Question

我在Android App ListView中工作，在片段片段下工作，但我无法使其工作。我收到一条错误消息：

对于新的Runnable（）{}
，未定义
setListAdapter方法（ListAdapter）

我不知道我需要改变什么才能让它发挥作用。

public class FragmentA extends Fragment {

    private String url = "http://192.168.2.150/54_tower/Json_Tower.php";

    private static final String J_NAME = "t_name";
    private static final String J_NUM = "t_num";
    private static final String J_FLOOR = "t_floor";
    private static final String J_CLASS = "t_room_class";
    private static final String J_TEACHER = "t_room_teacher";
    private static final String J_TOILET = "t_toilet";
    private static final String J_MAP = "t_map";

    private static final String D_NAME = "NAME";
    private static final String D_NUM = "NUM";
    private static final String D_FLOOR = "FLOOR";
    private static final String D_CLASS = "CLASS";
    private static final String D_TEACHER = "TEACHER";
    private static final String D_TOILET = "TOILET";
    private static final String D_MAP = "MAP";

    private static final String TAG_SUCCESS = "success";
    private static final String TAG_PRODUCTS = "products";

    Activity act;
    ListView ListView1;

    JSONArray products = null;

    private ProgressDialog pDialog;

    JSONParser jParser = new JSONParser();

    ArrayList<HashMap<String, String>> MyArrList;

    public static FragmentA newInstance(int page, String title) {
        FragmentA fragmentFirst = new FragmentA();
        Bundle args = new Bundle();
        args.putInt("someInt", page);
        args.putString("someTitle", title);
        fragmentFirst.setArguments(args);
        return fragmentFirst;
    }

    public View onCreateView(LayoutInflater inflater, ViewGroup container,
            Bundle savedInstanceState) {
        View rootView = inflater.inflate(R.layout.main_tower, container, false);

        // Permission StrictMode
        if (android.os.Build.VERSION.SDK_INT > 9) {
            StrictMode.ThreadPolicy policy = new StrictMode.ThreadPolicy.Builder()
                    .permitAll().build();
            StrictMode.setThreadPolicy(policy);
        }

        MyArrList = new ArrayList<HashMap<String, String>>();

        new LoadAllData().execute();

        final ListView lisView1 = (ListView) rootView
                .findViewById(R.id.listView1);

        lisView1.setOnItemClickListener(new OnItemClickListener() {

            public void onItemClick(AdapterView<?> parent, View view,
                    int position, long id) {

                Intent i = new Intent(getActivity(), Map.class);
                startActivity(i);

            }
        });

        return rootView;
    }

    public void onActivityResult(int requestCode, int resultCode, Intent data) {
        super.onActivityResult(requestCode, resultCode, data);
        // if result code 100
        if (resultCode == 100) {
            // if result code 100 is received
            // means user edited/deleted product
            // reload this screen again
            // Intent intent = act.getIntent();
            // act.finish();
            // startActivity(intent);
        }

    }

    class LoadAllData extends AsyncTask<String, String, String> {

        protected void onPreExecute() {
            super.onPreExecute();
            pDialog = new ProgressDialog(getActivity());
            pDialog.setMessage("Loading Please wait...");
            pDialog.setIndeterminate(false);
            pDialog.setCancelable(false);
            pDialog.show();
        }

        protected String doInBackground(String... args) {

            List<NameValuePair> params = new ArrayList<NameValuePair>();

            JSONObject json = jParser.makeHttpRequest(url, "GET", params);

            Log.d("All JSon: ", json.toString());

            try {
                int success = json.getInt(TAG_SUCCESS);

                if (success == 1) {
                    products = json.getJSONArray(TAG_PRODUCTS);

                    HashMap<String, String> map = new HashMap<String, String>();

                    // Log.d("TAG JSON",""+data.toString());

                    for (int i = 0; i < products.length(); i++) {
                        JSONObject c = products.getJSONObject(i);

                        // adding each child node to HashMap key => value
                        map = new HashMap<String, String>();
                        map.put(D_NAME, c.getString(J_NAME));
                        map.put(D_NUM, c.getString(J_NUM));
                        map.put(D_FLOOR, c.getString(J_FLOOR));
                        map.put(D_CLASS, c.getString(J_CLASS));
                        map.put(D_TEACHER, c.getString(J_TEACHER));
                        map.put(D_TOILET, c.getString(J_TOILET));
                        map.put(D_MAP, c.getString(J_MAP));

                        MyArrList.add(map);
                    }
                } else {
                    // no products found
                    // Launch Add New product Activity
                    // Intent i = new Intent(getApplicationContext(),
                    // NewProductActivity.class);
                    // Closing all previous activities
                    // i.addFlags(Intent.FLAG_ACTIVITY_CLEAR_TOP);
                    // startActivity(i);
                }
            } catch (JSONException e) {
                e.printStackTrace();
            }

            return null;
        }

        protected void onPostExecute(String file_url) {
            pDialog.dismiss();

            final ArrayList<HashMap<String, String>> MyArrList = new ArrayList<HashMap<String, String>>();
            final ListView myList = (ListView) getView().findViewById(
                    R.id.listView1);

            act.runOnUiThread(new Runnable() {
                public void run() {
                    ListAdapter sAdap = new SimpleAdapter(getActivity(),
                            MyArrList, R.layout.tower_column, new String[] {
                                    D_NAME, D_NUM, D_FLOOR, D_CLASS, D_TEACHER,
                                    D_TOILET, D_MAP }, new int[] { R.id.Name,
                                    R.id.Num, R.id.Floor, R.id.Room_Class,
                                    R.id.Room_Teacher, R.id.Toilet });
                    myList.setAdapter(sAdap);
                }
            });

        }

    }
}

这是LogCat：Image LogCat

Answer 1

自从您在UI线程上启动任务后，您无需在UI线程onPostExecute上发布。删除runOnUIThread，它应该可以。

Answer 2

而不是runOnUIThread只需创建一个Handler并将此runnable发布到该处理程序。

还将listview创建为此类的字段，并在onCreateView或onActivityCreated中获取它的引用。我认为它导致nullPointerException。重要的是你应该将Listview作为片段类的字段，而不是将它放在方法的本地范围内。

ListView中的.setAdapter上的NullPointerException与ListView不起作用

2 个答案: