how to display data from sqlite in custom listfragment

Question

I want to display data from sqlite database and I will show to listfragment, but until now have not been able to be displayed

Class Barang.java

public class Barang {

private long id;
private String nama_barang;
private String merk_barang;
private String harga_barang;

public Barang()
{

}

/**
 * @return the id
 */
public long getId() {
    return id;
}

/**
 * @param id the id to set
 */
public void setId(long id) {
    this.id = id;
}

/**
 * @return the nama_barang
 */
public String getNama_barang() {
    return nama_barang;
}

/**
 * @param nama_barang the nama_barang to set
 */
public void setNama_barang(String nama_barang) {
    this.nama_barang = nama_barang;
}

/**
 * @return the merk_barang
 */
public String getMerk_barang() {
    return merk_barang;
}

/**
 * @param merk_barang the merk_barang to set
 */
public void setMerk_barang(String merk_barang) {
    this.merk_barang = merk_barang;
}

/**
 * @return the harga_barang
 */
public String getHarga_barang() {
    return harga_barang;
}

/**
 * @param harga_barang the harga_barang to set
 */
public void setHarga_barang(String harga_barang) {
    this.harga_barang = harga_barang;
}

@Override
public String toString()
{
    return id +" "+ nama_barang +" "+ merk_barang + " "+ harga_barang;
}
}

DBHelper.java

public class DBHelper extends SQLiteOpenHelper{

public static final String TABLE_NAME = "data_inventori";
public static final String COLUMN_ID = "_id";
public static final String COLUMN_NAME = "nama_barang";
public static final String COLUMN_MERK = "merk_barang";
public static final String COLUMN_HARGA = "harga_barang";
private static final String db_name ="inventori.db";
private static final int db_version=1;

  private static final String db_create = "create table "
      + TABLE_NAME + "(" 
      + COLUMN_ID +" integer primary key autoincrement, " 
      + COLUMN_NAME+ " varchar(50) not null, "
      + COLUMN_MERK+ " varchar(50) not null, "
      + COLUMN_HARGA+ " varchar(50) not null);";

public DBHelper(Context context) {
    super(context, db_name, null, db_version);
    // TODO Auto-generated constructor stub
}

@Override
public void onCreate(SQLiteDatabase db) {
    // TODO Auto-generated method stub
    db.execSQL(db_create);
}

@Override
public void onUpgrade(SQLiteDatabase db, int oldVersion, int newVersion) {
    // TODO Auto-generated method stub
    Log.w(DBHelper.class.getName(),"Upgrading database from version " + oldVersion + " to "
            + newVersion + ", which will destroy all old data");
    db.execSQL("DROP TABLE IF EXISTS " + TABLE_NAME);
    onCreate(db);

}
}

DBDataSource.java

public class DBDataSource {

private SQLiteDatabase database;

private DBHelper dbHelper;

private String[] allColumns = { DBHelper.COLUMN_ID,
          DBHelper.COLUMN_NAME, DBHelper.COLUMN_MERK,DBHelper.COLUMN_HARGA};

public DBDataSource(Context context)
{
    dbHelper = new DBHelper(context);
}

public void open() throws SQLException {
    database = dbHelper.getWritableDatabase();
}

public void close() {
    dbHelper.close();
}

public Barang createBarang(String nama, String merk, String harga) {

    ContentValues values = new ContentValues();
    values.put(DBHelper.COLUMN_NAME, nama);
    values.put(DBHelper.COLUMN_MERK, merk);
    values.put(DBHelper.COLUMN_HARGA, harga);

    long insertId = database.insert(DBHelper.TABLE_NAME, null,
        values);

    Cursor cursor = database.query(DBHelper.TABLE_NAME,
        allColumns, DBHelper.COLUMN_ID + " = " + insertId, null,
        null, null, null);

    cursor.moveToFirst();

