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BrowseFragment

public class BrowseFragment
extends BrandedFragment

java.lang.Object
   ↳ android.app.Fragment
     ↳ android.support.v17.leanback.app.BrandedFragment
       ↳ android.support.v17.leanback.app.BrowseFragment


A fragment for creating Leanback browse screens. It is composed of a RowsFragment and a HeadersFragment.

A BrowseFragment renders the elements of its ObjectAdapter as a set of rows in a vertical list. The elements in this adapter must be subclasses of Row.

The HeadersFragment can be set to be either shown or hidden by default, or may be disabled entirely. See setHeadersState(int) for details.

By default the BrowseFragment includes support for returning to the headers when the user presses Back. For Activities that customize onBackPressed(), you must disable this default Back key support by calling setHeadersTransitionOnBackEnabled(boolean) with false and use BrowseFragment.BrowseTransitionListener and startHeadersTransition(boolean).

The recommended theme to use with a BrowseFragment is Theme_Leanback_Browse.

Summary

Nested classes

class BrowseFragment.BrowseTransitionListener

Listener for transitions between browse headers and rows. 

class BrowseFragment.FragmentFactory<T extends Fragment>

Factory class responsible for creating fragment given the current item. 

interface BrowseFragment.FragmentHost

Possible set of actions that BrowseFragment exposes to clients. 

class BrowseFragment.ListRowFragmentFactory

FragmentFactory implementation for ListRow

class BrowseFragment.MainFragmentAdapter<T extends Fragment>

Interface that defines the interaction between BrowseFragment and it's main content fragment. 

interface BrowseFragment.MainFragmentAdapterProvider

Interface to be implemented by all fragments for providing an instance of BrowseFragment.MainFragmentAdapter

class BrowseFragment.MainFragmentAdapterRegistry

Registry class maintaining the mapping of Row subclasses to BrowseFragment.FragmentFactory

class BrowseFragment.MainFragmentRowsAdapter<T extends Fragment>

This is used to pass information to RowsFragment or its subclasses. 

interface BrowseFragment.MainFragmentRowsAdapterProvider

Interface to be implemented by RowsFragment and it's subclasses for providing an instance of BrowseFragment.MainFragmentRowsAdapter

Inherited XML attributes

From class android.app.Fragment

Constants

int HEADERS_DISABLED

The headers fragment is disabled and will never be shown.

int HEADERS_ENABLED

The headers fragment is enabled and shown by default.

int HEADERS_HIDDEN

The headers fragment is enabled and hidden by default.

Inherited constants

From interface android.content.ComponentCallbacks2

Public constructors

BrowseFragment()

Public methods

static Bundle createArgs(Bundle args, String title, int headersState)

Creates arguments for a browse fragment.

void enableMainFragmentScaling(boolean enable)

Enables scaling of main fragment when headers are present.

void enableRowScaling(boolean enable)

This method is deprecated. use enableMainFragmentScaling(boolean) instead.

ObjectAdapter getAdapter()

Returns the adapter containing the rows for the fragment.

int getBrandColor()

Returns the brand color for the browse fragment.

HeadersFragment getHeadersFragment()

Get currently bound HeadersFragment or null if HeadersFragment has not been created yet.

int getHeadersState()

Returns the state of the headers column in the browse fragment.

final BrowseFragment.MainFragmentAdapterRegistry getMainFragmentRegistry()
OnItemViewClickedListener getOnItemViewClickedListener()

Returns the item Clicked listener.

OnItemViewSelectedListener getOnItemViewSelectedListener()

Returns an item selection listener.

final ProgressBarManager getProgressBarManager()

Returns the ProgressBarManager.

RowsFragment getRowsFragment()

Get RowsFragment if it's bound to BrowseFragment or null if either BrowseFragment has not been created yet or a different fragment is bound to it.

int getSelectedPosition()

Gets position of currently selected row.

final boolean isHeadersTransitionOnBackEnabled()

Returns true if headers transition on back key support is enabled.

boolean isInHeadersTransition()

Returns true if the headers transition is currently running.

boolean isShowingHeaders()

Returns true if headers are shown.

void onCreate(Bundle savedInstanceState)

Called to do initial creation of a fragment.

