I sqlite
auf einem ListView
durch eine CustomListAdapter
.Auf dargestellten Daten müssen gelöscht werden eine Reihe eine alert dialogue
knallt, klicken auf die den Benutzer auffordert, die einzelne Zeile von sqlite
in meiner Tätigkeit zu löschen:Wie eine einzelne Zeile in Android SQLite
private void deleteDialog() {
AlertDialog.Builder alertDialog = new AlertDialog.Builder(MyCart.this);
alertDialog.setCancelable(false);
alertDialog.setMessage("Delete item?");
alertDialog.setPositiveButton("Yes", new DialogInterface.OnClickListener() {
public void onClick(DialogInterface dialog, int which) {
myDb.deleteSingleContact(toString());
}
});
alertDialog.setNegativeButton("Cancel", new DialogInterface.OnClickListener() {
public void onClick(DialogInterface dialog, int which) {
dialog.cancel();
}
});
alertDialog.show();
}
Auf meinem DBHelper.java:
public void deleteSingleContact(String title){
SQLiteDatabase db = this.getWritableDatabase();
db.delete(CONTACTS_TABLE_NAME, CONTACTS_COLUMN_TITLE + "=?", new String[]{title});
//KEY_NAME is a column name
}
jedoch der obige Code nicht gelöscht anything.I seine Funktion denke, ich correctly.Any Vorschläge haben getan?
Voll DBHelper.java
public class DBHelper extends SQLiteOpenHelper {
public static final String DATABASE_NAME = "MyDBName.db";
public static final String CONTACTS_TABLE_NAME = "contacts";
public static final String CONTACTS_COLUMN_ID = "id";
public static final String CONTACTS_COLUMN_TITLE = "title";
public static final String CONTACTS_COLUMN_AMOUNT = "amount";
public static final String CONTACTS_COLUMN_DESC = "description";
private HashMap hp;
public DBHelper(Context context) {
super(context, DATABASE_NAME, null, 1);
}
@Override
public void onCreate(SQLiteDatabase db) {
// TODO Auto-generated method stub
db.execSQL(
"create table contacts " +
"(id integer primary key, title text,amount float,description text)"
);
}
@Override
public void onUpgrade(SQLiteDatabase db, int oldVersion, int newVersion) {
// TODO Auto-generated method stub
db.execSQL("DROP TABLE IF EXISTS contacts");
onCreate(db);
}
public boolean insertContact(String title, float amount, String description) {
SQLiteDatabase db = this.getWritableDatabase();
ContentValues contentValues = new ContentValues();
contentValues.put("title", title);
contentValues.put("amount", amount);
contentValues.put("description", description);
db.insert("contacts", null, contentValues);
return true;
}
public Cursor getData(int id) {
SQLiteDatabase db = this.getReadableDatabase();
Cursor res = db.rawQuery("select * from contacts where id=" + id + "", null);
return res;
}
public int numberOfRows() {
String countQuery = "SELECT * FROM " + CONTACTS_TABLE_NAME;
SQLiteDatabase db = this.getReadableDatabase();
Cursor cursor = db.rawQuery(countQuery, null);
int cnt = cursor.getCount();
cursor.close();
return cnt;
}
public boolean updateContact(Integer id, String title, float amount, String description) {
SQLiteDatabase db = this.getWritableDatabase();
ContentValues contentValues = new ContentValues();
contentValues.put("title", title);
contentValues.put("amount", amount);
contentValues.put("description", description);
db.update("contacts", contentValues, "id = ? ", new String[]{Integer.toString(id)});
return true;
}
public void deleteContact() {
SQLiteDatabase db = this.getWritableDatabase();
db.delete("contacts", null, null);
db.close();
}
public void deleteSingleContact(String title){
SQLiteDatabase db = this.getWritableDatabase();
db.delete(CONTACTS_TABLE_NAME, CONTACTS_COLUMN_TITLE + "=?", new String[]{title});
//KEY_NAME is a column name
}
public boolean checkForTables() {
boolean hasRows = false;
SQLiteDatabase db = getReadableDatabase();
Cursor cursor = db.rawQuery("SELECT COUNT(*) FROM " + CONTACTS_TABLE_NAME, null);
cursor.moveToFirst();
int count = cursor.getInt(0);
if(count > 0)
hasRows = true;
db.close();
return hasRows;
}
public ArrayList<ContactListItems> getAllContacts() {
ArrayList<ContactListItems> contactList = new ArrayList<>();
hp = new HashMap();
SQLiteDatabase db = this.getReadableDatabase();
Cursor res = db.rawQuery("select * from contacts", null);
res.moveToFirst();
while (!res.isAfterLast()) {
ContactListItems contactListItems = new ContactListItems();
contactListItems.setTitle(res.getString(res
.getColumnIndex("title")));
contactListItems.setAmount(res.getFloat(res
.getColumnIndex("amount")));
contactListItems.setDescription(res.getString(res
.getColumnIndex("description")));
contactList.add(contactListItems);
res.moveToNext();
}
res.close();
return contactList;
}
public int getTotalOfAmount(){
SQLiteDatabase db = this.getReadableDatabase();
Cursor c=db.rawQuery("SELECT SUM(amount) FROM " +CONTACTS_TABLE_NAME,null);
c.moveToFirst();
int i=c.getInt(0);
c.close();
return i;
}
}
EDIT
obj.setOnItemLongClickListener(new AdapterView.OnItemLongClickListener() {
@Override
public boolean onItemLongClick(AdapterView<?> arg0, View arg1, int arg2, long arg3) {
deleteDialog();
return true;
}
});
}
Logcat Fehler:
android.database.sqlite.SQLiteException: near "=": syntax error (code 1): , while compiling: DELETE FROM contacts WHERE title=
at android.database.sqlite.SQLiteConnection.nativePrepareStatement(Native Method)
at android.database.sqlite.SQLiteConnection.acquirePreparedStatement(SQLiteConnection.java:882)
at android.database.sqlite.SQLiteConnection.prepare(SQLiteConnection.java:493)
at android.database.sqlite.SQLiteSession.prepare(SQLiteSession.java:588)
at android.database.sqlite.SQLiteProgram.<init>(SQLiteProgram.java:58)
at android.database.sqlite.SQLiteStatement.<init>(SQLiteStatement.java:31)
at android.database.sqlite.SQLiteDatabase.executeSql(SQLiteDatabase.java:1663)
at android.database.sqlite.SQLiteDatabase.execSQL(SQLiteDatabase.java:1594)
at com.softtech.stevekamau.buyathome.DBHelper.removeSingleContact(DBHelper.java:157)
at com.softtech.stevekamau.buyathome.MyCart$6.onClick(MyCart.java:140)
at com.android.internal.app.AlertController$ButtonHandler.handleMessage(AlertController.java:166)
at android.os.Handler.dispatchMessage(Handler.java:99)
at android.os.Looper.loop(Looper.java:137)
at android.app.ActivityThread.main(ActivityThread.java:4745)
at java.lang.reflect.Method.invokeNative(Native Method)
at java.lang.reflect.Method.invoke(Method.java:511)
at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:786)
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:553)
at dalvik.system.NativeStart.main(Native Method)
Wir machen das Debuggen nicht für Sie. Bitte fügen Sie nur die sehr relevanten Codeteile hinzu. –
Ich dachte, die Spaltennamen könnten für diejenigen relevant sein, die daran interessiert sind. –
Die Spalte Namen ja, aber nicht vollständige Quelldateien. –