我正在使用sqllite。我已经成功创建了一个数据库，我可以在我的数据库中输入一些值。我也可以在listview中显示所有值，也可以通过listview的onitemclicklistener.i删除项目有一个问题。当我删除项目列表视图没有更新，但这个项目在database.ow中删除我可以解决这个问题吗？
DatabaseHandler .java代码
public class DatabaseHandler extends SQLiteOpenHelper {
private static final int DATABASE_VERSION = 1;
private static final String DATABASE_NAME = "lvstone_2";
private static final String TABLE_CONTACTS = "CardTable1";
private static final String KEY_ID = "id";
private static final String KEY_Tittle = "name";
private static final String KEY_Description = "description";
private static final String KEY_Price = "price";
private static final String KEY_Counter = "counter";
private static final String KEY_Image = "image";
private final ArrayList<Contact> contact_list = new ArrayList<Contact>();
public static SQLiteDatabase db;
public DatabaseHandler(Context context) {
super(context, DATABASE_NAME, null, DATABASE_VERSION);
}
// Creating Tables
@Override
public void onCreate(SQLiteDatabase db) {
String CREATE_CONTACTS_TABLE = "CREATE TABLE " + TABLE_CONTACTS + "("
+ KEY_ID + " INTEGER PRIMARY KEY," + KEY_Tittle + " TEXT,"
+ KEY_Description + " TEXT,"
+ KEY_Price + " TEXT,"
+ KEY_Counter + " TEXT,"
+ KEY_Image + " TEXT"
+ ")";
db.execSQL(CREATE_CONTACTS_TABLE);
}
@Override
public void onUpgrade(SQLiteDatabase db, int oldVersion, int newVersion) {
db.execSQL("DROP TABLE IF EXISTS " + TABLE_CONTACTS);
// Create tables again
onCreate(db);
}
// Adding new contact
public void Add_Contact(Contact contact) {
db = this.getWritableDatabase();
ContentValues values = new ContentValues();
if (!somethingExists(contact.getTitle())) {
values.put(KEY_Tittle, contact.getTitle()); // Contact title
values.put(KEY_Description, contact.getDescription()); // Contact//
// description
values.put(KEY_Price, contact.getPrice()); // Contact price
values.put(KEY_Counter, contact.getCounter()); // Contact image
values.put(KEY_Image, contact.getImage()); // Contact image
// Inserting Row
db.insert(TABLE_CONTACTS, null, values);
Log.e("Table Result isss", String.valueOf(values));
db.close(); // Closing database connection
}
}
public void deleteUser(String userName)
{
db = this.getWritableDatabase();
try
{
db.delete(TABLE_CONTACTS, "name = ?", new String[] { userName });
}
catch(Exception e)
{
e.printStackTrace();
}
finally
{
db.close();
}
}
// Getting single contact
Contact Get_Contact(int id) {
SQLiteDatabase db = this.getReadableDatabase();
Cursor cursor = db.query(TABLE_CONTACTS,
new String[] { KEY_ID, KEY_Tittle, KEY_Description, KEY_Price,
KEY_Counter, KEY_Image }, KEY_ID + "=?",
new String[] { String.valueOf(id) }, null, null, null);
if (cursor != null)
cursor.moveToFirst();
Contact contact = new Contact(cursor.getString(0), cursor.getString(1),
cursor.getString(2), cursor.getString(4), cursor.getString(5));
// return contact
cursor.close();
db.close();
return contact;
}
public boolean somethingExists(String x) {
Cursor cursor = db.rawQuery("select * from " + TABLE_CONTACTS
+ " where name like '%" + x + "%'", null);
boolean exists = (cursor.getCount() > 0);
Log.e("Databaseeeeeeeee", String.valueOf(cursor));
cursor.close();
return exists;
}
public ArrayList<Contact> Get_Contacts() {
try {
contact_list.clear();
// Select All Query
String selectQuery = "SELECT * FROM " + TABLE_CONTACTS;
SQLiteDatabase db = this.getWritableDatabase();
Cursor cursor = db.rawQuery(selectQuery, null);
// looping through all rows and adding to list
if (cursor.moveToFirst()) {
do {
Contact contact = new Contact();
contact.setTitle(cursor.getString(1));
contact.setDescription(cursor.getString(2));
contact.setPrice(cursor.getString(3));
contact.setCounter(cursor.getString(4));
contact.setImage(cursor.getString(5));
contact_list.add(contact);
} while (cursor.moveToNext());
}
cursor.close();
db.close();
return contact_list;
} catch (Exception e) {
// TODO: handle exception
Log.e("all_contact", "" + e);
}
return contact_list;
}
public int getProfilesCount() {
String countQuery = "SELECT * FROM " + TABLE_CONTACTS;
SQLiteDatabase db = this.getReadableDatabase();
Cursor cursor = db.rawQuery(countQuery, null);
int cnt = cursor.getCount();
cursor.close();
return cnt;
}
}
SQLAdapter.java代码
public class StradaSQLAdapter extends BaseAdapter {
Activity activity;
int layoutResourceId;
Contact user;
ArrayList<Contact> data = new ArrayList<Contact>();
public ImageLoader imageLoader;
UserHolder holder = null;
public int itemSelected = 0;
public StradaSQLAdapter(Activity act, int layoutResourceId,
ArrayList<Contact> data) {
this.layoutResourceId = layoutResourceId;
this.activity = act;
this.data = data;
imageLoader = new ImageLoader(act.getApplicationContext());
notifyDataSetChanged();
}
@Override
public View getView(final int position, View convertView, ViewGroup parent) {
View row = convertView;
if (row == null) {
LayoutInflater inflater = LayoutInflater.from(activity);
holder = new UserHolder();
