StaggeredGridLayoutManager


public class StaggeredGridLayoutManager extends RecyclerView.LayoutManager implements RecyclerView.SmoothScroller.ScrollVectorProvider


A LayoutManager that lays out children in a staggered grid formation. It supports horizontal &vertical layout as well as an ability to layout children in reverse.

Staggered grids are likely to have gaps at the edges of the layout. To avoid these gaps, StaggeredGridLayoutManager can offset spans independently or move items between spans. You can control this behavior via setGapStrategy.

Summary

Nested types

LayoutParams used by StaggeredGridLayoutManager.

Constants

static final int

This field is deprecated.

No longer supported.

static final int

When scroll state is changed to SCROLL_STATE_IDLE, StaggeredGrid will check if there are gaps in the because of full span items.

static final int

Does not do anything to hide gaps.

static final int
static final int

Public constructors

StaggeredGridLayoutManager(int spanCount, int orientation)

Creates a StaggeredGridLayoutManager with given parameters.

StaggeredGridLayoutManager(
    Context context,
    AttributeSet attrs,
    int defStyleAttr,
    int defStyleRes
)

Constructor used when layout manager is set in XML by RecyclerView attribute "layoutManager".

Public methods

void

Checks if RecyclerView is in the middle of a layout or scroll and throws an IllegalStateException if it is.

boolean

Query if horizontal scrolling is currently supported.

boolean

Query if vertical scrolling is currently supported.

boolean

Determines the validity of the supplied LayoutParams object.

int

Override this method if you want to support scroll bars.

int

Override this method if you want to support scroll bars.

int

Override this method if you want to support scroll bars.

PointF
computeScrollVectorForPosition(int targetPosition)

Should calculate the vector that points to the direction where the target position can be found.

int

Override this method if you want to support scroll bars.

int

Override this method if you want to support scroll bars.

int

Override this method if you want to support scroll bars.

int[]

Returns the adapter position of the first completely visible view for each span.

int[]

Returns the adapter position of the first visible view for each span.

int[]

Returns the adapter position of the last completely visible view for each span.

int[]

Returns the adapter position of the last visible view for each span.

RecyclerView.LayoutParams

Create a default LayoutParams object for a child of the RecyclerView.

RecyclerView.LayoutParams

Create a LayoutParams object suitable for this LayoutManager, copying relevant values from the supplied LayoutParams object if possible.

RecyclerView.LayoutParams

Create a LayoutParams object suitable for this LayoutManager from an inflated layout resource.

int

Returns the number of columns for accessibility.

int

Returns the current gap handling strategy for StaggeredGridLayoutManager.

int
boolean

Returns whether views are laid out in reverse order or not.

int

Returns the number of rows for accessibility.

int

Returns the number of spans laid out by StaggeredGridLayoutManager.

void

For consistency, StaggeredGridLayoutManager keeps a mapping between spans and items.

boolean

Returns whether the measuring pass of layout should use the AutoMeasure mechanism of RecyclerView or if it should be done by the LayoutManager's implementation of onMeasure.

boolean

Query if the layout is in reverse order.

void

Offset all child views attached to the parent RecyclerView by dx pixels along the horizontal axis.

void

Offset all child views attached to the parent RecyclerView by dy pixels along the vertical axis.

void

Called if the RecyclerView this LayoutManager is bound to has a different adapter set via setAdapter or swapAdapter.

void

Called when this LayoutManager is detached from its parent RecyclerView or when its parent RecyclerView is detached from its window.

@Nullable View
onFocusSearchFailed(
    View focused,
    int direction,
    RecyclerView.Recycler recycler,
    RecyclerView.State state
)

Called when searching for a focusable view in the given direction has failed for the current content of the RecyclerView.

void
void

Called by the AccessibilityDelegate when the information about the current layout should be populated.

void

Called by the AccessibilityDelegate when the accessibility information for a specific item should be populated.

void
onItemsAdded(
    RecyclerView recyclerView,
    int positionStart,
    int itemCount
)

Called when items have been added to the adapter.

void

Called in response to a call to notifyDataSetChanged or swapAdapter ()} and signals that the the entire data set has changed.

void
onItemsMoved(RecyclerView recyclerView, int from, int to, int itemCount)

Called when an item is moved withing the adapter.

void
onItemsRemoved(
    RecyclerView recyclerView,
    int positionStart,
    int itemCount
)

Called when items have been removed from the adapter.

void
onItemsUpdated(
    RecyclerView recyclerView,
    int positionStart,
    int itemCount,
    Object payload
)

Called when items have been changed in the adapter and with optional payload.

void

Lay out all relevant child views from the given adapter.

void

Called after a full layout calculation is finished.

void

Called when the RecyclerView is ready to restore the state based on a previous RecyclerView.

