解析 Fragment 中的 JSON 数组
Parse JSON array in Fragment
我一直在使用 this guide 解析 JSON 数组并遇到奇怪的错误：
01-20 14:56:40.511 28118-28118/com.cbsystematic.mobile.itvdn E/WindowManager﹕ Activity com.cbsystematic.mobile.itvdn.NavigationActivity has leaked window com.android.internal.policy.impl.PhoneWindow$DecorView@4151cdd0 that was originally added here
android.view.WindowLeaked: Activity com.cbsystematic.mobile.itvdn.NavigationActivity has leaked window com.android.internal.policy.impl.PhoneWindow$DecorView@4151cdd0 that was originally added here
at android.view.ViewRootImpl.<init>(ViewRootImpl.java:464)
at android.view.WindowManagerImpl.addView(WindowManagerImpl.java:419)
at android.view.WindowManagerImpl.addView(WindowManagerImpl.java:351)
at android.view.WindowManagerImpl$CompatModeWrapper.addView(WindowManagerImpl.java:171)
at android.view.Window$LocalWindowManager.addView(Window.java:558)
at android.app.Dialog.show(Dialog.java:282)
at com.cbsystematic.mobile.itvdn.CatalogFragment$GetContacts.onPreExecute(CatalogFragment.java:178)
at android.os.AsyncTask.executeOnExecutor(AsyncTask.java:586)
at android.os.AsyncTask.execute(AsyncTask.java:534)
at com.cbsystematic.mobile.itvdn.CatalogFragment.onCreate(CatalogFragment.java:89)
at android.support.v4.app.Fragment.performCreate(Fragment.java:1763)
at android.support.v4.app.FragmentManagerImpl.moveToState(FragmentManager.java:913)
at android.support.v4.app.FragmentManagerImpl.moveToState(FragmentManager.java:1126)
at android.support.v4.app.BackStackRecord.run(BackStackRecord.java:739)
at android.support.v4.app.FragmentManagerImpl.execPendingActions(FragmentManager.java:1489)
at android.support.v4.app.FragmentActivity.onStart(FragmentActivity.java:548)
at android.app.Instrumentation.callActivityOnStart(Instrumentation.java:1225)
at android.app.Activity.performStart(Activity.java:5076)
at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2328)
at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2391)
at android.app.ActivityThread.access0(ActivityThread.java:151)
at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1335)
at android.os.Handler.dispatchMessage(Handler.java:99)
at android.os.Looper.loop(Looper.java:155)
at android.app.ActivityThread.main(ActivityThread.java:5520)
at java.lang.reflect.Method.invokeNative(Native Method)
at java.lang.reflect.Method.invoke(Method.java:511)
at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:1029)
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:796)
at dalvik.system.NativeStart.main(Native Method)
程序结构为导航抽屉Activity，内容为3个片段。我正在使用扩展 AbsListView.OnItemClickListener:
的 CatalogFragment
JSON数组如下：
[
{
"Url":"windows-store-app-html5-and-vascript",
"LessonsCount":1,
"Name":"Разработка Windows Store приложений с JavaScript и HTML5.",
"IsFree":true,
"Price":0,
"Language":"ru",
"Difficulty":2,
"Author":{
"Id":"963163db-eee6-4e73-81b3-71b58a602f78","Name":"Дмитрий Охрименко",
"PhotoUrl":"https://itvdn.blob.core.windows.net/authors/authors-okhrimenko.jpg",
"Description":"Сертифицированный специалист Microsoft (MCTS, MCPD, MCT).Тренер-консультант, эксперт по построению распределенных и веб-ориентированных приложений.","Url":null}
},
.
.
]
GetCatalog class（与指南几乎相同）：
private class GetCatalog extends AsyncTask<Void, Void, Void> {
@Override
protected void onPreExecute() {
super.onPreExecute();
// Showing progress dialog
pDialog = new ProgressDialog(getActivity());
pDialog.setMessage("Please wait...");
pDialog.setCancelable(false);
pDialog.show();
}
@Override
protected Void doInBackground(Void... arg0) {
// Creating service handler class instance
ServiceHandler sh = new ServiceHandler();
// Making a request to url and getting response
String jsonStr = sh.makeServiceCall(url, ServiceHandler.GET);
Log.d("Response: ", "> " + jsonStr);
if (jsonStr != null) {
try {
// Getting JSON Array node
catalog = new JSONArray(jsonStr);
// looping through All Contacts
for (int i = 0; i < catalog.length(); i++) {
JSONObject c = catalog.getJSONObject(i);
String name = c.getString(TAG_NAME);
// tmp hashmap for single contact
HashMap<String, String> contact = new HashMap<String, String>();
// adding each child node to HashMap key => value
contact.put(TAG_NAME, name);
// adding contact to contact list
catalogList.add(contact);
}
} catch (JSONException e) {
e.printStackTrace();
}
} else {
Log.e("ServiceHandler", "Couldn't get any data from the url");
}
return null;
}
@Override
protected void onPostExecute(Void result) {
super.onPostExecute(result);
// Dismiss the progress dialog
if (pDialog.isShowing())
pDialog.dismiss();
/**
* Updating parsed JSON data into ListView
* */
ListAdapter adapter = new SimpleAdapter(
getActivity(), catalogList,
R.layout.catalog_list_item, new String[] {TAG_NAME}, new int[] {
R.id.name });
mListView.setAdapter(adapter);
}
}
我正在尝试传递 OnCreate()...
