FixedExpandableListActivity.java

package org.pyload.android.client.components;


import android.app.Activity;
import android.os.Bundle;
import android.view.ContextMenu;
import android.view.ContextMenu.ContextMenuInfo;
import android.view.View;
import android.view.View.OnCreateContextMenuListener;
import android.widget.ExpandableListAdapter;
import android.widget.ExpandableListView;

public class FixedExpandableListActivity extends Activity implements
        OnCreateContextMenuListener,
        ExpandableListView.OnChildClickListener, ExpandableListView.OnGroupCollapseListener,
        ExpandableListView.OnGroupExpandListener {   
    ExpandableListAdapter mAdapter;
    ExpandableListView mList;
    boolean mFinishedStart = false;

    /**
     * Override this to populate the context menu when an item is long pressed. menuInfo
     * will contain an {@link android.widget.ExpandableListView.ExpandableListContextMenuInfo}
     * whose packedPosition is a packed position
     * that should be used with {@link ExpandableListView#getPackedPositionType(long)} and
     * the other similar methods.
     * <p>
     * {@inheritDoc}
     */
    @Override
    public void onCreateContextMenu(ContextMenu menu, View v, ContextMenuInfo menuInfo) {
    }

    /**
     * Override this for receiving callbacks when a child has been clicked.
     * <p>
     * {@inheritDoc}
     */
    public boolean onChildClick(ExpandableListView parent, View v, int groupPosition,
            int childPosition, long id) {
        return false;
    }

    /**
     * Override this for receiving callbacks when a group has been collapsed.
     */
    public void onGroupCollapse(int groupPosition) {
    }

    /**
     * Override this for receiving callbacks when a group has been expanded.
     */
    public void onGroupExpand(int groupPosition) {
    }

    /**
     * Ensures the expandable list view has been created before Activity restores all
     * of the view states.
     * 
     *@see Activity#onRestoreInstanceState(Bundle)
     */
    @Override
    protected void onRestoreInstanceState(Bundle state) {
        ensureList();
        super.onRestoreInstanceState(state);
    }

    /**
     * Updates the screen state (current list and other views) when the
     * content changes.
     * 
     * @see Activity#onContentChanged()
     */
    @Override
    public void onContentChanged() {
        super.onContentChanged();
        View emptyView = findViewById(android.R.id.empty);
        /* Issue 3443 - http://code.google.com/p/android/issues/detail?id=3443
         * Just use another id to find expandable list view
         *  */
        //mList = (ExpandableListView)findViewById(com.android.internal.R.id.list);
        //mList = (ExpandableListView)findViewById(org.pyload.android.client.R.id.expandable_listview);
        if (mList == null) {
            throw new RuntimeException(
                    "Your content must have a ExpandableListView whose id attribute is " +
                    "'ru.ponkin.R.id.expandable_listview'");
        }
        if (emptyView != null) {
            mList.setEmptyView(emptyView);
        }
        mList.setOnChildClickListener(this);
        mList.setOnGroupExpandListener(this);
        mList.setOnGroupCollapseListener(this);
        
        if (mFinishedStart) {
            setListAdapter(mAdapter);
        }
        mFinishedStart = true;
    }

    /**
     * Provide the adapter for the expandable list.
     */
    public void setListAdapter(ExpandableListAdapter adapter) {
        synchronized (this) {
            ensureList();
            mAdapter = adapter;
            mList.setAdapter(adapter);
        }
    }

    /**
     * Get the activity's expandable list view widget.  This can be used to get the selection,
     * set the selection, and many other useful functions.
     * 
     * @see ExpandableListView
     */
    public ExpandableListView getExpandableListView() {
        ensureList();
        return mList;
    }
    
    /**
     * Get the ExpandableListAdapter associated with this activity's
     * ExpandableListView.
     */
    public ExpandableListAdapter getExpandableListAdapter() {
        return mAdapter;
    }

    private void ensureList() {
        if (mList != null) {
            return;
        }
        setContentView(android.R.layout.expandable_list_content);
    }

    /**
     * Gets the ID of the currently selected group or child.
     * 
     * @return The ID of the currently selected group or child.
     */
    public long getSelectedId() {
        return mList.getSelectedId();
    }

    /**
     * Gets the position (in packed position representation) of the currently
     * selected group or child. Use
     * {@link ExpandableListView#getPackedPositionType},
     * {@link ExpandableListView#getPackedPositionGroup}, and
     * {@link ExpandableListView#getPackedPositionChild} to unpack the returned
     * packed position.
     * 
     * @return A packed position representation containing the currently
     *         selected group or child's position and type.
     */
    public long getSelectedPosition() {
        return mList.getSelectedPosition();
    }

    /**
     * Sets the selection to the specified child. If the child is in a collapsed
     * group, the group will only be expanded and child subsequently selected if
     * shouldExpandGroup is set to true, otherwise the method will return false.
     * 
     * @param groupPosition The position of the group that contains the child.
     * @param childPosition The position of the child within the group.
     * @param shouldExpandGroup Whether the child's group should be expanded if
     *            it is collapsed.
     * @return Whether the selection was successfully set on the child.
     */
    public boolean setSelectedChild(int groupPosition, int childPosition, boolean shouldExpandGroup) {
        return mList.setSelectedChild(groupPosition, childPosition, shouldExpandGroup);
    }

    /**
     * Sets the selection to the specified group.
     * @param groupPosition The position of the group that should be selected.
     */
    public void setSelectedGroup(int groupPosition) {
        mList.setSelectedGroup(groupPosition);
    }

}