以下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变量所持有的值。这个类下面是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>
答案 0 :(得分：4)
第一个问题： 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);
您正尝试从后台线程中访问Ui元素。将这些代码行移至onPostExecute，以便在AsyncTask完成后从doInBackground更新用户界面。
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
* */
}
});
因为我们能够访问onPostExecute AsyncTask方法中的UI元素，因此无需使用runOnUiThread来更新onPostExecute中的UI元素，就像您的情况一样尝试在ListAdapter的{{1}}内使用访问ListView或runOnUiThread
以正确的方式使用onPostExecute更改您的LoadAllDates代码：
AsyncTask答案 1 :(得分：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.
答案 2 :(得分：1)
这是我的答案。希望能帮助到你。您还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));
}
}
}