/// <summary>
/// Measure the layout and its content to determine the measured width and the measured height.<br />
/// If this method is overridden, it is the subclass's responsibility to make
/// sure the measured height and width are at least the layout's minimum height
/// and width. <br />
/// </summary>
/// <param name="widthMeasureSpec">horizontal space requirements as imposed by the parent.</param>
/// <param name="heightMeasureSpec">vertical space requirements as imposed by the parent.</param>
protected override void OnMeasure(MeasureSpecification widthMeasureSpec, MeasureSpecification heightMeasureSpec)
{
LayoutLength measuredWidth = new LayoutLength(0.0f);
LayoutLength measuredHeight = new LayoutLength(0.0f);
// Layout takes size of largest child width and largest child height dimensions
foreach (LayoutItem childLayout in _children)
{
if (childLayout != null)
{
MeasureChild(childLayout, widthMeasureSpec, heightMeasureSpec);
LayoutLength childWidth = new LayoutLength(childLayout.MeasuredWidth.Size);
LayoutLength childHeight = new LayoutLength(childLayout.MeasuredHeight.Size);
Extents childMargin = childLayout.Margin;
measuredWidth = new LayoutLength(Math.Max(measuredWidth.AsDecimal(), childWidth.AsDecimal() + childMargin.Start + childMargin.End));
measuredHeight = new LayoutLength(Math.Max(measuredHeight.AsDecimal(), childHeight.AsDecimal() + childMargin.Top + childMargin.Bottom));
}
}
if (0 == _children.Count)
{
// Must be a leaf as has no children
measuredWidth = GetDefaultSize(SuggestedMinimumWidth, widthMeasureSpec);
measuredHeight = GetDefaultSize(SuggestedMinimumHeight, heightMeasureSpec);
}
SetMeasuredDimensions(new MeasuredSize(measuredWidth, MeasuredSize.StateType.MeasuredSizeOK),
new MeasuredSize(measuredHeight, MeasuredSize.StateType.MeasuredSizeOK));
}
/// <summary>
/// Utility to return a default size.<br />
/// Uses the supplied size if the MeasureSpecification imposed no constraints. Will get larger if allowed by the
/// MeasureSpecification.<br />
/// </summary>
/// <param name="size"> Default size for this layout.</param>
/// <param name="measureSpecification"> Constraints imposed by the parent.</param>
/// <returns>The size this layout should be.</returns>
/// <since_tizen> 6 </since_tizen>
public static LayoutLength GetDefaultSize(LayoutLength size, MeasureSpecification measureSpecification)
{
LayoutLength result = size;
MeasureSpecification.ModeType specMode = measureSpecification.Mode;
LayoutLength specSize = measureSpecification.Size;
switch (specMode)
{
case MeasureSpecification.ModeType.Unspecified:
{
result = size;
break;
}
case MeasureSpecification.ModeType.AtMost:
{
// Ensure the default size does not exceed the spec size unless the default size is 0.
// Another container could provide a default size of 0.
// Do not set size to 0, use specSize in this case as could be a legacy container
if ((size.AsDecimal() < specSize.AsDecimal()) && (size.AsDecimal() > 0))
{
result = size;
}
else
{
result = specSize;
}
break;
}
case MeasureSpecification.ModeType.Exactly:
{
result = specSize;
break;
}
}
return(result);
}
private void ReInitLocationsWithExpand(ref float[] locations, LayoutLength parentSize)
{
bool isHorizontal = (locations == hLocations);
Node[] edgeList = isHorizontal ? hEdgeList : vEdgeList;
int maxIndex = isHorizontal ? maxColumnConut : maxRowCount;
float space = isHorizontal ? ColumnSpacing : RowSpacing;
float totalExpand = isHorizontal ? totalHorizontalExpand : totalVerticalExpand;
float parentDecimalSize = parentSize.AsDecimal();
float maxExpandedSize = parentDecimalSize * LayoutChildren.Count;
float minExpandedSize = 0;
float newChildrenSize = locations[maxIndex] - locations[0] - space;
// No available sapce
if (newChildrenSize > parentDecimalSize)
{
return;
}
// binary search for finding maximum expanded size.
while ((int)(newChildrenSize + 0.5) != (int)parentDecimalSize)
{
float curExpandedSize = (maxExpandedSize + minExpandedSize) / 2;
for (int i = 0; i < edgeList.Length; i++)
{
Node node = edgeList[i];
// update expanded size.
if (node.Stretch.HasFlag(StretchFlags.Expand))
{
node.ExpandedSize = curExpandedSize / totalExpand;
}
}
// re-init locations based on updated expanded size.
InitLocations(ref locations);
newChildrenSize = locations[maxIndex] - locations[0] - space;
// internal child size cannot exceed the Gridlayout size.
if (newChildrenSize > parentDecimalSize)
{
maxExpandedSize = curExpandedSize;
}
else
{
minExpandedSize = curExpandedSize;
}
}
}
/// <summary>
/// Assign a size and position to each of its children.<br />
/// </summary>
/// <param name="changed">This is a new size or position for this layout.</param>
/// <param name="left">Left position, relative to parent.</param>
/// <param name="top"> Top position, relative to parent.</param>
/// <param name="right">Right position, relative to parent.</param>
/// <param name="bottom">Bottom position, relative to parent.</param>
/// <since_tizen> 6 </since_tizen>
protected override void OnLayout( bool changed, LayoutLength left, LayoutLength top, LayoutLength right, LayoutLength bottom )
{
bool isLayoutRtl = Owner.LayoutDirection == ViewLayoutDirectionType.RTL;
LayoutLength width = right - left;
LayoutLength height = bottom - top;
// Call to FlexLayout implementation to calculate layout values for later retrieval.
