Question

I have been unable to find a tutorial helping with multi-selects using cursors. As of right now my logic is working the way I want but the check boxes will not update properly. What am I overlooking?

return new AlertDialog.Builder(this).setTitle("Items")
            .setMultiChoiceItems(cur, CHECK, EDATE, new DialogInterface.OnMultiChoiceClickListener() {
                @Override
                public void onClick(DialogInterface dialog, int position, boolean checked)
                {
                    DBM.open();
                    AlertDialog AD = (AlertDialog) dialog;
                    ListView list = AD.getListView();
                    list.setChoiceMode(ListView.CHOICE_MODE_MULTIPLE);

                    itemCur = (Cursor) list.getItemAtPosition(position);

                    if (checked)
                    {
                        //update query
                        DBM.setChecked(checkCur.getInt(checkCur.getColumnIndex(ID)), itemId, userId, 1);
                        list.setItemChecked(1, true);
                    } else
                    {
                        DBM.setChecked(checkCur.getInt(checkCur.getColumnIndex(ID)), itemId, userId, 0);
                        list.setItemChecked(1, false);
                    }
                    DBM.close();
                }
            }).setPositiveButton("OK", new DialogButtonClickHandler()).create();

Answer 1

So after digging into the issue a bit and going through a couple different iterations I finally found a solution that I am fairly happy with. With school and work pushing hard I have had little time outside to work on extra projects and I have been sitting with this solution for while now but unable to get it posted.

The final piece to my puzzle was finding the changeCursor function, this fixed the issue of the old data that no longer matched the DB to load. My current hurdle is the time it takes to check a box, there is an obvious lag from clicked to updated. I have found that mutliple records update when one is clicked. I have not been able to find a valid reason for these extra updates.

Below is the code I currently have implemented to have the multi-select working. This just the dialog code, for a working demo I will be posting a project on GitHub for a working prototype of it all in action. (Now made public, Multiselect Dialog)

I am a fairly new Android developer, majority of my Android knowledge has been self taught and learned through the knowledge of online resources. I was working on a school project and wanted to implement a multiselect in a dialog that would update the main activity with the selected choices. Please lend any advice you can on how to improve this.

Pros:
– Populates check boxes properly on load.
– Updates database when check is clicked.
– Keeps display updated after data change.

Cons:
– Must click check box to update value.
– Unable to undo changes made while in dialog. The values save onClick, I have not been able to think of a way to temporarily store the new values until confirmed by the user.
– A single click updates multiple records, also sometimes when choices scroll off the screen values update

@Override
protected Dialog onCreateDialog(int id)
{
    switch (id) {

    case 0:
        LayoutInflater factory = LayoutInflater.from(this);

        // Setup of the view for the dialog
        final View bindListDialog = factory.inflate(R.layout.multi_list_layout, null);
        multiListView = (ListView) bindListDialog.findViewById(R.id.multiList);

        // Because I do not know how to properly handle an undo in this situation
        // I make the dialog only close if the button is pressed and confirms the changes
        return new AlertDialog.Builder(MultiSelectDemoActivity.this).setTitle(R.string.multiSelectTitle)
                .setCancelable(false).setView(bindListDialog)
                .setPositiveButton(R.string.btnClose, new DialogInterface.OnClickListener() {
                    public void onClick(DialogInterface dialog, int whichButton)
                    {
                        updateItemList(); // In my implementation there is a list view
                                          // that shows what has been selected.
                    }
                }).create();
    default:
        return null;
    }
}

private static final boolean ONCREATE = true;
private static final boolean ONUPDATE = false;

private void setupMultiList(Boolean newList)
{
    demoDBM.open();
    multiCur = demoDBM.getList(userId); // Gets all items tied to the user.
    startManagingCursor(multiCur);
    // Uses the cursor to populate a List item with an invisible ID column,
    // a name column, and the checkbox
    demoDBM.close();

    if (newList)
    {
        // Creates a new adapter to populate the list view on the dialog
        multiAdapter = new SimpleCursorAdapter(this, R.layout.check_list_item, multiCur, new String[] { DemoDBM.ID,
                DemoDBM.NAME, DemoDBM.SEL }, new int[] { R.id.itemId, R.id.itemName, R.id.itemCheck });
        multiAdapter.setViewBinder(new MyViewBinder());
        multiListView.setAdapter(multiAdapter);
    } else
    {
        // updates the previously made adapter with the new cursor, without changing position
        multiAdapter.changeCursor(multiCur);
    }
}

@Override
protected void onPrepareDialog(final int id, final Dialog dialog, Bundle args)
{
    setupMultiList(ONCREATE);
}

public class MyViewBinder implements ViewBinder
{
    @Override
    public boolean setViewValue(View view, Cursor cursor, int columnIndex)
    {
        int checkId = cursor.getColumnIndex(DemoDBM.SEL);

        if (columnIndex == checkId)
        {
            CheckBox cb = (CheckBox) view;
            // Sets checkbox to the value in the cursor
            boolean bChecked = (cursor.getInt(checkId) != 0);
            cb.setChecked(bChecked); // Switches the visual checkbox.

            cb.setOnCheckedChangeListener(new MyOnCheckedChangeListener());
            return true;
        }
        return false;
    }
}

public class MyOnCheckedChangeListener implements OnCheckedChangeListener
{
    @Override
    public void onCheckedChanged(CompoundButton checkBox, boolean newVal)
    {
        View item = (View) checkBox.getParent(); // Gets the plain_list_item(Parent) of the Check Box

        // Gets the DB _id value of the row clicked and updates the Database appropriately.
        int itemId = Integer.valueOf(((TextView) item.findViewById(R.id.itemId)).getText().toString());
        demoDBM.open();
        demoDBM.setChecked(itemId, userId, newVal);
        demoDBM.close();

        setupMultiList(ONUPDATE);
    }
}