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Fix horizontal margins #82

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52e2d01
:art: Reformat code
Maxr1998 Nov 5, 2023
ca29e14
:bug: Fix incorrect layouting of children with margins
Maxr1998 Nov 5, 2023
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148 changes: 87 additions & 61 deletions library/src/main/java/com/bekawestberg/loopinglayout/library/LoopingLayoutManager.kt
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Original file line number Diff line number Diff line change
Expand Up @@ -61,19 +61,21 @@ open class LoopingLayoutManager : LayoutManager, RecyclerView.SmoothScroller.Scr
*/
public val layoutWidth: Int
get() = width - paddingLeft - paddingRight

/**
* The height of the layout - not the recycler.
* AKA the height of the recycler, minus the padding on the top and bottom.
*/
public val layoutHeight: Int
get() = height - paddingTop - paddingBottom

/** Describes the adapter index of the view in the top/left -most position. */
public var topLeftIndex = 0
private set
private set

/** Describes the adapter index of the view in the bottom/right -most position. */
public var bottomRightIndex = 0
private set
private set

/**
* The adapter index of the view at the edge of the layout where the 0th item was
Expand All @@ -93,16 +95,21 @@ open class LoopingLayoutManager : LayoutManager, RecyclerView.SmoothScroller.Scr
* When the layout manager needs to scroll to a position (via smooth scrolling) it needs some
* method to decide which movement direction to scroll in. This variable stores that method.
*/
public var smoothScrollDirectionDecider: (Int, LoopingLayoutManager, Int) -> Int = ::defaultDecider

public var smoothScrollDirectionDecider: (Int, LoopingLayoutManager, Int) -> Int =
::defaultDecider

/**
* Creates a LoopingLayout manager with the given orientation and reverse layout option.
* @param context Current context, will be used to access resources.
* @param orientation Layout orientation. Should be [HORIZONTAL] or [VERTICAL].
* @param reverseLayout When set to true, lays out items in the opposite direction from default.
*/
@JvmOverloads
public constructor(context: Context, orientation: Int = VERTICAL, reverseLayout: Boolean = false) {
public constructor(
context: Context,
orientation: Int = VERTICAL,
reverseLayout: Boolean = false
) {
this.orientation = orientation
this.reverseLayout = reverseLayout
}
Expand Down Expand Up @@ -166,8 +173,10 @@ open class LoopingLayoutManager : LayoutManager, RecyclerView.SmoothScroller.Scr
}

public override fun generateDefaultLayoutParams(): LayoutParams {
return LayoutParams(ViewGroup.LayoutParams.WRAP_CONTENT,
ViewGroup.LayoutParams.WRAP_CONTENT)
return LayoutParams(
ViewGroup.LayoutParams.WRAP_CONTENT,
ViewGroup.LayoutParams.WRAP_CONTENT
)
}

public override fun onSaveInstanceState(): Parcelable? {
Expand All @@ -178,8 +187,9 @@ open class LoopingLayoutManager : LayoutManager, RecyclerView.SmoothScroller.Scr
null
} else {
LayoutRequest(
anchorIndex = getInitialIndex(direction),
scrollOffset = getInitialItem(direction).hiddenSize)
anchorIndex = getInitialIndex(direction),
scrollOffset = getInitialItem(direction).hiddenSize
)
}
}

Expand All @@ -189,7 +199,10 @@ open class LoopingLayoutManager : LayoutManager, RecyclerView.SmoothScroller.Scr
}
}

public override fun onLayoutChildren(recycler: RecyclerView.Recycler, state: RecyclerView.State) {
public override fun onLayoutChildren(
recycler: RecyclerView.Recycler,
state: RecyclerView.State
) {
layoutRequest.initialize(this, state)

detachAndScrapAttachedViews(recycler)
Expand All @@ -207,10 +220,12 @@ open class LoopingLayoutManager : LayoutManager, RecyclerView.SmoothScroller.Scr
val view = createViewForIndex(index, movementDir, recycler)
val item = getItemForView(movementDir, view)
var layoutRect = getNonScrollingEdges(view)
layoutRect = prevItem?.getPositionOfItemFollowingSelf(item, layoutRect) ?:
item.getPositionOfSelfAsFirst(layoutRect, layoutRequest.scrollOffset)
layoutDecorated(view, layoutRect.left, layoutRect.top,
layoutRect.right, layoutRect.bottom)
layoutRect = prevItem?.getPositionOfItemFollowingSelf(item, layoutRect)
?: item.getPositionOfSelfAsFirst(layoutRect, layoutRequest.scrollOffset)
layoutDecoratedWithMargins(
view, layoutRect.left, layoutRect.top,
layoutRect.right, layoutRect.bottom
)