中的内容
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
new GetCatalog().execute();
}
整个CatalogFragmentclass（如果需要的话）：
public class CatalogFragment extends android.support.v4.app.Fragment implements AbsListView.OnItemClickListener {
private static final String ARG_SECTION_NUMBER = "section_number";
private ProgressDialog pDialog;
// URL to get contacts JSON
private static String url = "http://api.androidhive.info/contacts/";
// JSON Node names
private static final String TAG_NAME = "Name";
// contacts JSONArray
JSONArray catalog = null;
// Hashmap for ListView
ArrayList<HashMap<String, String>> catalogList;
private OnFragmentInteractionListener mListener;
/**
* The fragment's ListView/GridView.
*/
private AbsListView mListView;
/**
* The Adapter which will be used to populate the ListView/GridView with
* Views.
*/
private ListAdapter mAdapter;
// TODO: Rename and change types of parameters
public static CatalogFragment newInstance( int sectionNumber) {
CatalogFragment fragment = new CatalogFragment();
Bundle args = new Bundle();
args.putInt(ARG_SECTION_NUMBER, sectionNumber);
fragment.setArguments(args);
return fragment;
}
/**
* Mandatory empty constructor for the fragment manager to instantiate the
* fragment (e.g. upon screen orientation changes).
*/
public CatalogFragment() {
}
@Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
new GetCatalog().execute();
}
@Override
public View onCreateView(LayoutInflater inflater, ViewGroup container,
Bundle savedInstanceState) {
View view = inflater.inflate(R.layout.fragment_catalog, container, false);
// Set the adapter
mListView = (AbsListView) view.findViewById(android.R.id.list);
((AdapterView<ListAdapter>) mListView).setAdapter(mAdapter);
// Set OnItemClickListener so we can be notified on item clicks
mListView.setOnItemClickListener(this);
return view;
}
@Override
public void onAttach(Activity activity) {
super.onAttach(activity);
try {
mListener = (OnFragmentInteractionListener) activity;
} catch (ClassCastException e) {
throw new ClassCastException(activity.toString()
+ " must implement OnFragmentInteractionListener");
}
((NavigationActivity) activity).onSectionAttached(
getArguments().getInt(ARG_SECTION_NUMBER));
}
@Override
public void onDetach() {
super.onDetach();
mListener = null;
}
@Override
public void onItemClick(AdapterView<?> parent, View view, int position, long id) {
}
/**
* The default content for this Fragment has a TextView that is shown when
* the list is empty. If you would like to change the text, call this method
* to supply the text it should use.
*/
public void setEmptyText(CharSequence emptyText) {
View emptyView = mListView.getEmptyView();
if (emptyView instanceof TextView) {
((TextView) emptyView).setText(emptyText);
}
}
/**
* This interface must be implemented by activities that contain this
* fragment to allow an interaction in this fragment to be communicated
* to the activity and potentially other fragments contained in that
* activity.
* <p/>
* See the Android Training lesson <a href=
* "http://developer.android.com/training/basics/fragments/communicating.html"
* >Communicating with Other Fragments</a> for more information.