Interop.FlexLayout.FlexLayout_CalculateLayout( swigCPtr, width.AsDecimal(), height.AsDecimal(), isLayoutRtl );
int count = LayoutChildren.Count;
for( int childIndex = 0; childIndex < count; childIndex++)
{
LayoutItem childLayout = LayoutChildren[childIndex];
if( childLayout != null )
{
// Get the frame for the child, start, top, end, bottom.
Vector4 frame = new Vector4(Interop.FlexLayout.FlexLayout_GetNodeFrame(swigCPtr, childIndex ), true);
childLayout.Layout( new LayoutLength(frame.X), new LayoutLength(frame.Y), new LayoutLength(frame.Z), new LayoutLength(frame.W) );
}
}
}
/// <summary>
/// Calculate the right measure spec for this child.
/// Does the hard part of MeasureChildren: figuring out the MeasureSpec to
/// pass to a particular child. This method figures out the right MeasureSpec
/// for one dimension (height or width) of one child view.<br />
/// </summary>
/// <param name="parentMeasureSpec">The requirements for this view. MeasureSpecification.</param>
/// <param name="padding">The padding of this view for the current dimension and margins, if applicable. LayoutLength.</param>
/// <param name="childDimension"> How big the child wants to be in the current dimension. LayoutLength.</param>
/// <returns>a MeasureSpec for the child.</returns>
public static MeasureSpecification GetChildMeasureSpecification(MeasureSpecification parentMeasureSpec, LayoutLength padding, LayoutLength childDimension)
{
MeasureSpecification.ModeType specMode = parentMeasureSpec.Mode;
MeasureSpecification.ModeType resultMode = MeasureSpecification.ModeType.Unspecified;
LayoutLength resultSize = new LayoutLength(Math.Max(0.0f, (parentMeasureSpec.Size.AsDecimal() - padding.AsDecimal()))); // reduce available size by the owners padding
switch (specMode)
{
// Parent has imposed an exact size on us
case MeasureSpecification.ModeType.Exactly:
{
if ((int)childDimension.AsRoundedValue() == LayoutParamPolicies.MatchParent)
{
// Child wants to be our size. So be it.
resultMode = MeasureSpecification.ModeType.Exactly;
}
else if ((int)childDimension.AsRoundedValue() == LayoutParamPolicies.WrapContent)
{
// Child wants to determine its own size. It can't be
// bigger than us.
resultMode = MeasureSpecification.ModeType.AtMost;
}
else
{
resultSize = childDimension;
resultMode = MeasureSpecification.ModeType.Exactly;
}
break;
}
// Parent has imposed a maximum size on us
case MeasureSpecification.ModeType.AtMost:
{
if (childDimension.AsRoundedValue() == LayoutParamPolicies.MatchParent)
{
// Child wants to be our size, but our size is not fixed.
// Constrain child to not be bigger than us.
resultMode = MeasureSpecification.ModeType.AtMost;
}
else if (childDimension.AsRoundedValue() == LayoutParamPolicies.WrapContent)
{
// Child wants to determine its own size. It can't be
// bigger than us.
resultMode = MeasureSpecification.ModeType.AtMost;
}
else
{
// Child wants a specific size... so be it
resultSize = childDimension + padding;
resultMode = MeasureSpecification.ModeType.Exactly;
}
break;
}
// Parent asked to see how big we want to be
case MeasureSpecification.ModeType.Unspecified:
{
if ((childDimension.AsRoundedValue() == LayoutParamPolicies.MatchParent))
{
// Child wants to be our size... find out how big it should be
resultMode = MeasureSpecification.ModeType.Unspecified;
}
else if (childDimension.AsRoundedValue() == (LayoutParamPolicies.WrapContent))
{
// Child wants to determine its own size.... find out how big
// it should be
resultMode = MeasureSpecification.ModeType.Unspecified;
}
else
{
// Child wants a specific size... let him have it
resultSize = childDimension + padding;
resultMode = MeasureSpecification.ModeType.Exactly;
}
break;
}
} // switch
return(new MeasureSpecification(resultSize, resultMode));
}
} // LayoutHorizontally
private void LayoutVertical(LayoutLength left, LayoutLength top, LayoutLength right, LayoutLength bottom)
{
LayoutLength childTop = new LayoutLength(Padding.Top);
LayoutLength childLeft = new LayoutLength(Padding.Start);
// Where end of child should go
LayoutLength width = new LayoutLength(right - left);
// Space available for child
LayoutLength childSpace = new LayoutLength(width - Padding.Start - Padding.End);
List <LayoutItem> LinearChildren = IterateLayoutChildren().ToList();
int count = LinearChildren.Count;
switch (LinearAlignment)
{
case Alignment.Bottom:
// totalLength contains the padding already
childTop = new LayoutLength(Padding.Top + bottom.AsDecimal() - top.AsDecimal() - _totalLength);
break;
case Alignment.CenterVertical: // FALL THROUGH
case Alignment.Center:
// totalLength contains the padding already
childTop = new LayoutLength(Padding.Top + (bottom.AsDecimal() - top.AsDecimal() - _totalLength) / 2.0f);
break;
case Alignment.Top: // FALL THROUGH (default)
default:
// totalLength contains the padding already
childTop = new LayoutLength(Padding.Top);
break;
}
for (int i = 0; i < count; i++)
{
LayoutItem childLayout = LinearChildren[i];
LayoutLength childWidth = childLayout.MeasuredWidth.Size;
LayoutLength childHeight = childLayout.MeasuredHeight.Size;
Extents childMargin = childLayout.Margin;
childTop += childMargin.Top;
switch (LinearAlignment)
{
case Alignment.Begin:
default:
{
childLeft = new LayoutLength(Padding.Start + childMargin.Start);
break;
}
case Alignment.End:
{
childLeft = new LayoutLength(width - Padding.End - childWidth - childMargin.End);
break;
}
case Alignment.CenterHorizontal:
case Alignment.Center: // FALL THROUGH
{
childLeft = new LayoutLength(Padding.Start + ((childSpace - childWidth).AsDecimal() / 2.0f) + childMargin.Start - childMargin.End);
break;
}
}
childLayout.Layout(childLeft, childTop, childLeft + childWidth, childTop + childHeight);
childTop += childHeight + childMargin.Bottom + ((i < count - 1) ? CellPadding.Height : 0);
}
} // LayoutVertical
} // MeasureVertical
private void LayoutHorizontal(LayoutLength left, LayoutLength top, LayoutLength right, LayoutLength bottom)
{
bool isLayoutRtl = Owner.LayoutDirection == ViewLayoutDirectionType.RTL;
LayoutLength childTop = new LayoutLength(Padding.Top);
LayoutLength childLeft = new LayoutLength(Padding.Start);
// Where bottom of child should go
LayoutLength height = new LayoutLength(bottom - top);
// Space available for child
LayoutLength childSpace = new LayoutLength(height - Padding.Top - Padding.Bottom);
List <LayoutItem> LinearChildren = IterateLayoutChildren().ToList();
int count = LinearChildren.Count;
switch (LinearAlignment)
{
case Alignment.End:
// totalLength contains the padding already
// In case of RTL map END alignment to the left edge
if (isLayoutRtl)
{
childLeft = new LayoutLength(Padding.Start);
}
else
{
childLeft = new LayoutLength(Padding.Start + right.AsDecimal() - left.AsDecimal() - _totalLength);
}
break;
case Alignment.CenterHorizontal: // FALL THROUGH
case Alignment.Center:
// totalLength contains the padding already
childLeft = new LayoutLength(Padding.Start + (right.AsDecimal() - left.AsDecimal() - _totalLength) / 2.0f);
break;
case Alignment.Begin: // FALL THROUGH (default)
default:
// totalLength contains the padding already
// In case of RTL map BEGIN alignment to the right edge
if (isLayoutRtl)
{
childLeft = new LayoutLength(Padding.Start + right.AsDecimal() - left.AsDecimal() - _totalLength);
}
else
{
childLeft = new LayoutLength(Padding.Start);
}
break;
}
int start = 0;
int dir = 1;
// In case of RTL, start drawing from the last child.
if (isLayoutRtl)
{
start = count - 1;
dir = -1;
}
for (int i = 0; i < count; i++)
{
int childIndex = start + dir * i;
// Get a reference to the childLayout at the given index
LayoutItem childLayout = LinearChildren[childIndex];
LayoutLength childWidth = childLayout.MeasuredWidth.Size;
LayoutLength childHeight = childLayout.MeasuredHeight.Size;
Extents childMargin = childLayout.Margin;
switch (LinearAlignment)
{
case Alignment.Bottom:
childTop = new LayoutLength(height - Padding.Bottom - childHeight - childMargin.Bottom);
break;
case Alignment.CenterVertical:
case Alignment.Center: // FALLTHROUGH
childTop = new LayoutLength(Padding.Top + ((childSpace - childHeight).AsDecimal() / 2.0f) + childMargin.Top - childMargin.Bottom);
break;
case Alignment.Top: // FALLTHROUGH default
default:
childTop = new LayoutLength(Padding.Top + childMargin.Top);
break;
}
childLeft += childMargin.Start;
childLayout.Layout(childLeft, childTop, childLeft + childWidth, childTop + childHeight);
childLeft += childWidth + childMargin.End + ((i < count - 1) ? CellPadding.Width : 0);
}
} // LayoutHorizontally
} // MeasureHorizontal
private void MeasureVertical(MeasureSpecification widthMeasureSpec, MeasureSpecification heightMeasureSpec)
{
var widthMode = widthMeasureSpec.Mode;
var heightMode = heightMeasureSpec.Mode;
bool isExactly = (heightMode == MeasureSpecification.ModeType.Exactly);
bool matchWidth = false;
bool allFillParent = true;
float maxWidth = 0.0f;
float alternativeMaxWidth = 0.0f;
float weightedMaxWidth = 0.0f;
float totalWeight = 0.0f;
int childrenCount = IterateLayoutChildren().Count();
// Reset total length
_totalLength = 0.0f;
float usedExcessSpace = 0.0f;
HeightAndWidthState childState = new HeightAndWidthState(MeasuredSize.StateType.MeasuredSizeOK,
MeasuredSize.StateType.MeasuredSizeOK);
// measure children, and determine if further resolution is required
// 1st phase:
// We cycle through all children and measure children with weight 0 (non weighted children) according to their specs
// to accumulate total used space in _totalLength.
// Weighted children are not measured in this phase.
// Available space for weighted children will be calculated in the phase 2 based on _totalLength value.
foreach (LayoutItem childLayout in IterateLayoutChildren())
{
childrenCount++;
int childDesiredWidth = childLayout.Owner.WidthSpecification;
float childWeight = childLayout.Owner.Weight;
Extents childMargin = childLayout.Margin;
totalWeight += childWeight;
bool useExcessSpace = (childLayout.Owner.HeightSpecification == 0) && (childWeight > 0);
if (isExactly && useExcessSpace)
{
_totalLength = Math.Max(_totalLength, (_totalLength + childMargin.Top + childMargin.Bottom));
}
else
{
if (useExcessSpace)
{
// The heightMode is either Unspecified or AtMost, and
// this child is only laid out using excess space. Measure
// using WrapContent so that we can find out the view's
// optimal height.
// We'll restore the original height of 0 after measurement.