index = stepIndex(index, movementDir, state, false)
sizeFilled += item.size
Expand Down Expand Up @@ -290,23 +305,27 @@ open class LoopingLayoutManager : LayoutManager, RecyclerView.SmoothScroller.Scr
val newItem = getItemForView(movementDir, newView)
var layoutRect = getNonScrollingEdges(newView)
layoutRect = selectedItem.getPositionOfItemFollowingSelf(newItem, layoutRect)
layoutDecorated(newView, layoutRect.left, layoutRect.top,
layoutRect.right, layoutRect.bottom)
layoutDecoratedWithMargins(
newView, layoutRect.left, layoutRect.top,
layoutRect.right, layoutRect.bottom
)
selectedItem = newItem
}
}

// The amount of extra (i.e not visible) space currently covered by views.
var viewSpace = selectedItem.hiddenSize
while(viewSpace < extraLayoutSpace) {
while (viewSpace < extraLayoutSpace) {
// We don't want the topLeftIndex or bottomRightIndex to reflect non-visible views.
index = stepIndex(index, movementDir, state, updateIndex = false)
val newView = createViewForIndex(index, movementDir, recycler)
val newItem = getItemForView(movementDir, newView)
var layoutRect = getNonScrollingEdges(newView)
layoutRect = selectedItem.getPositionOfItemFollowingSelf(newItem, layoutRect)
layoutDecorated(newView, layoutRect.left, layoutRect.top,
layoutRect.right, layoutRect.bottom)
layoutDecoratedWithMargins(
newView, layoutRect.left, layoutRect.top,
layoutRect.right, layoutRect.bottom
)
selectedItem = newItem
viewSpace += selectedItem.size
}
Expand Down Expand Up @@ -414,10 +433,10 @@ open class LoopingLayoutManager : LayoutManager, RecyclerView.SmoothScroller.Scr
* newest view. This functionality can be disabled by passing "false" to the [updateIndex] parameter.
*/
private fun stepIndex(
index: Int,
movementDir: Int,
state: RecyclerView.State,
updateIndex: Boolean = true
index: Int,
movementDir: Int,
state: RecyclerView.State,
updateIndex: Boolean = true
): Int {
val adapterDirection = getAdapterDirectionFromMovementDirection(movementDir)
val count = state.itemCount
Expand All @@ -435,7 +454,7 @@ open class LoopingLayoutManager : LayoutManager, RecyclerView.SmoothScroller.Scr
}
isTowardsTopLeft && isTowardsLowerIndices -> {
newIndex = index.loopedDecrement(count)
if (updateIndex) topLeftIndex = newIndex
if (updateIndex) topLeftIndex = newIndex
}
isTowardsBottomRight && isTowardsHigherIndices -> {
newIndex = index.loopedIncrement(count)
Expand Down Expand Up @@ -505,7 +524,7 @@ open class LoopingLayoutManager : LayoutManager, RecyclerView.SmoothScroller.Scr
val range = if (movementDir == TOWARDS_TOP_LEFT) {
0 until childCount
} else {
childCount-1 downTo 0
childCount - 1 downTo 0
}

// Ignore hidden views at the start of the range.
Expand All @@ -517,7 +536,7 @@ open class LoopingLayoutManager : LayoutManager, RecyclerView.SmoothScroller.Scr
foundVisibleView = true
}
distanceFromStart++
} else if (foundVisibleView){
} else if (foundVisibleView) {
viewsToRemove.add(i)
}
}
Expand All @@ -528,7 +547,7 @@ open class LoopingLayoutManager : LayoutManager, RecyclerView.SmoothScroller.Scr
removeAndRecycleViewAt(i, recycler)
}

