我已经被这个问题困扰了一个星期了,我有一个列表视图对话框片段,它使用了一个自定义的基本适配器,并与sqlite数据库连接。
我的数据库适配器:
public class DBAdapter {
// Column Product
static final String ROWID = "id";
static final String NAME = "name";
static final String DESC = "desc";
static final String PRICE = "price";
static final String DISPLAY = "display";
// DB Properties
static final String DBNAME = "db_prototype";
static final String TBNAME = "tbl_product";
static final int DBVERSION = 1;
static final String CREATE_TABLE = "CREATE TABLE tbl_product(id INTEGER PRIMARY KEY AUTOINCREMENT, name TEXT NOT NULL," +
" desc TEXT NOT NULL, price TEXT NOT NULL, display INTEGER NOT NULL)";
final Context c;
SQLiteDatabase db;
DBHelper helper;
public DBAdapter(Context c) {
this.c = c;
helper = new DBHelper(c);
}
private static class DBHelper extends SQLiteOpenHelper{
public DBHelper(Context context) {
super(context, DBNAME, null, DBVERSION);
}
@Override
public void onCreate(SQLiteDatabase db) {
try{
db.execSQL(CREATE_TABLE);
}catch (SQLException e){
e.printStackTrace();
}
}
@Override
public void onUpgrade(SQLiteDatabase db, int oldVersion, int newVersion) {
Log.w(DBHelper.class.getName(), "Upgrading DB");
db.execSQL("DROP TABLE IF EXIST tbl_product");
}
}
// Open Database
public DBAdapter openDB(){
try{
db = helper.getWritableDatabase();
}catch (SQLException e){
e.printStackTrace();
}
return this;
}
public void closeDB(){
helper.close();
}
// Insert Into Table
public long add(String name, String desc, String price, int display){
try{
ContentValues cv = new ContentValues();
cv.put(NAME, name);
cv.put(DESC, desc);
cv.put(PRICE, price);
cv.put(DISPLAY, display);
return db.insert(TBNAME, ROWID, cv);
}catch (SQLException e) {
e.printStackTrace();
}
return 0;
}
// Delete Table
public long delete(String name){
try{
return db.delete(TBNAME, NAME + "='" + name + "'", null);
}catch (SQLException e) {
e.printStackTrace();
}
return 0;
}
// Get All Value
public Cursor getAllValue(){
String[] columns = {ROWID, NAME, DESC, PRICE, DISPLAY};
return db.query(TBNAME, columns, null, null, null, null, null);
}
}
我的列表视图适配器(void refreshAdapter
用于刷新数据集):
public class CartAdapter extends BaseAdapter {
private Context c;
private ArrayList<Integer> display;
private ArrayList<String> nama;
private ArrayList<String> harga;
public CartAdapter(Context c, ArrayList<Integer> display, ArrayList<String> nama, ArrayList<String> harga) {
this.c = c;
this.display = display;
this.harga = harga;
this.nama = nama;
}
@Override
public int getCount() {
return nama.size();
}
@Override
public Object getItem(int position) {
return nama.get(position);
}
@Override
public long getItemId(int position) {
return position;
}
@Override
public View getView(int position, View convertView, ViewGroup parent) {
if(convertView==null){
LayoutInflater inflater = (LayoutInflater) c.getSystemService(Context.LAYOUT_INFLATER_SERVICE);
convertView = inflater.inflate(R.layout.cart_display, null);
}
// Get View
TextView txtNama = (TextView) convertView.findViewById(R.id.txtNama);
TextView txtHarga = (TextView) convertView.findViewById(R.id.txtHarga);
ImageView imgGambar = (ImageView) convertView.findViewById(R.id.imgGambar);
//Assign Data
txtNama.setText(nama.get(position));
txtHarga.setText(harga.get(position));
imgGambar.setImageResource(display.get(position));
return convertView;
}
public void refreshAdapter(ArrayList<Integer> display, ArrayList<String> nama, ArrayList<String> harga){
this.display.clear();
this.harga.clear();
this.nama.clear();
this.display = display;
this.harga = harga;
this.nama = nama;
this.notifyDataSetChanged();
}
}
我的列表视图对话框片段:
public class CartDialog extends DialogFragment {
ArrayList<String> cart_name;
ArrayList<String> cart_price;
ArrayList<Integer> cart_pict;
DBAdapter dbAdapter;
CartAdapter adapter;
@Override
public View onCreateView(LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState) {
View rootView = inflater.inflate(R.layout.fragment_cart_dialog, null);
ListView LV = (ListView) rootView.findViewById(R.id.listCart);
Button btnDelete = (Button) rootView.findViewById(R.id.button);
// Prepare ArrayList to assign with DB
cart_pict = new ArrayList<Integer>();
cart_name = new ArrayList<String>();
cart_price = new ArrayList<String>();
getDialog().setTitle("Keranjang Belanjaan");
dbAdapter = new DBAdapter(getActivity());
adapter = new CartAdapter(getActivity(), cart_pict, cart_name, cart_price);
refreshDB();
LV.setAdapter(adapter);
LV.setOnItemClickListener(new AdapterView.OnItemClickListener() {
@Override
public void onItemClick(AdapterView<?> parent, View view, int position, long id) {
String name = adapter.getItem(position).toString();
// Delete Selected Item on SQLite Database
dbAdapter.openDB();
long result = dbAdapter.delete(name);
dbAdapter.closeDB();
//Refresh Cart
refreshDB();
adapter.refreshAdapter(cart_pict, cart_name, cart_price);
}
});
return rootView;
}
public void refreshDB(){
// Refresh Data
dbAdapter.openDB();
Cursor c = dbAdapter.getAllValue();
while(c.moveToNext()){
String name = c.getString(1);
String price = c.getString(3);
int display = c.getInt(4);
cart_name.add(name);
cart_price.add(price);
cart_pict.add(display);
}
Toast.makeText(getActivity(), "Jumlah: " + c.getCount(), Toast.LENGTH_SHORT).show();
dbAdapter.closeDB();
}
}
因此,每当我点击列表视图中的一个项目时,DBAdapter就会从SQLite数据库中删除这些项目,然后CartAdapter会刷新列表视图。我一直在寻找这个问题的参考,添加notifyDatasetChange ()
,但问题是在我调用refreshData()
方法后,列表视图中的数据将为空。
1条答案
按热度按时间zlwx9yxi1#
试试这个兄弟