MeasureSpecification childWidthMeasureSpec = GetChildMeasureSpecification(
new MeasureSpecification(
new LayoutLength(widthMeasureSpec.Size - (childLayout.Margin.Start + childLayout.Margin.End)),
widthMeasureSpec.Mode),
new LayoutLength(Padding.Start + Padding.End),
new LayoutLength(childDesiredWidth));
MeasureSpecification childHeightMeasureSpec = GetChildMeasureSpecification(
new MeasureSpecification(
new LayoutLength(heightMeasureSpec.Size - (childLayout.Margin.Top + childLayout.Margin.Bottom)),
heightMeasureSpec.Mode),
new LayoutLength(Padding.Top + Padding.Bottom),
new LayoutLength(LayoutParamPolicies.WrapContent));
childLayout.Measure(childWidthMeasureSpec, childHeightMeasureSpec);
usedExcessSpace += childLayout.MeasuredHeight.Size.AsDecimal();
}
else
{
MeasureChildWithMargins(childLayout, widthMeasureSpec, new LayoutLength(0), heightMeasureSpec, new LayoutLength(0));
}
LayoutLength childHeight = childLayout.MeasuredHeight.Size;
LayoutLength length = childHeight + childMargin.Top + childMargin.Bottom;
_totalLength = Math.Max(_totalLength, _totalLength + length.AsDecimal());
}
bool matchWidthLocally = false;
if (widthMode != MeasureSpecification.ModeType.Exactly && childDesiredWidth == LayoutParamPolicies.MatchParent)
{
// Will have to re-measure at least this child when we know exact height.
matchWidth = true;
matchWidthLocally = true;
}
float marginWidth = childLayout.Margin.Start + childLayout.Margin.End;
float childWidth = childLayout.MeasuredWidth.Size.AsDecimal() + marginWidth;
if (childLayout.MeasuredWidth.State == MeasuredSize.StateType.MeasuredSizeTooSmall)
{
childState.widthState = MeasuredSize.StateType.MeasuredSizeTooSmall;
}
if (childLayout.MeasuredHeight.State == MeasuredSize.StateType.MeasuredSizeTooSmall)
{
childState.heightState = MeasuredSize.StateType.MeasuredSizeTooSmall;
}
maxWidth = Math.Max(maxWidth, childWidth);
allFillParent = (allFillParent && childDesiredWidth == LayoutParamPolicies.MatchParent);
if (childWeight > 0)
{
// Widths of weighted Views are bogus if we end up remeasuring, so keep them separate.
weightedMaxWidth = Math.Max(weightedMaxWidth, matchWidthLocally ? marginWidth : childWidth);
}
else
{
alternativeMaxWidth = Math.Max(alternativeMaxWidth, matchWidthLocally ? marginWidth : childWidth);
}
} // foreach
_totalLength = Math.Max(_totalLength, _totalLength + CellPadding.Height * (childrenCount - 1));
float heightSize = _totalLength;
heightSize = Math.Max(heightSize, SuggestedMinimumHeight.AsDecimal());
MeasuredSize heightSizeAndState = ResolveSizeAndState(new LayoutLength(heightSize + Padding.Top + Padding.Bottom), heightMeasureSpec, MeasuredSize.StateType.MeasuredSizeOK);
heightSize = heightSizeAndState.Size.AsDecimal();
// 2nd phase:
// We cycle through weighted children now (children with weight > 0).
// The children are measured with exact size equal to their share of the available space based on their weights.
// _totalLength is updated to include weighted children measured sizes.
float remainingExcess = heightSize - _totalLength + usedExcessSpace - (Padding.Top + Padding.Bottom);
if (remainingExcess != 0 && totalWeight > 0.0f)
{
float remainingWeight = totalWeight;
maxWidth = 0;
_totalLength = 0;
foreach (LayoutItem childLayout in IterateLayoutChildren())
{
float desiredChildWidth = childLayout.Owner.WidthSpecification;
float childWeight = childLayout.Owner.Weight;
Extents childMargin = childLayout.Margin;
if (childWeight > 0)
{
MeasureWeightedChild(childLayout, remainingExcess, remainingWeight, childWeight,
widthMeasureSpec, heightMeasureSpec, childState,
Orientation.Vertical);
}
float length = childLayout.MeasuredHeight.Size.AsDecimal() + childMargin.Top + childMargin.Bottom;
_totalLength += length;
bool matchWidthLocally = (widthMode != MeasureSpecification.ModeType.Exactly) && (desiredChildWidth == LayoutParamPolicies.MatchParent);
float marginWidth = childMargin.Start + childMargin.End;
float childWidth = childLayout.MeasuredWidth.Size.AsDecimal() + marginWidth;
maxWidth = Math.Max(maxWidth, childWidth);
alternativeMaxWidth = Math.Max(alternativeMaxWidth, matchWidthLocally ? marginWidth : childWidth);
allFillParent = (allFillParent && desiredChildWidth == LayoutParamPolicies.MatchParent);
} // for loop
_totalLength = Math.Max(_totalLength, _totalLength + CellPadding.Height * (childrenCount - 1));
}
else
{
alternativeMaxWidth = Math.Max(alternativeMaxWidth, weightedMaxWidth);
}
if (!allFillParent && widthMode != MeasureSpecification.ModeType.Exactly)
{
maxWidth = alternativeMaxWidth;
}
maxWidth += (Owner.WidthSpecification == LayoutParamPolicies.WrapContent) ? (Padding.Start + Padding.End) : 0;
maxWidth = Math.Max(maxWidth, SuggestedMinimumWidth.AsRoundedValue());
heightSizeAndState.State = childState.heightState;
SetMeasuredDimensions(ResolveSizeAndState(new LayoutLength(maxWidth), widthMeasureSpec, childState.widthState),
heightSizeAndState);
if (matchWidth)
{
ForceUniformWidth(heightMeasureSpec);
}
} // MeasureVertical
private void MeasureHorizontal(MeasureSpecification widthMeasureSpec, MeasureSpecification heightMeasureSpec)
{
var widthMode = widthMeasureSpec.Mode;
var heightMode = heightMeasureSpec.Mode;
bool isExactly = (widthMode == MeasureSpecification.ModeType.Exactly);
bool matchHeight = false;
bool allFillParent = true;
float maxHeight = 0.0f;
float alternativeMaxHeight = 0.0f;
float weightedMaxHeight = 0.0f;
float totalWeight = 0.0f;
int childrenCount = IterateLayoutChildren().Count();
// Reset measure variables
_totalLength = 0.0f;
float usedExcessSpace = 0.0f;
HeightAndWidthState childState = new HeightAndWidthState(MeasuredSize.StateType.MeasuredSizeOK,
MeasuredSize.StateType.MeasuredSizeOK);
// 1st phase:
// We cycle through all children and measure children with weight 0 (non weighted children) according to their specs
// to accumulate total used space in totalLength based on measured sizes and margins.