if (viewsToRemove.count() == 0) {
if (viewsToRemove.isEmpty()) {
// If we didn't find anything that needed to be disposed, no indices need to be updated.
return
}
Expand Down Expand Up @@ -779,8 +798,8 @@ open class LoopingLayoutManager : LayoutManager, RecyclerView.SmoothScroller.Scr
* position.
*/
public fun findViewByPosition(
adapterIndex: Int,
strategy: (targetIndex: Int, layoutManager: LoopingLayoutManager) -> View?
adapterIndex: Int,
strategy: (targetIndex: Int, layoutManager: LoopingLayoutManager) -> View?
): View? {
return strategy(adapterIndex, this)
}
Expand Down Expand Up @@ -808,7 +827,7 @@ open class LoopingLayoutManager : LayoutManager, RecyclerView.SmoothScroller.Scr
var lowestIndex = Int.MAX_VALUE;
for (i in 0 until childCount) {
val view = getChildAt(i);
if (view != null && getPosition(view) < lowestIndex && viewIsVisible(view)) {
if (view != null && getPosition(view) < lowestIndex && viewIsVisible(view)) {
lowestIndex = getPosition(view)
}
}
Expand All @@ -822,7 +841,7 @@ open class LoopingLayoutManager : LayoutManager, RecyclerView.SmoothScroller.Scr
var lowestIndex = Int.MAX_VALUE;
for (i in 0 until childCount) {
val view = getChildAt(i);
if (view != null && getPosition(view) < lowestIndex && viewIsFullyVisible(view)) {
if (view != null && getPosition(view) < lowestIndex && viewIsFullyVisible(view)) {
lowestIndex = getPosition(view)
}
}
Expand All @@ -837,7 +856,7 @@ open class LoopingLayoutManager : LayoutManager, RecyclerView.SmoothScroller.Scr
var highestIndex = 0;
for (i in 0 until childCount) {
val view = getChildAt(i)
if (view != null && getPosition(view) > highestIndex && viewIsVisible(view)) {
if (view != null && getPosition(view) > highestIndex && viewIsVisible(view)) {
highestIndex = getPosition(view)
}
}
Expand All @@ -851,7 +870,7 @@ open class LoopingLayoutManager : LayoutManager, RecyclerView.SmoothScroller.Scr
var highestIndex = 0;
for (i in 0 until childCount) {
val view = getChildAt(i)
if (view != null && getPosition(view) > highestIndex && viewIsFullyVisible(view)) {
if (view != null && getPosition(view) > highestIndex && viewIsFullyVisible(view)) {
highestIndex = getPosition(view)
}
}
Expand Down Expand Up @@ -882,12 +901,12 @@ open class LoopingLayoutManager : LayoutManager, RecyclerView.SmoothScroller.Scr
* Note that this change will not be reflected until the next layout call.
*/
public fun scrollToPosition(
adapterIndex: Int,
strategy: (
targetIndex: Int,
layoutManager: LoopingLayoutManager,
itemCount: Int
) -> Int
adapterIndex: Int,
strategy: (
targetIndex: Int,
layoutManager: LoopingLayoutManager,
itemCount: Int
) -> Int
) {
if (viewWithIndexIsFullyVisible(adapterIndex)) return
layoutRequest = LayoutRequest(anchorIndex = adapterIndex, scrollStrategy = strategy)
Expand All @@ -909,9 +928,9 @@ open class LoopingLayoutManager : LayoutManager, RecyclerView.SmoothScroller.Scr
}

public override fun smoothScrollToPosition(
recyclerView: RecyclerView,
state: RecyclerView.State,
position: Int
recyclerView: RecyclerView,
state: RecyclerView.State,
position: Int
) {
val loopingSmoothScroller = LoopingSmoothScroller(recyclerView.context, state)
loopingSmoothScroller.targetPosition = position
Expand Down Expand Up @@ -987,7 +1006,7 @@ open class LoopingLayoutManager : LayoutManager, RecyclerView.SmoothScroller.Scr
get() = getDecoratedRight(view)

public override val size: Int
get() = getDecoratedMeasuredWidth(view)
get() = getDecoratedMeasuredWidthWithMargins(view)

public override fun getPositionOfItemFollowingSelf(item: ListItem, rect: Rect): Rect {
rect.left = followingEdge
Expand Down Expand Up @@ -1016,7 +1035,7 @@ open class LoopingLayoutManager : LayoutManager, RecyclerView.SmoothScroller.Scr
get() = getDecoratedBottom(view)

public override val size: Int
get() = getDecoratedMeasuredHeight(view)
get() = getDecoratedMeasuredHeightWithMargins(view)


public override fun getPositionOfItemFollowingSelf(item: ListItem, rect: Rect): Rect {
Expand Down Expand Up @@ -1044,7 +1063,7 @@ open class LoopingLayoutManager : LayoutManager, RecyclerView.SmoothScroller.Scr
get() = getDecoratedLeft(view)

public override val size: Int
get() = getDecoratedMeasuredWidth(view)
get() = getDecoratedMeasuredWidthWithMargins(view)

public override fun getPositionOfItemFollowingSelf(item: ListItem, rect: Rect): Rect {
rect.right = followingEdge
Expand All @@ -1071,7 +1090,7 @@ open class LoopingLayoutManager : LayoutManager, RecyclerView.SmoothScroller.Scr
get() = getDecoratedTop(view)

public override val size: Int
get() = getDecoratedMeasuredHeight(view)
get() = getDecoratedMeasuredHeightWithMargins(view)

public override fun getPositionOfItemFollowingSelf(item: ListItem, rect: Rect): Rect {
rect.bottom = followingEdge
Expand All @@ -1093,8 +1112,8 @@ open class LoopingLayoutManager : LayoutManager, RecyclerView.SmoothScroller.Scr
* a scroll vector.
*/
private inner class LoopingSmoothScroller(
val context: Context,
val state: RecyclerView.State
val context: Context,
val state: RecyclerView.State
) : LinearSmoothScroller(context) {