View onCreateView(LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState)

Called to have the fragment instantiate its user interface view.

void onDestroy()

Called when the fragment is no longer in use.

void onDestroyView()

Called when the view previously created by onCreateView(LayoutInflater, ViewGroup, Bundle) has been detached from the fragment.

void onSaveInstanceState(Bundle outState)

Called to ask the fragment to save its current dynamic state, so it can later be reconstructed in a new instance of its process is restarted.

void onStart()

Called when the Fragment is visible to the user.

void onViewCreated(View view, Bundle savedInstanceState)

Called immediately after onCreateView(LayoutInflater, ViewGroup, Bundle) has returned, but before any saved state has been restored in to the view.

void prepareEntranceTransition()

Enables entrance transition.

void setAdapter(ObjectAdapter adapter)

Sets the adapter containing the rows for the fragment.

void setBrandColor(int color)

Sets the brand color for the browse fragment.

void setBrowseTransitionListener(BrowseFragment.BrowseTransitionListener listener)

Sets a listener for browse fragment transitions.

void setHeaderPresenterSelector(PresenterSelector headerPresenterSelector)

Sets the PresenterSelector used to render the row headers.

void setHeadersState(int headersState)

Sets the state for the headers column in the browse fragment.

final void setHeadersTransitionOnBackEnabled(boolean headersBackStackEnabled)

Enables/disables headers transition on back key support.

void setOnItemViewClickedListener(OnItemViewClickedListener listener)

Sets an item clicked listener on the fragment.

void setOnItemViewSelectedListener(OnItemViewSelectedListener listener)

Sets an item selection listener.

void setSelectedPosition(int position)

Sets the selected row position with smooth animation.

void setSelectedPosition(int rowPosition, boolean smooth, Presenter.ViewHolderTask rowHolderTask)

Selects a Row and perform an optional task on the Row.

void setSelectedPosition(int position, boolean smooth)

Sets the selected row position.

void startEntranceTransition()

When fragment finishes loading data, it should call startEntranceTransition() to execute the entrance transition.

void startHeadersTransition(boolean withHeaders)

Starts a headers transition.

Protected methods

Object createEntranceTransition()

Create entrance transition.

void onEntranceTransitionEnd()

Callback when entrance transition is ended.

void onEntranceTransitionPrepare()

Callback when entrance transition is prepared.

void onEntranceTransitionStart()

Callback when entrance transition is started.

void runEntranceTransition(Object entranceTransition)

Run entrance transition.

Inherited methods

From class android.support.v17.leanback.app.BrandedFragment
From class android.app.Fragment
From class java.lang.Object
From interface android.content.ComponentCallbacks2
From interface android.view.View.OnCreateContextMenuListener
From interface android.content.ComponentCallbacks

Constants

HEADERS_DISABLED

int HEADERS_DISABLED

The headers fragment is disabled and will never be shown.

Constant Value: 3 (0x00000003)

HEADERS_ENABLED

int HEADERS_ENABLED

The headers fragment is enabled and shown by default.

Constant Value: 1 (0x00000001)

HEADERS_HIDDEN

int HEADERS_HIDDEN

The headers fragment is enabled and hidden by default.

Constant Value: 2 (0x00000002)

Public constructors

BrowseFragment

BrowseFragment ()

Public methods

createArgs

Bundle createArgs (Bundle args, 
                String title, 
                int headersState)

Creates arguments for a browse fragment.

Parameters
args Bundle: The Bundle to place arguments into, or null if the method should return a new Bundle.
title String: The title of the BrowseFragment.
headersState int: The initial state of the headers of the BrowseFragment. Must be one of HEADERS_ENABLED, HEADERS_HIDDEN, or HEADERS_DISABLED.
Returns
Bundle A Bundle with the given arguments for creating a BrowseFragment.

enableMainFragmentScaling

void enableMainFragmentScaling (boolean enable)

Enables scaling of main fragment when headers are present. For the page/row fragment, scaling is enabled only when both this method and isScalingEnabled() are enabled.