    Barang newBarang = cursorToBarang(cursor);

    cursor.close();

    return newBarang;
  }

private Barang cursorToBarang(Cursor cursor)
{

    Barang barang = new Barang();
    barang.setId(cursor.getLong(0));
    barang.setNama_barang(cursor.getString(1));
    barang.setMerk_barang(cursor.getString(2));
    barang.setHarga_barang(cursor.getString(3));

    return barang;
}

public ArrayList<Barang> getAllBarang() {
    ArrayList<Barang> daftarBarang = new ArrayList<Barang>();


    Cursor cursor = database.query(DBHelper.TABLE_NAME,
        allColumns, null, null, null, null, null);

    cursor.moveToFirst();

    while (!cursor.isAfterLast()) {
      Barang barang = cursorToBarang(cursor);
      daftarBarang.add(barang);
      cursor.moveToNext();
    }

    cursor.close();
    return daftarBarang;
  }

public Barang getBarang(long id)
  {
      Barang barang = new Barang(); 

      Cursor cursor = database.query(DBHelper.TABLE_NAME, allColumns, "_id ="+id, null, null, null, null);

      cursor.moveToFirst();

      barang = cursorToBarang(cursor);

      cursor.close();

      return barang;
  }


public void updateBarang(Barang b)
{

    String strFilter = "_id=" + b.getId();

    ContentValues args = new ContentValues();

    args.put(DBHelper.COLUMN_NAME, b.getNama_barang());
    args.put(DBHelper.COLUMN_MERK, b.getMerk_barang());
    args.put(DBHelper.COLUMN_HARGA, b.getHarga_barang() );

    database.update(DBHelper.TABLE_NAME, args, strFilter, null);
}

public void deleteBarang(long id)
{
    String strFilter = "_id=" + id;
    database.delete(DBHelper.TABLE_NAME, strFilter, null);
}
}

MasterBarang.java

public class MasterBarang extends ListFragment implements OnItemLongClickListener {

private DBDataSource dataSource;
private ImageButton bTambah;
private ArrayList<Barang> values;
private Button editButton;
private Button delButton;
private AlertDialog.Builder alertDialogBuilder;
public MasterBarang(){}

@Override
public View onCreateView(LayoutInflater inflater, ViewGroup container,
        Bundle savedInstanceState) {

    View rootView = inflater.inflate(R.layout.fragment_masterbarang, container, false);
    bTambah = (ImageButton) rootView.findViewById(R.id.button_tambah);

    bTambah.setOnClickListener(new View.OnClickListener() {

      @Override
      public void onClick(View view) {
        Intent intent = new Intent(getActivity(), CreateData.class);
        startActivity(intent);
        getActivity().finish();
      }

    }); 

    ListView lv = (ListView) rootView.findViewById(android.R.id.list);
    lv.setOnItemLongClickListener(this);

    return rootView;
}

public void OnCreate(Bundle savedInstanceStat){


    dataSource = new DBDataSource(getActivity());

    dataSource.open();

    values = dataSource.getAllBarang();

    ArrayAdapter<Barang> adapter = new ArrayAdapter<Barang>(getActivity(),
    android.R.layout.simple_list_item_1, values);

          setListAdapter(adapter);


}

@Override
public boolean onItemLongClick(final AdapterView<?> adapter, View v, int pos,
        final long id) {

    final Barang b = (Barang) getListAdapter().getItem(pos);
     alertDialogBuilder.setTitle("Peringatan");
     alertDialogBuilder
             .setMessage("Pilih Aksi")
             .setCancelable(false)
             .setPositiveButton("Ubah",
                     new DialogInterface.OnClickListener() {
                         public void onClick(DialogInterface dialog,
                                 int id) {
                             switchToEdit(b.getId());
                             dialog.dismiss();
                         }
                     })
             .setNegativeButton("Hapus",
                     new DialogInterface.OnClickListener() {
                         public void onClick(DialogInterface dialog,
                                 int id) {
                           dataSource.deleteBarang(b.getId());
                           dialog.dismiss();
                           getActivity().finish();
                           startActivity(getActivity().getIntent());
                         }
                     }).create().show();


 return false;

