3

下面是我遇到问题的代码。php 文件就像一个魅力,你可以看到你是否转到 url_all_dates 变量保存的值。在这个类下面是我的 list_item 的 .xml 布局文件。该应用程序运行但不显示数据库中的任何日期。:

public class RequestTour extends ListActivity {

    // Progress Dialog
    private ProgressDialog pDialog;

    // Creating JSON Parser object
    JSONParser jParser = new JSONParser();

    ArrayList<HashMap<String, String>> datesList;

    // url to get all dates list
    private static String url_all_dates = "http://www.prayingmantesconcepts.com/androidfinal/get_all_avail_dates.php";

    // JSON Node names
    private static final String TAG_SUCCESS = "success";
    private static final String TAG_DATES = "dates";
    private static final String TAG_DATEID = "dateID";
    private static final String TAG_DATE = "date";

    // dates JSONArray
    JSONArray dates = null;

    @Override
    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.dates);//put dates layout here.

        // Hashmap for ListView
        datesList = new ArrayList<HashMap<String, String>>();

        // Loading dates in Background Thread
        new LoadAllDates().execute();

        // Get listview
        ListView lv = getListView();

        // on seleting single date
        // launching Book Tour Screen
        lv.setOnItemClickListener(new OnItemClickListener() {

            public void onItemClick(AdapterView<?> parent, View view,
                    int position, long id) {
                // getting values from selected ListItem
                String dateID = ((TextView) view.findViewById(R.id.dateID)).getText()
                        .toString();

                // Starting new intent
                Intent in = new Intent(getApplicationContext(),
                        BookTour.class);
                // sending dateID to next activity
                in.putExtra(TAG_DATEID, dateID);

                // starting new activity and expecting some response back
                startActivityForResult(in, 100);
            }
        });

    }

    // Response from Edit Product Activity
    @Override
    protected 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 booked a tour
            // reload this screen again
            Intent intent = getIntent();
            finish();
            startActivity(intent);
        }

    }

    /**
     * Background Async Task to Load all dates by making HTTP Request
     * */
    class LoadAllDates extends AsyncTask<String, String, String> {

        /**
         * Before starting background thread Show Progress Dialog
         * */
        @Override
        protected void onPreExecute() {
            super.onPreExecute();
            pDialog = new ProgressDialog(RequestTour.this);
            pDialog.setMessage("Loading dates. Please wait...");
            pDialog.setIndeterminate(false);
            pDialog.setCancelable(false);
            pDialog.show();
        }

        /**
         * getting All dates from url
         * */
        protected String doInBackground(String... args) {
            // Building Parameters
            List<NameValuePair> params = new ArrayList<NameValuePair>();
            // getting JSON string from URL
            JSONObject json = jParser.makeHttpRequest(url_all_dates, "GET", params);

            // Check your log cat for JSON response
            Log.d("All Dates: ", json.toString());

            try {
                // Checking for SUCCESS TAG
                int success = json.getInt(TAG_SUCCESS);

                if (success == 1) {
                    //  found
                    // Getting Array of 
                     dates = json.getJSONArray(TAG_DATES);

                    // looping through All Dates Available for Request
                    for (int i = 0; i < dates.length(); i++) {
                        JSONObject c = dates.getJSONObject(i);

                        // Storing each json item in variable
                        String id = c.getString(TAG_DATEID);
                        String date = c.getString(TAG_DATE);

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

                        // adding each child node to HashMap key => value
                        map.put(TAG_DATEID, id);
                        map.put(TAG_DATE, date);

                        // adding HashList to ArrayList
                        datesList.add(map);
                    }
                } else {
                    // no  found
                    // Launch Add New product Activity
                    Intent i = new Intent(getApplicationContext(),
                            Main.class);
                    // Closing all previous activities
                    i.addFlags(Intent.FLAG_ACTIVITY_CLEAR_TOP);
                    startActivity(i);
                }
            } catch (JSONException e) {
                e.printStackTrace();
            }

            return null;
        }

        /**
         * After completing background task Dismiss the progress dialog
         * **/
        protected void onPostExecute(String file_url) {
            // dismiss the dialog after getting all 
            pDialog.dismiss();
            // updating UI from Background Thread
            runOnUiThread(new Runnable() {
                public void run() {
                    /**
                     * Updating parsed JSON data into ListView
                     * */
                    ListAdapter adapter = new SimpleAdapter(
                            RequestTour.this, datesList,
                            R.layout.list_item, new String[] { TAG_DATEID,
                                    TAG_DATE},
                            new int[] { R.id.dateID, R.id.date });
                    // updating listview
                    setListAdapter(adapter);
                }
            });

