java.lang.NullPointerException: Tentativo di ricall il metodo virtuale 'int android.view.View.getImportntForAccessibility ()' in un riferimento di null object

Sto cercando di mettere insieme un'applicazione per la list di acquisto, basata sui campi di input, ArrayList e ListView . L'applicazione sarà basata su Fragments . Tuttavia, ho incontrato un problema e non so come risolverlo.

Ho guardato in giro su Google e StackOverflow hanno trovato alcune informazioni. Tuttavia, non lo ho fatto funzionare. Ora spero che posso avere aiuto con il mio codice.

  • Immagine di animation di background su ProgressBar su Android?
  • Come disegnare la vista in cima alla tastiera soft come WhatsApp?
  • NoSuchFieldError: Nessun field statico MapAttrs di tipo quando si utilizza MapFragment con Play Services 6.5
  • Il plug-in BluetoothSerial non funziona con gli ioni
  • ID elemento dinamico per setId (int) - Android
  • Conversione di YUV-> RGB (elaborazione di immagini) -> YUV durante onPreviewFrame in android?
  • Sono relativamente inesperto nello sviluppo di Android.

    Grazie in anticipo

    Main.java

     import java.util.ArrayList; import android.app.Fragment; import android.app.FragmentManager; import android.app.FragmentTransaction; import android.os.Bundle; import android.support.v4.app.FragmentActivity; import android.view.Menu; import android.view.MenuItem; public class Main extends FragmentActivity { ArrayList<Detail> items = new ArrayList<Detail>(); FragmentManager FM; FragmentTransaction FT; Input input = new Input(); @Override protected void onCreate(Bundle savedInstanceState) { super.onCreate(savedInstanceState); setContentView(R.layout.activity_main); replaceFragment(R.id.container, input); } public void replaceFragment(int container, Fragment fragment){ FM = getFragmentManager(); FT = FM.beginTransaction(); FT.replace(container, fragment); FT.commit(); } @Override public boolean onCreateOptionsMenu(Menu menu) { // Inflate the menu; this adds items to the action bar if it is present. getMenuInflater().inflate(R.menu.main, menu); return true; } @Override public boolean onOptionsItemSelected(MenuItem item) { // Handle action bar item clicks here. The action bar will // automatically handle clicks on the Home/Up button, so long // as you specify a parent activity in AndroidManifest.xml. int id = item.getItemId(); if (id == R.id.action_settings) { return true; } return super.onOptionsItemSelected(item); } } 

    ListAdapter.java

     public class ListAdapter extends BaseAdapter { Context context; ArrayList<Detail> items; public ListAdapter(Context context, ArrayList<Detail> items) { this.context = context; this.items = items; } @Override public int getCount() { return items.size(); } @Override public Object getItem(int position) { return items.get(position); } @Override public long getItemId(int position) { return items.indexOf(getItem(position)); } @Override public View getView(int position, View convertView, ViewGroup parent) { if(convertView == null){ LayoutInflater lInflater = (LayoutInflater)context.getSystemService( Activity.LAYOUT_INFLATER_SERVICE); convertView = lInflater.inflate(R.layout.list_row, null); } TextView title = (TextView)convertView.findViewById(R.id.itemTitle); CheckBox done = (CheckBox)convertView.findViewById(R.id.itemDone); Detail detail_position = items.get(position); title.setText(detail_position.getTitle()); done.setChecked(detail_position.isDone()); return null; } } 

    List.java

     import java.util.ArrayList; import android.app.ListFragment; import android.os.Bundle; import android.view.LayoutInflater; import android.view.View; import android.view.ViewGroup; import android.widget.AdapterView; import android.widget.AdapterView.OnItemClickListener; public class List extends ListFragment implements OnItemClickListener{ ArrayList<Detail> items; ListAdapter adapter; private onClickListener OCL; interface onClickListener{ public void onItemClick(int id); } public List(ArrayList<Detail> items) { this.items = items; } @Override public View onCreateView(LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState) { View root = inflater.inflate(R.layout.list_layout, container, false); return root; } @Override public void onActivityCreated(Bundle savedInstanceState) { super.onActivityCreated(savedInstanceState); if(items != null){ adapter = new ListAdapter(getActivity(), items); setListAdapter(adapter); getListView().setOnItemClickListener(this); } } @Override public void onItemClick(AdapterView<?> parent, View view, int position, long id) { if(OCL != null){ OCL.onItemClick(position); } } } 

    list_layout.xml

     <?xml version="1.0" encoding="utf-8"?> <LinearLayout xmlns:android="http://schemas.android.com/apk/res/android" android:id="@+id/LinearLayout1" android:layout_width="match_parent" android:layout_height="match_parent" android:orientation="vertical" > <ListView android:id="@+id/android:list" android:layout_width="match_parent" android:layout_height="match_parent" > </ListView> </LinearLayout> 

