Question

我有一个活动，它根据http请求返回的系列值列表创建一个列表。如果列表包含一个位置列表，我调用下一个活动并通过意图传递一些值。但是，如果响应不包含地点列表，我需要使用新的系列值列表重新填充我的活动，但我不确定如何在我已经进行的活动中调用相同的活动。我的尝试在下面。

编辑：刷新活动的目的是在网址中使用新参数发出https请求。我之前尝试过回忆一下http请求，但没有运气

protected void onPostExecute(JSONObject result){
        ArrayList<String> modelNames = new ArrayList<>();

        Log.d("JSON RESPONSE", result.toString());

        final ArrayList<JSONObject> modelsObjectList = new ArrayList<>();

        try {
            JSONObject info = result.getJSONObject("info");
            JSONArray models = info.getJSONArray("models");

            for(int i = 0; i < models.length(); i++){
                modelsObjectList.add(models.getJSONObject(i));
            }

            for(int i = 0; i < modelsObjectList.size(); i++){
                modelNames.add(modelsObjectList.get(i).getString("name"));
            }

        } catch(JSONException e ){
            Log.d("JSONEXCEPTION", e.getMessage().toString());
        }

        //TODO found problem, model names for whatever reason is passing in the names from previous activity
        Log.d("MODEL NAMES", modelNames.toString());
        Toast.makeText(AfterDestinationActivity.this, modelNames.toString(), Toast.LENGTH_LONG).show();

        mList = (ListView) findViewById(android.R.id.list);
        CustomMainAdapter mainAdapter = new CustomMainAdapter(AfterDestinationActivity.this, modelNames);
        mList.setAdapter(mainAdapter);


        setProgressBarIndeterminateVisibility(false);
        mList.setOnItemClickListener(new AdapterView.OnItemClickListener() {
            String name;
            Long id;
            public void onItemClick(AdapterView<?> parent, View view, int position, long id) {

                JSONObject passingObject = modelsObjectList.get(position);
                ArrayList<String> nextPlacesList = new ArrayList<>();
                Log.d("AD OBJECT PRESSED ON", passingObject.toString());

                //TODO found issues with debugging
                try {

                    JSONArray places;
                    JSONArray series = passingObject.getJSONArray("series");

                    name = passingObject.getString("name");
                    id = passingObject.getLong("id");
                    Log.d("NEXT ACTIVITY NAME", name);
                    System.out.println("NEXT ACTIVITY ID " + id);
                    Log.d("NEXT SERIES LIST", nextPlacesList.toString());

                    //if there are no places, launch http request again for series
                    if(passingObject.optJSONArray("places") == null){
                        ArrayList<String> sameSeries = new ArrayList();
                        System.out.println("WENT INTO FOR LOOP");
                        for(int i = 0; i < series.length(); i++){
                            sameSeries.add(series.getString(i));
                            Log.d("AD FOR LOOP SERIES", series.getString(i));
                        }
                        Intent refreshActivity = new Intent(AfterDestinationActivity.this, AfterDestinationActivity.class);
                        refreshActivity.setFlags(Intent.FLAG_ACTIVITY_CLEAR_TASK | Intent.FLAG_ACTIVITY_NEW_TASK);
                        refreshActivity.putExtra("id", id);
                        refreshActivity.putExtra("name", name);
                        refreshActivity.putExtra("placesList", nextPlacesList);
                        Log.v("RESTARTING ACTIVIY", "activity restating");
                        startActivity(refreshActivity);

                    }

                } catch(JSONException e){
                    Log.d("JSONEXCEPTION", "IN THERE " + e.getMessage());
                }

                Intent intent = new Intent(AfterDestinationActivity.this, PlacesListActivity.class);
                intent.putExtra("id", id);
                intent.putExtra("name", name);
                intent.putExtra("placesList", nextPlacesList);
                startActivity(intent);

            }
        });
    }

Answer 1

只需使用此，将此添加到您的清单中，

<activity android:name=".StartActivity" android:label="@string/app_name"
                android:clearTaskOnLaunch="true">
</activity>

从JAVA代码中使用此，

 Intent refreshActivity = new Intent(AfterDestinationActivity.this, AfterDestinationActivity.class);
                        refreshActivity.putExtra("id", id);
                        refreshActivity.putExtra("name", name);
                        refreshActivity.putExtra("placesList", nextPlacesList);
                        Log.v("RESTARTING ACTIVIY", "activity restarting");
                        startActivity(refreshActivity);

Answer 2

您不需要拨打相同的活动。只需使用活动中的新值更新相应的视图即可。

Answer 3

我会通过＆＃34;这个指针＆＃34;来访问它。或界面：

的修改

MyActivity extends Activity implements IUpdateListener
{
    public void onCreate(Bundle onSaveInstanceState)
    {
      //code
    }

    @Override
    void onUpdate(Result result)
    {
       //update data or do other stuff - like start another activity or populate urs.
    }
 }

下一篇AsynTask：

    MyAsyncTask extends AsyncTask<Void, Void, Result>
   {

       private IUpdateListener listener;
       public MyAsyncTask(IUpdateListener listener)
       {
          this.listener = listener;
       }

       Result doInBackground(Void.. voids)
      {
          //http request and parse - an object Result
         return result data;
      }
      void onPostExecute(Result result)
      {
         if(result!=null) - or other operation u want
         {
            listener.OnUpdate(result) - or other stuff you want.
         }
      }

接下来的界面：

interface IOnUpdateListener
{
   onUpdate(Result result);
}

＆＃34;这个指针＆＃34;： How can I access my Activity's instance variables from within an AlertDialog's onClickListener?
我希望我很清楚。

如何在同一活动中调用活动？

3 个答案: