;
    公共ReportActivity（）{
    }
公共查看onCreateView（LayoutInflater充气器，容器的ViewGroup，
                             捆绑savedInstanceState）{
        查看查看= inflater.inflate（R.layout.fragment_report_activity，集装箱，FALSE）;
        allVehicles =新AllVehicles（）;
        ArrayList的＆LT;汽车与GT; vehicleArrayList = allVehicles.getVehicleReportList（）;
}
 

解决方案

 公共静态的ArrayList＆LT;汽车与GT; vehicleList =新的ArrayList＆LT;车辆与GT;（）;
 

和使用 AllVehicles.vehicleList 在任何你想使用。

I am developing an android application that uses services. I am getting info from that service and hold json data into arraylist it is okay but I need these data from another class. I am trying to access this array list but it gives null every time I try. Here is my code:

public class AllVehicles extends android.app.Fragment {
public ArrayList<Vehicle> vehicleList= new ArrayList<Vehicle>();
public AllVehicles() {}

@Override
public void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);       
    GetAllVehicles getAllVehicles=new GetAllVehicles();
    getAllVehicles.execute("tr101", member.getAuthToken().toString(), String.valueOf(member.getMemberId()), String.valueOf(member.getFirmId()));
}
//onPostExecute of async task
 protected void onPostExecute(Long result) {
            try {
                JSONObject jsonObj = new JSONObject(response_vehicles);
                JSONArray jsonArray = jsonObj.getJSONArray("VehicleOnlineList");                      
                for (int i = 0; i < jsonArray.length(); i++) {
                    vehicle = new Vehicle();
                    vehicle_report=new Vehicle();
                    JSONArray jsonArr = jsonArray.getJSONArray(i);
                    vehicle.setVehicleId(jsonArr.isNull(0) ? 0 : jsonArr.getInt(0));
                    vehicle.setDeviceId(jsonArr.isNull(1) ? 0 : jsonArr.getInt(1));
                    vehicle.setPlate(jsonArr.isNull(2) ? "" : jsonArr.getString(2));
                    vehicle.setVehicleName(jsonArr.isNull(3) ? "" : jsonArr.getString(3));
                    vehicleList.add(vehicle);               
                }
//The method for calling vehicleList:
public ArrayList<Vehicle> getVehicleReportList(){
        return vehicleList;
    }

The class that I want to call this List:

public class ReportActivity extends android.app.Fragment {
    Vehicle vehicle;
    AllVehicles allVehicles;
    public ReportActivity() {
    }
public View onCreateView(LayoutInflater inflater, ViewGroup container,
                             Bundle savedInstanceState) {
        View view = inflater.inflate(R.layout.fragment_report_activity, container, false);
        allVehicles=new AllVehicles();
        ArrayList<Vehicle> vehicleArrayList=allVehicles.getVehicleReportList();
}

解决方案

public static ArrayList<Vehicle> vehicleList= new ArrayList<Vehicle>();

and use AllVehicles.vehicleList where ever you want to use.

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