ListView 内部片段错误
ListView inside fragment error
我的片段：
public class NewsFragment extends ListFragment {
private ProgressDialog pDialog;
// URL to get contacts JSON
private static String url = "url";
// JSON Node names
private static final String TAG_NEWS = "news";
private static final String TAG_ID = "id";
private static final String TAG_JUDUL = "judul";
private static final String TAG_TGL = "tanggal";
private static final String TAG_ISI = "isi";
private static final String TAG_SUMBER = "sumber";
private static final String TAG_GAMBAR = "gambar";
// contacts JSONArray
JSONArray news = null;
// Hashmap for ListView
ArrayList<HashMap<String, String>> newsList;
@Override
public View onCreateView(LayoutInflater inflater, ViewGroup container,
Bundle savedInstanceState) {
View newsView = inflater.inflate(R.layout.fragment_news, container, false) ;
newsList = new ArrayList<HashMap<String, String>>();
ListView lv = getListView();
lv.setOnItemClickListener(new AdapterView.OnItemClickListener() {
@Override
public void onItemClick(AdapterView<?> parent, View view,
int position, long id) {
// getting values from selected ListItem
String judul = ((TextView) view.findViewById(R.id.judul))
.getText().toString();
String tanggal = ((TextView) view.findViewById(R.id.tglPublish))
.getText().toString();
String sumber = ((TextView) view.findViewById(R.id.sumber))
.getText().toString();
// Starting single contact activity
Intent in = new Intent(getActivity().getApplicationContext(),
NewsDetailActivity.class);
in.putExtra(TAG_JUDUL, judul);
in.putExtra(TAG_TGL, tanggal);
in.putExtra(TAG_SUMBER, sumber);
startActivity(in);
}
});
// Calling async task to get json
new GetNews().execute();
return newsView ;
}
/**
* Async task class to get json by making HTTP call
* */
private class GetNews extends AsyncTask<Void, Void, Void> {
@Override
protected void onPreExecute() {
super.onPreExecute();
// Showing progress dialog
pDialog = new ProgressDialog(getActivity());
pDialog.setMessage("Mohon tunggu...");
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.POST);
Log.d("Response: ", "> " + jsonStr);
if (jsonStr != null) {
try {
JSONObject jsonObj = new JSONObject(jsonStr);
// Getting JSON Array node
news = jsonObj.getJSONArray("");
// looping through All Contacts
for (int i = 0; i < news.length(); i++) {
JSONObject c = news.getJSONObject(i);
String id = c.getString(TAG_ID);
String judul = c.getString(TAG_JUDUL);
String tgl = c.getString(TAG_TGL);
String sumber = c.getString(TAG_SUMBER);
// String gambar = c.getString(TAG_GENDER);
// tmp hashmap for single contact
HashMap<String, String> news = new HashMap<String, String>();
// adding each child node to HashMap key => value
news.put(TAG_ID, id);
news.put(TAG_JUDUL, judul);
news.put(TAG_TGL, tgl);
news.put(TAG_SUMBER, sumber);
// adding contact to contact list
newsList.add(news);
}
} 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().getApplicationContext(), newsList,
R.layout.list_item, new String[] { TAG_JUDUL, TAG_TGL,
TAG_SUMBER }, new int[] { R.id.judul,
R.id.tglPublish, R.id.sumber });
setListAdapter(adapter);
}
}
}
我的 xml :
<?xml version="1.0" encoding="utf-8"?>
<LinearLayout
xmlns:android="http://schemas.android.com/apk/res/android"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:orientation="vertical"
android:layout_marginLeft="12dp"
android:layout_marginRight="12dp">
<!-- Main ListView
Always give id value as list(@android:id/list)
-->
<ListView
android:id="@android:id/list"
android:layout_width="fill_parent"
android:layout_height="wrap_content"/>
</LinearLayout>
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"
android:padding="10dp"
android:paddingLeft="10dp"
android:paddingRight="10dp" >
<!-- Judul -->
<TextView
android:id="@+id/judul"
android:layout_width="fill_parent"
android:layout_height="wrap_content"
android:paddingBottom="2dip"
android:paddingTop="6dip"
android:textColor="#43bd00"
android:textSize="16sp"
android:textStyle="bold" />
<!-- Tgl Publish -->
<TextView
android:id="@+id/tglPublish"
android:layout_width="fill_parent"
