private void SetNativeDockRegion(
NativeView nativeView,
DockRegion dockRegion)
{
if (null == nativeView)
{
throw new ArgumentNullException(nameof(nativeView));
}
var layoutParameters = (NativeDockLayout.LayoutParams)nativeView.LayoutParameters();
layoutParameters.DockRegion = dockRegion;
}
protected override void OnLayout(
bool changed,
float left,
float top,
float right,
float bottom)
{
var layoutProperties = this.LayoutProperties();
Rectangle remainingRect = new Rectangle(
layoutProperties.Padding.Left,
layoutProperties.Padding.Top,
right - left - layoutProperties.Padding.Left - layoutProperties.Padding.Right,
bottom - top - layoutProperties.Padding.Top - layoutProperties.Padding.Bottom);
int childCount = this.ChildCount;
for (int i = 0; i < childCount; i += 1)
{
NativeView child = this.GetChildAt(i);
if (child.Hidden)
{
continue;
}
var layoutParams = (LayoutParams)child.LayoutParameters();
var dockRegion = layoutParams.DockRegion;
// Arrange all but the center elements in the first pass
if (dockRegion != DockRegion.CenterOverlay)
{
Rectangle arrangeRect = remainingRect;
Size childUsedSize = GetChildUsedSizeWithMargins(child, layoutParams);
if (dockRegion == DockRegion.Left)
{
arrangeRect.Width = childUsedSize.Width;
remainingRect.X += childUsedSize.Width;
remainingRect.Width = Math.Max(0, remainingRect.Width - childUsedSize.Width);
}
else if (dockRegion == DockRegion.LeftOverlay)
{
arrangeRect.Width = childUsedSize.Width;
}
else if (dockRegion == DockRegion.Top)
{
arrangeRect.Height = childUsedSize.Height;
remainingRect.Y += childUsedSize.Height;
remainingRect.Height = Math.Max(0, remainingRect.Height - childUsedSize.Height);
}
else if (dockRegion == DockRegion.TopOverlay)
{
arrangeRect.Height = childUsedSize.Height;
}
else if (dockRegion == DockRegion.Right)
{
arrangeRect.X = remainingRect.Right - childUsedSize.Width;
arrangeRect.Width = childUsedSize.Width;
remainingRect.Width = Math.Max(0, remainingRect.Width - childUsedSize.Width);
}
else if (dockRegion == DockRegion.RightOverlay)
{
arrangeRect.X = remainingRect.Right - childUsedSize.Width;
arrangeRect.Width = childUsedSize.Width;
}
else if (dockRegion == DockRegion.Bottom)
{
arrangeRect.Y = remainingRect.Bottom - childUsedSize.Height;
arrangeRect.Height = childUsedSize.Height;
remainingRect.Height = Math.Max(0, remainingRect.Height - childUsedSize.Height);
}
else if (dockRegion == DockRegion.BottomOverlay)
{
arrangeRect.Y = remainingRect.Bottom - childUsedSize.Height;
arrangeRect.Height = childUsedSize.Height;
}
else
{
throw new NotSupportedException("Unsupported dock region.");
}
this.LayoutChild(child, layoutParams, arrangeRect);
}
}
// Arrange the center elements now that the center rectangle has been calculated
for (int i = 0; i < childCount; i += 1)
{
NativeView child = this.GetChildAt(i);
if (child.Hidden)
{
continue;
}
var layoutParams = (LayoutParams)child.LayoutParameters();
// Arrange only the center elements in the second pass
if (layoutParams.DockRegion != DockRegion.CenterOverlay)
{
continue;
}
this.LayoutChild(child, layoutParams, remainingRect);
}
}
protected override void OnMeasure(
MeasureSpec widthMeasureSpec,
MeasureSpec heightMeasureSpec)
{
var layoutProperties = this.LayoutProperties();
Size availableSize = new Size(
widthMeasureSpec.Size - layoutProperties.Padding.Left - layoutProperties.Padding.Right,
heightMeasureSpec.Size - layoutProperties.Padding.Top - layoutProperties.Padding.Bottom);
// Keep track of the space used by children
float usedLeft = 0;
float usedTop = 0;
float usedRight = 0;
float usedBottom = 0;
// Keep track of the starting point for measuring each dimension
// in support of overlay regions
float startLeft = 0;
float startTop = 0;
float startRight = 0;
float startBottom = 0;
float minWidth = 0;
float minHeight = 0;
var remainingSize = availableSize;
var childWidthState = MeasuredStateFlags.None;
var childHeightState = MeasuredStateFlags.None;
int childCount = this.ChildCount;
for (int i = 0; i < childCount; i += 1)
{
NativeView child = this.GetChildAt(i);
if (child.Hidden)
{
continue;
}
var layoutParams = (LayoutParams)child.LayoutParameters();
var dockRegion = layoutParams.DockRegion;
// Arrange all but the center elements
if (dockRegion != DockRegion.CenterOverlay)
{
LayoutAxis axis = GetLayoutAxis(dockRegion);
// Save the child width and height
