/// <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