android:layout_height="wrap_content"
android:paddingBottom="2dip"
android:textColor="#acacac" />
<!-- Sumber -->
<TextView
android:id="@+id/sumber"
android:layout_width="fill_parent"
android:layout_height="wrap_content"
android:gravity="left"
android:textColor="#5d5d5d"
android:textStyle="bold" />
<ImageView
android:layout_width="wrap_content"
android:layout_height="wrap_content" />
</LinearLayout>
和错误日志：
05-20 00:24:41.091 20376-20376/com.emaszda.nutrisibunda E/AndroidRuntime﹕ FATAL EXCEPTION: main
java.lang.IllegalStateException: Content view not yet created
at android.support.v4.app.ListFragment.ensureList(ListFragment.java:328)
at android.support.v4.app.ListFragment.getListView(ListFragment.java:222)
at com.emaszda.nutrisibunda.NewsFragment.onCreateView(NewsFragment.java:58)
at android.support.v4.app.Fragment.performCreateView(Fragment.java:1786)
at android.support.v4.app.FragmentManagerImpl.moveToState(FragmentManager.java:953)
at android.support.v4.app.FragmentManagerImpl.moveToState(FragmentManager.java:1136)
at android.support.v4.app.BackStackRecord.run(BackStackRecord.java:739)
at android.support.v4.app.FragmentManagerImpl.execPendingActions(FragmentManager.java:1499)
at android.support.v4.app.FragmentManagerImpl.executePendingTransactions(FragmentManager.java:488)
at android.support.v4.app.FragmentPagerAdapter.finishUpdate(FragmentPagerAdapter.java:141)
at android.support.v4.view.ViewPager.populate(ViewPager.java:1073)
at android.support.v4.view.ViewPager.populate(ViewPager.java:919)
at android.support.v4.view.ViewPager.onMeasure(ViewPager.java:1441)
at android.view.View.measure(View.java:15891)
at android.view.ViewGroup.measureChildWithMargins(ViewGroup.java:5035)
at android.widget.FrameLayout.onMeasure(FrameLayout.java:310)
at android.view.View.measure(View.java:15891)
at android.view.ViewGroup.measureChildWithMargins(ViewGroup.java:5035)
at android.support.v7.internal.widget.ActionBarOverlayLayout.onMeasure(ActionBarOverlayLayout.java:453)
at android.view.View.measure(View.java:15891)
at android.view.ViewGroup.measureChildWithMargins(ViewGroup.java:5035)
at android.widget.FrameLayout.onMeasure(FrameLayout.java:310)
at android.view.View.measure(View.java:15891)
at android.view.ViewGroup.measureChildWithMargins(ViewGroup.java:5035)
at android.widget.LinearLayout.measureChildBeforeLayout(LinearLayout.java:1404)
at android.widget.LinearLayout.measureVertical(LinearLayout.java:695)
at android.widget.LinearLayout.onMeasure(LinearLayout.java:588)
at android.view.View.measure(View.java:15891)
at android.view.ViewGroup.measureChildWithMargins(ViewGroup.java:5035)
at android.widget.FrameLayout.onMeasure(FrameLayout.java:310)
at com.android.internal.policy.impl.PhoneWindow$DecorView.onMeasure(PhoneWindow.java:2208)
at android.view.View.measure(View.java:15891)
at android.view.ViewRootImpl.performMeasure(ViewRootImpl.java:1957)
at android.view.ViewRootImpl.measureHierarchy(ViewRootImpl.java:1156)
at android.view.ViewRootImpl.performTraversals(ViewRootImpl.java:1336)
at android.view.ViewRootImpl.doTraversal(ViewRootImpl.java:1056)
at android.view.ViewRootImpl$TraversalRunnable.run(ViewRootImpl.java:5542)
at android.view.Choreographer$CallbackRecord.run(Choreographer.java:749)
at android.view.Choreographer.doCallbacks(Choreographer.java:562)
at android.view.Choreographer.doFrame(Choreographer.java:532)
at android.view.Choreographer$FrameDisplayEventReceiver.run(Choreographer.java:735)
at android.os.Handler.handleCallback(Handler.java:730)
at android.os.Handler.dispatchMessage(Handler.java:92)
at android.os.Looper.loop(Looper.java:137)
at android.app.ActivityThread.main(ActivityThread.java:5162)
at java.lang.reflect.Method.invokeNative(Native Method)
at java.lang.reflect.Method.invoke(Method.java:525)
at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:756)
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:572)
at miui.dexspy.DexspyInstaller.main(DexspyInstaller.java:171)
at dalvik.system.NativeStart.main(Native Method)
作为 onCreateView:
Creates and returns the view hierarchy associated with the fragment.
