我想从数据库中获取数据并将其显示在listview上。

Question

xml file the first file is a xml file of the design.

        <ListView
            android:layout_width="match_parent"
            android:layout_height="wrap_content"
            android:id="@+id/listviewtask"/>

    </LinearLayout>
</RelativeLayout>

rawtask.xml file this is the raw file and here design of a list view

    <?xml version="1.0" encoding="utf-8"?>
   <RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:layout_width="match_parent"
    android:layout_height="match_parent">


    <LinearLayout
        android:orientation="vertical"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:layout_marginLeft="10dp"
        android:layout_marginRight="10dp"
        android:layout_marginTop="10dp"
        android:layout_marginBottom="10dp"
        android:background="@drawable/property_display_box"
        android:id="@+id/listview1ll">

        <TextView
            android:layout_width="match_parent"
            android:layout_height="wrap_content"
            android:hint="Task Name"
            android:layout_marginLeft="10dp"
            android:layout_marginRight="10dp"
            android:layout_marginTop="10dp"
            android:layout_marginBottom="10dp"
            android:textSize="30dp"
            android:id="@+id/lvtaskname" />
        <TextView
            android:layout_width="match_parent"
            android:layout_height="80dp"
            android:layout_marginLeft="10dp"
            android:layout_marginRight="10dp"
            android:layout_marginTop="10dp"
            android:layout_marginBottom="10dp"
            android:textSize="30dp"
            android:hint="Task Details"
            android:layout_gravity="center"
            android:id="@+id/lvtaskdetails"
            />
        <CheckBox
            android:layout_width="match_parent"
            android:layout_height="wrap_content"
            android:text="Add Details"
            android:layout_marginLeft="40dp"
            android:layout_marginRight="10dp"
            android:layout_marginTop="10dp"
            android:layout_marginBottom="10dp"
            android:textSize="30dp"
            android:id="@+id/lvchkbox"/>
        <LinearLayout
            android:layout_width="match_parent"
            android:layout_height="match_parent"
            android:layout_marginBottom="10dp"
            android:orientation="horizontal"
            android:id="@+id/lvl1">
            <TextView
                android:layout_width="wrap_content"
                android:layout_height="wrap_content"
                android:layout_marginLeft="10dp"
                android:layout_marginRight="10dp"
                android:layout_marginTop="10dp"
                android:layout_marginBottom="10dp"
                android:text="Remaining Time:"
                android:textSize="20dp"
                android:id="@+id/lvrt"/>
            <Button
                android:layout_width="wrap_content"
                android:layout_height="wrap_content"
                android:text="Done"
                android:layout_marginLeft="90dp"
                android:layout_marginTop="10dp"
                android:textSize="20dp"
                android:id="@+id/lvdone"/>
        </LinearLayout>
    </LinearLayout>
</RelativeLayout>

Listviewadapter.java the listviewadapter.java is shown

public class ListViewAdapter2 extends BaseAdapter {

    Context cntx;
    AlertDialog.Builder alertDialogBuilder;
    //int loader = R.drawable.ic_menu_gallery;

    ArrayList<String> t_id=new ArrayList<String>();
    ArrayList<String> t_tname=new ArrayList<String>();
    ArrayList<String> t_detail=new ArrayList<String>();

    // ArrayList<Float> itemRating=new ArrayList<Float>();
    LayoutInflater inflater;
    ArrayList<HashMap<String, String>> data;
    //ImageLoader imageLoader;
    HashMap<String, String> resultp = new HashMap<String, String>();

    /*
     * public ListViewAdapter(Context context, ArrayList<HashMap<String,
     * String>> arraylist) { this.cntx = context; data = arraylist; imageLoader
     * = new ImageLoader(context); }
     */

    public ListViewAdapter2(Context context,
                            ArrayList<String> taskid,
                            ArrayList<String> taskname,
                            ArrayList<String> taskdetail) {
        // TODO Auto-generated constructor stub
        cntx = context;
        t_id=taskid;
        t_tname = taskname;
        t_detail =taskdetail;


        //Log.d("xyz", security_id.toString());

        //ImageLoaderConfiguration config = new ImageLoaderConfiguration.Builder(context).build();
        //ImageLoader.getInstance().init(config);

        alertDialogBuilder = new AlertDialog.Builder(context);
        alertDialogBuilder.setMessage("Do You Want To Call....");
        // itemRating=itm_rating;

    }

    @Override
    public int getCount() {
        return t_id.size();
    }

    @Override
    public Object getItem(int position) {
        return t_id.get(position);
    }

    @Override
    public long getItemId(int position) {
        return position;
    }

    @SuppressWarnings("deprecation")
    public View getView(final int position, View convertView, ViewGroup parent) {

        @SuppressWarnings("unused")
        final TextView taskname, taskdetail;

        inflater = (LayoutInflater) cntx.getSystemService(Context.LAYOUT_INFLATER_SERVICE);
        LayoutInflater inflater = LayoutInflater.from(cntx);

        convertView = inflater.inflate(R.layout.rawtask, parent, false);

        /*ImageLoader imageLoader = ImageLoader.getInstance();
        DisplayImageOptions options = new DisplayImageOptions.Builder().cacheInMemory(true)
                .cacheOnDisc(true).resetViewBeforeLoading(true)
                .showImageForEmptyUri(loader)
                .showImageOnFail(loader)
                .showImageOnLoading(loader).build();*/

        taskname= (TextView) convertView.findViewById(R.id.lvtaskname);
        taskdetail= (TextView) convertView.findViewById(R.id.lvtaskdetails);

        taskname.setText("taskName : "+t_tname.get(position));
        taskdetail.setText("taskdetail: "+t_detail.get(position));

        return convertView;
    }

   }

main activity.java this is the final .java file of the project

package com.example.sachin.listview;

public class Main2Activity extends Fragment {

public Main2Activity(){};
private static final String TAG_SUCCESS = "success";

