OnboardingSupportFragment

abstract class OnboardingSupportFragment : Fragment
kotlin.Any
   ↳ androidx.fragment.app.Fragment
   ↳ androidx.leanback.app.OnboardingSupportFragment

An OnboardingSupportFragment provides a common and simple way to build onboarding screen for applications.

Building the screen The view structure of onboarding screen is composed of the common parts and custom parts. The common parts are composed of icon, title, description and page navigator and the custom parts are composed of background, contents and foreground.

To build the screen views, the inherited class should override:

  • onCreateBackgroundView to provide the background view. Background view has the same size as the screen and the lowest z-order.
  • onCreateContentView to provide the contents view. The content view is located in the content area at the center of the screen.
  • onCreateForegroundView to provide the foreground view. Foreground view has the same size as the screen and the highest z-order

Each of these methods can return null if the application doesn't want to provide it.

Page information The onboarding screen may have several pages which explain the functionality of the application. The inherited class should provide the page information by overriding the methods:

Note that the information is used in onCreateView, so should be initialized before calling super.onCreateView.

Animation Onboarding screen has three kinds of animations:

Logo Splash Animation When onboarding screen appears, the logo splash animation is played by default. The animation fades in the logo image, pauses in a few seconds and fades it out.

In most cases, the logo animation needs to be customized because the logo images of applications are different from each other, or some applications may want to show their own animations.

The logo animation can be customized in two ways:

If the inherited class provides neither the logo image nor the animation, the logo animation will be omitted.

Page enter animation After logo animation finishes, page enter animation starts, which causes the header section - title and description views to fade and slide in. Users can override the default fade + slide animation by overriding onCreateTitleAnimator() & onCreateDescriptionAnimator(). By default we don't animate the custom views but users can provide animation by overriding onCreateEnterAnimation. Page change animation When the page changes, the default animations of the title and description are played. The inherited class can override onPageChanged to start the custom animations.

Finishing the screen

If the user finishes the onboarding screen after navigating all the pages, onFinishFragment is called. The inherited class can override this method to show another fragment or activity, or just remove this fragment.

Theming

OnboardingSupportFragment must have access to an appropriate theme. Specifically, the fragment must receive R.style#Theme_Leanback_Onboarding, or a theme whose parent is set to that theme. Themes can be provided in one of three ways:

  • The simplest way is to set the theme for the host Activity to the Onboarding theme or a theme that derives from it.
  • If the Activity already has a theme and setting its parent theme is inconvenient, the existing Activity theme can have an entry added for the attribute R.styleable#LeanbackOnboardingTheme_onboardingTheme. If present, this theme will be used by OnboardingSupportFragment as an overlay to the Activity's theme.
  • Finally, custom subclasses of OnboardingSupportFragment may provide a theme through the onProvideTheme method. This can be useful if a subclass is used across multiple Activities.

If the theme is provided in multiple ways, the onProvideTheme override has priority, followed by the Activity's theme. (Themes whose parent theme is already set to the onboarding theme do not need to set the onboardingTheme attribute; if set, it will be ignored.) R.attr#onboardingTheme R.attr#onboardingHeaderStyle R.attr#onboardingTitleStyle R.attr#onboardingDescriptionStyle R.attr#onboardingNavigatorContainerStyle R.attr#onboardingPageIndicatorStyle R.attr#onboardingStartButtonStyle R.attr#onboardingLogoStyle

Summary

Public constructors

An OnboardingSupportFragment provides a common and simple way to build onboarding screen for applications.

Public methods
open Unit

Sets the background color of the dots.

Int

Returns the resource id of the main icon.

open Unit

Sets the text on the start button text.

Int

Returns the color of the arrow if it's set through setArrowColor(int).

Int

Returns the text color of TitleView if it's set through setTitleViewTextColor(int).

open Unit

Sets the color of the arrow.

Int

Returns the background color of the dot if it's set through setDotBackgroundColor(int).

open Unit

Sets the text color for TitleView.

open Int

Returns the theme used for styling the fragment.

open Unit
onViewCreated(@NonNull view: View, @Nullable savedInstanceState: Bundle?)

open Unit

Sets the background color of the arrow.

Unit

Sets the resource ID of the splash logo image.

Unit
setIconResouceId(resourceId: Int)

Sets the resource id for the main icon.

CharSequence!

Returns the start button text if it's set through setStartButtonText(CharSequence)}.

open Unit

open Unit

Sets the text color for DescriptionView.

open View?
onCreateView(inflater: LayoutInflater, container: ViewGroup?, savedInstanceState: Bundle?)