Parcelable

Called when the LayoutManager should save its state.

void

RecyclerView calls this method to notify LayoutManager that scroll state has changed.

int
scrollHorizontallyBy(
    int dx,
    RecyclerView.Recycler recycler,
    RecyclerView.State state
)

Scroll horizontally by dx pixels in screen coordinates and return the distance traveled.

void
scrollToPosition(int position)

Scroll to the specified adapter position.

void
scrollToPositionWithOffset(int position, int offset)

Scroll to the specified adapter position with the given offset from layout start.

int
scrollVerticallyBy(
    int dy,
    RecyclerView.Recycler recycler,
    RecyclerView.State state
)

Scroll vertically by dy pixels in screen coordinates and return the distance traveled.

void
setGapStrategy(int gapStrategy)

Sets the gap handling strategy for StaggeredGridLayoutManager.

void
setMeasuredDimension(Rect childrenBounds, int wSpec, int hSpec)

Sets the measured dimensions from the given bounding box of the children and the measurement specs that were passed into onMeasure.

void
setOrientation(int orientation)

Sets the orientation of the layout.

void
setReverseLayout(boolean reverseLayout)

Sets whether LayoutManager should start laying out items from the end of the UI.

void
setSpanCount(int spanCount)

Sets the number of spans for the layout.

void
smoothScrollToPosition(
    RecyclerView recyclerView,
    RecyclerView.State state,
    int position
)

Smooth scroll to the specified adapter position.

boolean

Returns whether this LayoutManager supports "predictive item animations".

Inherited methods

From androidx.recyclerview.widget.RecyclerView.LayoutManager
void

To be called only during onLayoutChildren to add a view to the layout that is known to be going away, either because it has been removed or because it is actually not in the visible portion of the container but is being laid out in order to inform RecyclerView in how to animate the item out of view.

void
addDisappearingView(View child, int index)

To be called only during onLayoutChildren to add a view to the layout that is known to be going away, either because it has been removed or because it is actually not in the visible portion of the container but is being laid out in order to inform RecyclerView in how to animate the item out of view.

void
addView(View child)

Add a view to the currently attached RecyclerView if needed.

void
addView(View child, int index)

Add a view to the currently attached RecyclerView if needed.

void

Checks if RecyclerView is in the middle of a layout or scroll and throws an IllegalStateException if it is not.

void

Reattach a previously detached view.

void
attachView(@NonNull View child, int index)

Reattach a previously detached view.

void
attachView(@NonNull View child, int index, RecyclerView.LayoutParams lp)

Reattach a previously detached view.

void
calculateItemDecorationsForChild(
    @NonNull View child,
    @NonNull Rect outRect
)

Calculates the item decor insets applied to the given child and updates the provided Rect instance with the inset values.

static int
chooseSize(int spec, int desired, int min)

Chooses a size from the given specs and parameters that is closest to the desired size and also complies with the spec.

void
collectInitialPrefetchPositions(
    int adapterItemCount,
    RecyclerView.LayoutManager.LayoutPrefetchRegistry layoutPrefetchRegistry
)

Gather all positions from the LayoutManager to be prefetched in preperation for its RecyclerView to come on screen, due to the movement of another, containing RecyclerView.

void

Temporarily detach and scrap all currently attached child views.

void
detachAndScrapView(
    @NonNull View child,
    @NonNull RecyclerView.Recycler recycler
)

Detach a child view and add it to a Recycler's scrap heap.

void

Detach a child view and add it to a Recycler's scrap heap.

void

Temporarily detach a child view.

void
detachViewAt(int index)

Temporarily detach a child view.

void

Ends all animations on the view created by the ItemAnimator.

@Nullable View

Traverses the ancestors of the given view and returns the item view that contains it and also a direct child of the LayoutManager.

@Nullable View
findViewByPosition(int position)

Finds the view which represents the given adapter position.

int

Returns offset of the RecyclerView's text baseline from the its top boundary.

int

Returns the total height of item decorations applied to child's bottom.

