nullpointer exception on custom adapter

Я создал проект для отображения списка с пользовательской раскладкой строк. После нажатия на элемент списка вызывается действие, которое извлекает данные из sqlite и отображает в listview с помощью настраиваемой строки. Но, я получаю исключения нулевого указателя при выполнении setadapter вnullpointer exception on custom adapter

DisplayCards.java

import android.os.Bundle; 
import android.app.Activity; 
import android.content.Context; 
import android.database.Cursor; 
import android.graphics.Color; 
import android.util.Log; 
import android.view.Menu; 
import android.view.View; 
import android.view.ViewGroup; 
import android.widget.ListView; 
import android.widget.SimpleCursorAdapter; 

public class DisplayCards extends Activity{ 


     private Divyadesamdb dbHelper; 

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

      dbHelper = new Divyadesamdb(this); 
      dbHelper.open(); 

      // Clean all data 
      dbHelper.deleteAllPasurams(); 
      // Add some data 
      dbHelper.insertPasurams(); 

      // Generate ListView from SQLite Database 
      displayListView(); 

     } 

     @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; 
     } 

     private void displayListView() { 
      String category = null; 
      String starting = "25"; 
      String ending = "30"; 
      int rowsFound = 0; 
      Cursor cursor = dbHelper.fetchAllPasurams(category,starting,ending); 
      /* 
      * How many rows returned from the query 
      */ 
      rowsFound = cursor.getCount(); 
      Log.d("VC", "Query returned "+rowsFound+" rows."); 
      // the desired columns to be bound 
      String[] columns = new String[] { Divyadesamdb.PASURAMS_COLUMN_PAASURAMNUMBER, 
        Divyadesamdb.PASURAMS_COLUMN_AAYIRAM, Divyadesamdb.PASURAMS_COLUMN_AZHWAAR, 
        Divyadesamdb.PASURAMS_COLUMN_CATEGORY, Divyadesamdb.PASURAMS_COLUMN_MANGALASASANAMON, 
        Divyadesamdb.PASURAMS_COLUMN_PAASURAM_EN_STR, Divyadesamdb.PASURAMS_COLUMN_SUBCATEGORY, 
        Divyadesamdb.PASURAMS_COLUMN_TITLE, Divyadesamdb.PASURAMS_COLUMN_TITLENUMBER }; 



      // the XML defined views which the data will be bound to 
      int[] to = new int[] { R.id.tvPaasuramNumber, R.id.tvAayiram, R.id.tvAzhwaar, 
        R.id.tvCategory, R.id.tvMangalasasanamOn, R.id.tvPaasuram, 
        R.id.tvSubCategory, R.id.tvTitle, R.id.tvtvTitleNumber}; 
Log.d("VC","Just before creating dataAdapter"); 
      // create the adapter using the cursor pointing to the desired data 
      // as well as the layout information 
      MyCursorAdapter dataAdapter = new MyCursorAdapter(this, 
        R.layout.paasuram_single_item, cursor, columns, to, 0); 
      Log.d("VC","Just after creating dataAdapter"); 
      ListView listView = (ListView) findViewById(R.id.listView1); 
      // Assign adapter to ListView 
      Log.d("VC","created listView"); 
      int myCount = dataAdapter.getCount(); 
      Log.d("VC","got data from dataAdapter "+myCount); 
      //listView.getAdapter(); 
      listView.setAdapter(dataAdapter); 
      Log.d("VC","completed setadapter dataAdapter"); 
     } 

     // extend the SimpleCursorAdapter to create a custom class where we 
     // can override the getView to change the row colors 
     private class MyCursorAdapter extends SimpleCursorAdapter { 

      public MyCursorAdapter(Context context, int layout, Cursor c, 
        String[] from, int[] to, int flags) { 
       super(context, layout, c, from, to, flags); 
      } 

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

       // get reference to the row 
       View view = super.getView(position, convertView, parent); 
       // check for odd or even to set alternate colors to the row 
       // background 
       if (position % 2 == 0) { 
        view.setBackgroundColor(Color.rgb(238, 233, 233)); 
       } else { 
        view.setBackgroundColor(Color.rgb(255, 255, 255)); 
       } 
       return view; 
      } 

     } 

    }

paasuram_single_item.xml

<?xml version="1.0" encoding="utf-8"?> 
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android" 
    android:layout_width="match_parent" 
    android:layout_height="wrap_content" 
    android:background="@drawable/mybackground" 
    android:orientation="vertical" > 

    <ImageView 
     android:id="@+id/ivAzhwaar" 
     android:layout_width="wrap_content" 
     android:layout_height="wrap_content" 
     android:layout_centerInParent="false" 
     android:layout_margin="10dp" 
     android:contentDescription="@string/Azhwaar" 
     android:padding="5dp" 
     android:src="@drawable/nammalwar" /> 

    <TextView 
     android:id="@+id/tvtvTitleNumber" 
     android:layout_width="wrap_content" 
     android:layout_height="wrap_content" 
     android:layout_alignTop="@+id/ivAzhwaar" 
     android:layout_toRightOf="@+id/ivAzhwaar" 
     android:text="TitleNumber" 
     android:textAppearance="?android:attr/textAppearanceMedium" /> 

    <TextView 
     android:id="@+id/tvHyphan1" 
     android:layout_width="wrap_content" 
     android:layout_height="wrap_content" 
     android:layout_alignBaseline="@+id/tvtvTitleNumber" 
     android:layout_alignBottom="@+id/tvtvTitleNumber" 
     android:layout_toRightOf="@+id/tvtvTitleNumber" 
     android:text=" " 
     android:textAppearance="?android:attr/textAppearanceMedium" /> 

