Android: Versuch, aus Feld zu lesen 'android.widget.TextView auf einem Nullobjekt Referenz

Question

Ich versuche, eine Löschfunktion zu meinem Listview zu erstellen, aber es gibt ein Problem, das ich nicht finden kann und sogar ich fand das Problem in der Logcat Ich weiß nicht, wo das Problem liegt, weil das Problem Zeiger auf einer Zeile ist, die in anderen Aktivitäten in Ordnung ist. bitte einige mir helfen, und Dank im Voraus :)

Hier ist der Fehler Wies:

**07-10 14:49:48.705 25554-25554/com.fingervoiz.app.tamla E/AndroidRuntime: FATAL EXCEPTION: main 
Process: com.fingervoiz.app.tamla, PID: 25554 
java.lang.NullPointerException: Attempt to read from field 'android.widget.TextView com.fingervoiz.app.tamla.Adapter.ListDIDadapter$Holder.txtFname' on a null object reference 
at com.fingervoiz.app.tamla.Adapter.ListDIDadapter.getView(ListDIDadapter.java:61)** 


at android.widget.AbsListView.obtainView(AbsListView.java:2467) 
at android.widget.ListView.makeAndAddView(ListView.java:1894) 
at android.widget.ListView.fillSpecific(ListView.java:1360) 
at android.widget.ListView.layoutChildren(ListView.java:1673) 
at android.widget.AbsListView.onLayout(AbsListView.java:2230) 
at android.view.View.layout(View.java:16001) 
at android.view.ViewGroup.layout(ViewGroup.java:5181) 
at android.widget.LinearLayout.setChildFrame(LinearLayout.java:1959) 
at android.widget.LinearLayout.layoutVertical(LinearLayout.java:1813) 
at android.widget.LinearLayout.onLayout(LinearLayout.java:1722) 
at android.view.View.layout(View.java:16001) 
at android.view.ViewGroup.layout(ViewGroup.java:5181) 
at android.widget.FrameLayout.layoutChildren(FrameLayout.java:639) 
at android.widget.FrameLayout.onLayout(FrameLayout.java:574) 
at android.view.View.layout(View.java:16001) 
at android.view.ViewGroup.layout(ViewGroup.java:5181) 
at android.widget.LinearLayout.setChildFrame(LinearLayout.java:1959) 
at android.widget.LinearLayout.layoutVertical(LinearLayout.java:1813) 
at android.widget.LinearLayout.onLayout(LinearLayout.java:1722) 
at android.view.View.layout(View.java:16001) 
at android.view.ViewGroup.layout(ViewGroup.java:5181) 
at android.widget.FrameLayout.layoutChildren(FrameLayout.java:639) 
at android.widget.FrameLayout.onLayout(FrameLayout.java:574) 
at android.view.View.layout(View.java:16001) 
at android.view.ViewGroup.layout(ViewGroup.java:5181) 
at android.view.ViewRootImpl.performLayout(ViewRootImpl.java:2492) 
at android.view.ViewRootImpl.performTraversals(ViewRootImpl.java:2189) 
at android.view.ViewRootImpl.doTraversal(ViewRootImpl.java:1301) 
at android.view.ViewRootImpl$TraversalRunnable.run(ViewRootImpl.java:6673) 
at android.view.Choreographer$CallbackRecord.run(Choreographer.java:800) 
at android.view.Choreographer.doCallbacks(Choreographer.java:603) 
at android.view.Choreographer.doFrame(Choreographer.java:572) 
at android.view.Choreographer$FrameDisplayEventReceiver.run(Choreographer.java:786) 
at android.os.Handler.handleCallback(Handler.java:815) 
at android.os.Handler.dispatchMessage(Handler.java:104) 
at android.os.Looper.loop(Looper.java:194) 
at android.app.ActivityThread.main(ActivityThread.java:5637) 
at java.lang.reflect.Method.invoke(Native Method) 
at java.lang.reflect.Method.invoke(Method.java:372) 
at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:959) 
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:754) 

meinen Code in Listview-Adapter

public class ListDIDadapter extends ArrayAdapter<TamlaDataIdntModel> { 

    Context context; 
    int layoutResourceId; 
    ArrayList<TamlaDataIdntModel> data = new ArrayList<TamlaDataIdntModel>(); 

    public ListDIDadapter (Context context,int layoutResourceId,ArrayList<TamlaDataIdntModel> data){ 
     super(context,layoutResourceId,data); 
     this.layoutResourceId = layoutResourceId; 
     this.context = context; 
     this.data = data; 
    } 

    @Override 
    public View getView(int position, View convertView, ViewGroup parent) { 
     View view = convertView; 
     Holder holder; 

     if (view == null){ 
      LayoutInflater inflater = ((Activity)context).getLayoutInflater(); 
      view = inflater.inflate(layoutResourceId,parent,false); 

      holder = new Holder(); 
      holder.txtFname = (TextView) view.findViewById(R.id.did_item_fname); 
      holder.txtMname = (TextView) view.findViewById(R.id.did_item_mname); 
      holder.txtLname = (TextView) view.findViewById(R.id.did_item_lname); 
      holder.txtGender = (TextView) view.findViewById(R.id.did_item_gender); 
      holder.txtBplace = (TextView) view.findViewById(R.id.did_item_bplace); 
      holder.txtBday = (TextView) view.findViewById(R.id.did_item_bday); 
      holder.txtAddress = (TextView) view.findViewById(R.id.did_item_address); 
      holder.imgProfile = (CircleImageView) view.findViewById(R.id.did_item_profilepic); 

