java - 如何在android中将arraylist变量从一个类调用到另一个类

Question

如何在 android 中从一个类到另一个类调用 ArrayList 变量？我从 Json 服务构建了 ArrayList，我尝试了很多方法，但是在如何从一个类到另一个类调用数组列表时遇到问题。我使用以下代码通过 HashMap 构建数组列表:

下面显示的是 FirstActivityCLass

protected Integer doInBackground(Void... arg0) {

            try {
                
                JSONObject e = null;
                System.out.println("In Background...");
                StrictMode.ThreadPolicy policy = new StrictMode.ThreadPolicy.Builder()
                        .detectAll().penaltyLog().build();
                StrictMode.setThreadPolicy(policy);
                String API = "http://traininglabs.com/nic/a-remainders-list.php?email="+email;
                System.out.println(API);
                JSONObject loginjson = JSONfunctions1.getJSONfromURL(API);
                responseArray=loginjson.getJSONArray("user");
                
                mylist=new ArrayList<HashMap<String,String>>();
                for (int i = 0; i < responseArray.length(); i++)
                        {
                    map = new HashMap<String, String>();                     

                JSONObject obj= responseArray.getJSONObject(i);

                    **String ss = obj.getString("id");
                    map.put("id", obj.getString("id"));**
                    map.put("state", obj.getString("status"));
                    map.put("entity", obj.getString("company"));
                    map.put("date", obj.getString("adate"));
                     s1 = e.getString("state");
                     s2 = e.getString("entity");
                     s3 = e.getString("date");
                    System.out.println("this is string--->" + ss);
                    mylist.add(map);
                }

            } catch (Exception e) {
                Log.d("Error", "Error in API" + e.getStackTrace().toString());
                return 1;
            }
            return 0;
        }

这是我的 ArryaList 的第二个 Activity 参数是 id

protected Integer doInBackground(Void... arg0) {

            System.out.println("In Background...");
            StrictMode.ThreadPolicy policy = new StrictMode.ThreadPolicy.Builder()
            .detectAll().penaltyLog().build();
    StrictMode.setThreadPolicy(policy);

            try {
                String ssp_state = sp_state.getSelectedItem().toString();
                String ssp_entity = sp_entity.getSelectedItem().toString();
                String ssp_date = sp_date.getText().toString();
                String ssp_time = sp_time.getText().toString();

                String API = "http://traininglabs.com/projects/nic/a-edit-remainder.php?id="+**id**+ "&email="+ mail_str+ "&sid="+ sp_id+ "entity="+ ssp_entity+datetime="+ ssp_date+ ssp_time;
                System.out.println(API);

                JSONArray loginjson = JSONfunctions.getJSONfromURL(API);

                Log.d(TAG, "JSON_RES" + loginjson);

                return 0;

            } catch (Exception e) {
                Log.d("Error", "Error in API" + e.getStackTrace().toString());
                return 1;

            } // return null;

        }

Answer 1

将其设为全局，或将其放入单例中，这是一种更复杂但更持久的方式，因为您通过共享首选项处理网络共享。