Since the method does not return the view, you will not able to access the
ListView through getListView().
将 getListView() 放入 onViewCreated() 方法中，如下所示：
@Override
public void onViewCreated(View view, Bundle savedInstanceState) {
super.onViewCreated(view, savedInstanceState);
ListView lv = getListView();
lv.setOnItemClickListener(new AdapterView.OnItemClickListener() {
@Override
public void onItemClick(AdapterView<?> parent, View view,
int position, long id) {
// getting values from selected ListItem
String judul = ((TextView) view.findViewById(R.id.judul))
.getText().toString();
String tanggal = ((TextView) view.findViewById(R.id.tglPublish))
.getText().toString();
String sumber = ((TextView) view.findViewById(R.id.sumber))
.getText().toString();
// Starting single contact activity
Intent in = new Intent(getActivity().getApplicationContext(),
NewsDetailActivity.class);
in.putExtra(TAG_JUDUL, judul);
in.putExtra(TAG_TGL, tanggal);
in.putExtra(TAG_SUMBER, sumber);
startActivity(in);
}
});
}
onViewCreated是在api level 13中添加的，所以如果你的minSdkVersion低于13那么使用onActivityCreated获取Listview对象。
只需覆盖 onActivityCreated 并输入您的代码：
// Calling async task to get json
new GetNews().execute();
这里的问题是你试图在 UI 尚未创建时对其进行操作，因为 onCreateView 尚未执行 return 语句
在 onActivityCreated() 而不是 onCreateView() 中调用您的 GetNews().execute(); 方法，因为当您启动 AsyncTask 时您的视图甚至还没有创建。
@Override
public void onActivityCreated(Bundle savedInstanceState) {
super.onActivityCreated(savedInstanceState);
new GetNews().execute();
}
将此 ListView lv = getListView(); 代码放入片段
的 onActivityCreated() 或 onCreate() 中
我的片段：
public class NewsFragment extends ListFragment {
private ProgressDialog pDialog;
// URL to get contacts JSON
private static String url = "url";
// JSON Node names
private static final String TAG_NEWS = "news";
private static final String TAG_ID = "id";
private static final String TAG_JUDUL = "judul";
private static final String TAG_TGL = "tanggal";
private static final String TAG_ISI = "isi";
private static final String TAG_SUMBER = "sumber";
private static final String TAG_GAMBAR = "gambar";
// contacts JSONArray
JSONArray news = null;
// Hashmap for ListView
ArrayList<HashMap<String, String>> newsList;
@Override
public View onCreateView(LayoutInflater inflater, ViewGroup container,
Bundle savedInstanceState) {
View newsView = inflater.inflate(R.layout.fragment_news, container, false) ;
newsList = new ArrayList<HashMap<String, String>>();
ListView lv = getListView();
lv.setOnItemClickListener(new AdapterView.OnItemClickListener() {
@Override
public void onItemClick(AdapterView<?> parent, View view,
int position, long id) {
// getting values from selected ListItem
String judul = ((TextView) view.findViewById(R.id.judul))
.getText().toString();
String tanggal = ((TextView) view.findViewById(R.id.tglPublish))
.getText().toString();
String sumber = ((TextView) view.findViewById(R.id.sumber))
.getText().toString();
// Starting single contact activity
Intent in = new Intent(getActivity().getApplicationContext(),
NewsDetailActivity.class);
in.putExtra(TAG_JUDUL, judul);
in.putExtra(TAG_TGL, tanggal);
in.putExtra(TAG_SUMBER, sumber);
startActivity(in);
}
});
// Calling async task to get json
new GetNews().execute();
return newsView ;
}
/**
* Async task class to get json by making HTTP call
* */
private class GetNews extends AsyncTask<Void, Void, Void> {
@Override
protected void onPreExecute() {
super.onPreExecute();
// Showing progress dialog
pDialog = new ProgressDialog(getActivity());
pDialog.setMessage("Mohon tunggu...");
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.POST);
Log.d("Response: ", "> " + jsonStr);
if (jsonStr != null) {
try {
JSONObject jsonObj = new JSONObject(jsonStr);
// Getting JSON Array node
news = jsonObj.getJSONArray("");