*/
public interface OnFragmentInteractionListener {
// TODO: Update argument type and name
public void onCatalogFragmentInteraction(String id);
}
private class GetCatalog extends AsyncTask<Void, Void, Void> {
@Override
protected void onPreExecute() {
super.onPreExecute();
// Showing progress dialog
pDialog = new ProgressDialog(getActivity());
pDialog.setMessage("Please wait...");
pDialog.setCancelable(false);
pDialog.show();
}
@Override
protected Void doInBackground(Void... arg0) {
// Creating service handler class instance
ServiceHandler sh = new ServiceHandler();
// Making a request to url and getting response
String jsonStr = sh.makeServiceCall(url, ServiceHandler.GET);
Log.d("Response: ", "> " + jsonStr);
if (jsonStr != null) {
try {
// Getting JSON Array node
catalog = new JSONArray(jsonStr);
// looping through All Contacts
for (int i = 0; i < catalog.length(); i++) {
JSONObject c = catalog.getJSONObject(i);
String name = c.getString(TAG_NAME);
// tmp hashmap for single contact
HashMap<String, String> contact = new HashMap<String, String>();
// adding each child node to HashMap key => value
contact.put(TAG_NAME, name);
// adding contact to contact list
catalogList.add(contact);
}
} catch (JSONException e) {
e.printStackTrace();
}
} else {
Log.e("ServiceHandler", "Couldn't get any data from the url");
}
return null;
}
@Override
protected void onPostExecute(Void result) {
super.onPostExecute(result);
// Dismiss the progress dialog
if (pDialog.isShowing())
pDialog.dismiss();
/**
* Updating parsed JSON data into ListView
* */
ListAdapter adapter = new SimpleAdapter(
getActivity(), catalogList,
R.layout.catalog_list_item, new String[] {TAG_NAME}, new int[] {
R.id.name });
mListView.setAdapter(adapter);
}
}
}
P.S。我一直在尝试从指南中下载完整的代码，这很有效。但是当在我的代码中使用相同的代码时，它不会。
感谢您的帮助
编辑：
在评论与 ProgressDialog 有关的操作后：
01-20 16:11:33.641 4969-5281/com.cbsystematic.mobile.itvdn E/AndroidRuntime﹕ FATAL EXCEPTION: AsyncTask #1
java.lang.RuntimeException: An error occured while executing doInBackground()
at android.os.AsyncTask.done(AsyncTask.java:299)
at java.util.concurrent.FutureTask$Sync.innerSetException(FutureTask.java:273)
at java.util.concurrent.FutureTask.setException(FutureTask.java:124)
at java.util.concurrent.FutureTask$Sync.innerRun(FutureTask.java:307)
at java.util.concurrent.FutureTask.run(FutureTask.java:137)
at android.os.AsyncTask$SerialExecutor.run(AsyncTask.java:230)
at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1076)
at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:569)
at java.lang.Thread.run(Thread.java:864)
Caused by: java.lang.SecurityException: Permission denied (missing INTERNET permission?)
at java.net.InetAddress.lookupHostByName(InetAddress.java:428)
at java.net.InetAddress.getAllByNameImpl(InetAddress.java:239)
at java.net.InetAddress.getAllByName(InetAddress.java:214)
at org.apache.http.impl.conn.DefaultClientConnectionOperator.openConnection(DefaultClientConnectionOperator.java:137)
at org.apache.http.impl.conn.AbstractPoolEntry.open(AbstractPoolEntry.java:164)
at org.apache.http.impl.conn.AbstractPooledConnAdapter.open(AbstractPooledConnAdapter.java:119)
at org.apache.http.impl.client.DefaultRequestDirector.execute(DefaultRequestDirector.java:367)
at org.apache.http.impl.client.AbstractHttpClient.execute(AbstractHttpClient.java:593)
at org.apache.http.impl.client.AbstractHttpClient.execute(AbstractHttpClient.java:510)
at org.apache.http.impl.client.AbstractHttpClient.execute(AbstractHttpClient.java:488)
at com.cbsystematic.mobile.itvdn.ServiceHandler.makeServiceCall(ServiceHandler.java:73)
at com.cbsystematic.mobile.itvdn.ServiceHandler.makeServiceCall(ServiceHandler.java:37)
at com.cbsystematic.mobile.itvdn.CatalogFragment$GetCatalog.doInBackground(CatalogFragment.java:187)
at com.cbsystematic.mobile.itvdn.CatalogFragment$GetCatalog.doInBackground(CatalogFragment.java:169)
at android.os.AsyncTask.call(AsyncTask.java:287)
at java.util.concurrent.FutureTask$Sync.innerRun(FutureTask.java:305)
at java.util.concurrent.FutureTask.run(FutureTask.java:137)
at android.os.AsyncTask$SerialExecutor.run(AsyncTask.java:230)
at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1076)
at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:569)
at java.lang.Thread.run(Thread.java:864)
Caused by: libcore.io.GaiException: getaddrinfo failed: EAI_NODATA (No address associated with hostname)
at libcore.io.Posix.getaddrinfo(Native Method)
at libcore.io.ForwardingOs.getaddrinfo(ForwardingOs.java:55)
