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У меня возникли проблемы с отображением списка категорий, зарегистрированных в базе данных, возвращает мне эти ошибки в logcat.

logcat:

 04-26 10:43:18.475: ERROR/AndroidRuntime(2570): Uncaught handler: thread main exiting due to uncaught exception
04-26 10:43:18.494: ERROR/AndroidRuntime(2570): java.lang.NullPointerException
04-26 10:43:18.494: ERROR/AndroidRuntime(2570):     at br.com.codecreative.superlista.DisplayCategoria$CategoriaAdapter.getView(DisplayCategoria.java:112)
04-26 10:43:18.494: ERROR/AndroidRuntime(2570):     at android.widget.AbsListView.obtainView(AbsListView.java:1274)
04-26 10:43:18.494: ERROR/AndroidRuntime(2570):     at android.widget.ListView.makeAndAddView(ListView.java:1668)
04-26 10:43:18.494: ERROR/AndroidRuntime(2570):     at android.widget.ListView.fillDown(ListView.java:637)
04-26 10:43:18.494: ERROR/AndroidRuntime(2570):     at android.widget.ListView.fillFromTop(ListView.java:694)
04-26 10:43:18.494: ERROR/AndroidRuntime(2570):     at android.widget.ListView.layoutChildren(ListView.java:1521)
04-26 10:43:18.494: ERROR/AndroidRuntime(2570):     at android.widget.AbsListView.onLayout(AbsListView.java:1113)
04-26 10:43:18.494: ERROR/AndroidRuntime(2570):     at android.view.View.layout(View.java:6830)
04-26 10:43:18.494: ERROR/AndroidRuntime(2570):     at android.widget.LinearLayout.setChildFrame(LinearLayout.java:1119)
04-26 10:43:18.494: ERROR/AndroidRuntime(2570):     at android.widget.LinearLayout.layoutVertical(LinearLayout.java:998)
04-26 10:43:18.494: ERROR/AndroidRuntime(2570):     at android.widget.LinearLayout.onLayout(LinearLayout.java:918)
04-26 10:43:18.494: ERROR/AndroidRuntime(2570):     at android.view.View.layout(View.java:6830)
04-26 10:43:18.494: ERROR/AndroidRuntime(2570):     at android.widget.FrameLayout.onLayout(FrameLayout.java:333)
04-26 10:43:18.494: ERROR/AndroidRuntime(2570):     at android.view.View.layout(View.java:6830)
04-26 10:43:18.494: ERROR/AndroidRuntime(2570):     at android.widget.LinearLayout.setChildFrame(LinearLayout.java:1119)
04-26 10:43:18.494: ERROR/AndroidRuntime(2570):     at android.widget.LinearLayout.layoutVertical(LinearLayout.java:998)
04-26 10:43:18.494: ERROR/AndroidRuntime(2570):     at android.widget.LinearLayout.onLayout(LinearLayout.java:918)
04-26 10:43:18.494: ERROR/AndroidRuntime(2570):     at android.view.View.layout(View.java:6830)
04-26 10:43:18.494: ERROR/AndroidRuntime(2570):     at android.widget.FrameLayout.onLayout(FrameLayout.java:333)
04-26 10:43:18.494: ERROR/AndroidRuntime(2570):     at android.view.View.layout(View.java:6830)
04-26 10:43:18.494: ERROR/AndroidRuntime(2570):     at android.view.ViewRoot.performTraversals(ViewRoot.java:996)
04-26 10:43:18.494: ERROR/AndroidRuntime(2570):     at android.view.ViewRoot.handleMessage(ViewRoot.java:1633)
04-26 10:43:18.494: ERROR/AndroidRuntime(2570):     at android.os.Handler.dispatchMessage(Handler.java:99)
04-26 10:43:18.494: ERROR/AndroidRuntime(2570):     at android.os.Looper.loop(Looper.java:123)
04-26 10:43:18.494: ERROR/AndroidRuntime(2570):     at android.app.ActivityThread.main(ActivityThread.java:4363)
04-26 10:43:18.494: ERROR/AndroidRuntime(2570):     at java.lang.reflect.Method.invokeNative(Native Method)
04-26 10:43:18.494: ERROR/AndroidRuntime(2570):     at java.lang.reflect.Method.invoke(Method.java:521)
04-26 10:43:18.494: ERROR/AndroidRuntime(2570):     at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:860)
04-26 10:43:18.494: ERROR/AndroidRuntime(2570):     at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:618)
04-26 10:43:18.494: ERROR/AndroidRuntime(2570):     at dalvik.system.NativeStart.main(Native Method)
  