// Weighted children are not measured at this phase.
// Available space for weighted children will be calculated in the phase 2 based on totalLength value.
// Max height of children is stored.
foreach (LayoutItem childLayout in IterateLayoutChildren())
{
int childDesiredHeight = childLayout.Owner.HeightSpecification;
float childWeight = childLayout.Owner.Weight;
Extents childMargin = childLayout.Margin;
totalWeight += childWeight;
bool useExcessSpace = (childLayout.Owner.WidthSpecification == 0) && (childWeight > 0);
if (isExactly && useExcessSpace)
{
// Children to be laid out with excess space can be measured later
_totalLength = Math.Max(_totalLength, (_totalLength + childMargin.Start + childMargin.End));
}
else
{
if (useExcessSpace)
{
// Parent is not defiend!!!
// The widthMode is either Unspecified or AtMost, and
// this child is only laid out using excess space. Measure
// using WrapContent so that we can find out the view's
// optimal width.
MeasureSpecification childWidthMeasureSpec = GetChildMeasureSpecification(
new MeasureSpecification(
new LayoutLength(widthMeasureSpec.Size - (childLayout.Margin.Start + childLayout.Margin.End)),
widthMeasureSpec.Mode),
new LayoutLength(Padding.Start + Padding.End),
new LayoutLength(LayoutParamPolicies.WrapContent));
MeasureSpecification childHeightMeasureSpec = GetChildMeasureSpecification(
new MeasureSpecification(
new LayoutLength(heightMeasureSpec.Size - (childLayout.Margin.Top + childLayout.Margin.Bottom)),
heightMeasureSpec.Mode),
new LayoutLength(Padding.Top + Padding.Bottom),
new LayoutLength(childDesiredHeight));
childLayout.Measure(childWidthMeasureSpec, childHeightMeasureSpec);
usedExcessSpace += childLayout.MeasuredWidth.Size.AsDecimal();
}
else
{
MeasureChildWithMargins(childLayout, widthMeasureSpec, new LayoutLength(0), heightMeasureSpec, new LayoutLength(0));
}
LayoutLength childWidth = childLayout.MeasuredWidth.Size;
LayoutLength length = childWidth + childMargin.Start + childMargin.End;
_totalLength = Math.Max(_totalLength, _totalLength + length.AsDecimal());
}
bool matchHeightLocally = false;
if (heightMode != MeasureSpecification.ModeType.Exactly && childDesiredHeight == LayoutParamPolicies.MatchParent)
{
// A child has set to MatchParent on it's height.
// Will have to re-measure at least this child when we know exact height.
matchHeight = true;
matchHeightLocally = true;
}
float marginHeight = childMargin.Top + childMargin.Bottom;
float childHeight = childLayout.MeasuredHeight.Size.AsDecimal() + marginHeight;
if (childLayout.MeasuredWidth.State == MeasuredSize.StateType.MeasuredSizeTooSmall)
{
childState.widthState = MeasuredSize.StateType.MeasuredSizeTooSmall;
}
if (childLayout.MeasuredHeight.State == MeasuredSize.StateType.MeasuredSizeTooSmall)
{
childState.heightState = MeasuredSize.StateType.MeasuredSizeTooSmall;
}
maxHeight = Math.Max(maxHeight, childHeight);
allFillParent = (allFillParent && childDesiredHeight == LayoutParamPolicies.MatchParent);
if (childWeight > 0)
{
// Heights of weighted Views are invalid if we end up remeasuring, so store them separately.
weightedMaxHeight = Math.Max(weightedMaxHeight, matchHeightLocally ? marginHeight : childHeight);
}
else
{
alternativeMaxHeight = Math.Max(alternativeMaxHeight, matchHeightLocally ? marginHeight : childHeight);
}
} // foreach
_totalLength = Math.Max(_totalLength, _totalLength + CellPadding.Width * (childrenCount - 1));
float widthSize = _totalLength;
widthSize = Math.Max(widthSize, SuggestedMinimumWidth.AsDecimal());
MeasuredSize widthSizeAndState = ResolveSizeAndState(new LayoutLength(widthSize + Padding.Start + Padding.End), widthMeasureSpec, MeasuredSize.StateType.MeasuredSizeOK);
widthSize = widthSizeAndState.Size.AsDecimal();
// 2nd phase:
// Expand children with weight to take up available space
// We cycle through weighted children now (children with weight > 0).
// The children are measured with exact size equal to their share of the available space based on their weights.