    list_row

     <?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="horizontal" android:padding="10dp" > <TextView android:id="@+id/itemTitle" android:layout_width="wrap_content" android:layout_height="wrap_content" android:layout_weight="0.96" android:text="Medium Text" android:textAppearance="?android:attr/textAppearanceMedium" /> <CheckBox android:id="@+id/itemDone" android:layout_width="wrap_content" android:layout_height="wrap_content" android:text="Done" /> </LinearLayout> 

    activity_main.xml

     <RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android" xmlns:tools="http://schemas.android.com/tools" android:id="@+id/container" android:layout_width="match_parent" android:layout_height="match_parent" android:paddingBottom="@dimen/activity_vertical_margin" android:paddingLeft="@dimen/activity_horizontal_margin" android:paddingRight="@dimen/activity_horizontal_margin" android:paddingTop="@dimen/activity_vertical_margin" tools:context="com.example.com.hermods.lab2_2.Main" > </RelativeLayout> 

    Login

     02-19 09:10:47.421: E/AndroidRuntime(12745): Process: com.example.com.hermods.lab2_2, PID: 12745 02-19 09:10:47.421: E/AndroidRuntime(12745): java.lang.NullPointerException: Attempt to invoke virtual method 'int android.view.View.getImportntForAccessibility()' on a null object reference 02-19 09:10:47.421: E/AndroidRuntime(12745): at android.widget.AbsListView.obtainView(AbsListView.java:2360) 02-19 09:10:47.421: E/AndroidRuntime(12745): at android.widget.ListView.makeAndAddView(ListView.java:1864) 02-19 09:10:47.421: E/AndroidRuntime(12745): at android.widget.ListView.fillDown(ListView.java:698) 02-19 09:10:47.421: E/AndroidRuntime(12745): at android.widget.ListView.fillFromTop(ListView.java:759) 02-19 09:10:47.421: E/AndroidRuntime(12745): at android.widget.ListView.layoutChildren(ListView.java:1673) 02-19 09:10:47.421: E/AndroidRuntime(12745): at android.widget.AbsListView.onLayout(AbsListView.java:2148) 02-19 09:10:47.421: E/AndroidRuntime(12745): at android.view.View.layout(View.java:15596) 02-19 09:10:47.421: E/AndroidRuntime(12745): at android.view.ViewGroup.layout(ViewGroup.java:4966) 02-19 09:10:47.421: E/AndroidRuntime(12745): at android.widget.LinearLayout.setChildFrame(LinearLayout.java:1703) 02-19 09:10:47.421: E/AndroidRuntime(12745): at android.widget.LinearLayout.layoutVertical(LinearLayout.java:1557) 02-19 09:10:47.421: E/AndroidRuntime(12745): at android.widget.LinearLayout.onLayout(LinearLayout.java:1466) 02-19 09:10:47.421: E/AndroidRuntime(12745): at android.view.View.layout(View.java:15596) 02-19 09:10:47.421: E/AndroidRuntime(12745): at android.view.ViewGroup.layout(ViewGroup.java:4966) 02-19 09:10:47.421: E/AndroidRuntime(12745): at android.widget.RelativeLayout.onLayout(RelativeLayout.java:1076) 02-19 09:10:47.421: E/AndroidRuntime(12745): at android.view.View.layout(View.java:15596) 02-19 09:10:47.421: E/AndroidRuntime(12745): at android.view.ViewGroup.layout(ViewGroup.java:4966) 02-19 09:10:47.421: E/AndroidRuntime(12745): at android.widget.FrameLayout.layoutChildren(FrameLayout.java:573) 02-19 09:10:47.421: E/AndroidRuntime(12745): at android.widget.FrameLayout.onLayout(FrameLayout.java:508) 02-19 09:10:47.421: E/AndroidRuntime(12745): at android.view.View.layout(View.java:15596) 02-19 09:10:47.421: E/AndroidRuntime(12745): at android.view.ViewGroup.layout(ViewGroup.java:4966) 02-19 09:10:47.421: E/AndroidRuntime(12745): at android.widget.LinearLayout.setChildFrame(LinearLayout.java:1703) 02-19 09:10:47.421: E/AndroidRuntime(12745): at android.widget.LinearLayout.layoutVertical(LinearLayout.java:1557) 02-19 09:10:47.421: E/AndroidRuntime(12745): at android.widget.LinearLayout.onLayout(LinearLayout.java:1466) 02-19 09:10:47.421: E/AndroidRuntime(12745): at android.view.View.layout(View.java:15596) 02-19 09:10:47.421: E/AndroidRuntime(12745): at android.view.ViewGroup.layout(ViewGroup.java:4966) 02-19 09:10:47.421: E/AndroidRuntime(12745): at android.widget.FrameLayout.layoutChildren(FrameLayout.java:573) 02-19 09:10:47.421: E/AndroidRuntime(12745): at android.widget.FrameLayout.onLayout(FrameLayout.java:508) 02-19 09:10:47.421: E/AndroidRuntime(12745): at android.view.View.layout(View.java:15596) 02-19 09:10:47.421: E/AndroidRuntime(12745): at android.view.ViewGroup.layout(ViewGroup.java:4966) 02-19 09:10:47.421: E/AndroidRuntime(12745): at android.view.ViewRootImpl.performLayout(ViewRootImpl.java:2072) 02-19 09:10:47.421: E/AndroidRuntime(12745): at android.view.ViewRootImpl.performTraversals(ViewRootImpl.java:1829) 02-19 09:10:47.421: E/AndroidRuntime(12745): at android.view.ViewRootImpl.doTraversal(ViewRootImpl.java:1054) 02-19 09:10:47.421: E/AndroidRuntime(12745): at android.view.ViewRootImpl$TraversalRunnable.run(ViewRootImpl.java:5779) 02-19 09:10:47.421: E/AndroidRuntime(12745): at android.view.Choreographer$CallbackRecord.run(Choreographer.java:767) 02-19 09:10:47.421: E/AndroidRuntime(12745): at android.view.Choreographer.doCallbacks(Choreographer.java:580) 02-19 09:10:47.421: E/AndroidRuntime(12745): at android.view.Choreographer.doFrame(Choreographer.java:550) 02-19 09:10:47.421: E/AndroidRuntime(12745): at android.view.Choreographer$FrameDisplayEventReceiver.run(Choreographer.java:753) 02-19 09:10:47.421: E/AndroidRuntime(12745): at android.os.Handler.handleCallback(Handler.java:739) 02-19 09:10:47.421: E/AndroidRuntime(12745): at android.os.Handler.dispatchMessage(Handler.java:95) 02-19 09:10:47.421: E/AndroidRuntime(12745): at android.os.Looper.loop(Looper.java:135) 02-19 09:10:47.421: E/AndroidRuntime(12745): at android.app.ActivityThread.main(ActivityThread.java:5221) 02-19 09:10:47.421: E/AndroidRuntime(12745): at java.lang.reflect.Method.invoke(Native Method) 02-19 09:10:47.421: E/AndroidRuntime(12745): at java.lang.reflect.Method.invoke(Method.java:372) 02-19 09:10:47.421: E/AndroidRuntime(12745): at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:899) 02-19 09:10:47.421: E/AndroidRuntime(12745): at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:694) 

