Question

我在我的应用中使用了导航抽屉。有两个片段。一个用于配置文件，另一个用于反馈。在配置文件片段中，我需要每5秒调用一次函数。所以，我使用了一个处理程序。这里，onStart每5秒调用一次该函数。我认为，这是更改片段时应用崩溃的主要原因。如果我评论onStart和onPause，一切都会好起来的。我该如何处理这个问题？

public class ProfileFragment extends Fragment {

private ListView listView;
TextView textView;

Handler h = new Handler();
int delay = 5000; // 5 seconds
Runnable runnable;

public ProfileFragment() {
    // Required empty public constructor
}

@Override
public View onCreateView(LayoutInflater inflater, ViewGroup container,
                         Bundle savedInstanceState) {
    // Inflate the layout for this fragment
    View view= inflater.inflate(R.layout.fragment_profile, container, false);

    textView = (TextView) view.findViewById(R.id.textViewUsername);
    listView = (ListView) view.findViewById(R.id.listView);
    //sendRequest();
    return view;
}

@Override
public void onViewCreated(View view, @Nullable Bundle savedInstanceState) {
    super.onViewCreated(view, savedInstanceState);
    //you can set the title for your toolbar here for different fragments different titles
    getActivity().setTitle("Profile");
}

@Override
public void onStart() {
//start handler as activity become visible
    h.postDelayed(new Runnable() {
        public void run() {
            //do something
            sendRequest();
            runnable=this;

            h.postDelayed(runnable, delay);
        }
    }, delay);

    super.onStart();
}

@Override
public void onPause() {
    h.removeCallbacks(runnable); //stop handler when activity not visible
    super.onPause();
}

private void sendRequest(){

    StringRequest stringRequest = new StringRequest(Config.LOCATION_URL,
            new Response.Listener<String>() {
                @Override
                public void onResponse(String response) {
                    Log.d("location", response.toString());
                    showJSON(response);
                    //Toast.makeText(getContext().getApplicationContext(), "Data loaded successfully!", Toast.LENGTH_LONG).show();

                }
            },
            new Response.ErrorListener() {
                @Override
                public void onErrorResponse(VolleyError error) {
                    Toast.makeText(getContext().getApplicationContext(),error.getMessage(), Toast.LENGTH_LONG).show();
                }
            });

    RequestQueue requestQueue = Volley.newRequestQueue(this.getActivity().getApplicationContext());
    requestQueue.add(stringRequest);
}
private void showJSON(String json){
    ParseJSON pj = new ParseJSON(json);
    pj.parseJSON();
    CustomList cl = new CustomList(this.getActivity(), ParseJSON.ids,ParseJSON.busNames,ParseJSON.busLocations,ParseJSON.times);
    listView.setAdapter(cl);
  }
}

Answer 1

我建议你使用TimerTask类而不是处理程序来完成一段时间后要重复的任务：

  <ListView ItemsSource="{Binding obsCommonList}" HasUnevenRows="True" BackgroundColor="Black" SeparatorVisibility="None" SelectedItem="{Binding SelectedProp,Mode=TwoWay}">
      <ListView.Behaviors>
          <b:EventToCommandBehavior EventName="ItemTapped" Command="{Binding ItemTappedCommand}"  EventArgsParameterPath="Item"/>
      </ListView.Behaviors>

希望这有帮助。

不幸的是，由于处理程序，在更改导航抽屉中的片段时停止app

1 个答案: