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我試圖開發一個依賴於Web服務的Android應用程序，我使用片段來讓我的應用程序在移動設備和平板電腦上運行。 。java.lang.NullPointerException當我嘗試獲取片段之間的數據android
這是保持在兩種模式下的片段，並檢查哪個模式 然後定義依賴於在其中模式，詳細信息顯示在一個DetailFragment（橫向）onItemClickListener或DetailActivity（肖像）
public class AppelsFragment extends Fragment implements AdapterView.OnItemClickListener {
boolean mDualPane;
int mCurCheckPosition = 0;
public static List<Appel> appels = null;
ListView mListView;
@Override
public View onCreateView(LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState) {
View view = inflater.inflate(R.layout.list_fragment, container, false);
return view;
}
@Override
public void onActivityCreated(Bundle savedInstanceState) {
super.onActivityCreated(savedInstanceState);
mListView = (ListView) getActivity().findViewById(R.id.listAppels);
if (this.mListView != null) {
this.mListView.setOnItemClickListener(this);
this.mListView.setChoiceMode(ListView.CHOICE_MODE_SINGLE);
}
// this is an asynctask that retreive data from RestAPI and set the Adapter for my listview
new Appels().execute();
View detailsFrame = getActivity().findViewById(R.id.details);
mDualPane = detailsFrame != null
&& detailsFrame.getVisibility() == View.VISIBLE;
if (savedInstanceState != null) {
// Restore last state for checked position.
mCurCheckPosition = savedInstanceState.getInt("curChoice", 0);
}
if (mDualPane) {
showDetails(mCurCheckPosition);
} else {
mListView.setItemChecked(mCurCheckPosition, true);
}
}
@Override
public void onSaveInstanceState(Bundle outState) {
super.onSaveInstanceState(outState);
outState.putInt("curChoice", mCurCheckPosition);
}
@Override
public void onItemClick(AdapterView<?> l, View v, int position, long id) {
showDetails(position);
}
void showDetails(int index) {
mCurCheckPosition = index;
if (mDualPane) {
mListView.setItemChecked(index, true);
DetailsFragment details = (DetailsFragment) getFragmentManager()
.findFragmentById(R.id.details);
if (details == null || details.getShownIndex() != index) {
details = DetailsFragment.newInstance(index);
FragmentTransaction ft = getFragmentManager()
.beginTransaction();
ft.replace(R.id.details, details);
ft.setTransition(FragmentTransaction.TRANSIT_FRAGMENT_FADE);
ft.commit();
}
} else {
Intent intent = new Intent();
intent.setClass(getActivity(), DetailsActivity.class);
intent.putExtra("index", index);
startActivity(intent);
}
}
class Appels extends AsyncTask<String, Void, List<Appel>> {
..... }
}
我面對的問題是DetailFragment中的NullPointerException，在肖像模式下我hav E無問題
java.lang.RuntimeException: Unable to start activity ComponentInfo{com.mycompany.marocbusiness11.app/com.mycompany.marocbusiness11.app.FragmentLayout}: java.lang.NullPointerException
at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2195)
at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2245)
at android.app.ActivityThread.access$800(ActivityThread.java:135)
at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1196)
at android.os.Handler.dispatchMessage(Handler.java:102)
at android.os.Looper.loop(Looper.java:136)
at android.app.ActivityThread.main(ActivityThread.java:5017)
at java.lang.reflect.Method.invokeNative(Native Method)
at java.lang.reflect.Method.invoke(Method.java:515)
at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:779)
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:595)
at dalvik.system.NativeStart.main(Native Method)
Caused by: java.lang.NullPointerException
at com.mycompany.marocbusiness11.app.DetailsFragment.onCreateView(DetailsFragment.java:42)
at android.app.Fragment.performCreateView(Fragment.java:1700)
at android.app.FragmentManagerImpl.moveToState(FragmentManager.java:890)
at android.app.FragmentManagerImpl.moveToState(FragmentManager.java:1062)
at android.app.BackStackRecord.run(BackStackRecord.java:684)
at android.app.FragmentManagerImpl.execPendingActions(FragmentManager.java:1447)
at android.app.Activity.performStart(Activity.java:5240)
at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2168)
at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2245)
at android.app.ActivityThread.access$800(ActivityThread.java:135)
at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1196)
at android.os.Handler.dispatchMessage(Handler.java:102)
at android.os.Looper.loop(Looper.java:136)
at android.app.ActivityThread.main(ActivityThread.java:5017)
at java.lang.reflect.Method.invokeNative(Native Method)
at java.lang.reflect.Method.invoke(Method.java:515)
這是對DetailFragment
public class DetailsFragment extends Fragment {
public static DetailsFragment newInstance(int index) {
DetailsFragment f = new DetailsFragment();
// Supply index input as an argument.
Bundle args = new Bundle();
args.putInt("index", index);
f.setArguments(args);
return f;
}
public int getShownIndex() {
return getArguments().getInt("index", 0);
}
@Override
public View onCreateView(LayoutInflater inflater, ViewGroup container,
Bundle savedInstanceState) {
if(container == null)
return null;
View v = inflater.inflate(R.layout.details,container,false);
TextView txtAffichage = (TextView) v.findViewById(R.id.txtAffichage);
txtAffichage.setText(AppelsFragment.appels.get(getShownIndex()).getNumOrdre().toString());
return v;
}
}
的問題，通過這個指令
txtAffichage.setText(AppelsFragment.appels.get(getShownIndex()).getNumOrdre().toString());
我想我定義我的列表的方式，是
觸發代碼public static List<Appel> appels = null;
可能是這個問題的原因，如果有我怎麼能應付任何建議 或者我應該改變
由於提前
///////帖子編輯
在我使用DetailsActivity肖像模式實例化DetailsFragment所以它總是對碎片..
這是對DetailsActivity
代碼和details.xml佈局
<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:orientation="vertical" android:layout_width="match_parent"
android:layout_height="match_parent">
<TextView
android:id="@+id/txtAffichage"
android:layout_width="match_parent"
android:layout_height="match_parent" />
</LinearLayout>