JSONArray jsonarray;
JSONObject jsonobject;
ListView listview;
String img;
ListViewAdapter2 listadapter;
//ProgressDialog mProgressDialog;
ArrayList<HashMap<String, String>> arraylist;
private static String url_task = "http://10.0.2.2/portal/aFetchtask.php";
//  private static String url_profile ="http://10.0.2.2/myapp/fetchmember.php";

JSONParser jParser = new JSONParser();

ArrayList<String> t_id = new ArrayList<String>();
ArrayList<String> t_tname = new ArrayList<String>();
ArrayList<String> t_detail = new ArrayList<String>();
View view;
@Override
public View onCreateView(LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState) {
    // Inflate the layout for this fragment
    // don't look at this layout it's just a listView to show how to handle the keyboard
    View view = inflater.inflate(R.layout.activity_main, container, false);
    getActivity().setTitle("tasks");
    new DownloadJSON().execute();
    return  view;
}


private class DownloadJSON extends AsyncTask<Void, Void, Void> {

    @Override
    protected void onPreExecute() {
        super.onPreExecute();
        // Create a progressdialog
        //mProgressDialog = new ProgressDialog(getActivity());
        //mProgressDialog.setTitle("Please Wait");
        // Set progressdialog message
        //mProgressDialog.setMessage("Loading...");
        //mProgressDialog.setIndeterminate(false);
        // Show progressdialog
        //mProgressDialog.show();

    }

    @Override
    protected Void doInBackground(Void... args) {
        // Create an array
        try {
            arraylist = new ArrayList<HashMap<String, String>>();

            List<NameValuePair> params = new ArrayList<NameValuePair>();
            params.add(new BasicNameValuePair("abc", "abc"));
            JSONObject json = jParser.makeHttpRequest(url_task, "POST", params);

            int success1 = Integer.parseInt(json.getString(TAG_SUCCESS));
            Log.d("success", json.toString());

            if (success1 == 0) {
                Snackbar.make(view, "Not Data Found", Snackbar.LENGTH_LONG).show();
            }

            if (success1 == 1) {
                JSONArray ownerObj = json.getJSONArray("tasks");
                // arraylist = new ArrayList<HashMap<String, String>>();
                // Retrieve JSON Objects from the given URL address
                // Locate the array name in JSON
                // jsonarray = jsonobject.getJSONArray("images");


                for (int i = 0; i < ownerObj.length(); i++) {
                    //  HashMap<String, String> map = new HashMap<String, String>();
                    jsonobject = ownerObj.getJSONObject(i);
                    // Retrive JSON Objects

                    //securityId.add(jsonobject.getString("security_id"));
                    //   t_id.add(jsonobject.getString("t_id"));
                    t_tname.add(jsonobject.getString("t_tname"));
                    t_detail.add(jsonobject.getString("t_detail"));
                    // Number.add(jsonobject.getString("number"));

                    Log.d("DATA", jsonobject.toString());
                    //img="http://10.0.2.2/momskitchen/image/";
                    //proImage.add(img + jsonobject.getString("image"));
                             /* System.out.println(jsonobject.getString(TA));
                                System.out.println(g);*/

                }
            }
        } catch (Exception e) {
        }
        return null;
    }

    @Override
    protected void onPostExecute(Void args) {
        listview = (ListView) getActivity().findViewById(R.id.listviewtask);

        ListViewAdapter2 listadapter = new ListViewAdapter2(getActivity(), t_id, t_tname, t_detail);
        // Set the adapter to the ListView
        listview.setAdapter(listadapter);
        // Close the progressdialog

        //mProgressDialog.dismiss();
    }
}
@Override
public void onSaveInstanceState(Bundle outState) {
    //add the values which need to be saved from the drawer to the bundle
    // outState = result.saveInstanceState(outState);
    super.onSaveInstanceState(outState);
}

}

and the lastly is the file is my api file..

  <?php

include("connection.php");


    $response = array();    

    // get all products from products table
    $result = mysql_query("SELECT * FROM task") or die(mysql_error());

    // check for empty result
    if (mysql_num_rows($result) > 0) {
        // looping through all results
        // products node
        $response["tasks"] = array();

        while ($row = mysql_fetch_array($result))
        {

            $tasks = array();
            $tasks["t_id"] = $row["t_id"];
            $tasks["t_tname"] = $row["t_tname"];
            $tasks["t_udetail"] = $row["t_udetail"];

           // push single product into final response array
            array_push($response["tasks"], $tasks);
        }

            $response["success"] = 1;
        // echoing JSON response
        echo json_encode($response);


    }

    else 
    {
        // no products found
        $response["success"] = 0;
        $response["message"] = "No picture found";

        // echo no users JSON
        echo json_encode($response);
    }
  ?>        

here the all files are available. but the data is not fetched from the database. please help me out for this..

Answer 1

There are lot of coding faults are there.

• The Asynchronus class is return types are not in the exact manner to retrive the data.
• After protected Void doInBackground(Void... args) {} is returning null then you can get null value to onPostExcute(Void args) you have to write get whole repose in doInBackground() method only if you are not returning any response.
• In rawtask.xml file should contains views which are inflating by adapter but in your case other view are mentioned. So refere this following link to get the data from webservices into listView. here