Parameters
enable boolean: true to enable row scaling

enableRowScaling

void enableRowScaling (boolean enable)

This method is deprecated.
use enableMainFragmentScaling(boolean) instead.

Parameters
enable boolean: true to enable row scaling

getAdapter

ObjectAdapter getAdapter ()

Returns the adapter containing the rows for the fragment.

Returns
ObjectAdapter

getBrandColor

int getBrandColor ()

Returns the brand color for the browse fragment. The default is transparent.

Returns
int

getHeadersFragment

HeadersFragment getHeadersFragment ()

Get currently bound HeadersFragment or null if HeadersFragment has not been created yet.

Returns
HeadersFragment Currently bound HeadersFragment or null if HeadersFragment has not been created yet.

getHeadersState

int getHeadersState ()

Returns the state of the headers column in the browse fragment.

Returns
int

getMainFragmentRegistry

BrowseFragment.MainFragmentAdapterRegistry getMainFragmentRegistry ()

Returns
BrowseFragment.MainFragmentAdapterRegistry

getOnItemViewClickedListener

OnItemViewClickedListener getOnItemViewClickedListener ()

Returns the item Clicked listener.

Returns
OnItemViewClickedListener

getOnItemViewSelectedListener

OnItemViewSelectedListener getOnItemViewSelectedListener ()

Returns an item selection listener.

Returns
OnItemViewSelectedListener

getProgressBarManager

ProgressBarManager getProgressBarManager ()

Returns the ProgressBarManager.

Returns
ProgressBarManager

getRowsFragment

RowsFragment getRowsFragment ()

Get RowsFragment if it's bound to BrowseFragment or null if either BrowseFragment has not been created yet or a different fragment is bound to it.

Returns
RowsFragment RowsFragment if it's bound to BrowseFragment or null otherwise.

getSelectedPosition

int getSelectedPosition ()

Gets position of currently selected row.

Returns
int Position of currently selected row.

isHeadersTransitionOnBackEnabled

boolean isHeadersTransitionOnBackEnabled ()

Returns true if headers transition on back key support is enabled.

Returns
boolean

isInHeadersTransition

boolean isInHeadersTransition ()

Returns true if the headers transition is currently running.

Returns
boolean

isShowingHeaders

boolean isShowingHeaders ()

Returns true if headers are shown.

Returns
boolean

onCreate

void onCreate (Bundle savedInstanceState)

Called to do initial creation of a fragment. This is called after onAttach(Activity) and before onCreateView(LayoutInflater, ViewGroup, Bundle), but is not called if the fragment instance is retained across Activity re-creation (see setRetainInstance(boolean)).

Note that this can be called while the fragment's activity is still in the process of being created. As such, you can not rely on things like the activity's content view hierarchy being initialized at this point. If you want to do work once the activity itself is created, see onActivityCreated(Bundle).

If your app's targetSdkVersion is 23 or lower, child fragments being restored from the savedInstanceState are restored after onCreate returns. When targeting N or above and running on an N or newer platform version they are restored by Fragment.onCreate.

Parameters
savedInstanceState Bundle: If the fragment is being re-created from a previous saved state, this is the state.

onCreateView

View onCreateView (LayoutInflater inflater, 
                ViewGroup container, 
                Bundle savedInstanceState)

Called to have the fragment instantiate its user interface view. This is optional, and non-graphical fragments can return null (which is the default implementation). This will be called between onCreate(Bundle) and onActivityCreated(Bundle).

If you return a View from here, you will later be called in onDestroyView() when the view is being released.

Parameters
inflater LayoutInflater: The LayoutInflater object that can be used to inflate any views in the fragment,
container ViewGroup: If non-null, this is the parent view that the fragment's UI should be attached to. The fragment should not add the view itself, but this can be used to generate the LayoutParams of the view.
savedInstanceState Bundle: If non-null, this fragment is being re-constructed from a previous saved state as given here.
Returns
View Return the View for the fragment's UI, or null.

onDestroy

void onDestroy ()

Called when the fragment is no longer in use. This is called after onStop() and before onDetach().

onDestroyView

void onDestroyView ()