        }

    }
}


<!------------------------------------------------------------------------------------>


list_item.xml:

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:layout_width="fill_parent"
    android:layout_height="wrap_content"
    android:orientation="vertical" >

    <!-- Date id (dateID) - will be HIDDEN - used to pass to other activity -->
    <TextView
        android:id="@+id/dateID"
        android:layout_width="fill_parent"
        android:layout_height="wrap_content"
        android:visibility="gone" />


    <!-- Date Label -->
    <TextView
        android:id="@+id/date"
        android:layout_width="fill_parent"
        android:layout_height="wrap_content"
        android:paddingTop="6dip"
        android:paddingLeft="6dip"
        android:textSize="17dip"
        android:textStyle="bold" />

</LinearLayout>
4

3 回答 3

4

第一期: 这里

            // no  found
            // Launch Add New product Activity
            Intent i = new Intent(getApplicationContext(),
                    Main.class);
            // Closing all previous activities
            i.addFlags(Intent.FLAG_ACTIVITY_CLEAR_TOP);
            startActivity(i);

您正在尝试从后台线程访问 Ui 元素。将这些代码行移动到完成后onPostExecute更新 UI 。 AsyncTaskdoInBackground


第二期:

这里

  protected void onPostExecute(String file_url) {
            // dismiss the dialog after getting all 
            pDialog.dismiss();
            // updating UI from Background Thread
            runOnUiThread(new Runnable() {
                public void run() {
                    /**
                     * Updating parsed JSON data into ListView
                     * */

                }
            });

因为我们能够以onPostExecute方法访问 UI 元素,AsyncTask所以无需在您尝试使用访问或内部的情况下runOnUiThread更新 UI 元素onPostExecuteListAdapterListViewrunOnUiThreadonPostExecute


解决方案 :

以正确的方式更改您的LoadAllDates代码:AsyncTask

class LoadAllDates extends AsyncTask<String, String,
                                    ArrayList<HashMap<String, String>>> {
    datesList=new ArrayList<HashMap<String, String>>;
        @Override
        protected void onPreExecute() {
            super.onPreExecute();
          //YOUR CODE HERE
        }


        protected ArrayList<HashMap<String, String>> 
                                doInBackground(String... args) {
         // Building Parameters
         List<NameValuePair> params = new ArrayList<NameValuePair>();
        // getting JSON string from URL
        JSONObject json = 
                    jParser.makeHttpRequest(url_all_dates, "GET", params);

            // Check your log cat for JSON response
            Log.d("All Dates: ", json.toString());

            try {
                // Checking for SUCCESS TAG
                int success = json.getInt(TAG_SUCCESS);

                if (success == 1) {
                    //  found
                    // Getting Array of 
                     dates = json.getJSONArray(TAG_DATES);

                    // looping through All Dates Available for Request
                    for (int i = 0; i < dates.length(); i++) {
                        JSONObject c = dates.getJSONObject(i);

                        // Storing each json item in variable
                        String id = c.getString(TAG_DATEID);
                        String date = c.getString(TAG_DATE);

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

                        // adding each child node to HashMap key => value
                        map.put(TAG_DATEID, id);
                        map.put(TAG_DATE, date);

                        // adding HashList to ArrayList
                        datesList.add(map);
                    }
                } else {
                    // no  found

                }
            } catch (JSONException e) {
                e.printStackTrace();
            }

            return ArrayList<HashMap<String, String>>;
        }

        /**
         * After completing background task Dismiss the progress dialog
         * **/
        protected void onPostExecute(
                     ArrayList<HashMap<String, String>> file_url) {
            // dismiss the dialog after getting all 
            pDialog.dismiss();
            // updating UI from Background Thread

                  if(file_url.size()>0)
                   {
                    ListAdapter adapter = new SimpleAdapter(
                            RequestTour.this, file_url,
                            R.layout.list_item, new String[] { TAG_DATEID,
                                    TAG_DATE},
                            new int[] { R.id.dateID, R.id.date });
                    // updating listview
                    setListAdapter(adapter);
                  }
                 else{
                    // Launch Add New product Activity
                    Intent i = new Intent(getApplicationContext(),
                            Main.class);
                    // Closing all previous activities
                    i.addFlags(Intent.FLAG_ACTIVITY_CLEAR_TOP);
                    startActivity(i);
                    }


        }

    }
于 2012-12-09T05:23:51.187 回答
1
You have to use Gson Json parsing this is a good way to parse Json object

eg:

String json1 = "[{\"contactName\":\"3\",\"contactNumber\":\"3\"},{\"contactName\":\"4\",\"contactNumber\":\"4\"}]";