// _totalLength is updated to include weighted children measured sizes.
float remainingExcess = widthSize - _totalLength + usedExcessSpace - (Padding.Start + Padding.End);
if (remainingExcess != 0 && totalWeight > 0)
{
float remainingWeight = totalWeight;
maxHeight = 0;
_totalLength = 0;
foreach (LayoutItem childLayout in IterateLayoutChildren())
{
float desiredChildHeight = childLayout.Owner.HeightSpecification;
float childWeight = childLayout.Owner.Weight;
Extents childMargin = childLayout.Margin;
if (childWeight > 0)
{
MeasureWeightedChild(childLayout, remainingExcess, remainingWeight, childWeight,
widthMeasureSpec, heightMeasureSpec, childState,
Orientation.Horizontal);
}
float length = childLayout.MeasuredWidth.Size.AsDecimal() + childMargin.Start + childMargin.End;
_totalLength += length;
bool matchHeightLocally = (heightMode != MeasureSpecification.ModeType.Exactly) && (desiredChildHeight == LayoutParamPolicies.MatchParent);
float marginHeight = childMargin.Top + childMargin.Bottom;
float childHeight = childLayout.MeasuredHeight.Size.AsDecimal() + marginHeight;
maxHeight = Math.Max(maxHeight, childHeight);
alternativeMaxHeight = Math.Max(alternativeMaxHeight, matchHeightLocally ? marginHeight : childHeight);
allFillParent = (allFillParent && desiredChildHeight == LayoutParamPolicies.MatchParent);
} // for loop
_totalLength = Math.Max(_totalLength, _totalLength + CellPadding.Width * (childrenCount - 1));
}
else
{
// No excess space or no weighted children
alternativeMaxHeight = Math.Max(alternativeMaxHeight, weightedMaxHeight);
}
if (!allFillParent && heightMode != MeasureSpecification.ModeType.Exactly)
{
maxHeight = alternativeMaxHeight;
}
// Padding should be concerned when specification is Wrapcontent.
maxHeight += (Owner.HeightSpecification == LayoutParamPolicies.WrapContent) ? (Padding.Top + Padding.Bottom) : 0;
maxHeight = Math.Max(maxHeight, SuggestedMinimumHeight.AsRoundedValue());
widthSizeAndState.State = childState.widthState;
SetMeasuredDimensions(widthSizeAndState,
ResolveSizeAndState(new LayoutLength(maxHeight), heightMeasureSpec, childState.heightState));
if (matchHeight)
{
ForceUniformHeight(widthMeasureSpec);
}
} // MeasureHorizontal
} // MeasureHorizontally
void MeasureVertical(MeasureSpecification widthMeasureSpec, MeasureSpecification heightMeasureSpec)
{
var widthMode = widthMeasureSpec.Mode;
var heightMode = heightMeasureSpec.Mode;
bool isExactly = (heightMode == MeasureSpecification.ModeType.Exactly);
bool matchWidth = false;
bool allFillParent = true;
float maxWidth = 0.0f;
float alternativeMaxWidth = 0.0f;
float weightedMaxWidth = 0.0f;
float totalWeight = 0.0f;
// Reset total length
_totalLength = 0.0f;
LayoutLength usedExcessSpace = new LayoutLength(0);
HeightAndWidthState childState = new HeightAndWidthState(MeasuredSize.StateType.MeasuredSizeOK,
MeasuredSize.StateType.MeasuredSizeTooSmall);
// measure children, and determine if further resolution is required
// 1st phase:
// We cycle through all children and measure children with weight 0 (non weighted children) according to their specs
// to accumulate total used space in mTotalLength based on measured sizes and margins.
// Weighted children are not measured at this phase.
// Available space for weighted children will be calculated in the phase 2 based on mTotalLength value.
uint index = 0;
foreach (LayoutItem childLayout in _children)
{
LayoutLength childDesiredWidth = new LayoutLength(childLayout.Owner.WidthSpecification);
LayoutLength childDesiredHeight = new LayoutLength(childLayout.Owner.HeightSpecification);
float childWeight = childLayout.Owner.Weight;
Extents childMargin = childLayout.Margin;
totalWeight += childWeight;
bool useExcessSpace = (childDesiredHeight.AsRoundedValue() == 0) && (childWeight > 0);
if (isExactly && useExcessSpace)
{
LayoutLength totalLength = new LayoutLength(_totalLength);
_totalLength = Math.Max(totalLength.AsDecimal(), (totalLength + childMargin.Top + childMargin.Bottom).AsDecimal());
}
else
{
LayoutLength childHeight = new LayoutLength(0);
if (useExcessSpace)
{
// The heightMode is either Unspecified or AtMost, and
// this child is only laid out using excess space. Measure
// using WrapContent so that we can find out the view's
// optimal height. We'll restore the original height of 0
// after measurement.
MeasureSpecification childWidthMeasureSpec = GetChildMeasureSpecification(widthMeasureSpec,
new LayoutLength(childLayout.Padding.Start + childLayout.Padding.End),
childDesiredWidth);
MeasureSpecification childHeightMeasureSpec = GetChildMeasureSpecification(heightMeasureSpec,
new LayoutLength(childLayout.Padding.Top + childLayout.Padding.Bottom),
new LayoutLength(LayoutParamPolicies.WrapContent));
childLayout.Measure(childWidthMeasureSpec, childHeightMeasureSpec);
childHeight = childLayout.MeasuredHeight.Size;
usedExcessSpace += childHeight;
}
else
{
MeasureChild(childLayout, widthMeasureSpec, heightMeasureSpec);
childHeight = childLayout.MeasuredHeight.Size;
}
float length = (childHeight + childMargin.Top + childMargin.Bottom).AsDecimal();
float cellPadding = CellPadding.Height;
// No need to add cell padding to the end of last item.
if (index >= _children.Count - 1)
{
cellPadding = 0.0f;
}
_totalLength = Math.Max(_totalLength, _totalLength + length + cellPadding);
}
bool matchWidthLocally = false;
if (widthMode != MeasureSpecification.ModeType.Exactly && childDesiredWidth == new LayoutLength(LayoutParamPolicies.MatchParent))
{
// Will have to re-measure at least this child when we know exact height.
