java - 我们需要在哪个 fragment 方法中消费长期的weservice

Question

哪种方法适合从 android fragment 调用 Web 服务？

• oncreateView() 或
• oncreate() 或
• onViewCreated()

Answer 1

使用onStart()方法

• 在 onStart() mentod 中使用 Async Task 调用并运行 后台线程
• 在 AsyncTask 中使用 doInBackground() 来运行采取的方法 执行时间更长
• 在 onPreExecute()、onPostExecute() 中更新 UI 线程， onProgressUpdate()

---

Async task Example :

public class FrgLatein extends Fragment {
    //New-Instance
    public static FrgLatein newInstance(){
        Log.d("FrgLatein", "newInstance");
        FrgLatein fragment = new FrgLatein();
        return  fragment;
    }

    @Override
    public View onCreateView(LayoutInflater inflater, ViewGroup container,
            Bundle savedInstanceState) {
        Log.d("FrgLatein", "onCreateView");
        View view=inflater.inflate(R.layout.frg_latein, container, false);
        setHasOptionsMenu(true);


        return view;
    }

    @Override
    public void onActivityCreated(Bundle savedInstanceState) {
        Log.d("FrgLatein", "onActivityCreated");
        super.onActivityCreated(savedInstanceState);

    }

    @Override
    public void onStart() {
        Log.d("FrgLatein", "onStart");
        super.onStart();
        new LongOperation().execute("");

    }

private class LongOperation extends AsyncTask<String, Void, String> {

        @Override
        protected String doInBackground(String... params) {
             // Do the Web service long run here
            return "Executed";
        }

        @Override
        protected void onPostExecute(String result) {
          // Do the UI-task here
        }

        @Override
        protected void onPreExecute() {
          // Do the UI-task here
        }

        @Override
        protected void onProgressUpdate(Void... values) {
          // Do the UI-task here which has to be done during backgroung tasks are running like a downloading process
        }
    }

}