@Nullable View
getChildAt(int index)

Return the child view at the given index

int

Return the current number of child views attached to the parent RecyclerView.

static int
getChildMeasureSpec(
    int parentSize,
    int padding,
    int childDimension,
    boolean canScroll
)

This method is deprecated.

use getChildMeasureSpec

static int
getChildMeasureSpec(
    int parentSize,
    int parentMode,
    int padding,
    int childDimension,
    boolean canScroll
)

Calculate a MeasureSpec value for measuring a child view in one dimension.

boolean

Check if the RecyclerView is configured to clip child views to its padding.

int

Returns the bottom edge of the given child view within its parent, offset by any applied ItemDecorations.

void

Returns the bounds of the view including its decoration and margins.

int

Returns the left edge of the given child view within its parent, offset by any applied ItemDecorations.

int

Returns the measured height of the given child, plus the additional size of any insets applied by ItemDecorations.

int

Returns the measured width of the given child, plus the additional size of any insets applied by ItemDecorations.

int

Returns the right edge of the given child view within its parent, offset by any applied ItemDecorations.

int

Returns the top edge of the given child view within its parent, offset by any applied ItemDecorations.

@Nullable View

Returns the item View which has or contains focus.

@Px int

Returns the height that is currently relevant to the LayoutManager.

int

Return the height measurement spec mode that is currently relevant to the LayoutManager.

int

Returns the number of items in the adapter bound to the parent RecyclerView.

int

Returns the View type defined by the adapter.

int

Returns the resolved layout direction for this RecyclerView.

int

Returns the total width of item decorations applied to child's left.

@Px int
@Px int
@Px int

Return the bottom padding of the parent RecyclerView

@Px int

Return the end padding of the parent RecyclerView

@Px int

Return the left padding of the parent RecyclerView

@Px int

Return the right padding of the parent RecyclerView

@Px int

Return the start padding of the parent RecyclerView

@Px int

Return the top padding of the parent RecyclerView

int

Returns the adapter position of the item represented by the given View.

static RecyclerView.LayoutManager.Properties
getProperties(
    @NonNull Context context,
    @Nullable AttributeSet attrs,
    int defStyleAttr,
    int defStyleRes
)

Parse the xml attributes to get the most common properties used by layout managers.

int

Returns the total width of item decorations applied to child's right.

int

Returns the selection mode for accessibility.

int

Returns the total height of item decorations applied to child's top.

void
getTransformedBoundingBox(
    @NonNull View child,
    boolean includeDecorInsets,
    @NonNull Rect out
)

Calculates the bounding box of the View while taking into account its matrix changes (translation, scale etc) with respect to the RecyclerView.

@Px int

Returns the width that is currently relevant to the LayoutManager.

int

Return the width measurement spec mode that is currently relevant to the LayoutManager.

boolean

Returns true if the RecyclerView this LayoutManager is bound to has or contains focus.

void

Flags a view so that it will not be scrapped or recycled.

boolean

Returns whether LayoutManager is currently attached to a RecyclerView which is attached to a window.

boolean

Returns true if the RecyclerView this LayoutManager is bound to has focus.

final boolean

Sets whether the LayoutManager should be queried for views outside of its viewport while the UI thread is idle between frames.

boolean

Returns whether layout is hierarchical or not to be used for accessibility.

boolean

In addition to the View Framework's measurement cache, RecyclerView uses its own additional measurement cache for its children to avoid re-measuring them when not necessary.

boolean
boolean
isViewPartiallyVisible(
    @NonNull View child,
    boolean completelyVisible,
    boolean acceptEndPointInclusion
)

Returns whether the given child view is partially or fully visible within the padded bounded area of RecyclerView, depending on the input parameters.

void
layoutDecorated(
    @NonNull View child,
    int left,
    int top,
    int right,
    int bottom
)

Lay out the given child view within the RecyclerView using coordinates that include any current ItemDecorations.

void
layoutDecoratedWithMargins(
    @NonNull View child,
    int left,
    int top,
    int right,
    int bottom
)

Lay out the given child view within the RecyclerView using coordinates that include any current ItemDecorations and margins.

void
measureChild(@NonNull View child, int widthUsed, int heightUsed)

Measure a child view using standard measurement policy, taking the padding of the parent RecyclerView and any added item decorations into account.