matchWidth = true;
matchWidthLocally = true;
}
float marginWidth = (childLayout.Margin.Start) + (childLayout.Margin.End);
LayoutLength childWidth = new LayoutLength(childLayout.MeasuredWidth.Size.AsDecimal() + marginWidth);
// was combineMeasuredStates()
if (childLayout.MeasuredWidthAndState.State == MeasuredSize.StateType.MeasuredSizeTooSmall)
{
childState.widthState = MeasuredSize.StateType.MeasuredSizeTooSmall;
}
if (childLayout.MeasuredHeightAndState.State == MeasuredSize.StateType.MeasuredSizeTooSmall)
{
childState.heightState = MeasuredSize.StateType.MeasuredSizeTooSmall;
}
maxWidth = (Math.Max(maxWidth, childWidth.AsDecimal()));
allFillParent = (allFillParent && (childDesiredWidth == new LayoutLength(LayoutParamPolicies.MatchParent)));
float widthforWeight = childWidth.AsDecimal();
if (matchWidthLocally)
{
widthforWeight = marginWidth;
}
if (childWeight > 0)
{
/*
* Widths of weighted Views are bogus if we end up remeasuring, so keep them separate.
*/
weightedMaxWidth = Math.Max(weightedMaxWidth, widthforWeight);
}
else
{
alternativeMaxWidth = Math.Max(alternativeMaxWidth, widthforWeight);
}
} // foreach
Extents padding = Padding;
_totalLength += padding.Top + padding.Bottom;
LayoutLength heightSize = new LayoutLength(_totalLength);
heightSize = new LayoutLength(Math.Max(heightSize.AsDecimal(), SuggestedMinimumHeight.AsDecimal()));
MeasuredSize heightSizeAndState = ResolveSizeAndState(heightSize, heightMeasureSpec, MeasuredSize.StateType.MeasuredSizeOK);
heightSize = heightSizeAndState.Size;
// Either expand children with weight to take up available space or
// shrink them if they extend beyond our current bounds. If we skipped
// measurement on any children, we need to measure them now.
// 2nd phase:
// We cycle through weighted children now (children with weight > 0).
// The children are measured with exact size equal to their share of the available space based on their weights.
// TotalLength is updated to include weighted children measured sizes.
float remainingExcess = heightSize.AsDecimal() - _totalLength + usedExcessSpace.AsDecimal();
if (remainingExcess != 0 && totalWeight > 0.0f)
{
float remainingWeightSum = totalWeight;
_totalLength = 0;
foreach (LayoutItem childLayout in _children)
{
int desiredWidth = childLayout.Owner.WidthSpecification;
int desiredHeight = childLayout.Owner.HeightSpecification;
float childWeight = childLayout.Owner.Weight;
Extents childMargin = childLayout.Margin;
float childHeight = 0;
if (childWeight > 0)
{
float share = (childWeight * remainingExcess) / remainingWeightSum;
remainingExcess -= share;
remainingWeightSum -= childWeight;
// Always lay out weighted elements with intrinsic size regardless of the parent spec
// for consistency between specs.
if (desiredHeight == 0)
{
// This child needs to be laid out from scratch using
// only its share of excess space.
childHeight = share;
}
else
{
// This child had some intrinsic width to which we
// need to add its share of excess space.
childHeight = childLayout.MeasuredHeight.Size.AsDecimal() + share;
}
MeasureSpecification childWidthMeasureSpec = GetChildMeasureSpecification(widthMeasureSpec,
new LayoutLength(Padding.Start + Padding.End),
new LayoutLength(desiredWidth));
MeasureSpecification childHeightMeasureSpec = new MeasureSpecification(new LayoutLength(childHeight), MeasureSpecification.ModeType.Exactly);
childLayout.Measure(childWidthMeasureSpec, childHeightMeasureSpec);
// Child may now not fit in vertical dimension.
if (childLayout.MeasuredHeightAndState.State == MeasuredSize.StateType.MeasuredSizeTooSmall)
{
childState.heightState = MeasuredSize.StateType.MeasuredSizeTooSmall;
}
}
bool matchWidthLocally = false;
if (widthMode != MeasureSpecification.ModeType.Exactly && desiredWidth == (int)ChildLayoutData.MatchParent)
{
// Will have to re-measure at least this child when we know exact height.
matchWidth = true;
matchWidthLocally = true;
}
float marginWidth = childMargin.Start + childMargin.End;
float childWidth = childLayout.MeasuredWidth.Size.AsDecimal() + marginWidth;
maxWidth = Math.Max(maxWidth, childWidth);
allFillParent = allFillParent && desiredWidth == (int)ChildLayoutData.MatchParent;
alternativeMaxWidth = Math.Max(alternativeMaxWidth, matchWidthLocally ? marginWidth : childWidth);
childHeight = childLayout.MeasuredHeight.Size.AsDecimal();
float length = childHeight + childMargin.Top + childMargin.Bottom;
float cellPadding = CellPadding.Height;
// No need to add cell padding to the end of last item.
