doinbackground中的runOnUiThread

Question

我想在UI线程上运行doinbackground()，但是出现cannot resolve runOnUiThread错误。我需要这样做，因为主线程上的负载过多

这是我的活动：

public class valance extends Fragment {


Button get,add;
ListView list;
SimpleAdapter ADAhere;
ProgressBar progressBar;
Connection connect;
String ConnectionResult = "";
@Override
public View onCreateView(LayoutInflater inflater, ViewGroup container,
                         Bundle savedInstanceState) {
    View rootView = inflater.inflate(R.layout.fragment_valance, container, false);

    list = (ListView)rootView.findViewById(R.id.raill);
    add = (Button)rootView.findViewById(R.id.btn_add);
    progressBar = (ProgressBar)rootView.findViewById(R.id.PB_Getting);
    progressBar.setVisibility(View.GONE);

    add.setOnClickListener(new View.OnClickListener() {
        @Override
        public void onClick(View v) {
            Intent i = new Intent(getActivity(),Add_valance.class);
            startActivity(i);
        }
    });


    new GetValence().execute();





    list.setOnItemClickListener(new AdapterView.OnItemClickListener() {



        @Override
        public void onItemClick(AdapterView<?> parent, View view, int position, long id) {
            /** To change selected state view */
            view.setSelected(true);
            HashMap<String, Object> obj = (HashMap<String, Object>) ADAhere.getItem(position);
            String SlectedName = (String) obj.get("NAME");
            String SlectedPrice = (String) obj.get("PRICE");
            String SlectedSize = (String) obj.get("SIZE");
            String SlectedRange = (String) obj.get("RANGE");
            String SlectedSupp = (String) obj.get("SUPPLIER");
           // Toast.makeText(getActivity().getApplicationContext(), SlectedName, Toast.LENGTH_SHORT).show();

            final Dialog dialog = new Dialog(getActivity());
            dialog.getWindow();
            //dialog.setTitle("Confirm your Vote");
            dialog.requestWindowFeature(Window.FEATURE_NO_TITLE);
            dialog.setContentView(R.layout.diaglog);

            final TextView VName = (TextView) dialog.findViewById(R.id.Name);
            final TextView VRange = (TextView) dialog.findViewById(R.id.Range);
            final TextView VSUPPLIER = (TextView) dialog.findViewById(R.id.Supplier);
            final TextView VSIZE = (TextView) dialog.findViewById(R.id.Size);
            final TextView VPrice = (TextView) dialog.findViewById(R.id.Price);


            VName.setText(SlectedName);
            VRange.setText(SlectedRange);
            VSUPPLIER.setText(SlectedSupp);
            VSIZE.setText(SlectedSize);
            VPrice.setText(SlectedPrice);
            dialog.show();
            Button cancelBtn = (Button) dialog.findViewById(R.id.cancel_btn);
            cancelBtn.setOnClickListener(new View.OnClickListener() {

                @Override
                public void onClick(View v) {
                    // TODO Auto-generated method stub
                    dialog.dismiss();
                }
            });

            dialog.show();

        }
    });




    return rootView;
}

public class GetValence extends AsyncTask<String, Integer, List<Map<String, String>>> {
    Connection connect;
    String ConnectionResult = "";
    Boolean isSuccess = false;

    public List<Map<String, String>> doInBackground(String... params) {

        List<Map<String, String>> data = null;
        data = new ArrayList<>();

        try {
            ConnectionHelper conStr = new ConnectionHelper();
            connect = conStr.connectionclass();        // Connect to database
            if (connect == null) {
                ConnectionResult = "Check Your Internet Access!";
            } else {
                // Change below query according to your own database.
                String query = "select * from cc_valence";
                Statement stmt = connect.createStatement();
                ResultSet rs = stmt.executeQuery(query);
                while (rs.next()) {
                    Map<String, String> datanum = new HashMap<String, String>();
                    datanum.put("NAME", rs.getString("VALENCE_NAME"));

                    datanum.put("PRICE", rs.getString("VALENCE_UNIT_PRICE"));

                    datanum.put("RANGE", rs.getString("VALENCE_RANGE"));

                    datanum.put("SUPPLIER", rs.getString("VALENCE_SUPPLIER"));

                    datanum.put("SIZE", rs.getString("VALENCE_SIZE"));
                    data.add(datanum);
                }


                ConnectionResult = " successful";
                isSuccess = true;
                connect.close();
            }
        } catch (Exception ex) {
            isSuccess = false;
            ConnectionResult = ex.getMessage();
        }

        return data;
    }

    public void onPostExecute(List<Map<String, String>> result) {
        String[] fromwhere = {"NAME", "PRICE", "SIZE", "RANGE", "SUPPLIER"};

        int[] viewswhere = {R.id.Name_txtView, R.id.price_txtView, R.id.size_txtView};

        ADAhere = new SimpleAdapter(getActivity(), result, R.layout.list_valence, fromwhere, viewswhere);

        list.setAdapter(ADAhere);
    }

}

我在某处读到AsyncTask在不同的线程上工作，但doinbackground却没有，因此导致一些严重的滞后，因为我正在处理我的主线程，所以我想知道我是否可以实现UI线程，但我以前从未使用过它，因此即使在观看了教程之后

Answer 1

如果您在片段中使用runOnUiThread，请尝试以下代码

getActivity().runOnUiThread(new Runnable() {
    @Override
    public void run() {
        // Code 
    }
});

Answer 2

runOnUiThread()是Activity的一部分（请参见docs），因此，如果要在Fragment中使用它，则需要先获取片段的活动对象，并使用getActivity()方法。

getActivity().runOnUiThread(runnable);

Answer 3

我在您的问题中没有看到runOnUiThread的任何内容，但除此之外，还有几点：

• doInBackground中的AsyncTask例程不是在UI线程上运行，而是使用它。它在后台线程上运行，因此您可以在那里进行更长的操作而不会阻塞UI线程。
• onPreExecute do 中的onPostExecute和AsyncTask方法在UI线程上运行，因此您可以在其中更新视图或与UI交互
• 您在问题中说“我想在UI线程上运行doinbackground()”，所以我认为您误解了UI线程（一个处理UI的线程）和其他后台线程（非-UI线程，您要在其中运行更长的操作）。也许某些答案here有助于澄清。