AndroidFastScroll-kt

Fast scroll for Android RecyclerView.

• This is a Kotlin rewrite of AndroidFastScroll with better popup position.

Contents

• Why AndroidFastScroll-kt?
• Preview
• Integration
• Usage
• License

Why AndroidFastScroll-kt?

• Fully customizable: Override track, thumb, popup, animation and scrolling.
• Easy-to-use defaults: Predefined default style, Material Design 1 style and animation.
• Better popup position: Considers adjacent items instead of first visible item, enhancing the popup position during fast scrolling for a more intuitive user experience.
• Extensive view support: Out-of-box support for RecyclerView, ScrollView, NestedScrollView and WebView, plus any view with a ViewHelper implementation.
• Window insets friendly: Support setting a separate padding for scrollbar.
• Clean implementation: Decoupled touch handling, animation and scrolling logic.

Preview

preview.mp4

Default style	Material Design 1 style

Integration

1. In settings.gradle

• Kotlin:

dependencyResolutionManagement {
    repositoriesMode.set(RepositoriesMode.FAIL_ON_PROJECT_REPOS)
    repositories {
        // .. other stuff ..
        maven("https://jitpack.io")
    }
}

• Groovy:

dependencyResolutionManagement {
    repositoriesMode.set(RepositoriesMode.FAIL_ON_PROJECT_REPOS)
    repositories {
        // .. other stuff ..
        maven { url 'https://jitpack.io' }
    }
}

2. In app build.gradle

• Kotlin:

dependencies {
    // .. other stuff ..
    implementation("com.github.StellarSand:AndroidFastScroll-kt:v1.0.8")
}

• Groovy:

dependencies {
    // .. other stuff ..
    implementation 'com.github.StellarSand:AndroidFastScroll-kt:v1.0.8'
}

Usage

• Simply create a FastScroller as follows:

FastScrollerBuilder(recyclerView).build()

• To show a popup, implement PopupTextProvider in your RecyclerView.Adapter.

class RvAdapter(
  private val aListViewItems: ArrayList<RvData>
): RecyclerView.Adapter<RvAdapter.ListViewHolder>(), PopupTextProvider {

  // .... other code ....

  override fun getPopupText(view: View, position: Int): CharSequence {
    return aListViewItems[position].title.substring(0, 1)
  }

}

• For more customization, please use the methods on FastScrollerBuilder. Namely:

  • setViewHelper() - allows providing a custom ViewHelper to support more views.
  • setPopupTextProvider() - allows providing a custom PopupTextProvider if your RecyclerView.Adapter cannot implement that interface.
  • setPadding() - allows setting a custom padding for the scrollbar, instead of the padding of the view.
  • setTrackDrawable() and setThumbDrawable() - allow setting custom drawables for the scrollbar. The android:state_pressed state will be updated for them so you can use a selector. The track drawable needs to have an intrinsic width and the thumb drawable needs to have an intrinsic size, in order to allow proper touch event handling.
  • setPopupStyle() - allows customizing the popup view with a lambda that will receive the view.
  • setAnimationHelper() - allows providing a custom AnimationHelper to use an alternative scrollbar animation.
  • disableScrollbarAutoHide() - allows disabling the auto hide animation for scrollbar. This implies using a DefaultAnimationHelper.
  • useDefaultStyle() and useMd1Style() - allow using the predefined styles, which sets the drawables and popup style. useDefaultStyle(), as its name suggests, is the default style when a FastScrollerBuilder is created.

• The default ViewHelper implementation for RecyclerView supports both LinearLayoutManager and GridLayoutManager, but assumes that each item has the same height when calculating scroll, as there's no common way to deal with variable item height. If you know how to measure for scrolling in your specific case, you can provide your own ViewHelper implementation and fast scroll will work correctly again.

• If you are using any RecyclerView.ItemDecoration that implements onDrawOver(), you might be interested in FixItemDecorationRecyclerView which can fix the drawing order.

• If you are using any other library that makes use of RecyclerView.OnItemTouchListener (e.g. recyclerview-selection), you might be interested in FixOnItemTouchListenerRecyclerView which can correctly handle cancellations when dispatching touch events to listeners. You may also want to configure this library before others so that this library can take precedence in touch event handling.

License

This project is licensed under the terms of Apache v2.0 license.