row = inflater.inflate(layoutResourceId, parent, false);
holder.Title = (TextView) row.findViewById(R.id.smalltitle1);
holder.counter = (TextView) row.findViewById(R.id.smallCounter1);
holder.dbcounter = (TextView) row
.findViewById(R.id.DBSliderCounter);
holder.Description = (TextView) row.findViewById(R.id.smallDesc1);
holder.layout = (RelativeLayout) row
.findViewById(R.id.DBSlideLayout);
holder.layoutmain = (RelativeLayout) row
.findViewById(R.id.DBSlideLayoutMain);
holder.Price = (TextView) row.findViewById(R.id.smallPrice1);
holder.pt = (ImageView) row.findViewById(R.id.smallthumb1);
holder.close = (ImageView) row.findViewById(R.id.DBSliderClose);
holder.c_minus = (ImageView) row.findViewById(R.id.counter_minus);
holder.c_plus = (ImageView) row.findViewById(R.id.counter_plus);
row.setTag(holder);
} else {
holder = (UserHolder) row.getTag();
}
user = data.get(position);
holder.Title.setText(user.getTitle());
holder.Description.setText(user.getDescription());
holder.Price.setText(user.getPrice() + " GEL");
holder.counter.setText(user.getCounter());
holder.dbcounter.setText(user.getCounter());
Log.e("image Url is........", data.get(position).toString());
imageLoader.DisplayImage(user.getImage(), holder.pt);
return row;
}
@Override
public int getCount() {
return data.size();
}
@Override
public Object getItem(int position) {
return data.get(position);
}
@Override
public long getItemId(int position) {
return 0;
}
public class UserHolder {
public TextView Price, counter, Description, Title, dbcounter;
public ImageView pt,close,c_plus,c_minus;
public RelativeLayout layout, layoutmain;
}
} 和主要的java代码
public class StradaChartFragments extends Fragment {
public static ListView list;
ArrayList<Contact> contact_data = new ArrayList<Contact>();
StradaSQLAdapter cAdapter;
private DatabaseHandler dbHelper;
UserHolder holder;
private RelativeLayout.LayoutParams layoutParams;
private ArrayList<Contact> contact_array_from_db;
@Override
public View onCreateView(LayoutInflater inflater, ViewGroup container,
Bundle savedInstanceState) {
View rootView = inflater.inflate(R.layout.strada_chart_fragment,
container, false);
dbHelper = new DatabaseHandler(getActivity());
list = (ListView) rootView.findViewById(R.id.chart_listview);
cAdapter = new StradaSQLAdapter(getActivity(),
R.layout.listview_row_db, contact_data);
contact_array_from_db = dbHelper.Get_Contacts();
Set_Referash_Data();
list.setOnItemClickListener(new OnItemClickListener() {
@Override
public void onItemClick(AdapterView<?> parent, View view,
final int position, long id) {
holder = (UserHolder) view.getTag();
layoutParams = (RelativeLayout.LayoutParams) holder.layoutmain
.getLayoutParams();
if (holder.layout.getVisibility() != View.VISIBLE) {
ValueAnimator varl = ValueAnimator.ofInt(0, -170);
varl.setDuration(1000);
varl.addUpdateListener(new AnimatorUpdateListener() {
@Override
public void onAnimationUpdate(ValueAnimator animation) {
layoutParams.setMargins(
(Integer) animation.getAnimatedValue(), 0,
0, 0);
holder.layoutmain.setLayoutParams(layoutParams);
}
});
varl.start();
holder.layout.setVisibility(View.VISIBLE);
}
holder.close.setOnClickListener(new OnClickListener() {
@Override
public void onClick(View arg0) {
ValueAnimator var2 = ValueAnimator.ofInt(-170, 0);
var2.setDuration(1000);
var2.addUpdateListener(new AnimatorUpdateListener() {
@Override
public void onAnimationUpdate(
ValueAnimator animation) {
dbHelper.deleteUser(contact_array_from_db.get(position).getTitle());
if (contact_data.size() > 0)
contact_data.remove(position);
layoutParams.setMargins(0, 0,
(Integer) animation.getAnimatedValue(),
0);
holder.layoutmain.setLayoutParams(layoutParams);
holder.layout.setVisibility(View.INVISIBLE);
}
});
var2.start();
}
});
}
});
return rootView;
}
public void Set_Referash_Data() {
contact_data.clear();
for (int i = 0; i < contact_array_from_db.size(); i++) {
String title = contact_array_from_db.get(i).getTitle();
String Description = contact_array_from_db.get(i).getDescription();
String Price = contact_array_from_db.get(i).getPrice();
String Counter = contact_array_from_db.get(i).getCounter();
String image = contact_array_from_db.get(i).getImage();
Contact cnt = new Contact();
cnt.setTitle(title);
cnt.setDescription(Description);
cnt.setPrice(Price);
cnt.setCounter(Counter);
cnt.setImage(image);
contact_data.add(cnt);
}
dbHelper.close();
list.setAdapter(cAdapter);
Log.e("Adapter issss ...", String.valueOf(cAdapter));
}
}
我可以删除数据库中的项目，但listview没有更新。我究竟做错了什么 ？如果有人知道解决方案帮助我 感谢
答案 0 :(得分：0)
根据您的方法dbHelper.deleteUser添加以下代码：
contact_data.remove(position);
除了从数据库中删除它之外，还必须删除发送给适配器的对象数组。
编辑：
在适配器中添加一个remove方法，以便删除对象。代码：
适配器：
public void removeObject (int position) {
this.data.remove(position);
}
的活动：
变化：
contact_data.remove(position);
为：
cAdapter.removeObject(position);
cAdapter.notifyDataSetChanged();
编辑2：
只需删除ArrayList中的所有对象。
contact_data.clear();
或在您的适配器中
data.clear();