at java.net.InetAddress.lookupHostByName(InetAddress.java:415)
at java.net.InetAddress.getAllByNameImpl(InetAddress.java:239)
at java.net.InetAddress.getAllByName(InetAddress.java:214)
at org.apache.http.impl.conn.DefaultClientConnectionOperator.openConnection(DefaultClientConnectionOperator.java:137)
at org.apache.http.impl.conn.AbstractPoolEntry.open(AbstractPoolEntry.java:164)
at org.apache.http.impl.conn.AbstractPooledConnAdapter.open(AbstractPooledConnAdapter.java:119)
at org.apache.http.impl.client.DefaultRequestDirector.execute(DefaultRequestDirector.java:367)
at org.apache.http.impl.client.AbstractHttpClient.execute(AbstractHttpClient.java:593)
at org.apache.http.impl.client.AbstractHttpClient.execute(AbstractHttpClient.java:510)
at org.apache.http.impl.client.AbstractHttpClient.execute(AbstractHttpClient.java:488)
at com.cbsystematic.mobile.itvdn.ServiceHandler.makeServiceCall(ServiceHandler.java:73)
at com.cbsystematic.mobile.itvdn.ServiceHandler.makeServiceCall(ServiceHandler.java:37)
at com.cbsystematic.mobile.itvdn.CatalogFragment$GetCatalog.doInBackground(CatalogFragment.java:187)
at com.cbsystematic.mobile.itvdn.CatalogFragment$GetCatalog.doInBackground(CatalogFragment.java:169)
at android.os.AsyncTask.call(AsyncTask.java:287)
at java.util.concurrent.FutureTask$Sync.innerRun(FutureTask.java:305)
at java.util.concurrent.FutureTask.run(FutureTask.java:137)
at android.os.AsyncTask$SerialExecutor.run(AsyncTask.java:230)
at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1076)
at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:569)
at java.lang.Thread.run(Thread.java:864)
Caused by: libcore.io.ErrnoException: getaddrinfo failed: EACCES (Permission denied)
at libcore.io.Posix.getaddrinfo(Native Method)
at libcore.io.ForwardingOs.getaddrinfo(ForwardingOs.java:55)
at java.net.InetAddress.lookupHostByName(InetAddress.java:415)
at java.net.InetAddress.getAllByNameImpl(InetAddress.java:239)
at java.net.InetAddress.getAllByName(InetAddress.java:214)
at org.apache.http.impl.conn.DefaultClientConnectionOperator.openConnection(DefaultClientConnectionOperator.java:137)
at org.apache.http.impl.conn.AbstractPoolEntry.open(AbstractPoolEntry.java:164)
at org.apache.http.impl.conn.AbstractPooledConnAdapter.open(AbstractPooledConnAdapter.java:119)
at org.apache.http.impl.client.DefaultRequestDirector.execute(DefaultRequestDirector.java:367)
at org.apache.http.impl.client.AbstractHttpClient.execute(AbstractHttpClient.java:593)
at org.apache.http.impl.client.AbstractHttpClient.execute(AbstractHttpClient.java:510)
at org.apache.http.impl.client.AbstractHttpClient.execute(AbstractHttpClient.java:488)
at com.cbsystematic.mobile.itvdn.ServiceHandler.makeServiceCall(ServiceHandler.java:73)
at com.cbsystematic.mobile.itvdn.ServiceHandler.makeServiceCall(ServiceHandler.java:37)
at com.cbsystematic.mobile.itvdn.CatalogFragment$GetCatalog.doInBackground(CatalogFragment.java:187)
at com.cbsystematic.mobile.itvdn.CatalogFragment$GetCatalog.doInBackground(CatalogFragment.java:169)
at android.os.AsyncTask.call(AsyncTask.java:287)
at java.util.concurrent.FutureTask$Sync.innerRun(FutureTask.java:305)
at java.util.concurrent.FutureTask.run(FutureTask.java:137)
at android.os.AsyncTask$SerialExecutor.run(AsyncTask.java:230)
at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1076)
at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:569)
at java.lang.Thread.run(Thread.java:864)
和DoInBackground方法仔细看看：
@Override
protected Void doInBackground(Void... arg0) {
// Creating service handler class instance
ServiceHandler sh = new ServiceHandler();
// Making a request to url and getting response
String jsonStr = sh.makeServiceCall(url, ServiceHandler.GET);
Log.d("Response: ", "> " + jsonStr);
if (jsonStr != null) {
try {
// Getting JSON Array node
catalog = new JSONArray(jsonStr);
// looping through All Courses
for (int i = 0; i < catalog.length(); i++) {
JSONObject c = catalog.getJSONObject(i);
String name = c.getString(TAG_NAME);
// tmp hashmap for single course
HashMap<String, String> contact = new HashMap<String, String>();
// adding each child node to HashMap key => value
contact.put(TAG_NAME, name);
// adding course name to contact list
catalogList.add(contact);
}
} catch (JSONException e) {
e.printStackTrace();
}
} else {
Log.e("ServiceHandler", "Couldn't get any data from the url");
}
return null;
}
作为例外明确指出：
java.lang.SecurityException: Permission denied (missing INTERNET permission?)
您必须添加行
<uses-permission android:name="android.permission.INTERNET" />
进入你的 manifest file.
