customize fastScroller(change overlay and scroller) for Android

gistfile1.java

// Activity sample
@Override
protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.main);

    TestAdapter adapter = new TestAdapter(getApplicationContext(), createBindDataList());
    ListView listView = (ListView) findViewById(R.id.listview);
    listView.setAdapter(adapter);

    // 高速スクローラ有効化設定
    listView.setFastScrollEnabled(true);

    // AbsListView#setFastScrollEnabled 直後に実行
    Drawable overlay = getResources().getDrawable(R.drawable.ic_launcher);
    Drawable scroller = getResources().getDrawable(R.drawable.ic_launcher);
    customizeFastScroller(listView, overlay, scroller);
}

/**
 * 高速スクローラカスタマイズ
 * @param listView 対象のAbsListView({@link AbsListView})
 * @param overlay overlay描画に使用するdrawable
 * @param scroller スクローラ描画に使用するdrawable
 */
private void customizeFastScroller(AbsListView listView, Drawable overlay, Drawable scroller) {
    try {
        // 新FastScrollerインスタンス生成
        Class<?> clazz = Class.forName("android.widget.FastScroller");
        Constructor<?> constructor = clazz.getConstructor(Context.class, AbsListView.class);
        Object newFastScroller = constructor.newInstance(this, listView);

        // ガイド用drawable(グレーの四角)を上書き
        Field fieldOverlay = clazz.getDeclaredField("mOverlayDrawable");
        fieldOverlay.setAccessible(true);
        fieldOverlay.set(newFastScroller, overlay);

        // スクローラ用drawableを上書き
        Field fieldThumb = clazz.getDeclaredField("mThumbDrawable");
        fieldThumb.setAccessible(true);
        fieldThumb.set(newFastScroller, scroller);

        // FastScrollerインスタンス(オリジナル)を上書き
        Field orgFastScroller = AbsListView.class.getDeclaredField("mFastScroller");
        orgFastScroller.setAccessible(true);
        orgFastScroller.set(listView, newFastScroller);

    } catch (Exception e) {
        e.printStackTrace();
    }
}

// 以下、ListView構築用

private List<BindData> createBindDataList() {
    List<BindData> list = new ArrayList<BindData>();
    for (int i = 0; i < ITEM_SIZE; i++) {
        list.add(new BindData("[" + i + "]"));
    }
    return list;
}

private static class TestAdapter extends ArrayAdapter<BindData> implements SectionIndexer {
    private LayoutInflater inflater;

    public TestAdapter(Context context, List<BindData> objects) {
        super(context, 0, objects);
        inflater = (LayoutInflater) getContext().getSystemService(Context.LAYOUT_INFLATER_SERVICE);
    }

    @Override
    public View getView(int position, View convertView, ViewGroup parent) {
        ViewHolder holder;
        if (convertView == null) {
            convertView = inflater.inflate(R.layout.list_item, null);
            holder = new ViewHolder();
            holder.textView = (TextView) convertView.findViewById(R.id.textView);
            convertView.setTag(holder);

        } else {
            holder = (ViewHolder) convertView.getTag();
        }

        // BindData反映
        BindData bindData = getItem(position);
        holder.textView.setText(bindData.getText());
        return convertView;
    }

    // SectionIndexer関連
    private static final String[] sections;
    static {
        sections = new String[ITEM_SIZE];
        for (int i = 0; i < ITEM_SIZE; i++) {
            sections[i] = "i=" + i;
        }
    }

    @Override
    public int getPositionForSection(int section) {
        return section;
    }

    @Override
    public int getSectionForPosition(int position) {
        return position;
    }

    @Override
    public Object[] getSections() {
        return sections;
    }
}

private static class ViewHolder {
    private TextView textView;
}

private static class BindData {
    private String text;

    public BindData(String text) {
        this.text = text;
    }

    public String getText() {
        return text;
    }

    @Override
    public String toString() {
        StringBuilder log = new StringBuilder();
        log.append("[");
        log.append("text=").append(text);
        log.append("]");
        return log.toString();
    }
}

list_item.xml

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:background="#64ffffff" >

    <TextView
        android:id="@+id/textView"
        android:layout_width="match_parent"
        android:layout_height="wrap_content" >
    </TextView>

</LinearLayout>