Code example for ExpandableListView

    /** Provide the cursor for the list view. */ 
    public void setListAdapter(ExpandableListAdapter adapter) {
        boolean hadAdapter = mAdapter != null;
        mAdapter = adapter;
        if (mList != null) {
            mList.setAdapter(adapter);
            if (!mListShown && !hadAdapter) {
                // The list was hidden, and previously didn't have an 
                // adapter.  It is now time to show it. 
                setListShown(true, getView().getWindowToken() != null);
            } 
        } 
    } 
 
    /** 
     * Set the currently selected list item to the specified 
     * position with the adapter's data 
     */ 
    public void setSelection(int position) {
        ensureList(); 
        mList.setSelection(position);
    } 
 
    public long getSelectedPosition() { 
        ensureList(); 
        return mList.getSelectedPosition();
    } 
 
    public long getSelectedId() { 
        ensureList(); 
        return mList.getSelectedId();
    } 
 
    public ExpandableListView getExpandableListView() {
        ensureList(); 
        return mList;
    } 
 
    /** 
     * The default content for a ListFragment has a TextView that can 
     * be shown when the list is empty.  If you would like to have it 
     * shown, call this method to supply the text it should use. 
     */ 
    public void setEmptyText(CharSequence text) {
        ensureList(); 
        if (mStandardEmptyView == null) {
            throw new IllegalStateException("Can't be used with a custom content view");
        } 
        mStandardEmptyView.setText(text);
        if (!mSetEmptyText) {
            mList.setEmptyView(mStandardEmptyView);
            mSetEmptyText = true;
        } 
    } 
 
    /** 
     * Control whether the list is being displayed.  You can make it not 
     * displayed if you are waiting for the initial data to show in it.  During 
     * this time an indeterminant progress indicator will be shown instead. 
     * <p/> 
     * <p>Applications do not normally need to use this themselves.  The default 
     * behavior of ListFragment is to start with the list not being shown, only 
     * showing it once an adapter is given with {@link #setListAdapter(ListAdapter)}. 
     * If the list at that point had not been shown, when it does get shown 
     * it will be do without the user ever seeing the hidden state. 
     * @param shown If true, the list view is shown; if false, the progress 
     *              indicator.  The initial value is true. 
     */ 
    public void setListShown(boolean shown) {
        setListShown(shown, true);
    } 
 
    /** 
     * Like {@link #setListShown(boolean)}, but no animation is used when 
     * transitioning from the previous state. 
     */ 
    public void setListShownNoAnimation(boolean shown) {
        setListShown(shown, false);
    } 
 
    /** 
     * Control whether the list is being displayed.  You can make it not 
     * displayed if you are waiting for the initial data to show in it.  During 
     * this time an indeterminant progress indicator will be shown instead. 
     * @param shown   If true, the list view is shown; if false, the progress 
     *                indicator.  The initial value is true. 
     * @param animate If true, an animation will be used to transition to the 
     *                new state. 
     */ 
    private void setListShown(boolean shown, boolean animate) {
        ensureList(); 
        if (mListShown == shown) {
            return; 
        } 
        mListShown = shown;
        if (mListContainer != null) {
            if (shown) {
                if (animate) {
                    mListContainer.startAnimation(AnimationUtils.loadAnimation(getActivity(), android.R.anim.fade_in));
                } 
                mListContainer.setVisibility(View.VISIBLE);
            } else { 
                if (animate) {
                    mListContainer.startAnimation(AnimationUtils.loadAnimation(getActivity(), android.R.anim.fade_out));
                } 
                mListContainer.setVisibility(View.GONE);
            } 
        } 
    } 
 
    /** Get the ListAdapter associated with this activity's ListView. */ 
    public ExpandableListAdapter getExpandableListAdapter() {
        return mAdapter;
    } 
 
    private void ensureList() { 
        if (mList != null) {
            return; 
        } 
        View root = getView();
        if (root == null) {
            throw new IllegalStateException("Content view not yet created");
        } 
        if (root instanceof ExpandableListView) {
            mList = (ExpandableListView) root;
        } else { 
            mStandardEmptyView = (TextView) root.findViewById(INTERNAL_EMPTY_ID);
            if (mStandardEmptyView == null) {
                mEmptyView = root.findViewById(android.R.id.empty);
            } 
            mListContainer = root.findViewById(INTERNAL_LIST_CONTAINER_ID);
            View rawListView = root.findViewById(android.R.id.list);
            if (!(rawListView instanceof ExpandableListView)) {
                if (rawListView == null) {
                    throw new RuntimeException("Your content must have a ExpandableListView whose id attribute is " +
                            "'android.R.id.list'"); 
                } 
                throw new RuntimeException("Content has view with id attribute 'android.R.id.list' " +
                        "that is not a ExpandableListView class"); 
            } 
            mList = (ExpandableListView) rawListView;
            if (mEmptyView != null) {
                mList.setEmptyView(mEmptyView);
            } 
        } 
        mListShown = true;
        mList.setOnItemClickListener(mOnClickListener);
        if (mAdapter != null) {
            setListAdapter(mAdapter);
        } else { 
            // We are starting without an adapter, so assume we won't 
            // have our data right away and start with the progress indicator.