我一直在使用 this guide 解析 JSON 数组并遇到奇怪的错误：
01-20 14:56:40.511 28118-28118/com.cbsystematic.mobile.itvdn E/WindowManager﹕ Activity com.cbsystematic.mobile.itvdn.NavigationActivity has leaked window com.android.internal.policy.impl.PhoneWindow$DecorView@4151cdd0 that was originally added here
android.view.WindowLeaked: Activity com.cbsystematic.mobile.itvdn.NavigationActivity has leaked window com.android.internal.policy.impl.PhoneWindow$DecorView@4151cdd0 that was originally added here
at android.view.ViewRootImpl.<init>(ViewRootImpl.java:464)
at android.view.WindowManagerImpl.addView(WindowManagerImpl.java:419)
at android.view.WindowManagerImpl.addView(WindowManagerImpl.java:351)
at android.view.WindowManagerImpl$CompatModeWrapper.addView(WindowManagerImpl.java:171)
at android.view.Window$LocalWindowManager.addView(Window.java:558)
at android.app.Dialog.show(Dialog.java:282)
at com.cbsystematic.mobile.itvdn.CatalogFragment$GetContacts.onPreExecute(CatalogFragment.java:178)
at android.os.AsyncTask.executeOnExecutor(AsyncTask.java:586)
at android.os.AsyncTask.execute(AsyncTask.java:534)
at com.cbsystematic.mobile.itvdn.CatalogFragment.onCreate(CatalogFragment.java:89)
at android.support.v4.app.Fragment.performCreate(Fragment.java:1763)
at android.support.v4.app.FragmentManagerImpl.moveToState(FragmentManager.java:913)
at android.support.v4.app.FragmentManagerImpl.moveToState(FragmentManager.java:1126)
at android.support.v4.app.BackStackRecord.run(BackStackRecord.java:739)
at android.support.v4.app.FragmentManagerImpl.execPendingActions(FragmentManager.java:1489)
at android.support.v4.app.FragmentActivity.onStart(FragmentActivity.java:548)
at android.app.Instrumentation.callActivityOnStart(Instrumentation.java:1225)
at android.app.Activity.performStart(Activity.java:5076)
at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2328)
at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2391)
at android.app.ActivityThread.access0(ActivityThread.java:151)
at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1335)
at android.os.Handler.dispatchMessage(Handler.java:99)
at android.os.Looper.loop(Looper.java:155)
at android.app.ActivityThread.main(ActivityThread.java:5520)
at java.lang.reflect.Method.invokeNative(Native Method)
at java.lang.reflect.Method.invoke(Method.java:511)
at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:1029)
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:796)
at dalvik.system.NativeStart.main(Native Method)
程序结构为导航抽屉Activity，内容为3个片段。我正在使用扩展 AbsListView.OnItemClickListener:
CatalogFragment
JSON数组如下：
[
{
"Url":"windows-store-app-html5-and-vascript",
"LessonsCount":1,
"Name":"Разработка Windows Store приложений с JavaScript и HTML5.",
"IsFree":true,
"Price":0,
"Language":"ru",
"Difficulty":2,
"Author":{
"Id":"963163db-eee6-4e73-81b3-71b58a602f78","Name":"Дмитрий Охрименко",
"PhotoUrl":"https://itvdn.blob.core.windows.net/authors/authors-okhrimenko.jpg",
"Description":"Сертифицированный специалист Microsoft (MCTS, MCPD, MCT).Тренер-консультант, эксперт по построению распределенных и веб-ориентированных приложений.","Url":null}
},
.
.
]
GetCatalog class（与指南几乎相同）：
private class GetCatalog extends AsyncTask<Void, Void, Void> {
@Override
protected void onPreExecute() {
super.onPreExecute();
// Showing progress dialog
pDialog = new ProgressDialog(getActivity());
pDialog.setMessage("Please wait...");
pDialog.setCancelable(false);
pDialog.show();
}
@Override
protected Void doInBackground(Void... arg0) {
// Creating service handler class instance
ServiceHandler sh = new ServiceHandler();
// Making a request to url and getting response
String jsonStr = sh.makeServiceCall(url, ServiceHandler.GET);
Log.d("Response: ", "> " + jsonStr);
if (jsonStr != null) {
try {
// Getting JSON Array node
catalog = new JSONArray(jsonStr);
// looping through All Contacts
for (int i = 0; i < catalog.length(); i++) {
JSONObject c = catalog.getJSONObject(i);
String name = c.getString(TAG_NAME);
// tmp hashmap for single contact
HashMap<String, String> contact = new HashMap<String, String>();
// adding each child node to HashMap key => value
contact.put(TAG_NAME, name);
// adding contact to contact list
catalogList.add(contact);
}
} catch (JSONException e) {
e.printStackTrace();
}
} else {
Log.e("ServiceHandler", "Couldn't get any data from the url");
}
return null;
}
@Override
protected void onPostExecute(Void result) {
super.onPostExecute(result);
// Dismiss the progress dialog
if (pDialog.isShowing())
pDialog.dismiss();
/**
* Updating parsed JSON data into ListView
* */
ListAdapter adapter = new SimpleAdapter(
getActivity(), catalogList,
R.layout.catalog_list_item, new String[] {TAG_NAME}, new int[] {
R.id.name });
mListView.setAdapter(adapter);
}
}
我正在尝试传递 OnCreate()...