if (index >= _children.Count - 1)
{
cellPadding = 0.0f;
}
_totalLength = Math.Max(_totalLength, _totalLength + length + cellPadding);
} // foreach
// Add in our padding
_totalLength += Padding.Top + Padding.Bottom;
}
else
{
alternativeMaxWidth = Math.Max(alternativeMaxWidth, weightedMaxWidth);
}
if (!allFillParent && widthMode != MeasureSpecification.ModeType.Exactly)
{
maxWidth = alternativeMaxWidth;
}
maxWidth += padding.Start + padding.End;
maxWidth = Math.Max(maxWidth, SuggestedMinimumWidth.AsRoundedValue());
heightSizeAndState.State = childState.heightState;
SetMeasuredDimensions(ResolveSizeAndState(new LayoutLength(maxWidth), widthMeasureSpec, childState.widthState),
heightSizeAndState);
if (matchWidth)
{
ForceUniformWidth(_children.Count, heightMeasureSpec);
}
} // MeasureVertically
private void MeasureHorizontal(MeasureSpecification widthMeasureSpec, MeasureSpecification heightMeasureSpec)
{
var widthMode = widthMeasureSpec.Mode;
var heightMode = heightMeasureSpec.Mode;
bool isExactly = (widthMode == MeasureSpecification.ModeType.Exactly);
bool matchHeight = false;
bool allFillParent = true;
float maxHeight = 0.0f;
float alternativeMaxHeight = 0.0f;
float weightedMaxHeight = 0.0f;
float totalWeight = 0.0f;
// Reset total length
_totalLength = 0.0f;
LayoutLength usedExcessSpace = new LayoutLength(0);
HeightAndWidthState childState = new HeightAndWidthState(MeasuredSize.StateType.MeasuredSizeOK,
MeasuredSize.StateType.MeasuredSizeOK);
// Measure children, and determine if further resolution is required
// 1st phase:
// We cycle through all children and measure children with weight 0 (non weighted children) according to their specs
// to accumulate total used space in totalLength based on measured sizes and margins.
// Weighted children are not measured at this phase.
// Available space for weighted children will be calculated in the phase 2 based on totalLength value.
foreach (LayoutItem childLayout in _children)
{
LayoutLength childDesiredWidth = new LayoutLength(childLayout.Owner.WidthSpecification);
LayoutLength childDesiredHeight = new LayoutLength(childLayout.Owner.HeightSpecification);
float childWeight = childLayout.Owner.Weight;
Extents childMargin = childLayout.Margin;
totalWeight += childWeight;
bool useExcessSpace = (childDesiredWidth.AsRoundedValue() == 0) && (childWeight > 0);
if (isExactly && useExcessSpace)
{
_totalLength += childMargin.Start + childMargin.End;
}
else
{
if (useExcessSpace)
{
// The widthMode is either UNSPECIFIED or AT_MOST, and
// this child is only laid out using excess space. Measure
// using WRAP_CONTENT so that we can find out the view's
// optimal width.
MeasureSpecification childWidthMeasureSpec = GetChildMeasureSpecification(widthMeasureSpec, new LayoutLength(childLayout.Padding.Start + childLayout.Padding.End),
new LayoutLength(LayoutParamPolicies.WrapContent));
MeasureSpecification childHeightMeasureSpec = GetChildMeasureSpecification(heightMeasureSpec, new LayoutLength(childLayout.Padding.Top + childLayout.Padding.Bottom),
childDesiredHeight);
childLayout.Measure(childWidthMeasureSpec, childHeightMeasureSpec);
usedExcessSpace += childLayout.MeasuredWidth.Size;
}
else
{
MeasureChild(childLayout, widthMeasureSpec, heightMeasureSpec);
}
LayoutLength childWidth = childLayout.MeasuredWidth.Size;
LayoutLength length = childWidth + childMargin.Start + childMargin.End;
if (isExactly)
{
_totalLength += length.AsDecimal();
}
else
{
_totalLength = Math.Max(_totalLength, _totalLength + length.AsDecimal() + CellPadding.Width);
}
}
bool matchHeightLocally = false;
if (heightMode != MeasureSpecification.ModeType.Exactly && (int)childDesiredHeight.AsRoundedValue() == LayoutParamPolicies.MatchParent)
{
// Will have to re-measure at least this child when we know exact height.
matchHeight = true;
matchHeightLocally = true;
}
LayoutLength marginHeight = new LayoutLength(childMargin.Top + childMargin.Bottom);
LayoutLength childHeight = childLayout.MeasuredHeight.Size + marginHeight;
if (childLayout.MeasuredWidthAndState.State == MeasuredSize.StateType.MeasuredSizeTooSmall)
{
childState.widthState = MeasuredSize.StateType.MeasuredSizeTooSmall;
}
if (childLayout.MeasuredHeightAndState.State == MeasuredSize.StateType.MeasuredSizeTooSmall)
{
childState.heightState = MeasuredSize.StateType.MeasuredSizeTooSmall;
}
maxHeight = Math.Max(maxHeight, childHeight.AsDecimal());
allFillParent = (allFillParent && childDesiredHeight.AsRoundedValue() == LayoutParamPolicies.MatchParent);
if (childWeight > 0)
{
/*
* Heights of weighted Views are bogus if we end up
* remeasuring, so keep them separate.
*/
weightedMaxHeight = Math.Max(weightedMaxHeight, matchHeightLocally ? marginHeight.AsDecimal() : childHeight.AsDecimal());
}
else
{
alternativeMaxHeight = Math.Max(alternativeMaxHeight, matchHeightLocally ? marginHeight.AsDecimal() : childHeight.AsDecimal());
}
} // foreach
Extents padding = Padding;
_totalLength += padding.Start + padding.End;
LayoutLength widthSize = new LayoutLength(_totalLength);
widthSize = new LayoutLength(Math.Max(widthSize.AsDecimal(), SuggestedMinimumWidth.AsDecimal()));
MeasuredSize widthSizeAndState = ResolveSizeAndState(widthSize, widthMeasureSpec, MeasuredSize.StateType.MeasuredSizeOK);
widthSize = widthSizeAndState.Size;
if (!allFillParent && heightMode != MeasureSpecification.ModeType.Exactly)
{
maxHeight = alternativeMaxHeight;
}
maxHeight += padding.Top + padding.Bottom;
maxHeight = Math.Max(maxHeight, SuggestedMinimumHeight.AsRoundedValue());
widthSizeAndState.State = childState.widthState;
SetMeasuredDimensions(widthSizeAndState,
ResolveSizeAndState(new LayoutLength(maxHeight), heightMeasureSpec, childState.heightState));
if (matchHeight)
{
ForceUniformHeight(_children.Count, widthMeasureSpec);
}
} // MeasureHorizontally
