RecyclerView-FastScroll

A simple FastScroller for Android's RecyclerView.

Supports vertical RecyclerViews using either LinearLayoutManager or GridLayoutManager (including multiple spans).

The style is loosely based on the ListView FastScroller from whatever the last version of Lollipop was. This library borrows heavily from Google's Launcher3 FastScroller

Gradle

compile 'com.simplecityapps:recyclerview-fastscroll:2.0.1'

Usage

You must use FastScrollRecyclerView as your base RecyclerView. See the sample project if you're having trouble.

Via xml:

<com.simplecityapps.recyclerview_fastscroll.views.FastScrollRecyclerView
    android:id="@+id/recycler"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    app:fastScrollPopupBgColor="@color/colorAccent"
    app:fastScrollPopupTextColor="@android:color/primary_text_dark"
    app:fastScrollThumbColor="@color/colorAccent" />

To display the FastScrollPopup, your adapter must implement FastScrollRecyclerView.SectionedAdapter and override getSectionName().

If you need to know when fast-scrolling starts or stops, you can attach an OnFastScrollStateChangedListener to the FastScrollRecyclerView.

Varying Row Heights

By default, FastScrollRecyclerView assumes that all items in the adapter have the same height. If your adapter has item views with different heights, then you should make your adapter implement the MeasurableAdapter interface and override getViewTypeHeight() – otherwise the scroll thumb may not appear in the correct position and scrolling may be inconsistent.

getViewTypeHeight() returns the height of a single view of a given type in pixels. The height of each view must be fixed and constant between all instances of a view type. Because the implementor is responsible for computing this value before views are laid out, this is not suitable for view types where the height of a view is determined by a variable number of lines of text that the item consumes.

Currently, MeasurableAdapter only works with LinearLayoutManager. Using MeasurableAdapter with a GridLayoutManager that has more than one span will cause the scrollbar thumb to reach the bottom of the list before the halfway point on the scrollbar's background.

Customisation

You can enable/disable autohide using the fastScrollAutoHide & fastScrollAutoHideDelay attributes in xml:

 <com.simplecityapps.recyclerview_fastscroll.views.FastScrollRecyclerView
     app:fastScrollAutoHide="true"
     app:fastScrollAutoHideDelay="1500"
     ...

Or programmatically via setAutoHideDelay(int hideDelay) and setAutoHideEnabled(boolean autoHideEnabled)

The following can be styled via xml:

• Popup background
• Popup text
• Popup background size
• Popup text size
• Track width and background
• Thumb width and color
• Popup position
• Popup text vertical alignment mode

<com.simplecityapps.recyclerview_fastscroll.views.FastScrollRecyclerView
    app:fastScrollPopupBgColor="@color/colorAccent"
    app:fastScrollPopupTextColor="@android:color/primary_text_dark"
    app:fastScrollPopupTextSize="56sp"
    app:fastScrollPopupBackgroundSize="88dp"
    app:fastScrollThumbColor="@color/colorAccent"
    app:fastScrollThumbWidth="6dp"
    app:fastScrollTrackColor="#1f000000"
    app:fastScrollTrackWidth="8dp"
    app:fastScrollPopupPosition="adjacent"
    app:fastScrollPopupTextVerticalAlignmentMode="fontMetrics"/>
    ...

Or programmatically via

• setThumbColor(@ColorInt int color)
• setTrackColor(@ColorInt int color)
• setPopupBgColor(@ColorInt int color)
• setPopupTextColor(@ColorInt int color)
• setPopupTextSize(int size)
• setPopupPosition(@FastScroller.FastScrollerPopupPosition int position)

You can enable/disable fast-scrolling via:

<com.simplecityapps.recyclerview_fastscroll.views.FastScrollRecyclerView
    app:fastScrollThumbEnabled="false"
    ...

Or programmatically via setFastScrollThumbEnabled(boolean enabled)