// looping through All Contacts
for (int i = 0; i < news.length(); i++) {
JSONObject c = news.getJSONObject(i);
String id = c.getString(TAG_ID);
String judul = c.getString(TAG_JUDUL);
String tgl = c.getString(TAG_TGL);
String sumber = c.getString(TAG_SUMBER);
// String gambar = c.getString(TAG_GENDER);
// tmp hashmap for single contact
HashMap<String, String> news = new HashMap<String, String>();
// adding each child node to HashMap key => value
news.put(TAG_ID, id);
news.put(TAG_JUDUL, judul);
news.put(TAG_TGL, tgl);
news.put(TAG_SUMBER, sumber);
// adding contact to contact list
newsList.add(news);
}
} 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().getApplicationContext(), newsList,
R.layout.list_item, new String[] { TAG_JUDUL, TAG_TGL,
TAG_SUMBER }, new int[] { R.id.judul,
R.id.tglPublish, R.id.sumber });
setListAdapter(adapter);
}
}
}
我的 xml :
<?xml version="1.0" encoding="utf-8"?>
<LinearLayout
xmlns:android="http://schemas.android.com/apk/res/android"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:orientation="vertical"
android:layout_marginLeft="12dp"
android:layout_marginRight="12dp">
<!-- Main ListView
Always give id value as list(@android:id/list)
-->
<ListView
android:id="@android:id/list"
android:layout_width="fill_parent"
android:layout_height="wrap_content"/>
</LinearLayout>
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"
android:padding="10dp"
android:paddingLeft="10dp"
android:paddingRight="10dp" >
<!-- Judul -->
<TextView
android:id="@+id/judul"
android:layout_width="fill_parent"
android:layout_height="wrap_content"
android:paddingBottom="2dip"
android:paddingTop="6dip"
android:textColor="#43bd00"
android:textSize="16sp"
android:textStyle="bold" />
<!-- Tgl Publish -->
<TextView
android:id="@+id/tglPublish"
android:layout_width="fill_parent"
android:layout_height="wrap_content"
android:paddingBottom="2dip"
android:textColor="#acacac" />
<!-- Sumber -->
<TextView
android:id="@+id/sumber"
android:layout_width="fill_parent"
android:layout_height="wrap_content"
android:gravity="left"
android:textColor="#5d5d5d"
android:textStyle="bold" />
<ImageView
android:layout_width="wrap_content"
android:layout_height="wrap_content" />
</LinearLayout>
和错误日志：
05-20 00:24:41.091 20376-20376/com.emaszda.nutrisibunda E/AndroidRuntime﹕ FATAL EXCEPTION: main
java.lang.IllegalStateException: Content view not yet created
at android.support.v4.app.ListFragment.ensureList(ListFragment.java:328)
at android.support.v4.app.ListFragment.getListView(ListFragment.java:222)
at com.emaszda.nutrisibunda.NewsFragment.onCreateView(NewsFragment.java:58)
at android.support.v4.app.Fragment.performCreateView(Fragment.java:1786)
at android.support.v4.app.FragmentManagerImpl.moveToState(FragmentManager.java:953)
at android.support.v4.app.FragmentManagerImpl.moveToState(FragmentManager.java:1136)
at android.support.v4.app.BackStackRecord.run(BackStackRecord.java:739)
at android.support.v4.app.FragmentManagerImpl.execPendingActions(FragmentManager.java:1499)
at android.support.v4.app.FragmentManagerImpl.executePendingTransactions(FragmentManager.java:488)
at android.support.v4.app.FragmentPagerAdapter.finishUpdate(FragmentPagerAdapter.java:141)
at android.support.v4.view.ViewPager.populate(ViewPager.java:1073)
at android.support.v4.view.ViewPager.populate(ViewPager.java:919)
at android.support.v4.view.ViewPager.onMeasure(ViewPager.java:1441)
at android.view.View.measure(View.java:15891)
at android.view.ViewGroup.measureChildWithMargins(ViewGroup.java:5035)
at android.widget.FrameLayout.onMeasure(FrameLayout.java:310)
at android.view.View.measure(View.java:15891)
at android.view.ViewGroup.measureChildWithMargins(ViewGroup.java:5035)