    <TextView 
     android:id="@+id/tvTitle" 
     android:layout_width="wrap_content" 
     android:layout_height="match_parent" 
     android:layout_alignBaseline="@+id/tvHyphan1" 
     android:layout_alignBottom="@+id/tvHyphan1" 
     android:layout_alignParentRight="true" 
     android:layout_toRightOf="@+id/tvHyphan1" 
     android:text="Title" 
     android:textAppearance="?android:attr/textAppearanceMedium" /> 

    <TextView 
     android:id="@+id/tvAayiram" 
     android:layout_width="wrap_content" 
     android:layout_height="wrap_content" 
     android:layout_alignLeft="@+id/tvtvTitleNumber" 
     android:layout_below="@+id/tvtvTitleNumber" 
     android:text="Aayiram" 
     android:textAppearance="?android:attr/textAppearanceSmall" /> 

    <TextView 
     android:id="@+id/tvHyphan2" 
     android:layout_width="wrap_content" 
     android:layout_height="wrap_content" 
     android:layout_below="@+id/tvtvTitleNumber" 
     android:layout_toRightOf="@+id/tvAayiram" 
     android:text=" - " 
     android:textAppearance="?android:attr/textAppearanceSmall" /> 

    <TextView 
     android:id="@+id/tvCategory" 
     android:layout_width="wrap_content" 
     android:layout_height="wrap_content" 
     android:layout_alignBaseline="@+id/tvHyphan2" 
     android:layout_alignBottom="@+id/tvHyphan2" 
     android:layout_toRightOf="@+id/tvHyphan2" 
     android:text="Category" 
     android:textAppearance="?android:attr/textAppearanceSmall" /> 

    <TextView 
     android:id="@+id/tvHyphan3" 
     android:layout_width="wrap_content" 
     android:layout_height="wrap_content" 
     android:layout_alignBaseline="@+id/tvCategory" 
     android:layout_alignBottom="@+id/tvCategory" 
     android:layout_toRightOf="@+id/tvCategory" 
     android:text=" - " 
     android:textAppearance="?android:attr/textAppearanceSmall" /> 

    <TextView 
     android:id="@+id/tvSubCategory" 
     android:layout_width="wrap_content" 
     android:layout_height="wrap_content" 
     android:layout_alignBaseline="@+id/tvHyphan3" 
     android:layout_alignBottom="@+id/tvHyphan3" 
     android:layout_toRightOf="@+id/tvHyphan3" 
     android:text="SubCategory" 
     android:textAppearance="?android:attr/textAppearanceSmall" /> 

    <TextView 
     android:id="@+id/tvPaasuram" 
     android:layout_width="wrap_content" 
     android:layout_height="wrap_content" 
     android:layout_alignLeft="@+id/tvAayiram" 
     android:layout_below="@+id/tvAayiram" 
     android:padding="5dp" 
     android:text="paasuram" 
     android:textAppearance="?android:attr/textAppearanceSmall" /> 

    <TextView 
     android:id="@+id/tvPaasuramNumber" 
     android:layout_width="wrap_content" 
     android:layout_height="wrap_content" 
     android:layout_alignBaseline="@+id/tvPaasuram" 
     android:layout_alignBottom="@+id/tvPaasuram" 
     android:layout_alignParentBottom="true" 
     android:layout_alignParentRight="true" 
     android:text="PaasuramNumber" 
     android:textAppearance="?android:attr/textAppearanceMedium" /> 

    <TextView 
     android:id="@+id/tvAzhwaar" 
     android:layout_width="wrap_content" 
     android:layout_height="wrap_content" 
     android:layout_alignBaseline="@+id/tvMangalasasanamOn" 
     android:layout_alignBottom="@+id/tvMangalasasanamOn" 
     android:layout_alignLeft="@+id/tvPaasuram" 
     android:text="Azhwaar" 
     android:textAppearance="?android:attr/textAppearanceSmall" /> 

    <TextView 
     android:id="@+id/tvMangalasasanamOn" 
     android:layout_width="wrap_content" 
     android:layout_height="wrap_content" 
     android:layout_alignLeft="@+id/tvCategory" 
     android:layout_below="@+id/tvPaasuram" 
     android:layout_centerHorizontal="true" 
     android:text="MangalasasanamOn" 
     android:textAppearance="?android:attr/textAppearanceSmall" /> 

</RelativeLayout>

paasuram_list_fragment.xml

<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android" 
    xmlns:tools="http://schemas.android.com/tools" 
    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=".MainActivity" > 



    <ListView 
     android:id="@android:id/list" 
     android:layout_width="match_parent" 
     android:layout_height="wrap_content" > 
    </ListView> 



</RelativeLayout>

NPE происходит на DisplayCards.java

listView.setAdapter(dataAdapter);

Возможность получить правильное количество в DataAdapter

любая помощь приветствуется.

источник

2014-03-19 Suresh PB

сообщение 'activity_main.xml' – Raghunandan

Нет элемента с идентификатором listView1 внутри activity_main.xml вот почему listView is null.

источник

2014-03-19 16:21:15 Divers

Great! Это сработало ... Большое спасибо. –

Добро пожаловать. – Divers

Изменить

ListView listView = (ListView) findViewById(R.id.listView1);

ListView listView = (ListView) findViewById(android.R.id.list);

источник

2014-03-19 16:32:15 Julisch

nullpointer exception on custom adapter

ответ

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