  • Esiste una sostituzione per il widget di Gallery con il recupero Vista?
  • java.lang.IllegalStateExeception: imansible trovare il metodo nella class attività
  • InflateException: Linea file binaria binaria # 1: errore di gonfiaggio della class <unknown> causato da OutOfMemoryError
  • Passaggio di animation tra le attività che utilizzano FLAG_ACTIVITY_CLEAR_TOP
  • Stampa di un'image utilizzando una printingnte termica Bluetooth da un'applicazione Android?
  • Android: CalendarView OnDateChangeLIstener
  • 3 Solutions collect form web for “java.lang.NullPointerException: Tentativo di ricall il metodo virtuale 'int android.view.View.getImportntForAccessibility ()' in un riferimento di null object”

    Nel tuo public View getView metodo public View getView change return null; per return convertView; .

    #use return convertView;

    Codice:

      public View getView(final int position, View convertView, ViewGroup parent) { convertView = null; if (convertView == null) { LayoutInflater mInflater = (LayoutInflater) context .getSystemService(Activity.LAYOUT_INFLATER_SERVICE); convertView = mInflater.inflate(R.layout.list_item, null); TextView tv = (TextView) convertView.findViewById(R.id.name); Button rm_btn = (Button) convertView.findViewById(R.id.rm_btn); Model m = modelList.get(position); tv.setText(m.getName()); // click listiner for remove button คลิกลบปุ่ม rm_btn.setOnClickListener(new View.OnClickListener() { @Override public void onClick(View v) { modelList.remove(position); notifyDataSetChanged(); } }); } ///#use return convertView; return convertView; } 

    nel tuo constructor di class baseadapter tenta di inizializzare LayoutInflater , normalmente preferivo in questo modo,

     public ClassBaseAdapter(Context context,ArrayList<Integer> listLoanAmount) { this.context = context; this.listLoanAmount = listLoanAmount; this.layoutInflater = LayoutInflater.from(context); } 

    nella parte superiore della class crea la variabile LayoutInflater , spero che questo ti aiuterà

    L'Android è un fan Android di Google, tutto su telefoni Android, Android Wear, Android Dev e applicazioni Android Games e così via.