     }else { 
      holder = (Holder) view.getTag(); 
     } 

     //Feed Data 
     TamlaDataIdntModel dids = data.get(position); 
     holder.txtFname.setText("GIVEN NAME: "+dids.get_fname()); 
     holder.txtMname.setText("MIDDLE NAME: "+dids.get_mname()); 
     holder.txtLname.setText("FAMILY NAME: "+dids.get_lname()); 
     holder.txtGender.setText("Gender: "+dids.get_gender()); 
     holder.txtBplace.setText("Place of Birth: "+dids.get_bplace()); 
     holder.txtBday.setText("Birthday: "+dids.get_bday()); 
     holder.txtAddress.setText("Address: "+dids.get_address()); 

     byte[] outImage = dids.get_dp(); 
     ByteArrayInputStream imageStream = new ByteArrayInputStream(outImage); 
     Bitmap theImage = BitmapFactory.decodeStream(imageStream); 
     holder.imgProfile.setImageBitmap(theImage); 

     return view; 
    } 

    static class Holder{ 
     CircleImageView imgProfile; 
     TextView txtFname,txtMname,txtLname,txtGender,txtBplace,txtBday,txtAddress; 
    } 
} 

Code in Löschfunktion

/*DELETE DATA IDENTITY*/ 
    public void deleteDID(long id){ 

     SQLiteDatabase db = this.mDBHelper.getWritableDatabase(); 
     db.delete(TamlaDatabaseHelper.TABLE_DATAIDNT,TamlaDatabaseHelper.COLUMN_DI_ID + " = ?", 
       new String[]{String.valueOf(id)}); 
     db.close(); 
    } 

und hier ist die Listview-Aktivität

public class ListDataIdntActivity extends Activity{ 

    ArrayList<TamlaDataIdntModel> imgArray = new ArrayList<TamlaDataIdntModel>(); 
    ListDIDadapter adapter; 

    @Override 
    protected void onCreate(Bundle savedInstanceState) { 
     super.onCreate(savedInstanceState); 
     setContentView(R.layout.activity_list_did); 

     DataIdntDAO db = new DataIdntDAO(this); 
     List<TamlaDataIdntModel> inData = db.getAllDID(); 

     for (TamlaDataIdntModel cn : inData){ 
      imgArray.add(cn); 
     } 

     /*BACK BUTTON*/ 
     Button back = (Button)findViewById(R.id.back_list_did); 
     back.setOnClickListener(new View.OnClickListener() { 
      @Override 
      public void onClick(View v) { 
       Intent intent = new Intent(getApplicationContext(),MainActivity.class); 
       startActivity(intent); 
       finish(); 
      } 
     }); 

     /*LIST ADAPTER*/ 
     adapter = new ListDIDadapter(this,R.layout.list_item_did_details,imgArray); 
     final ListView dataList = (ListView) findViewById(R.id.list_did); 
     dataList.setAdapter(adapter); 

     /*LIST ADAPTER ITEM LONG CLICK*/ 
     dataList.setOnItemLongClickListener(new AdapterView.OnItemLongClickListener() { 
      @Override 
      public boolean onItemLongClick(AdapterView<?> parent, View view, final int position, long id) { 
       final TamlaDataIdntModel num = (TamlaDataIdntModel) parent.getItemAtPosition(position); 

       final CharSequence[] items = {"EDIT","DELETE","CANCEL"}; 
       AlertDialog.Builder builder = new AlertDialog.Builder(ListDataIdntActivity.this); 
       builder.setTitle("YOUR CHOICE"); 
       builder.setItems(items, new DialogInterface.OnClickListener() { 
        @Override 
        public void onClick(DialogInterface dialog, int item) { 

         if (items[item].equals("EDIT")) { 

          /*Intent pass = new Intent(ListDataIdntActivity.this, UserEdit.class); 
          pass.putExtra("Edit_Ses", idd); 
          startActivity(pass);*/ 

         } else if (items[item].equals("DELETE")) { 

          DataIdntDAO db = new DataIdntDAO(ListDataIdntActivity.this); 
          db.deleteDID(position); 
          adapter.notifyDataSetChanged(); 

         } else if (items[item].equals("CANCEL")) { 
          dialog.dismiss(); 
         } 
        } 
       }); 
       builder.show(); 
       return true; 
      } 
     }); 

    } 
} 

Answer 1

ListDIDadapter $ Holder.txtFname‘auf ein Null-Objekt Referenz

Aufgrund dieser Linie

holder = (Holder) view.getTag(); 

view.getTag() Rückkehr null weil view.setTag(holder) ist nicht aufgerufen in if-block