Int

Returns the resource ID of the splash logo image.

Int

Returns the text color of DescriptionView if it's set through setDescriptionViewTextColor(int).

Int

Returns the background color of the arrow if it's set through setArrowBackgroundColor(int).

Protected methods
Unit

Called to start entrance transition.

open Animator!

Provides the entry animation for title view.

abstract CharSequence!
getPageTitle(pageIndex: Int)

Returns the title of the given page.

abstract CharSequence!
getPageDescription(pageIndex: Int)

Returns the description of the given page.

abstract View?

Called to have the inherited class create foreground view.

open Unit

Navigates to the next page.

Int

Returns the index of the current page.

abstract View?

Called to have the inherited class create background view.

open Unit

Navigates to the previous page.

open Animator!

Provides the entry animation for description view.

open Unit

Called when the onboarding flow finishes.

abstract Int

Returns the page count.

open Unit

Called immediately after the logo animation is complete or no logo animation is specified.

open Unit
onPageChanged(newPage: Int, previousPage: Int)

Called when the page has been changed.

Boolean

Returns whether the logo enter animation is finished.

abstract View?
onCreateContentView(inflater: LayoutInflater!, container: ViewGroup!)

Called to have the inherited class create content view.

open Animator?

Called to have the inherited class create its enter animation.

open Animator?

Called to have the inherited class create its own logo animation.

Inherited functions

Public constructors

<init>

OnboardingSupportFragment()

An OnboardingSupportFragment provides a common and simple way to build onboarding screen for applications.

Building the screen The view structure of onboarding screen is composed of the common parts and custom parts. The common parts are composed of icon, title, description and page navigator and the custom parts are composed of background, contents and foreground.

To build the screen views, the inherited class should override:

  • onCreateBackgroundView to provide the background view. Background view has the same size as the screen and the lowest z-order.
  • onCreateContentView to provide the contents view. The content view is located in the content area at the center of the screen.
  • onCreateForegroundView to provide the foreground view. Foreground view has the same size as the screen and the highest z-order

Each of these methods can return null if the application doesn't want to provide it.

Page information The onboarding screen may have several pages which explain the functionality of the application. The inherited class should provide the page information by overriding the methods:

Note that the information is used in onCreateView, so should be initialized before calling super.onCreateView.

Animation Onboarding screen has three kinds of animations:

Logo Splash Animation When onboarding screen appears, the logo splash animation is played by default. The animation fades in the logo image, pauses in a few seconds and fades it out.

In most cases, the logo animation needs to be customized because the logo images of applications are different from each other, or some applications may want to show their own animations.

The logo animation can be customized in two ways:

If the inherited class provides neither the logo image nor the animation, the logo animation will be omitted.

Page enter animation After logo animation finishes, page enter animation starts, which causes the header section - title and description views to fade and slide in. Users can override the default fade + slide animation by overriding onCreateTitleAnimator() & onCreateDescriptionAnimator(). By default we don't animate the custom views but users can provide animation by overriding onCreateEnterAnimation. Page change animation When the page changes, the default animations of the title and description are played. The inherited class can override onPageChanged to start the custom animations.

Finishing the screen

If the user finishes the onboarding screen after navigating all the pages, onFinishFragment is called. The inherited class can override this method to show another fragment or activity, or just remove this fragment.

Theming

OnboardingSupportFragment must have access to an appropriate theme. Specifically, the fragment must receive R.style#Theme_Leanback_Onboarding, or a theme whose parent is set to that theme. Themes can be provided in one of three ways:

  • The simplest way is to set the theme for the host Activity to the Onboarding theme or a theme that derives from it.
  • If the Activity already has a theme and setting its parent theme is inconvenient, the existing Activity theme can have an entry added for the attribute R.styleable#LeanbackOnboardingTheme_onboardingTheme. If present, this theme will be used by OnboardingSupportFragment as an overlay to the Activity's theme.
  • Finally, custom subclasses of OnboardingSupportFragment may provide a theme through the onProvideTheme method. This can be useful if a subclass is used across multiple Activities.

