Check and Uncheck All CheckBoxes in ListView

Question

I was surprised that I couldn't find an existing answer on Stack that I could use for this, so here I am.

I have a ListFragment with a list attached to a SimpleCursorAdapter comprised of the rows defined by the following row.xml file:

<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
   android:layout_width="fill_parent"
   android:layout_height="wrap_content"
   android:orientation="vertical"
   android:padding="6dip" >

   <CheckBox
       android:id="@+id/story_check_box"
       android:layout_width="wrap_content"
       android:layout_height="wrap_content"
       android:layout_alignParentLeft="true"
       android:focusable="false"
       android:focusableInTouchMode="false" />

   <TextView
       android:id="@+id/story"
       android:layout_width="wrap_content"
       android:layout_height="24sp"
       android:lines="1"
       android:scrollHorizontally="true"
       android:singleLine="true"
       android:layout_alignBaseline="@+id/story_check_box"
       android:layout_alignBottom="@+id/story_check_box"
       android:layout_toRightOf="@+id/story_check_box" />

</RelativeLayout>

I connect the list with the adapter with the following code in my ListFragment:

adapter = new SimpleCursorAdapter(getActivity(), R.layout.row, null, new String[] { CProvider.Stories.TITLE }, new int[] { R.id.story }, 0);
setListAdapter(adapter);

I then try to use a CheckBox in my fragment to toggle all the list checkboxes as follows:

CheckBox selectAll = (CheckBox) rootView.findViewById(R.id.select_check_box);
    selectAll.setOnCheckedChangeListener(new CompoundButton.OnCheckedChangeListener() {
        @Override
        public void onCheckedChanged(CompoundButton buttonView, boolean isChecked) {
            final ListView listView = getListView();
            for(int i=0; i < getListAdapter().getCount(); i++){
                View view = getViewByPosition(i, listView);
                CheckBox cb = (CheckBox)view.findViewById(R.id.story_check_box);
                if (isChecked) {
                    cb.setChecked(true);
                }
                else {
                    cb.setChecked(false);
                }
            }
        }

    });

I got getViewByPositionfrom here: Get ListView children that are not in view, and that almost works, but a few of the checkboxes don't get checked (and there is a pattern to it, but I can't seem to figure it out). It also seems a bit kludgier than I would think is necessary.

I want the checkboxes on the left, so I don't want to use checkedtextviews. Maybe I need to extend CursorAdapter and override getView?

Thanks in advance.

Answer 1

Maybe I'm not correctly understanding your question but what I understood was that you wanted to check and uncheck all the checkboxes thanks to one "Select All checkbox".

Then, what I would do is to put the state of the "select all checkbox" as a variable of the class (as a boolean) which is overwritten by your selectAll.setOnCheckedChangeListener and say to the adapter "Hey, my state changed!" every time the checkbox changed its state. Something like this:

class Dummy{
    boolean isAllSelected = false;
    Checkbox selectAll = (find or create your CheckBox)
    selectAll.setOnCheckedChangeListener(new CompoundButton.OnCheckedChangeListener() {
        @Override
        public void onCheckedChanged(CompoundButton buttonView, boolean isChecked) {
            if (isChecked) isAllSelected = true;
            else isAllSelected = false;
            listView.getAdapter().notifyDataSetChanged();
        }
    }

And then, you just have to override the getView() of this adapter (like you suggested) adding a "if (isAllSlected)" condition.

To me, it sounds the easiest to do but it's maybe not that good to call the notifyDataSetChanged() method every time the user clicks on a checkbox (it's not that efficient for so minor changes). Anyway, hope it helps (the code I wrote is maybe not with the correct syntax: I wrote it directly on the website form)!

Answer 2

Below is what I wound up doing. In addition to taking care of the "select all/ unselect all" functionality, it handles checking/unchecking a checkbox when the text of a list item is selected/unselected, and vice versa. I was concerned about getView being called frequently, but setItemChecked causes getView to be called no matter what, so there's a limit to how much calls to getView can be avoided. As ataulm mentioned in a comment, maybe a composite view would a solution with less fuss.

In onCreateView:

selectAllCheckBox = (CheckBox) rootView.findViewById(R.id.select_all_check_box);
    selectAllCheckBox.setOnCheckedChangeListener(new CompoundButton.OnCheckedChangeListener() {
        @Override
        public void onCheckedChanged(CompoundButton buttonView, boolean isChecked) {
            final ListView listView = getListView();
            for(int i=0; i < getListAdapter().getCount(); i++){
                listView.setItemChecked(i, isChecked);
            }
        }
    });

I also created a custom SimpleCursorAdapter with the following code, which also uses a simple ViewHolder class. In getView I check which items in the list are selected and check the checkboxes corresponding to those items. There's also code that sets a list item as selected or not if its corresponding checkbox has been clicked (i.e., checked or unchecked).

class AvailableCursorAdapter extends SimpleCursorAdapter {
    AvailableCursorAdapter(Context context, int layout, Cursor c, String[] from, int[] to, int flags) {
        super(context, layout, c, from, to, flags);
    }

    @Override
    public View getView(final int position, View convertView, ViewGroup parent) {
        View row = super.getView(position, convertView, parent);
        ViewHolder holder = (ViewHolder)row.getTag();       
        if (holder == null) {                         
            holder = new ViewHolder(row);
            row.setTag(holder);
        }
        holder.storyCheckBox.setChecked(false);
        holder.story.setTextColor(Color.LTGRAY);
        long [] checkedIds = getListView().getCheckedItemIds();
        if (checkedIds != null) {
            for (int i = 0; i < checkedIds.length; i++) {
                if (checkedIds[i] == getListAdapter().getItemId(position)) {
                    holder.storyCheckBox.setChecked(true);
                    holder.story.setTextColor(Color.WHITE);
                    break;
                }
            }
        }
        final boolean isChecked = holder.storyCheckBox.isChecked();
        holder.storyCheckBox.setOnClickListener(new OnClickListener() {
            @Override
            public void onClick(View v) {
                getListView().setItemChecked(position, !isChecked);
            }
        });
        return(row);
    }
}

.

class ViewHolder {
    CheckBox storyCheckBox;
    TextView story = null;

    ViewHolder(final View row) {
        storyCheckBox = (CheckBox) row.findViewById(R.id.story_check_box);
        story = (TextView) row.findViewById(R.id.story);
    }
}

Finally, the following code causes getView to be called when a single ListItem is clicked, so that its corresponding checkbox gets selected or unselected, as appropriate:

@Override
public void onListItemClick(ListView l, View v, int position, long id) {
    ViewHolder holder = (ViewHolder) v.getTag();
    holder.storyCheckBox.setChecked(false);
    holder.story.setTextColor(Color.LTGRAY);
    long [] checkedIds = l.getCheckedItemIds();
    if (checkedIds != null) {
        for (int i = 0; i < checkedIds.length; i++) {
            if (checkedIds[i] == getListAdapter().getItemId(position)) {
                holder.storyCheckBox.setChecked(true);
                holder.story.setTextColor(Color.WHITE);
                break;
            }
        }
    }
}