код:

 public class DisplayCategoria extends ListActivity {

    MeuBanco dba;
    CategoriaAdapter myAdapter;

    private class MyCategoria {
        public MyCategoria(String d) {
            descricao = d;
        }
        public String descricao;
    }

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        dba = new MeuBanco(this);
        dba.open();
        requestWindowFeature(Window.FEATURE_CUSTOM_TITLE);
        setContentView(R.layout.listacategoria);
        getWindow().setFeatureInt(Window.FEATURE_CUSTOM_TITLE, R.layout.window_title);

        ImageView btnInserelista = (ImageView) findViewById(R.id.insere);

        btnInserelista.setOnClickListener(new OnClickListener() {

            @Override
            public void onClick(View v) {
                Intent telaInsere = new Intent(DisplayCategoria.this,CadastraCategoria.class);
                DisplayCategoria.this.startActivity(telaInsere);
            }
        });

        super.onCreate(savedInstanceState);
        myAdapter = new CategoriaAdapter(this);
        this.setListAdapter(myAdapter);
    }

    private class CategoriaAdapter extends BaseAdapter {

        private LayoutInflater mInflater;
        private ArrayList<MyCategoria> categorias;
        public CategoriaAdapter(Context context){
            mInflater = LayoutInflater.from(context);
            categorias = new ArrayList<MyCategoria>();
            getData();
        }

        private void getData() {
            Cursor c = dba.getCategorias();
            startManagingCursor(c);
            if (c.moveToFirst()) {
                do {
                    String descricao = c.getString(c.getColumnIndex(Constants.TITLE_NAME));
                    MyCategoria temp = new MyCategoria(descricao);
                    categorias.add(temp);
                } while (c.moveToNext());
            }
        }

        @Override
        public int getCount() {
            return categorias.size();
        }

        @Override
        public MyCategoria getItem(int position) {
            return categorias.get(position);
        }

        @Override
        public long getItemId(int position) {
            return position;
        }

        @Override
        public View getView(int position, View convertView, ViewGroup parent) {

            final ViewHolder holder;
            View v = convertView;
            if ((v == null) || (v.getTag() == null)) {
                v = mInflater.inflate(R.layout.categoriarow, null);
                holder = new ViewHolder();
                holder.mDescricao = (TextView) findViewById(R.id.desc_cat);
                v.setTag(holder);
            } else {
                holder = (ViewHolder) v.getTag();
            }

            holder.mcategoria = getItem(position);
            holder.mDescricao.setText(holder.mcategoria.descricao);

            v.setTag(holder);

            return v;
        }

        public class ViewHolder {
            MyCategoria mcategoria;
            TextView mDescricao;
        }
    }
}

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
  android:orientation="vertical"
  android:layout_width="fill_parent"
  android:layout_height="fill_parent"
  android:background="@drawable/backgroundlista">
  <ListView
    android:id="@android:id/list"
    android:layout_width="fill_parent"
    android:dividerHeight="1px"
    android:layout_height="fill_parent">
  </ListView>
</LinearLayout>
  

 holder.mDescricao = (TextView) findViewById(R.id.desc_cat);
  

необходимо

 holder.mDescricao = (TextView) v.findViewById(R.id.desc_cat);
  

Вызов его первым способом возвращает null … отсюда исключение NullPointerException при вызове setText().