void
measureChildWithMargins(
    @NonNull View child,
    int widthUsed,
    int heightUsed
)

Measure a child view using standard measurement policy, taking the padding of the parent RecyclerView, any added item decorations and the child margins into account.

void
moveView(int fromIndex, int toIndex)

Moves a View from one position to another.

boolean
onAddFocusables(
    @NonNull RecyclerView recyclerView,
    @NonNull ArrayList<View> views,
    int direction,
    int focusableMode
)

Called to populate focusable views within the RecyclerView.

void

Called when this LayoutManager is both attached to a RecyclerView and that RecyclerView is attached to a window.

void

This method is deprecated.

override onDetachedFromWindow

void

Called by the accessibility delegate to initialize an accessibility event.

@Nullable View
onInterceptFocusSearch(@NonNull View focused, int direction)

This method gives a LayoutManager an opportunity to intercept the initial focus search before the default behavior of FocusFinder is used.

void
onItemsUpdated(
    @NonNull RecyclerView recyclerView,
    int positionStart,
    int itemCount
)

Called when items have been changed in the adapter.

void
onMeasure(
    @NonNull RecyclerView.Recycler recycler,
    @NonNull RecyclerView.State state,
    int widthSpec,
    int heightSpec
)

Measure the attached RecyclerView.

boolean
onRequestChildFocus(
    @NonNull RecyclerView parent,
    @NonNull View child,
    @Nullable View focused
)

This method is deprecated.

Use onRequestChildFocus

boolean
onRequestChildFocus(
    @NonNull RecyclerView parent,
    @NonNull RecyclerView.State state,
    @NonNull View child,
    @Nullable View focused
)

Called when a descendant view of the RecyclerView requests focus.

boolean
performAccessibilityAction(
    @NonNull RecyclerView.Recycler recycler,
    @NonNull RecyclerView.State state,
    int action,
    @Nullable Bundle args
)

Called by AccessibilityDelegate when an action is requested from the RecyclerView.

boolean
performAccessibilityActionForItem(
    @NonNull RecyclerView.Recycler recycler,
    @NonNull RecyclerView.State state,
    @NonNull View view,
    int action,
    @Nullable Bundle args
)

Called by AccessibilityDelegate when an accessibility action is requested on one of the children of LayoutManager.

void

Causes the Runnable to execute on the next animation time step.

void

Remove all views from the currently attached RecyclerView.

void

Removes all views and recycles them using the given recycler.

void
removeAndRecycleView(
    @NonNull View child,
    @NonNull RecyclerView.Recycler recycler
)

Remove a child view and recycle it using the given Recycler.

void
removeAndRecycleViewAt(
    int index,
    @NonNull RecyclerView.Recycler recycler
)

Remove a child view and recycle it using the given Recycler.

boolean

Removes the specified Runnable from the message queue.

void

Finish removing a view that was previously temporarily detached.

void

Remove a view from the currently attached RecyclerView if needed.

void
removeViewAt(int index)

Remove a view from the currently attached RecyclerView if needed.

boolean
requestChildRectangleOnScreen(
    @NonNull RecyclerView parent,
    @NonNull View child,
    @NonNull Rect rect,
    boolean immediate
)

Called when a child of the RecyclerView wants a particular rectangle to be positioned onto the screen.

boolean
requestChildRectangleOnScreen(
    @NonNull RecyclerView parent,
    @NonNull View child,
    @NonNull Rect rect,
    boolean immediate,
    boolean focusedChildVisible
)

Requests that the given child of the RecyclerView be positioned onto the screen.

void

Calls RecyclerView#requestLayout on the underlying RecyclerView

void

A LayoutManager can call this method to force RecyclerView to run simple animations in the next layout pass, even if there is not any trigger to do so.

void
setAutoMeasureEnabled(boolean enabled)

This method is deprecated.

Implementors of LayoutManager should define whether or not it uses AutoMeasure by overriding isAutoMeasureEnabled.

final void
setItemPrefetchEnabled(boolean enabled)

Sets whether the LayoutManager should be queried for views outside of its viewport while the UI thread is idle between frames.

void
setMeasuredDimension(int widthSize, int heightSize)

Set the measured dimensions of the host RecyclerView.

void
setMeasurementCacheEnabled(boolean measurementCacheEnabled)

Sets whether RecyclerView should use its own measurement cache for the children.

void

Starts a smooth scroll using the provided SmoothScroller.

void

View can be scrapped and recycled again.

