Deleting and Updating values from a cusrsor adapter

问题

I am new to android development and I have populated values to a listview using a cursor adapter. I am trying to Delete and update the values using the list view but I am not sure how this is done using a cursor adapter. Nor I am able to click on the list view item

The below methods I have used in my database handler class to delete and update values

Delete Method

 public void DeletingCustodian(Custodians custodians)
    {
        SQLiteDatabase db_database = getWritableDatabase();
        //Deleting the custodian from the Database where the custodian ID matches to the selcted ID
        db_database.delete(TABLE_CUSTODIAN,CUSTODIAN_ID + "=?" , new String[]{String.valueOf(custodians.getCust_id())});
        db_database.close();
    }

Updating Method

public  int updateCustodian(Custodians cust)
    {
        SQLiteDatabase db_database = getWritableDatabase();
        ContentValues values = new ContentValues();
        values.put(CUSTODIAN_NAME,cust.getCust_Name());
        values.put(CUSTODIAN_DESIGNATION,cust.getCust_Design());
        values.put(CUSTODIAN_DEPARTMENT,cust.getDepartment());

        int roweffected = db_database.update(TABLE_CUSTODIAN,values,CUSTODIAN_ID + "=?", new String[]{String.valueOf(cust.getCust_id())});
        db_database.close();
        return roweffected;
    }

I have created a context Menu which displays edit and delete this is shown when a certain item is selected.

 public void onCreateContxtManu(ContextMenu menu,View view, ContextMenu.ContextMenuInfo menuInfo)
    {
        super.onCreateContextMenu(menu,view,menuInfo);

        menu.setHeaderTitle("Custodian Options");
        menu.add(Menu.NONE,EDIT,menu.NONE,"Edit Custodian");
        menu.add(Menu.NONE,DELETE,menu.NONE,"Delete Custodian");
    }

 public void deletingitemsfromlist()
    {
        CustodianListview.setOnItemLongClickListener(new AdapterView.OnItemLongClickListener() {
            @Override
            public boolean onItemLongClick(AdapterView<?> parent, View view, int position, long id) {

                return false;
            }
        });

    }
   public boolean onContextItemSelected(MenuItem item)
    {
        switch(item.getItemId())
        {
            case EDIT:


                break;
            case DELETE:


                break;
        }

        return false;
    }

回答1:

try this , It may help you

Delete code in Database Connector

// Delete a row in Local database
    public void delete(int ids) {

        database.delete(TABLE_NAME, KEY_ROWID + " = " + ids, null);
    }

in Your Listview page code Onitem long click Delete

@Override
               public boolean onItemLongClick(AdapterView arg0, View v,
                 int position, long arg3)
             {
                 try
                 {

                TextView id = (TextView) v.findViewById(R.id.textView4);

                 ids1 = Integer.parseInt(id.getText().toString());
                AlertDialog.Builder ad = new AlertDialog.Builder(Page1_Landing.this);
                //ad.setTitle("Notice");
                ad.setMessage("Sure you want to delete this Item ?");

                //Delete Positive Button
                ad.setPositiveButton(android.R.string.ok, new DialogInterface.OnClickListener() 
                {


                @SuppressWarnings("deprecation")
                @Override
                 public void onClick(DialogInterface dialog, int which)
                 {
                     try
                     {



                          //Delete of record from Database and List view.
                          helper.delete(ids1);
                          cur.requery();
                          myCursorAdap.notifyDataSetChanged();
                          List.setAdapter(myCursorAdap);
                          Toast.makeText(Page1_Landing.this,"Selected Product is Successfully Deleted...!", Toast.LENGTH_SHORT).show();



                     }
                     catch(Exception e)
                     {
                         e.printStackTrace();
                           Log.i("Exception ", "in Delete a Product");
                     }
                 }
                });

                //long press delete cancel
                ad.setNegativeButton(android.R.string.cancel, new DialogInterface.OnClickListener() 
                {

                 @Override
                 public void onClick(DialogInterface dialog, int which) 
                 {


                     dialog.dismiss();


                 }
                });
                ad.show();



                 }
                 catch(Exception e)
                 {
                     e.printStackTrace();
                 }
                 return true;
               }

Update code

DatabaseConnector helper = new DatabaseConnector(this);

helper.open();

helper.updatedetails(rowID,name1,desc, dept);
Toast.makeText(getApplicationContext(),"Updated Successfully...!", Toast.LENGTH_SHORT).show();

Update Database code

// updating the data ....
    public boolean updatedetails(long rowId, String name,
            String desc, String dept)
    {
        ContentValues args = new ContentValues();

        args.put(KEY_ROWID, rowId);
        args.put(KEY_NAME, product);
        args.put(KEY_DESC, cat);
        args.put(KEY_DEPT, serial);



        return database.update(TABLE_NAME, args, KEY_ROWID + "=" + rowId, null) > 0;
    }

回答2:

Update the data in the database and get the new cursor by querying the database again then call

oldCursor = myCursorAdapter.swapCursor(newCursor); // hands you back oldCursor

or:

myCursorAdapter.changeCursor(newCursor); // automatically closes old Cursor

myCursorAdapter.notifyDataSetChanged() notifies the ListView that the data set has changed, and it should refresh itself

来源：https://stackoverflow.com/questions/30724048/deleting-and-updating-values-from-a-cusrsor-adapter