at android.support.v7.internal.widget.ActionBarOverlayLayout.onMeasure(ActionBarOverlayLayout.java:453)
at android.view.View.measure(View.java:15891)
at android.view.ViewGroup.measureChildWithMargins(ViewGroup.java:5035)
at android.widget.FrameLayout.onMeasure(FrameLayout.java:310)
at android.view.View.measure(View.java:15891)
at android.view.ViewGroup.measureChildWithMargins(ViewGroup.java:5035)
at android.widget.LinearLayout.measureChildBeforeLayout(LinearLayout.java:1404)
at android.widget.LinearLayout.measureVertical(LinearLayout.java:695)
at android.widget.LinearLayout.onMeasure(LinearLayout.java:588)
at android.view.View.measure(View.java:15891)
at android.view.ViewGroup.measureChildWithMargins(ViewGroup.java:5035)
at android.widget.FrameLayout.onMeasure(FrameLayout.java:310)
at com.android.internal.policy.impl.PhoneWindow$DecorView.onMeasure(PhoneWindow.java:2208)
at android.view.View.measure(View.java:15891)
at android.view.ViewRootImpl.performMeasure(ViewRootImpl.java:1957)
at android.view.ViewRootImpl.measureHierarchy(ViewRootImpl.java:1156)
at android.view.ViewRootImpl.performTraversals(ViewRootImpl.java:1336)
at android.view.ViewRootImpl.doTraversal(ViewRootImpl.java:1056)
at android.view.ViewRootImpl$TraversalRunnable.run(ViewRootImpl.java:5542)
at android.view.Choreographer$CallbackRecord.run(Choreographer.java:749)
at android.view.Choreographer.doCallbacks(Choreographer.java:562)
at android.view.Choreographer.doFrame(Choreographer.java:532)
at android.view.Choreographer$FrameDisplayEventReceiver.run(Choreographer.java:735)
at android.os.Handler.handleCallback(Handler.java:730)
at android.os.Handler.dispatchMessage(Handler.java:92)
at android.os.Looper.loop(Looper.java:137)
at android.app.ActivityThread.main(ActivityThread.java:5162)
at java.lang.reflect.Method.invokeNative(Native Method)
at java.lang.reflect.Method.invoke(Method.java:525)
at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:756)
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:572)
at miui.dexspy.DexspyInstaller.main(DexspyInstaller.java:171)
at dalvik.system.NativeStart.main(Native Method)
作为 onCreateView:
Creates and returns the view hierarchy associated with the fragment. Since the method does not return the view, you will not able to access the ListView through getListView().
将 getListView() 放入 onViewCreated() 方法中，如下所示：
@Override
public void onViewCreated(View view, Bundle savedInstanceState) {
super.onViewCreated(view, savedInstanceState);
ListView lv = getListView();
lv.setOnItemClickListener(new AdapterView.OnItemClickListener() {
@Override
public void onItemClick(AdapterView<?> parent, View view,
int position, long id) {
// getting values from selected ListItem
String judul = ((TextView) view.findViewById(R.id.judul))
.getText().toString();
String tanggal = ((TextView) view.findViewById(R.id.tglPublish))
.getText().toString();
String sumber = ((TextView) view.findViewById(R.id.sumber))
.getText().toString();
// Starting single contact activity
Intent in = new Intent(getActivity().getApplicationContext(),
NewsDetailActivity.class);
in.putExtra(TAG_JUDUL, judul);
in.putExtra(TAG_TGL, tanggal);
in.putExtra(TAG_SUMBER, sumber);
startActivity(in);
}
});
}
onViewCreated是在api level 13中添加的，所以如果你的minSdkVersion低于13那么使用onActivityCreated获取Listview对象。
只需覆盖 onActivityCreated 并输入您的代码：
// Calling async task to get json
new GetNews().execute();
这里的问题是你试图在 UI 尚未创建时对其进行操作，因为 onCreateView 尚未执行 return 语句
在 onActivityCreated() 而不是 onCreateView() 中调用您的 GetNews().execute(); 方法，因为当您启动 AsyncTask 时您的视图甚至还没有创建。
@Override
public void onActivityCreated(Bundle savedInstanceState) {
super.onActivityCreated(savedInstanceState);
new GetNews().execute();
}
将此 ListView lv = getListView(); 代码放入片段
onActivityCreated() 或 onCreate() 中