How can you implement multi-selection and Contextual ActionMode in ActionBarSherlock?

Yaroslav Mytkalyk picture Yaroslav Mytkalyk · Feb 6, 2013 · Viewed 17.6k times · Source

How should I implement multi selection on AdapterView with ActionBarSherlock, because it does not provide MultiChoiceModeListener?

This is what it looks like

Contextual Action Mode

How can you do this?

Answer

Yaroslav Mytkalyk picture Yaroslav Mytkalyk · Feb 6, 2013

So here's what I did.

Edit: Over a year passed since I found out the previous answer had alot of useless code (woops) and the CAB thing can be achieved with much less effort and a cleaner code, so I took some time and updated it

The LibraryFragment ListView should be defined with choice mode "none"

<ListView
    android:id="@android:id/list"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:choiceMode="none"/>

The list item should have an ?attr/activatedBackgroundIndicator foreground in order to automatically draw highlighted semitransparent overlay on list.setItemChecked(pos, true)

list_item_library.xml

<FrameLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:foreground="?attr/activatedBackgroundIndicator"
    android:paddingBottom="5dp"
    android:paddingTop="5dp" >

....

The ListFragment

import android.support.v4.app.DialogFragment;
import com.actionbarsherlock.app.SherlockListFragment;
import com.actionbarsherlock.view.ActionMode;
import com.actionbarsherlock.view.Menu;

public final class LibraryFragment
        extends SherlockListFragment
{

    private MyListAdapter adapter;
    private ListView list;

    // if ActoinMode is null - assume we are in normal mode
    private ActionMode actionMode;

    @Override
    public View onCreateView(LayoutInflater inflater, ViewGroup container,
            Bundle savedInstanceState)
    {
        View v = inflater.inflate(R.layout.fragment_library, null);
        this.list = (ListView) v.findViewById(android.R.id.list);
        this.initListView();
        return v;
    }

    @Override
    public void onPause()
    {
        super.onPause();
        if (this.actionMode != null) {
            this.actionMode.finish();
        }
    }

    @Override
    public void onResume() {
        super.onResume();
        updateData();
    }

    // update ListView
    protected void updateData()
    {
        if (adapter == null) {
            return;
        }
        adapter.clear();
        // my kinda stuff :)
        File[] items = scan();
        if (items != null) {
            adapter.updateData(items);
            if (actionMode != null) {
                actionMode.invalidate();
            }
        }
        // if empty - finish action mode.
        if (actionMode != null && (files == null || files.length == 0)) {
            actionMode.finish();
        }
    }

    private void initListView()
    {
        this.adapter = new MyAdapter(getActivity());
        this.list.setAdapter(adapter);
        this.list.setOnItemLongClickListener(new AdapterView.OnItemLongClickListener()
        {

            @Override
            public boolean onItemLongClick(AdapterView<?> arg0,
                    View arg1, int arg2, long arg3)
            {
                if (actionMode != null) {
                    // if already in action mode - do nothing
                    return false;
                }
                // set checked selected item and enter multi selection mode
                list.setChoiceMode(AbsListView.CHOICE_MODE_MULTIPLE);
                list.setItemChecked(arg2, true);

                getSherlockActivity().startActionMode(
                        new ActionModeCallback());
                return true;
            }
        });
        this.list.setOnItemClickListener(new AdapterView.OnItemClickListener()
        {
            @Override
            public void onItemClick(AdapterView<?> arg0, View arg1, int arg2,
                    long arg3)
            {
                if (actionMode != null) {
                    // the items are auomatically "checked" becaise we've set AbsListView.CHOICE_MODE_MULTIPLE before
                    // starting action mode, so the only thing we have to care about is invalidating the actionmode
                    actionMode.invalidate(); //invalidate title and menus.
                } else {
                    // do whatever you should on item click
                }
            }
        });
    }


    // all our ActionMode stuff here :)
    private final class ActionModeCallback
            implements ActionMode.Callback
    {

        // " selected" string resource to update ActionBar text
        private String selected = getActivity().getString(
                R.string.library_selected);

        @Override
        public boolean onCreateActionMode(ActionMode mode, Menu menu)
        {
            actionMode = mode;
            return true;
        }

        @Override
        public boolean onPrepareActionMode(ActionMode mode, Menu menu)
        {
            // remove previous items
            menu.clear();
            final int checked = list.getCheckedItemCount();
            // update title with number of checked items
            mode.setTitle(checked + this.selected);
            switch (checked) {
            case 0:
                // if nothing checked - exit action mode
                mode.finish();
                return true;
            case 1:
                // all items - rename + delete
                getSherlockActivity().getSupportMenuInflater().inflate(
                        R.menu.library_context, menu);
                return true;
            default:
                getSherlockActivity().getSupportMenuInflater().inflate(
                        R.menu.library_context, menu);
                // remove rename option - because we have more than one selected
                menu.removeItem(R.id.library_context_rename);
                return true;
            }
        }

        @Override
        public boolean onActionItemClicked(ActionMode mode,
                com.actionbarsherlock.view.MenuItem item)
        {
            SparseBooleanArray checked;
            switch (item.getItemId()) {
            case R.id.library_context_rename:
                // the rename action is present only when only one item is selected. 
                // so when the first checked item found, show the dialog and break
                checked = list.getCheckedItemPositions();
                for (int i = 0; i < checked.size(); i++) {
                    final int index = checked.keyAt(i);
                    if (checked.get(index)) {
                        final DialogFragment d = RenameDialog.instantiate(adapter.getItem(index).getFile(), LibraryFragment.this);
                        d.show(getActivity().getSupportFragmentManager(), "dialog");
                        break;
                    }
                }
                return true;

            case R.id.library_context_delete:
                // delete every checked item
                checked = list.getCheckedItemPositions();
                for (int i = 0; i < checked.size(); i++) {
                    final int index = checked.keyAt(i);
                    if (checked.get(index)) {
                        adapter.getItem(index).getFile().delete();
                    }
                }
                updateData();
                return true;
            default:
                return false;
            }
        }

        @Override
        public void onDestroyActionMode(ActionMode mode)
        {
            list.clearChoices();

            //workaround for some items not being unchecked.
            //see http://stackoverflow.com/a/10542628/1366471
            for (int i = 0; i < list.getChildCount(); i++) {
                (list.getChildAt(i).getBackground()).setState(new int[] { 0 });
            }

            list.setChoiceMode(AbsListView.CHOICE_MODE_NONE);
            actionMode = null;
        }

    }