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
new GetCatalog().execute();
}
整个CatalogFragmentclass（如果需要的话）：
public class CatalogFragment extends android.support.v4.app.Fragment implements AbsListView.OnItemClickListener {
private static final String ARG_SECTION_NUMBER = "section_number";
private ProgressDialog pDialog;
// URL to get contacts JSON
private static String url = "http://api.androidhive.info/contacts/";
// JSON Node names
private static final String TAG_NAME = "Name";
// contacts JSONArray
JSONArray catalog = null;
// Hashmap for ListView
ArrayList<HashMap<String, String>> catalogList;
private OnFragmentInteractionListener mListener;
/**
* The fragment's ListView/GridView.
*/
private AbsListView mListView;
/**
* The Adapter which will be used to populate the ListView/GridView with
* Views.
*/
private ListAdapter mAdapter;
// TODO: Rename and change types of parameters
public static CatalogFragment newInstance( int sectionNumber) {
CatalogFragment fragment = new CatalogFragment();
Bundle args = new Bundle();
args.putInt(ARG_SECTION_NUMBER, sectionNumber);
fragment.setArguments(args);
return fragment;
}
/**
* Mandatory empty constructor for the fragment manager to instantiate the
* fragment (e.g. upon screen orientation changes).
*/
public CatalogFragment() {
}
@Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
new GetCatalog().execute();
}
@Override
public View onCreateView(LayoutInflater inflater, ViewGroup container,
Bundle savedInstanceState) {
View view = inflater.inflate(R.layout.fragment_catalog, container, false);
// Set the adapter
mListView = (AbsListView) view.findViewById(android.R.id.list);
((AdapterView<ListAdapter>) mListView).setAdapter(mAdapter);
// Set OnItemClickListener so we can be notified on item clicks
mListView.setOnItemClickListener(this);
return view;
}
@Override
public void onAttach(Activity activity) {
super.onAttach(activity);
try {
mListener = (OnFragmentInteractionListener) activity;
} catch (ClassCastException e) {
throw new ClassCastException(activity.toString()
+ " must implement OnFragmentInteractionListener");
}
((NavigationActivity) activity).onSectionAttached(
getArguments().getInt(ARG_SECTION_NUMBER));
}
@Override
public void onDetach() {
super.onDetach();
mListener = null;
}
@Override
public void onItemClick(AdapterView<?> parent, View view, int position, long id) {
}
/**
* The default content for this Fragment has a TextView that is shown when
* the list is empty. If you would like to change the text, call this method
* to supply the text it should use.
*/
public void setEmptyText(CharSequence emptyText) {
View emptyView = mListView.getEmptyView();
if (emptyView instanceof TextView) {
((TextView) emptyView).setText(emptyText);
}
}
/**
* This interface must be implemented by activities that contain this
* fragment to allow an interaction in this fragment to be communicated
* to the activity and potentially other fragments contained in that
* activity.
* <p/>
* See the Android Training lesson <a href=
* "http://developer.android.com/training/basics/fragments/communicating.html"
* >Communicating with Other Fragments</a> for more information.