}

public void switchToEdit(long id)
{
    Barang b = dataSource.getBarang(id);
    Intent i = new Intent(getActivity(), EditData.class);
    Bundle bun = new Bundle();
    bun.putLong("id", b.getId());
    bun.putString("nama", b.getNama_barang());
    bun.putString("merk", b.getMerk_barang());
    bun.putString("harga", b.getHarga_barang());
    i.putExtras(bun);
    finale();
    startActivity(i);
}

public void finale()
{
    MasterBarang.this.getActivity().finish();
    dataSource.close();
}
@Override
public void onResume() {
    dataSource.open();
    super.onResume();
}

@Override
public void onPause() {
    dataSource.close();
    super.onPause();
}
}

in simple not displayed

Answer 1

The problem is you are closing your database in onPause() method, so the reference of the database will get destroyed. Then, you again trying to open the database in onResume() method. So here the null pointer exception occurs.

Solution:

change your onResume() method like this.

@Override
public void onResume() {
    dataSource = new DBDataSource(getActivity());
    dataSource.open();
    super.onResume();
}

Now check it and if you got any error please post it here,.

Answer 2

Here is the example code.

First create a layout for one list row.

example : list_row.xml

<?xml version="1.0" encoding="utf-8"?>
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:layout_width="fill_parent"
    android:layout_height="wrap_content"
    android:padding="8dp"
    >
    <TextView
        android:id="@+id/name"
        android:layout_width="fill_parent"
        android:layout_height="wrap_content"
        android:textStyle="bold" />

    <TextView
        android:id="@+id/merk"
        android:layout_width="fill_parent"
        android:layout_height="wrap_content"
        android:layout_below="@id/name"
        android:layout_marginTop="5dp" />

    <TextView
        android:id="@+id/harga"
        android:layout_width="fill_parent"
        android:layout_height="wrap_content"
        android:layout_below="@id/merk"
        android:layout_marginTop="5dp"/>

</RelativeLayout>

After creating this list_row.xml layout, create a adapter class.

create CustomListAdapter.java

public class CustomListAdapter extends BaseAdapter {

private Activity activity;
private LayoutInflater inflater;
private ArrayList<Barang> barangList;

public CustomListAdapter(Activity activity, ArrayList<Barang> barangList) {
    this.activity = activity;
    this.barangList = barangList;
}

/*
get count of the barangList
 */

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

@Override
public Object getItem(int location) {
    return barangList.get(location);
}

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

/*
inflate the items in the list view
 */
@Override
public View getView(int position, View convertView, ViewGroup parent) {

    if (inflater == null) {
        inflater = (LayoutInflater) activity.getSystemService(Context.LAYOUT_INFLATER_SERVICE);
    }
    if (convertView == null) {
        convertView = inflater.inflate(R.layout.list_row, null);
    }


    /*
    creating objects to access the views
     */
    TextView name = (TextView) convertView.findViewById(R.id.name);
    TextView merk = (TextView) convertView.findViewById(R.id.merk);
    TextView harga = (TextView) convertView.findViewById(R.id.harga);



    // getting barang data for the row

    Barang barang = barangList.get(position);

    name.setText(barang.getNama_barang());

    merk.setText(barang.getMerk_barang());

    harga.setText(barang.getHarga_barang());

    return convertView;
}}

Now in your MasterBarang.java, put the following code in your onCreate method.

values = dataSource.getAllBarang();
CustomListAdapter adapter;
adapter = new CustomListAdapter(getActivity(), values);
setListAdapter(adapter);

Now run the application.. Cheers !

Answer 3

You are using simple list templete as a list view. But in case of custom list view, you should create your custom list model and "BaseAdapter" for the custom list model.

Below links will help you to make custom list view in easier way.

https://www.caveofprogramming.com/guest-posts/custom-listview-with-imageview-and-textview-in-android.html

http://www.androidhive.info/2012/02/android-custom-listview-with-image-and-text/