If the theme is provided in multiple ways, the onProvideTheme override has priority, followed by the Activity's theme. (Themes whose parent theme is already set to the onboarding theme do not need to set the onboardingTheme attribute; if set, it will be ignored.) R.attr#onboardingTheme R.attr#onboardingHeaderStyle R.attr#onboardingTitleStyle R.attr#onboardingDescriptionStyle R.attr#onboardingNavigatorContainerStyle R.attr#onboardingPageIndicatorStyle R.attr#onboardingStartButtonStyle R.attr#onboardingLogoStyle

Public methods

setDotBackgroundColor

open fun setDotBackgroundColor(color: Int): Unit

Sets the background color of the dots. If not set, the default color from attr R.styleable#PagingIndicator_dotBgColor in the theme will be used.

Parameters
color Int: the color to use for dot backgrounds

getIconResourceId

fun getIconResourceId(): Int

Returns the resource id of the main icon.

setStartButtonText

open fun setStartButtonText(text: CharSequence!): Unit

Sets the text on the start button text. If not set, the default text set in R.styleable#LeanbackOnboardingTheme_onboardingStartButtonStyle will be used.

Parameters
text CharSequence!: the start button text

getArrowColor

fun getArrowColor(): Int

Returns the color of the arrow if it's set through setArrowColor(int). If no color was set, transparent is returned.

getTitleViewTextColor

fun getTitleViewTextColor(): Int

Returns the text color of TitleView if it's set through setTitleViewTextColor(int). If no color was set, transparent is returned.

setArrowColor

open fun setArrowColor(color: Int): Unit

Sets the color of the arrow. This color will supersede the color set in the theme attribute R.styleable#PagingIndicator_arrowColor if provided. If none of these two are set, the arrow will have its original bitmap color.

Parameters
color Int: the color to use for arrow background

getDotBackgroundColor

fun getDotBackgroundColor(): Int

Returns the background color of the dot if it's set through setDotBackgroundColor(int). If no color was set, transparent is returned.

setTitleViewTextColor

open fun setTitleViewTextColor(color: Int): Unit

Sets the text color for TitleView. If not set, the default textColor set in style referenced by attr R.attr#onboardingTitleStyle will be used.

Parameters
color Int: the color to use as the text color for TitleView

onProvideTheme

open fun onProvideTheme(): Int

Returns the theme used for styling the fragment. The default returns -1, indicating that the host Activity's theme should be used.

Return
Int: The theme resource ID of the theme to use in this fragment, or -1 to use the host Activity's theme.

onViewCreated

open fun onViewCreated(@NonNull view: View, @Nullable savedInstanceState: Bundle?): Unit

setArrowBackgroundColor

open fun setArrowBackgroundColor(color: Int): Unit

Sets the background color of the arrow. If not set, the default color from attr R.styleable#PagingIndicator_arrowBgColor in the theme will be used.

Parameters
color Int: the color to use for arrow background

setLogoResourceId

fun setLogoResourceId(id: Int): Unit

Sets the resource ID of the splash logo image. If the logo resource id set, the default logo splash animation will be played.

Parameters
id Int: The resource ID of the logo image.

setIconResouceId

fun setIconResouceId(resourceId: Int): Unit

Sets the resource id for the main icon.

getStartButtonText

fun getStartButtonText(): CharSequence!

Returns the start button text if it's set through setStartButtonText(CharSequence)}. If no string was set, null is returned.

onSaveInstanceState

open fun onSaveInstanceState(outState: Bundle): Unit

setDescriptionViewTextColor

open fun setDescriptionViewTextColor(color: Int): Unit

Sets the text color for DescriptionView. If not set, the default textColor set in style referenced by attr R.attr#onboardingDescriptionStyle will be used.

Parameters
color Int: the color to use as the text color for DescriptionView

onCreateView

@Nullable open fun onCreateView(inflater: LayoutInflater, container: ViewGroup?, savedInstanceState: Bundle?): View?

getLogoResourceId

fun getLogoResourceId(): Int

Returns the resource ID of the splash logo image.

Return
Int: The resource ID of the splash logo image.

getDescriptionViewTextColor

fun getDescriptionViewTextColor(): Int

Returns the text color of DescriptionView if it's set through setDescriptionViewTextColor(int). If no color was set, transparent is returned.

getArrowBackgroundColor

fun getArrowBackgroundColor(): Int

Returns the background color of the arrow if it's set through setArrowBackgroundColor(int). If no color was set, transparent is returned.

Protected methods

startEnterAnimation

protected fun startEnterAnimation(force: Boolean): Unit

Called to start entrance transition. This can be called by subclasses when the logo animation and data loading is complete. If force flag is set to false, it will only start the animation if it's not already done yet. Otherwise, it will always start the enter animation. In both cases, the logo view will hide and the rest of fragment views become visible after this call.

