Fast scroll in ListView

Sometimes when the list is very big, We need to make a fast scroll view. FastScroll is something like that:

Now we leart how to make a fast scroll in listView.
We need these things:

-Style in values-v14.
-Style.
-Colors.
-Layout.
-An adapter for list.
-Activity.

in directory values-v14/styles.xml we have to add three things:
fastScrollThumbDrawable
fastScrollTextColor
fastScrollPreviewBackgroundRight

<?xml version="1.0" encoding="utf-8"?>
<resources>
 
    <style name="AppTheme" parent="android:Theme.Holo.Light.DarkActionBar">
        <!-- API 14 theme customizations can go here. -->
        <item name="android:fastScrollThumbDrawable">@drawable/fastscroll_thumb_holo</item>
        <item name="android:fastScrollTextColor">@android:color/white</item>
        <item name="android:fastScrollPreviewBackgroundRight">@color/apptheme_color</item>
    </style>
 
</resources>

In directory values/styles.xml

<resources>
 
    <!-- Base application theme. -->
    <style name="AppTheme" parent="Theme.AppCompat.Light.DarkActionBar">
        <!-- Customize your theme here. -->
        <item name="colorPrimary">@color/colorPrimary</item>
        <item name="colorPrimaryDark">@color/colorPrimaryDark</item>
        <item name="colorAccent">@color/colorAccent</item>
        <item name="android:fastScrollThumbDrawable">@drawable/fastscroll_thumb_holo</item>
        <item name="android:fastScrollTextColor">@android:color/white</item>
        <item name="android:fastScrollPreviewBackgroundRight">@color/apptheme_color</item>
    </style>
 
</resources>

In Colors we have to add one color:

<?xml version="1.0" encoding="utf-8"?>
<resources>
    <color name="colorPrimary">#3F51B5</color>
    <color name="colorPrimaryDark">#303F9F</color>
    <color name="colorAccent">#FF4081</color>
    <color name="apptheme_color">#DA4A38</color>
</resources>

You can doing without style, so you can skip last steps, and start since here:

The color of the indicator is your colorAccent

You can find the complete code in GitHub

res/layout/list_item

<?xml version="1.0" encoding="utf-8"?>
<TextView xmlns:android="http://schemas.android.com/apk/res/android"
    android:layout_width="match_parent"
    android:layout_height="40dp" />

In activity_layout our listView.

<?xml version="1.0" encoding="utf-8"?>
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:tools="http://schemas.android.com/tools"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:paddingBottom="@dimen/activity_vertical_margin"
    android:paddingLeft="@dimen/activity_horizontal_margin"
    android:paddingRight="@dimen/activity_horizontal_margin"
    android:paddingTop="@dimen/activity_vertical_margin"
    tools:context="com.example.javier.fastscrollerwithandroidstyle.MainActivity">
 
    <ListView
        android:id="@+id/activity_main_list"
        android:layout_width="fill_parent"
        android:layout_height="fill_parent"
        android:scrollbarStyle="outsideOverlay" />
</RelativeLayout>

Our ListAdapter

public class ListAdapter extends ArrayAdapter<String> implements SectionIndexer {
 
    HashMap<String, Integer> mapIndex;
    String[] sections;
    List<String> fruits;
 
    public ListAdapter(Context context, List<String> fruitList) {
        super(context, R.layout.list_item, fruitList);
 
        this.fruits = fruitList;
        mapIndex = new LinkedHashMap<String, Integer>();
 
        for (int x = 0; x < fruits.size(); x++) {
            String fruit = fruits.get(x);
            String ch = fruit.substring(0, 1);
            ch = ch.toUpperCase(Locale.US);
 
            // HashMap will prevent duplicates
            mapIndex.put(ch, x);
        }
 
        Set<String> sectionLetters = mapIndex.keySet();
 
        // create a list from the set to sort
        ArrayList<String> sectionList = new ArrayList<String>(sectionLetters);
 
        Log.d("sectionList", sectionList.toString());
        Collections.sort(sectionList);
 
        sections = new String[sectionList.size()];
 
        sectionList.toArray(sections);
    }
 
    public int getPositionForSection(int section) {
        Log.d("section", "" + section);
        return mapIndex.get(sections[section]);
    }
 
    public int getSectionForPosition(int position) {
        Log.d("position", "" + position);
        return 0;
    }
 
    public Object[] getSections() {
        return sections;
    }
}

In our activity

public class MainActivity extends Activity {
 
    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
 
        ListView listView = (ListView) findViewById(R.id.activity_main_list);
        listView.setFastScrollEnabled(true);
        String[] fruits = getResources().getStringArray(R.array.fruits_array);
 
        List<String> fruitList = Arrays.asList(fruits);
        ListAdapter listAdapter = new ListAdapter(this, fruitList);
        listView.setAdapter(listAdapter);
 
    }
}

And in our strings, something like that:

<resources>
    <string name="app_name">FastScrollerWithAndroidStyle</string>
    <string-array name="fruits_array">
        <item>Apples</item>
        <item>Apricots</item>
        <item>Avocado</item>
        <item>Annona</item>
        <item>Banana</item>
        <item>Bilberry</item>
        <item>Blackberry</item>
        <item>Custard Apple</item>
        <item>Clementine</item>
        <item>Cantalope</item>
        <item>Coconut</item>
        <item>Currant</item>
        <item>Cherry</item>
        <item>Cherimoya</item>
        <item>Date</item>
        <item>Damson</item>
        <item>Durian</item>
        <item>Elderberry</item>
        <item>Fig</item>
        <item>Feijoa</item>
        <item>Grapefruit</item>
        <item>Grape</item>
        <item>Gooseberry</item>
        <item>Guava</item>
        <item>Honeydew melon</item>
        <item>Huckleberry</item>
        <item>Jackfruit</item>
        <item>Juniper Berry</item>
        <item>Jambul</item>
        <item>Jujube</item>
        <item>Kiwi</item>
        <item>Kumquat</item>
        <item>Lemons</item>
        <item>Limes</item>
        <item>Lychee</item>
        <item>Mango</item>
        <item>Mandarin</item>
        <item>Mangostine</item>
        <item>Nectaraine</item>
        <item>Orange</item>
        <item>Olive</item>
        <item>Prunes</item>
        <item>Pears</item>
        <item>Plum</item>
        <item>Pineapple</item>
        <item>Peach</item>
        <item>Papaya</item>
        <item>Passionfruit</item>
        <item>Pomegranate</item>
        <item>Pomelo</item>
        <item>Raspberries</item>
        <item>Rock melon</item>
        <item>Rambutan</item>
        <item>Strawberries</item>
        <item>Sweety</item>
        <item>Salmonberry</item>
        <item>Satsuma</item>
        <item>Tangerines</item>
        <item>Tomato</item>
        <item>Ugli</item>
        <item>Watermelon</item>
        <item>Woodapple</item>
    </string-array>
</resources>

You can find the complete code in GitHub