Called when the view previously created by onCreateView(LayoutInflater, ViewGroup, Bundle) has been detached from the fragment. The next time the fragment needs to be displayed, a new view will be created. This is called after onStop() and before onDestroy(). It is called regardless of whether onCreateView(LayoutInflater, ViewGroup, Bundle) returned a non-null view. Internally it is called after the view's state has been saved but before it has been removed from its parent.

onSaveInstanceState

void onSaveInstanceState (Bundle outState)

Called to ask the fragment to save its current dynamic state, so it can later be reconstructed in a new instance of its process is restarted. If a new instance of the fragment later needs to be created, the data you place in the Bundle here will be available in the Bundle given to onCreate(Bundle), onCreateView(LayoutInflater, ViewGroup, Bundle), and onActivityCreated(Bundle).

This corresponds to Activity.onSaveInstanceState(Bundle) and most of the discussion there applies here as well. Note however: this method may be called at any time before onDestroy(). There are many situations where a fragment may be mostly torn down (such as when placed on the back stack with no UI showing), but its state will not be saved until its owning activity actually needs to save its state.

Parameters
outState Bundle: Bundle in which to place your saved state.

onStart

void onStart ()

Called when the Fragment is visible to the user. This is generally tied to Activity.onStart of the containing Activity's lifecycle.

onViewCreated

void onViewCreated (View view, 
                Bundle savedInstanceState)

Called immediately after onCreateView(LayoutInflater, ViewGroup, Bundle) has returned, but before any saved state has been restored in to the view. This gives subclasses a chance to initialize themselves once they know their view hierarchy has been completely created. The fragment's view hierarchy is not however attached to its parent at this point.

Parameters
view View: The View returned by onCreateView(LayoutInflater, ViewGroup, Bundle).
savedInstanceState Bundle: If non-null, this fragment is being re-constructed from a previous saved state as given here.

prepareEntranceTransition

void prepareEntranceTransition ()

Enables entrance transition.

Entrance transition is the standard slide-in transition that shows rows of data in browse screen and details screen.

The method is ignored before LOLLIPOP (API21).

This method must be called in or before onCreate(). Typically entrance transition should be enabled when savedInstance is null so that fragment restored from instanceState does not run an extra entrance transition. When the entrance transition is enabled, the fragment will make headers and content hidden initially. When data of rows are ready, app must call startEntranceTransition() to kick off the transition, otherwise the rows will be invisible forever.

It is similar to android:windowsEnterTransition and can be considered a late-executed android:windowsEnterTransition controlled by app. There are two reasons that app needs it:

  • Workaround the problem that activity transition is not available between launcher and app. Browse activity must programmatically start the slide-in transition.
  • Separates DetailsOverviewRow transition from other rows transition. So that the DetailsOverviewRow transition can be executed earlier without waiting for all rows to be loaded.
  • Transition object is returned by createEntranceTransition(). Typically the app does not need override the default transition that browse and details provides.

    setAdapter

    void setAdapter (ObjectAdapter adapter)

    Sets the adapter containing the rows for the fragment.

    The items referenced by the adapter must be be derived from Row. These rows will be used by the rows fragment and the headers fragment (if not disabled) to render the browse rows.

    Parameters
    adapter ObjectAdapter: An ObjectAdapter for the browse rows. All items must derive from Row.

    setBrandColor

    void setBrandColor (int color)

    Sets the brand color for the browse fragment. The brand color is used as the primary color for UI elements in the browse fragment. For example, the background color of the headers fragment uses the brand color.

    Parameters
    color int: The color to use as the brand color of the fragment.

    setBrowseTransitionListener

    void setBrowseTransitionListener (BrowseFragment.BrowseTransitionListener listener)

    Sets a listener for browse fragment transitions.

    Parameters
    listener BrowseFragment.BrowseTransitionListener: The listener to call when a browse headers transition begins or ends.

    setHeaderPresenterSelector

    void setHeaderPresenterSelector (PresenterSelector headerPresenterSelector)

    Sets the PresenterSelector used to render the row headers.

    Parameters
    headerPresenterSelector PresenterSelector: The PresenterSelector that will determine the Presenter for each row header.

    setHeadersState

    void setHeadersState (int headersState)

    Sets the state for the headers column in the browse fragment. Must be one of HEADERS_ENABLED, HEADERS_HIDDEN, or HEADERS_DISABLED.

