我有这个代码调用一个用json回复的php脚本。 json用于显示为listview。 问题是，即使这些数据在php脚本连接的数据库中不再存在，下面的代码总是给我相同的json。
我遵循了本指南 http://www.androidhive.info/2012/05/how-to-connect-android-with-php-mysql/
但我无法弄清楚运行时会发生什么。 我希望有人可以帮助我。
public class ShiftListFragment extends ListFragment {
// Progress Dialog
private static ProgressDialog pDialog;
// Creating JSON Parser object
JSONParser jParser = new JSONParser();
ArrayList<HashMap<String, String>> productsList;
// url to get all products list
private static String url_all_products = "http://www.changeshifts.netsons.org/android_connect/get_all_shifts.php";
// JSON Node names
private static final String TAG_SUCCESS = "success";
private static final String TAG_AVAILABLE_SHIFTS = "Available shifts";
private static final String TAG_IDSHIFT = "shift id";
private static final String TAG_DATE = "date";
private static final String TAG_SHIFT = "shift";
private static final String TAG_START_LOCATION = "start location";
private static final String TAG_BEGIN = "begin";
private static final String TAG_END = "end";
private static final String TAG_IDENTIFICATION_NUMBER = "identification number";
// products JSONArray
JSONArray products = null;
// Custom adapter to view list of shifts
private CustomAdapter adapter;
/**
* The serialization (saved instance state) Bundle key representing the
* activated item position. Only used on tablets.
*/
private static final String STATE_ACTIVATED_POSITION = "activated_position";
/**
* The fragment's current callback object, which is notified of list item
* clicks.
*/
private Callbacks mCallbacks = sDummyCallbacks;
/**
* The current activated item position. Only used on tablets.
*/
private int mActivatedPosition = ListView.INVALID_POSITION;
/**
* A callback interface that all activities containing this fragment must
* implement. This mechanism allows activities to be notified of item
* selections.
*/
public interface Callbacks {
/**
* Callback for when an item has been selected.
*/
public void onItemSelected(String id);
}
/**
* A dummy implementation of the {@link Callbacks} interface that does
* nothing. Used only when this fragment is not attached to an activity.
*/
private static Callbacks sDummyCallbacks = new Callbacks() {
@Override
public void onItemSelected(String id) {
}
};
/**
* Mandatory empty constructor for the fragment manager to instantiate the
* fragment (e.g. upon screen orientation changes).
*/
public ShiftListFragment() {
}
@Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
// Hashmap for ListView
productsList = new ArrayList<HashMap<String, String>>();
// Loading products in Background Thread
new LoadAllProducts().execute();
}
@Override
public void onViewCreated(View view, Bundle savedInstanceState) {
super.onViewCreated(view, savedInstanceState);
// Restore the previously serialized activated item position.
if (savedInstanceState != null
&& savedInstanceState.containsKey(STATE_ACTIVATED_POSITION)) {
setActivatedPosition(savedInstanceState
.getInt(STATE_ACTIVATED_POSITION));
}
}
@Override
public void onAttach(Activity activity) {
super.onAttach(activity);
// Activities containing this fragment must implement its callbacks.
if (!(activity instanceof Callbacks)) {
throw new IllegalStateException(
"Activity must implement fragment's callbacks.");
}
mCallbacks = (Callbacks) activity;
}
@Override
public void onDetach() {
super.onDetach();
// Reset the active callbacks interface to the dummy implementation.
mCallbacks = sDummyCallbacks;
}
@Override
public void onListItemClick(ListView listView, View view, int position,
long id) {
super.onListItemClick(listView, view, position, id);
// Notify the active callbacks interface (the activity, if the
// fragment is attached to one) that an item has been selected.
mCallbacks.onItemSelected(productsList.get(position).get(TAG_IDSHIFT));
}
@Override
public void onSaveInstanceState(Bundle outState) {
super.onSaveInstanceState(outState);
if (mActivatedPosition != ListView.INVALID_POSITION) {
// Serialize and persist the activated item position.
outState.putInt(STATE_ACTIVATED_POSITION, mActivatedPosition);
}
}
/**
* Turns on activate-on-click mode. When this mode is on, list items will be
* given the 'activated' state when touched.
*/
public void setActivateOnItemClick(boolean activateOnItemClick) {
// When setting CHOICE_MODE_SINGLE, ListView will automatically
// give items the 'activated' state when touched.
getListView().setChoiceMode(
activateOnItemClick ? ListView.CHOICE_MODE_SINGLE
: ListView.CHOICE_MODE_NONE);
}
private void setActivatedPosition(int position) {
if (position == ListView.INVALID_POSITION) {
getListView().setItemChecked(mActivatedPosition, false);
} else {
getListView().setItemChecked(position, true);
}
mActivatedPosition = position;
}
/**
* Background Async Task to Load all product by making HTTP Request
* */
class LoadAllProducts extends AsyncTask<String, String, String> {
/**
* Before starting background thread Show Progress Dialog
* */
@Override
protected void onPreExecute() {
super.onPreExecute();
pDialog = new ProgressDialog(getActivity());
pDialog.setMessage("Loading Shifts. Please wait...");
pDialog.setIndeterminate(false);
pDialog.setCancelable(false);
pDialog.show();
}
/**
* getting All products 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_products, "GET", params);
// Check your log cat for JSON reponse
Log.d("All Products: ", json.toString());
try {
// Checking for SUCCESS TAG
int success = json.getInt(TAG_SUCCESS);
if (success == 1) {
// products found
// Getting Array of Products
products = json.getJSONArray(TAG_AVAILABLE_SHIFTS);
productsList = new ArrayList<HashMap<String,String>>();
// looping through All Products
for (int i = 0; i < products.length(); i++) {
JSONObject c = products.getJSONObject(i);
// Storing each json item in variable
// String idShift = c.getString(TAG_IDSHIFT);
String date = c.getString(TAG_DATE);
String shift = c.getString(TAG_SHIFT);
String location = c.getString(TAG_START_LOCATION);
String begin = c.getString(TAG_BEGIN);
String end = c.getString(TAG_END);
String sn = c.getString(TAG_IDENTIFICATION_NUMBER);
// creating new HashMap
HashMap<String, String> map = new HashMap<String, String>();
// adding each child node to HashMap key => value
// map.put(TAG_IDSHIFT, idShift);
map.put(TAG_DATE, date);
map.put(TAG_SHIFT, shift);
map.put(TAG_START_LOCATION, location);
map.put(TAG_BEGIN, begin);
map.put(TAG_END, end);
map.put(TAG_IDENTIFICATION_NUMBER, sn);
// adding HashList to ArrayList
productsList.add(map);
}
} else {
// no Shifts found
// Launch Add New product Activity
}
} catch (JSONException e) {
e.printStackTrace();
}
return null;
}
/**
* After completing background task Dismiss the progress dialog
* **/
protected void onPostExecute(String file_url) {
super.onPostExecute(file_url);
// dismiss the dialog after getting all products
pDialog.dismiss();
// updating UI from Background Thread
getActivity().runOnUiThread(new Runnable(){
public void run(){
/**
* Updating parsed JSON data into ListView
* */
adapter = new CustomAdapter(getActivity(), R.layout.list_item, productsList);
setListAdapter(adapter);
}
});
}
}
}