Gson gson = new Gson();
Type collectionType = new TypeToken<List<ContactDetail>>(){}.getType();
List<ContactDetail> details = gson.fromJson(json1, collectionType);

Here ContactDetail class consists of String contactName and String contactNumber and their corresponding getters and setters.
Note: make List<ContactDetail> details as a public static variable in your class and 
from your activity class pass this list object in your listview adapter.
于 2012-12-09T05:53:50.820 回答
1

这是我的答案。希望能帮助到你。也可以访问我解析的网址:http ://redsox.tcs.auckland.ac.nz/734A/CSService.svc/courses

import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStream;
import java.io.InputStreamReader;
import java.io.UnsupportedEncodingException;
import java.net.URL;
import java.util.ArrayList;
import java.util.zip.GZIPInputStream;

import org.apache.http.HttpEntity;
import org.apache.http.HttpResponse;
import org.apache.http.StatusLine;
import org.apache.http.client.ClientProtocolException;
import org.apache.http.client.HttpClient;
import org.apache.http.client.methods.HttpGet;
import org.apache.http.impl.client.DefaultHttpClient;
import org.json.JSONArray;
import org.json.JSONException;
import org.json.JSONObject;

import android.app.Activity;
import android.app.ListActivity;
import android.graphics.Color;
import android.os.AsyncTask;
import android.os.Bundle;
import android.util.Log;
import android.widget.ArrayAdapter;
import android.widget.ListView;

public class Courses extends Activity {

    ArrayList<String> items = new ArrayList<String>();

    //URL requestUrl = new URL(url);
    JSONArray courses = null;
    //private static final String TAG_COURSES = "Courses";
    static JSONObject jObj = null;
    static String json = "";

    @Override
    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.courses);
        new MyTask().execute("http://redsox.tcs.auckland.ac.nz/734A/CSService.svc/courses");

    }


    private class MyTask extends AsyncTask<String, Void, JSONObject> {

        @Override
        protected JSONObject doInBackground(String... urls) {
           // return loadJSON(url);
            String url = new String(urls[0]);
            try {

                // defaultHttpClient
                DefaultHttpClient httpClient = new DefaultHttpClient();
                //HttpPost httpPost = new HttpPost(url);
                HttpGet httpGet = new HttpGet(url);
                HttpResponse httpResponse = httpClient.execute(httpGet);

                HttpEntity httpEntity = httpResponse.getEntity();
                is = httpEntity.getContent();

            } catch (UnsupportedEncodingException e) {
                e.printStackTrace();
            } catch (ClientProtocolException e) {
                e.printStackTrace();
            } catch (IOException e) {
                e.printStackTrace();
            }
          try {
            /*BufferedReader reader = new BufferedReader(new InputStreamReader(
                    is, "UTF-8"), 8);*/
            InputStream inputStream = is;
            GZIPInputStream input = new GZIPInputStream(inputStream);
            InputStreamReader reader = new InputStreamReader(input);
            BufferedReader in = new BufferedReader(reader);
            StringBuilder sb = new StringBuilder();
            String line = null;
            while ((line = in.readLine()) != null) {
                sb.append(line);
                //System.out.println(line);
            }
            is.close();
            json = sb.toString();
        } catch (Exception e) {
            Log.e("Buffer Error", "Error converting result " + e.toString());
        }

        // try parse the string to a JSON object

        try {

            JSONArray courses = new JSONArray(json);
            //JSONArray people = new JSONArray(json);
            for (int i = 0; i < courses.length(); i++) {
                //System.out.println(courses.getJSONObject(i).toString());
                JSONObject c = courses.getJSONObject(i);

                // Storing each json item in variable
                String course_id = c.getString("codeField");
                String course_name = c.getString("titleField");
                String course_semester = c.getString("semesterField");

                items.add(course_id +"\n"+course_name+"\t"+course_semester);

                /*Log.v("--", "Course:" + course_id + "\n Course Title: " + course_name
                        + "\n Semesters offered: " + course_semester);*/
            }


            //jObj = new JSONObject(json);
        } catch (JSONException e) {
            Log.e("JSON Parser", "Error parsing data " + e.toString());
        } 


        // return JSON String
        return jObj;
        }

        @SuppressWarnings("unchecked")
        protected void onPostExecute(JSONObject json) {
            ListView myListView = (ListView)findViewById(R.id.coursesList);
            myListView.setAdapter(new ArrayAdapter(getApplicationContext(), android.R.layout.simple_list_item_1, items));

    }
    }




}
于 2013-05-21T07:13:50.237 回答