Constants

GAP_HANDLING_LAZY

Added in 1.0.0
Deprecated in 1.0.0
public static final int GAP_HANDLING_LAZY = 1

GAP_HANDLING_MOVE_ITEMS_BETWEEN_SPANS

Added in 1.0.0
public static final int GAP_HANDLING_MOVE_ITEMS_BETWEEN_SPANS = 2

When scroll state is changed to SCROLL_STATE_IDLE, StaggeredGrid will check if there are gaps in the because of full span items. If it finds, it will re-layout and move items to correct positions with animations.

For example, if LayoutManager ends up with the following layout due to adapter changes:

AAA
_BC
DDD

It will animate to the following state:

AAA
BC_
DDD

GAP_HANDLING_NONE

Added in 1.0.0
public static final int GAP_HANDLING_NONE = 0

Does not do anything to hide gaps.

HORIZONTAL

Added in 1.0.0
public static final int HORIZONTAL = 0

VERTICAL

Added in 1.0.0
public static final int VERTICAL = 1

Public constructors

StaggeredGridLayoutManager

Added in 1.0.0
public StaggeredGridLayoutManager(int spanCount, int orientation)

Creates a StaggeredGridLayoutManager with given parameters.

Parameters
int spanCount

If orientation is vertical, spanCount is number of columns. If orientation is horizontal, spanCount is number of rows.

int orientation

VERTICAL or HORIZONTAL

StaggeredGridLayoutManager

Added in 1.0.0
public StaggeredGridLayoutManager(
    Context context,
    AttributeSet attrs,
    int defStyleAttr,
    int defStyleRes
)

Constructor used when layout manager is set in XML by RecyclerView attribute "layoutManager". Defaults to single column and vertical.

Public methods

assertNotInLayoutOrScroll

public void assertNotInLayoutOrScroll(String message)

Checks if RecyclerView is in the middle of a layout or scroll and throws an IllegalStateException if it is.

Parameters
String message

The message for the exception. Can be null.

canScrollHorizontally

public boolean canScrollHorizontally()

Query if horizontal scrolling is currently supported. The default implementation returns false.

Returns
boolean

True if this LayoutManager can scroll the current contents horizontally

canScrollVertically

public boolean canScrollVertically()

Query if vertical scrolling is currently supported. The default implementation returns false.

Returns
boolean

True if this LayoutManager can scroll the current contents vertically

checkLayoutParams

public boolean checkLayoutParams(RecyclerView.LayoutParams lp)

Determines the validity of the supplied LayoutParams object.

This should check to make sure that the object is of the correct type and all values are within acceptable ranges. The default implementation returns true for non-null params.

Parameters
RecyclerView.LayoutParams lp

LayoutParams object to check

Returns
boolean

true if this LayoutParams object is valid, false otherwise

computeHorizontalScrollExtent

public int computeHorizontalScrollExtent(RecyclerView.State state)

Override this method if you want to support scroll bars.

Read computeHorizontalScrollExtent for details.

Default implementation returns 0.

Parameters
RecyclerView.State state

Current state of RecyclerView

Returns
int

The horizontal extent of the scrollbar's thumb

computeHorizontalScrollOffset

public int computeHorizontalScrollOffset(RecyclerView.State state)

Override this method if you want to support scroll bars.

Read computeHorizontalScrollOffset for details.

Default implementation returns 0.

Parameters
RecyclerView.State state

Current State of RecyclerView where you can find total item count

Returns
int

The horizontal offset of the scrollbar's thumb

computeHorizontalScrollRange

public int computeHorizontalScrollRange(RecyclerView.State state)

Override this method if you want to support scroll bars.

Read computeHorizontalScrollRange for details.

Default implementation returns 0.

Parameters
RecyclerView.State state

Current State of RecyclerView where you can find total item count

Returns
int

The total horizontal range represented by the horizontal scrollbar

computeScrollVectorForPosition

Added in 1.4.0
public PointF computeScrollVectorForPosition(int targetPosition)

Should calculate the vector that points to the direction where the target position can be found.

This method is used by the LinearSmoothScroller to initiate a scroll towards the target position.

The magnitude of the vector is not important. It is always normalized before being used by the