*/
public interface OnFragmentInteractionListener {
// TODO: Update argument type and name
public void onCatalogFragmentInteraction(String id);
}
private class GetCatalog extends AsyncTask<Void, Void, Void> {
@Override
protected void onPreExecute() {
super.onPreExecute();
// Showing progress dialog
pDialog = new ProgressDialog(getActivity());
pDialog.setMessage("Please wait...");
pDialog.setCancelable(false);
pDialog.show();
}
@Override
protected Void doInBackground(Void... arg0) {
// Creating service handler class instance
ServiceHandler sh = new ServiceHandler();
// Making a request to url and getting response
String jsonStr = sh.makeServiceCall(url, ServiceHandler.GET);
Log.d("Response: ", "> " + jsonStr);
if (jsonStr != null) {
try {
// Getting JSON Array node
catalog = new JSONArray(jsonStr);
// looping through All Contacts
for (int i = 0; i < catalog.length(); i++) {
JSONObject c = catalog.getJSONObject(i);
String name = c.getString(TAG_NAME);
// tmp hashmap for single contact
HashMap<String, String> contact = new HashMap<String, String>();
// adding each child node to HashMap key => value
contact.put(TAG_NAME, name);
// adding contact to contact list
catalogList.add(contact);
}
} catch (JSONException e) {
e.printStackTrace();
}
} else {
Log.e("ServiceHandler", "Couldn't get any data from the url");
}
return null;
}
@Override
protected void onPostExecute(Void result) {
super.onPostExecute(result);
// Dismiss the progress dialog
if (pDialog.isShowing())
pDialog.dismiss();
/**
* Updating parsed JSON data into ListView
* */
ListAdapter adapter = new SimpleAdapter(
getActivity(), catalogList,
R.layout.catalog_list_item, new String[] {TAG_NAME}, new int[] {
R.id.name });
mListView.setAdapter(adapter);
}
}
}
P.S。我一直在尝试从指南中下载完整的代码，这很有效。但是当在我的代码中使用相同的代码时，它不会。
感谢您的帮助
编辑： 在评论与 ProgressDialog 有关的操作后：
01-20 16:11:33.641 4969-5281/com.cbsystematic.mobile.itvdn E/AndroidRuntime﹕ FATAL EXCEPTION: AsyncTask #1
java.lang.RuntimeException: An error occured while executing doInBackground()
at android.os.AsyncTask.done(AsyncTask.java:299)
at java.util.concurrent.FutureTask$Sync.innerSetException(FutureTask.java:273)
at java.util.concurrent.FutureTask.setException(FutureTask.java:124)
at java.util.concurrent.FutureTask$Sync.innerRun(FutureTask.java:307)
at java.util.concurrent.FutureTask.run(FutureTask.java:137)
at android.os.AsyncTask$SerialExecutor.run(AsyncTask.java:230)
at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1076)
at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:569)
at java.lang.Thread.run(Thread.java:864)
Caused by: java.lang.SecurityException: Permission denied (missing INTERNET permission?)
at java.net.InetAddress.lookupHostByName(InetAddress.java:428)
at java.net.InetAddress.getAllByNameImpl(InetAddress.java:239)
at java.net.InetAddress.getAllByName(InetAddress.java:214)
at org.apache.http.impl.conn.DefaultClientConnectionOperator.openConnection(DefaultClientConnectionOperator.java:137)
at org.apache.http.impl.conn.AbstractPoolEntry.open(AbstractPoolEntry.java:164)
at org.apache.http.impl.conn.AbstractPooledConnAdapter.open(AbstractPooledConnAdapter.java:119)
at org.apache.http.impl.client.DefaultRequestDirector.execute(DefaultRequestDirector.java:367)
at org.apache.http.impl.client.AbstractHttpClient.execute(AbstractHttpClient.java:593)
at org.apache.http.impl.client.AbstractHttpClient.execute(AbstractHttpClient.java:510)
at org.apache.http.impl.client.AbstractHttpClient.execute(AbstractHttpClient.java:488)
at com.cbsystematic.mobile.itvdn.ServiceHandler.makeServiceCall(ServiceHandler.java:73)
at com.cbsystematic.mobile.itvdn.ServiceHandler.makeServiceCall(ServiceHandler.java:37)
at com.cbsystematic.mobile.itvdn.CatalogFragment$GetCatalog.doInBackground(CatalogFragment.java:187)
at com.cbsystematic.mobile.itvdn.CatalogFragment$GetCatalog.doInBackground(CatalogFragment.java:169)
at android.os.AsyncTask.call(AsyncTask.java:287)
at java.util.concurrent.FutureTask$Sync.innerRun(FutureTask.java:305)
at java.util.concurrent.FutureTask.run(FutureTask.java:137)
at android.os.AsyncTask$SerialExecutor.run(AsyncTask.java:230)
at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1076)
at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:569)
at java.lang.Thread.run(Thread.java:864)
Caused by: libcore.io.GaiException: getaddrinfo failed: EAI_NODATA (No address associated with hostname)
at libcore.io.Posix.getaddrinfo(Native Method)
at libcore.io.ForwardingOs.getaddrinfo(ForwardingOs.java:55)