/**
Expand Down Expand Up @@ -1184,12 +1203,12 @@ open class LoopingLayoutManager : LayoutManager, RecyclerView.SmoothScroller.Scr
}

public constructor(
anchorIndex: Int = RecyclerView.NO_POSITION,
scrollOffset: Int = 0,
adapterDirection: Int = TOWARDS_LOWER_INDICES,
scrollStrategy: ((Int, LoopingLayoutManager, Int) -> Int)? = null,
layoutManager: LoopingLayoutManager? = null,
state: RecyclerView.State? = null
anchorIndex: Int = RecyclerView.NO_POSITION,
scrollOffset: Int = 0,
adapterDirection: Int = TOWARDS_LOWER_INDICES,
scrollStrategy: ((Int, LoopingLayoutManager, Int) -> Int)? = null,
layoutManager: LoopingLayoutManager? = null,
state: RecyclerView.State? = null
) : this() {
this.anchorIndex = anchorIndex
this.scrollOffset = scrollOffset
Expand All @@ -1199,8 +1218,9 @@ open class LoopingLayoutManager : LayoutManager, RecyclerView.SmoothScroller.Scr
if (layoutManager != null && state != null) initialize(layoutManager, state)

if (!hasBeenInitialized
&& anchorIndex != RecyclerView.NO_POSITION
&& scrollStrategy == null) {
&& anchorIndex != RecyclerView.NO_POSITION
&& scrollStrategy == null
) {
hasBeenInitialized = true
}
}
Expand All @@ -1213,16 +1233,19 @@ open class LoopingLayoutManager : LayoutManager, RecyclerView.SmoothScroller.Scr
hasBeenInitialized = true
// If this is executing a scrollTo, the anchorIndex will be set, but the
// adapterDirection still needs to be decided.
adapterDirection = scrollStrategy?.invoke(anchorIndex, layoutManager, state.itemCount)?.let {
layoutManager.getAdapterDirectionFromMovementDirection(it) }
adapterDirection =
scrollStrategy?.invoke(anchorIndex, layoutManager, state.itemCount)?.let {
layoutManager.getAdapterDirectionFromMovementDirection(it)
}
?: adapterDirection
// If this is an adapter data update, the adapterDirection will be set but the
// anchorIndex and scrollOffset still need to be decided.
if (anchorIndex == RecyclerView.NO_POSITION) {
if (layoutManager.childCount == 0) {
anchorIndex = 0
} else {
val direction = layoutManager.getMovementDirectionFromAdapterDirection(adapterDirection)
val direction =
layoutManager.getMovementDirectionFromAdapterDirection(adapterDirection)
anchorIndex = layoutManager.getInitialIndex(direction)
scrollOffset = layoutManager.getInitialItem(direction).hiddenSize
}
Expand Down Expand Up @@ -1276,6 +1299,7 @@ open class LoopingLayoutManager : LayoutManager, RecyclerView.SmoothScroller.Scr
* top/left.
*/
public const val TOWARDS_TOP_LEFT = -1

/**
* Describes the user scrolling towards the bottom/right of the screen. NOTE: this does
* *not* describe the direction views are moving in. The user is trying to see new views
Expand All @@ -1289,6 +1313,7 @@ open class LoopingLayoutManager : LayoutManager, RecyclerView.SmoothScroller.Scr
* indices.
*/
public const val TOWARDS_LOWER_INDICES = -1

/**
* Describes the direction we need to traverse view indices in to get to larger adapter indices.
* In this case we need to traverse the views forwards (0 -> Max) to get to higher adapter
Expand All @@ -1302,11 +1327,12 @@ open class LoopingLayoutManager : LayoutManager, RecyclerView.SmoothScroller.Scr
*
*/
private const val SCROLL_OFFSET = 100

/**
* A constant returned by the [computeScrollRange] function so that accessibility knows
* the layout is always scrollable.
*/
private const val SCROLL_RANGE = 200
}

}
}
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