Parameters
force Boolean: true if enter animation has to be performed regardless of whether it's been done in the past, false otherwise

onCreateTitleAnimator

protected open fun onCreateTitleAnimator(): Animator!

Provides the entry animation for title view. This allows users to override the default fade and slide animation. Returning null will disable the animation.

getPageTitle

protected abstract fun getPageTitle(pageIndex: Int): CharSequence!

Returns the title of the given page.

Parameters
pageIndex Int: The page index.
Return
CharSequence!: The title of the page.

getPageDescription

protected abstract fun getPageDescription(pageIndex: Int): CharSequence!

Returns the description of the given page.

Parameters
pageIndex Int: The page index.
Return
CharSequence!: The description of the page.

onCreateForegroundView

@Nullable protected abstract fun onCreateForegroundView(inflater: LayoutInflater!, container: ViewGroup!): View?

Called to have the inherited class create foreground view. This is optional and the fragment which doesn't need the foreground view can return null. This is called inside onCreateView.

This foreground view would have the highest z-order.

Parameters
inflater LayoutInflater!: The LayoutInflater object that can be used to inflate the views,
container LayoutInflater!: The parent view that the additional views are attached to.The fragment should not add the view by itself.
Return
View?: The foreground view for the onboarding screen, or null.

moveToNextPage

protected open fun moveToNextPage(): Unit

Navigates to the next page.

getCurrentPageIndex

protected fun getCurrentPageIndex(): Int

Returns the index of the current page.

Return
Int: The index of the current page.

onCreateBackgroundView

@Nullable protected abstract fun onCreateBackgroundView(inflater: LayoutInflater!, container: ViewGroup!): View?

Called to have the inherited class create background view. This is optional and the fragment which doesn't have the background view can return null. This is called inside onCreateView.

Parameters
inflater LayoutInflater!: The LayoutInflater object that can be used to inflate the views,
container LayoutInflater!: The parent view that the additional views are attached to.The fragment should not add the view by itself.
Return
View?: The background view for the onboarding screen, or null.

moveToPreviousPage

protected open fun moveToPreviousPage(): Unit

Navigates to the previous page.

onCreateDescriptionAnimator

protected open fun onCreateDescriptionAnimator(): Animator!

Provides the entry animation for description view. This allows users to override the default fade and slide animation. Returning null will disable the animation.

onFinishFragment

protected open fun onFinishFragment(): Unit

Called when the onboarding flow finishes.

getPageCount

protected abstract fun getPageCount(): Int

Returns the page count.

Return
Int: The page count.

onLogoAnimationFinished

protected open fun onLogoAnimationFinished(): Unit

Called immediately after the logo animation is complete or no logo animation is specified. This method can also be called when the activity is recreated, i.e. when no logo animation are performed. By default, this method will hide the logo view and start the entrance animation for this fragment. Overriding subclasses can provide their own data loading logic as to when the entrance animation should be executed.

onPageChanged

protected open fun onPageChanged(newPage: Int, previousPage: Int): Unit

Called when the page has been changed.

Parameters
newPage Int: The new page.
previousPage Int: The previous page.

isLogoAnimationFinished

protected fun isLogoAnimationFinished(): Boolean

Returns whether the logo enter animation is finished.

Return
Boolean: true if the logo enter transition is finished, false otherwise

onCreateContentView

@Nullable protected abstract fun onCreateContentView(inflater: LayoutInflater!, container: ViewGroup!): View?

Called to have the inherited class create content view. This is optional and the fragment which doesn't have the content view can return null. This is called inside onCreateView.

The content view would be located at the center of the screen.

Parameters
inflater LayoutInflater!: The LayoutInflater object that can be used to inflate the views,
container LayoutInflater!: The parent view that the additional views are attached to.The fragment should not add the view by itself.
Return
View?: The content view for the onboarding screen, or null.

onCreateEnterAnimation

@Nullable protected open fun onCreateEnterAnimation(): Animator?

Called to have the inherited class create its enter animation. The start animation runs after logo animation ends.

Return
Animator?: The Animator object which runs the page enter animation.

onCreateLogoAnimation

@Nullable protected open fun onCreateLogoAnimation(): Animator?

Called to have the inherited class create its own logo animation.

This is called only if the logo image resource ID is not set by setLogoResourceId. If this returns null, the logo animation is skipped.

Return
Animator?: The Animator object which runs the logo animation.