var childWidth = layoutParams.Width;
var childHeight = layoutParams.Height;
// Overwrite child MatchParent size on the stacking axis
if ((axis == LayoutAxis.Horizontal) && (childWidth == LayoutParams.MatchParent))
{
childWidth = LayoutParams.WrapContent;
}
else if ((axis == LayoutAxis.Vertical) && (childHeight == LayoutParams.MatchParent))
{
childHeight = LayoutParams.WrapContent;
}
// Measure the child
this.MeasureChildWithMarginsOverride(
child,
widthMeasureSpec,
usedLeft + usedRight,
childWidth,
heightMeasureSpec,
usedTop + usedBottom,
childHeight);
Size childUsedSize = GetChildUsedSizeWithMargins(child, layoutParams);
if (dockRegion == DockRegion.Left)
{
usedLeft = Math.Max(usedLeft, startLeft + childUsedSize.Width);
startLeft += childUsedSize.Width;
minHeight = Math.Max(minHeight, usedTop + usedBottom + childUsedSize.Height);
}
else if (dockRegion == DockRegion.LeftOverlay)
{
usedLeft = Math.Max(usedLeft, startLeft + childUsedSize.Width);
minHeight = Math.Max(minHeight, usedTop + usedBottom + childUsedSize.Height);
}
else if (dockRegion == DockRegion.Top)
{
usedTop = Math.Max(usedTop, startTop + childUsedSize.Height);
startTop += childUsedSize.Height;
minWidth = Math.Max(minWidth, usedLeft + usedRight + childUsedSize.Width);
}
else if (dockRegion == DockRegion.TopOverlay)
{
usedTop = Math.Max(usedTop, startTop + childUsedSize.Height);
minWidth = Math.Max(minWidth, usedLeft + usedRight + childUsedSize.Width);
}
else if (dockRegion == DockRegion.Right)
{
usedRight = Math.Max(usedRight, startRight + childUsedSize.Width);
startRight += childUsedSize.Width;
minHeight = Math.Max(minHeight, usedTop + usedBottom + childUsedSize.Height);
}
else if (dockRegion == DockRegion.RightOverlay)
{
usedRight = Math.Max(usedRight, startRight + childUsedSize.Width);
minHeight = Math.Max(minHeight, usedTop + usedBottom + childUsedSize.Height);
}
else if (dockRegion == DockRegion.Bottom)
{
usedBottom = Math.Max(usedBottom, startBottom + childUsedSize.Height);
startBottom += childUsedSize.Height;
minWidth = Math.Max(minWidth, usedLeft + usedRight + childUsedSize.Width);
}
else if (dockRegion == DockRegion.BottomOverlay)
{
usedBottom = Math.Max(usedBottom, startBottom + childUsedSize.Height);
minWidth = Math.Max(minWidth, usedLeft + usedRight + childUsedSize.Width);
}
else
{
throw new NotSupportedException("Unsupported dock region.");
}
// Update the remaining size
remainingSize = new Size(
(float)Math.Max(0, availableSize.Width - startLeft - startRight),
(float)Math.Max(0, availableSize.Height - startTop - startBottom));
// Update the child state
childWidthState |= child.LayoutProperties().MeasuredSize.WidthState;
childHeightState |= child.LayoutProperties().MeasuredSize.HeightState;
}
}
// Measure the center elements now that the center size has been completely calculated
Size usedCenterSize = new Size(0, 0);
for (int i = 0; i < childCount; i += 1)
{
NativeView child = this.GetChildAt(i);
if (child.Hidden)
{
continue;
}
var layoutParams = (LayoutParams)child.LayoutParameters();
var dockRegion = layoutParams.DockRegion;
// Arrange only the center elements
if (dockRegion != DockRegion.CenterOverlay)
{
continue;
}
this.MeasureChildWithMarginsOverride(
child,
widthMeasureSpec,
usedLeft + usedRight,
layoutParams.Width,
heightMeasureSpec,
usedTop + usedBottom,
layoutParams.Height);
Size childUsedSize = GetChildUsedSizeWithMargins(child, layoutParams);
usedCenterSize = new Size(
Math.Max(usedCenterSize.Width, childUsedSize.Width),
Math.Max(usedCenterSize.Height, childUsedSize.Height));
childWidthState |= child.LayoutProperties().MeasuredSize.WidthState;
childHeightState |= child.LayoutProperties().MeasuredSize.HeightState;
}
// Calculate the total size used by children
Size usedSize = new Size(
(float)Math.Max(minWidth, usedLeft + usedRight + usedCenterSize.Width),
(float)Math.Max(minHeight, usedTop + usedBottom + usedCenterSize.Height));
// Default the final size to the size used by children
var finalSize = new Size(
usedSize.Width + layoutProperties.Padding.Left + layoutProperties.Padding.Right,
usedSize.Height + layoutProperties.Padding.Top + layoutProperties.Padding.Bottom);
var dimensionX = ResolveSizeAndState(finalSize.Width, widthMeasureSpec, childWidthState);
var dimensionY = ResolveSizeAndState(finalSize.Height, heightMeasureSpec, childHeightState);
this.SetMeasuredSize(dimensionX, dimensionY);
}