at java.net.InetAddress.lookupHostByName(InetAddress.java:415)
at java.net.InetAddress.getAllByNameImpl(InetAddress.java:239)
at java.net.InetAddress.getAllByName(InetAddress.java:214)
at org.apache.http.impl.conn.DefaultClientConnectionOperator.openConnection(DefaultClientConnectionOperator.java:137)
at org.apache.http.impl.conn.AbstractPoolEntry.open(AbstractPoolEntry.java:164)
at org.apache.http.impl.conn.AbstractPooledConnAdapter.open(AbstractPooledConnAdapter.java:119)
at org.apache.http.impl.client.DefaultRequestDirector.execute(DefaultRequestDirector.java:367)
at org.apache.http.impl.client.AbstractHttpClient.execute(AbstractHttpClient.java:593)
at org.apache.http.impl.client.AbstractHttpClient.execute(AbstractHttpClient.java:510)
at org.apache.http.impl.client.AbstractHttpClient.execute(AbstractHttpClient.java:488)
at com.cbsystematic.mobile.itvdn.ServiceHandler.makeServiceCall(ServiceHandler.java:73)
at com.cbsystematic.mobile.itvdn.ServiceHandler.makeServiceCall(ServiceHandler.java:37)
at com.cbsystematic.mobile.itvdn.CatalogFragment$GetCatalog.doInBackground(CatalogFragment.java:187)
at com.cbsystematic.mobile.itvdn.CatalogFragment$GetCatalog.doInBackground(CatalogFragment.java:169)
at android.os.AsyncTask.call(AsyncTask.java:287)
at java.util.concurrent.FutureTask$Sync.innerRun(FutureTask.java:305)
at java.util.concurrent.FutureTask.run(FutureTask.java:137)
at android.os.AsyncTask$SerialExecutor.run(AsyncTask.java:230)
at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1076)
at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:569)
at java.lang.Thread.run(Thread.java:864)
Caused by: libcore.io.ErrnoException: getaddrinfo failed: EACCES (Permission denied)
at libcore.io.Posix.getaddrinfo(Native Method)
at libcore.io.ForwardingOs.getaddrinfo(ForwardingOs.java:55)
at java.net.InetAddress.lookupHostByName(InetAddress.java:415)
at java.net.InetAddress.getAllByNameImpl(InetAddress.java:239)
at java.net.InetAddress.getAllByName(InetAddress.java:214)
at org.apache.http.impl.conn.DefaultClientConnectionOperator.openConnection(DefaultClientConnectionOperator.java:137)
at org.apache.http.impl.conn.AbstractPoolEntry.open(AbstractPoolEntry.java:164)
at org.apache.http.impl.conn.AbstractPooledConnAdapter.open(AbstractPooledConnAdapter.java:119)
at org.apache.http.impl.client.DefaultRequestDirector.execute(DefaultRequestDirector.java:367)
at org.apache.http.impl.client.AbstractHttpClient.execute(AbstractHttpClient.java:593)
at org.apache.http.impl.client.AbstractHttpClient.execute(AbstractHttpClient.java:510)
at org.apache.http.impl.client.AbstractHttpClient.execute(AbstractHttpClient.java:488)
at com.cbsystematic.mobile.itvdn.ServiceHandler.makeServiceCall(ServiceHandler.java:73)
at com.cbsystematic.mobile.itvdn.ServiceHandler.makeServiceCall(ServiceHandler.java:37)
at com.cbsystematic.mobile.itvdn.CatalogFragment$GetCatalog.doInBackground(CatalogFragment.java:187)
at com.cbsystematic.mobile.itvdn.CatalogFragment$GetCatalog.doInBackground(CatalogFragment.java:169)
at android.os.AsyncTask.call(AsyncTask.java:287)
at java.util.concurrent.FutureTask$Sync.innerRun(FutureTask.java:305)
at java.util.concurrent.FutureTask.run(FutureTask.java:137)
at android.os.AsyncTask$SerialExecutor.run(AsyncTask.java:230)
at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1076)
at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:569)
at java.lang.Thread.run(Thread.java:864)
和DoInBackground方法仔细看看：
@Override
protected Void doInBackground(Void... arg0) {
// Creating service handler class instance
ServiceHandler sh = new ServiceHandler();
// Making a request to url and getting response
String jsonStr = sh.makeServiceCall(url, ServiceHandler.GET);
Log.d("Response: ", "> " + jsonStr);
if (jsonStr != null) {
try {
// Getting JSON Array node
catalog = new JSONArray(jsonStr);
// looping through All Courses
for (int i = 0; i < catalog.length(); i++) {
JSONObject c = catalog.getJSONObject(i);
String name = c.getString(TAG_NAME);
// tmp hashmap for single course
HashMap<String, String> contact = new HashMap<String, String>();
// adding each child node to HashMap key => value
contact.put(TAG_NAME, name);
// adding course name to contact list
catalogList.add(contact);
}
} catch (JSONException e) {
e.printStackTrace();
}
} else {
Log.e("ServiceHandler", "Couldn't get any data from the url");
}
return null;
}
作为例外明确指出：
java.lang.SecurityException: Permission denied (missing INTERNET permission?)
您必须添加行
<uses-permission android:name="android.permission.INTERNET" />
进入你的 manifest file.