I have a problem.I have read many forums and topics but I can not understand how to create a class file to load JSON data like:
{"city":[{"id":"1","name":"London"},{"id":"2","name":"Berlin"},{"id":"3","name":"New York"}],"success":1}
to an ListPreference list for saving one value to shared preference file. Like my saved url:
<string name="URL">192.168.1.100/data</string>
without deprecated methods (findPreference("city")).
The preference xml which I use is
<?xml version="1.0" encoding="utf-8"?>
<PreferenceScreen xmlns:android="http://schemas.android.com/apk/res/android" >
<PreferenceCategory android:title="@string/settings_menu" >
<ListPreference
android:defaultValue="192.168.1.100/data"
android:entries="@array/URLArray"
android:entryValues="@array/URLValues"
android:key="URL"
android:summary="@string/filter_for_searches"
android:title="@string/your_country" />
<ListPreference
android:defaultValue=""
android:entries="@array/listArray"
android:entryValues="@array/listValues"
android:key="city"
android:title="@string/your_city"/>
<ListPreference
android:defaultValue=""
android:entries="@array/listLang"
android:entryValues="@array/listLangValues"
android:key="Language"
android:summary=""
android:title="@string/select_your_language" />
</PreferenceCategory>
</PreferenceScreen>
and my source code
package com.sono.famlocator;
import java.util.ArrayList;
import java.util.HashMap;
import java.util.List;
import org.apache.http.NameValuePair;
import org.apache.http.message.BasicNameValuePair;
import org.json.JSONArray;
import org.json.JSONException;
import org.json.JSONObject;
import android.app.ListActivity;
import android.app.ProgressDialog;
import android.content.Context;
import android.net.ConnectivityManager;
import android.net.NetworkInfo;
import android.os.AsyncTask;
import android.os.Bundle;
import android.util.Log;
import android.widget.ListView;
public class CityLoader extends ListActivity {
A cls2= new A();
JSONArray city;
JSONObject jsonobject;
PrefAdapter adapter;
private ProgressDialog pDialog;
private String loader;
JSONParser jParser = new JSONParser();
ArrayList<HashMap<String, String>> cList;
public static String url2;
public static String country;
static final String TAG_SUCCESS = "success";
static final String TAG_EVENTS = "city";
static final String TAG_ID = "id";
static final String TAG_NAME = "name";
static final String TAG_LOADER = "TAG_LOADER";
@Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.listview_f_all);
cls2.url(this);
cls2.country(this);
country = A.country;
url2 = A.url2;
loader = "http://" + url2 + "/get_citylist.php";
String title = getResources().getString(R.string.app_name);
setTitle(title + " - Country");
cList = new ArrayList<HashMap<String, String>>();
new LoadCity().execute();
}
public boolean isOnline() {
Context context = getApplicationContext();
ConnectivityManager cm = (ConnectivityManager) context.getSystemService(Context.CONNECTIVITY_SERVICE);
NetworkInfo ni = cm.getActiveNetworkInfo();
if (ni != null && ni.isConnected())
return true;
else
return false;
}
public class LoadCity extends AsyncTask<String, String, String> {
@Override
protected void onPreExecute() {
super.onPreExecute();
pDialog = new ProgressDialog(CityLoader.this);
pDialog.setMessage("Loading. Please wait...");
pDialog.setIndeterminate(false);
pDialog.setCancelable(false);
pDialog.show();
}
/**
* getting All city from url
* */
protected String doInBackground(String... args) {
if (isOnline()) {
List<NameValuePair> params = new ArrayList<NameValuePair>();
params.add(new BasicNameValuePair("country", country));
JSONObject json = jParser.makeHttpRequest(loader, "GET", params);
Log.d("All Events: ", json.toString());
try {
int success = json.getInt(TAG_SUCCESS);
if (success == 1) {
city = json.getJSONArray(TAG_EVENTS);
for (int i = 0; i < city.length(); i++) {
jsonobject = city.getJSONObject(i);
//key for adapter
String key = "CITY";
String id = jsonobject.getString(TAG_ID);
String name = jsonobject.getString(TAG_NAME);
HashMap<String, String> map = new HashMap<String, String>();
map.put(TAG_LOADER, key);
map.put(TAG_ID, id);
map.put(TAG_NAME, name);
cList.add(map);
}
} else {
}
} catch (JSONException e) {
e.printStackTrace();
}
}
return null;
}
protected void onPostExecute(final String file_url) {
pDialog.dismiss();
ListView lv = getListView();
adapter = new PrefAdapter(CityLoader.this, cList);
lv.setAdapter(adapter);
}
}
}
Thanks in advance and sorry for my bad English!
Well, in simplest case when you want to support API < 11 and use PreferenceActivity this is how you can populate your ListPreference with data read from JSON Object:
MainActivity.java
package com.example.abc;
import java.util.ArrayList;
import org.json.JSONArray;
import org.json.JSONException;
import org.json.JSONObject;
import android.os.Bundle;
import android.preference.ListPreference;
import android.preference.PreferenceActivity;
import android.util.Log;
public class MainActivity extends PreferenceActivity {
private static final String TAG = MainActivity.class.getSimpleName();
@SuppressWarnings("deprecation")
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
addPreferencesFromResource(R.xml.preferences);
ArrayList<String> entries = new ArrayList<>();
ArrayList<String> entryValues = new ArrayList<>();
String jsonString = "{\"city\":[{\"id\":\"1\",\"name\":\"London\"},{\"id\":\"2\",\"name\":\"Berlin\"},{\"id\":\"3\",\"name\":\"New York\"}],\"success\":1}";
try {
JSONObject json = new JSONObject(jsonString);
JSONArray jsonArray = json.getJSONArray("city");
for(int i = 0; i < jsonArray.length(); ++i) {
JSONObject cityObject = (JSONObject) jsonArray.get(i);
entryValues.add(cityObject.getString("id"));
entries.add(cityObject.getString("name"));
}
} catch (JSONException e) {
Log.i(TAG ,"Improper JSON string");
}
ListPreference listPreference = (ListPreference) findPreference("CityList");
listPreference.setEntries(entries.toArray(new String[entries.size()]));
listPreference.setEntryValues(entryValues.toArray(new String[entryValues.size()]));
}
}
preferences.xml
<?xml version="1.0" encoding="utf-8"?>
<PreferenceScreen xmlns:android="http://schemas.android.com/apk/res/android" >
<ListPreference
android:key="CityList"
android:title="Cities" />
</PreferenceScreen>