    Parameters
    headersState int: The state of the headers for the browse fragment.

    setHeadersTransitionOnBackEnabled

    void setHeadersTransitionOnBackEnabled (boolean headersBackStackEnabled)

    Enables/disables headers transition on back key support. This is enabled by default. The BrowseFragment will add a back stack entry when headers are showing. Running a headers transition when the back key is pressed only works when the headers state is HEADERS_ENABLED or HEADERS_HIDDEN.

    NOTE: If an Activity has its own onBackPressed() handling, you must disable this feature. You may use startHeadersTransition(boolean) and BrowseFragment.BrowseTransitionListener in your own back stack handling.

    Parameters
    headersBackStackEnabled boolean

    setOnItemViewClickedListener

    void setOnItemViewClickedListener (OnItemViewClickedListener listener)

    Sets an item clicked listener on the fragment. OnItemViewClickedListener will override View.OnClickListener that item presenter sets during onCreateViewHolder(ViewGroup). So in general, developer should choose one of the listeners but not both.

    Parameters
    listener OnItemViewClickedListener

    setOnItemViewSelectedListener

    void setOnItemViewSelectedListener (OnItemViewSelectedListener listener)

    Sets an item selection listener.

    Parameters
    listener OnItemViewSelectedListener

    setSelectedPosition

    void setSelectedPosition (int position)

    Sets the selected row position with smooth animation.

    Parameters
    position int

    setSelectedPosition

    void setSelectedPosition (int rowPosition, 
                    boolean smooth, 
                    Presenter.ViewHolderTask rowHolderTask)

    Selects a Row and perform an optional task on the Row. For example setSelectedPosition(10, true, new ListRowPresenterSelectItemViewHolderTask(5)) scrolls to 11th row and selects 6th item on that row. The method will be ignored if RowsFragment has not been created (i.e. before onCreateView(LayoutInflater, ViewGroup, Bundle)).

    Parameters
    rowPosition int: Which row to select.
    smooth boolean: True to scroll to the row, false for no animation.
    rowHolderTask Presenter.ViewHolderTask: Optional task to perform on the Row. When the task is not null, headers fragment will be collapsed.

    setSelectedPosition

    void setSelectedPosition (int position, 
                    boolean smooth)

    Sets the selected row position.

    Parameters
    position int
    smooth boolean

    startEntranceTransition

    void startEntranceTransition ()

    When fragment finishes loading data, it should call startEntranceTransition() to execute the entrance transition. startEntranceTransition() will start transition only if both two conditions are satisfied:

  • prepareEntranceTransition() was called.
  • has not executed entrance transition yet.
  • If startEntranceTransition() is called before onViewCreated(), it will be pending and executed when view is created.

    startHeadersTransition

    void startHeadersTransition (boolean withHeaders)

    Starts a headers transition.

    This method will begin a transition to either show or hide the headers, depending on the value of withHeaders. If headers are disabled for this browse fragment, this method will throw an exception.

    Parameters
    withHeaders boolean: True if the headers should transition to being shown, false if the transition should result in headers being hidden.

    Protected methods

    createEntranceTransition

    Object createEntranceTransition ()

    Create entrance transition. Subclass can override to load transition from resource or construct manually. Typically app does not need to override the default transition that browse and details provides.

    Returns
    Object

    onEntranceTransitionEnd

    void onEntranceTransitionEnd ()

    Callback when entrance transition is ended.

    onEntranceTransitionPrepare

    void onEntranceTransitionPrepare ()

    Callback when entrance transition is prepared. This is when fragment should stop user input and animations.

    onEntranceTransitionStart

    void onEntranceTransitionStart ()

    Callback when entrance transition is started. This is when fragment should stop processing layout.

    runEntranceTransition

    void runEntranceTransition (Object entranceTransition)

    Run entrance transition. Subclass may use TransitionManager to perform go(Scene) or beginDelayedTransition(). App should not override the default implementation of browse and details fragment.

    Parameters
    entranceTransition Object

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