嗨，我正在开发一个使用Xamarin表格PCL的应用程序 . 我正在使用水平方向的stacklayout，其中我使用了大量按钮 . 但是按钮因为它们的堆叠宽度而被切断 . 我不想使用scrollview . 我希望他们在stacklayout的第一行没有空格时立即转到新行 .
我想要这个：
stacklayout是否有任何linebreak类型的属性？怎么做到这一点？
你想要的是 WrapLayout 你可以使用自定义控件here
WrapLayout
我也将在这里发布链接断点：
using System; using System.Linq; using System.Collections.Generic; namespace Xamarin.Forms { /// <summary> /// New WrapLayout /// </summary> /// <author>Jason Smith</author> public class WrapLayout : Layout<View> { Dictionary<View, SizeRequest> layoutCache = new Dictionary<View, SizeRequest> (); /// <summary> /// Backing Storage for the Spacing property /// </summary> public static readonly BindableProperty SpacingProperty = BindableProperty.Create<WrapLayout, double> (w => w.Spacing, 5, propertyChanged: (bindable, oldvalue, newvalue) => ((WrapLayout)bindable).layoutCache.Clear()); /// <summary> /// Spacing added between elements (both directions) /// </summary> /// <value>The spacing.</value> public double Spacing { get { return (double)GetValue (SpacingProperty); } set { SetValue (SpacingProperty, value); } } public WrapLayout () { VerticalOptions = HorizontalOptions = LayoutOptions.FillAndExpand; } protected override void OnChildMeasureInvalidated () { base.OnChildMeasureInvalidated (); layoutCache.Clear (); } protected override SizeRequest OnSizeRequest (double widthConstraint, double heightConstraint) { double lastX; double lastY; var layout = NaiveLayout (widthConstraint, heightConstraint, out lastX, out lastY); return new SizeRequest (new Size (lastX, lastY)); } protected override void LayoutChildren (double x, double y, double width, double height) { double lastX, lastY; var layout = NaiveLayout (width, height, out lastX, out lastY); foreach (var t in layout) { var offset = (int) ((width - t.Last ().Item2.Right) / 2); foreach (var dingus in t) { var location = new Rectangle(dingus.Item2.X + x + offset, dingus.Item2.Y + y, dingus.Item2.Width, dingus.Item2.Height); LayoutChildIntoBoundingRegion (dingus.Item1, location); } } } private List<List<Tuple<View, Rectangle>>> NaiveLayout (double width, double height, out double lastX, out double lastY) { double startX = 0; double startY = 0; double right = width; double nextY = 0; lastX = 0; lastY = 0; var result = new List<List<Tuple<View, Rectangle>>> (); var currentList = new List<Tuple<View, Rectangle>> (); foreach (var child in Children) { SizeRequest sizeRequest; if (!layoutCache.TryGetValue (child, out sizeRequest)) { layoutCache[child] = sizeRequest = child.GetSizeRequest (double.PositiveInfinity, double.PositiveInfinity); } var paddedWidth = sizeRequest.Request.Width + Spacing; var paddedHeight = sizeRequest.Request.Height + Spacing; if (startX + paddedWidth > right) { startX = 0; startY += nextY; if (currentList.Count > 0) { result.Add (currentList); currentList = new List<Tuple<View, Rectangle>> (); } } currentList.Add (new Tuple<View, Rectangle> (child, new Rectangle (startX, startY, sizeRequest.Request.Width, sizeRequest.Request.Height))); lastX = Math.Max (lastX, startX + paddedWidth); lastY = Math.Max (lastY, startY + paddedHeight); nextY = Math.Max (nextY, paddedHeight); startX += paddedWidth; } result.Add (currentList); return result; } } /// <summary> /// Simple Layout panel which performs wrapping on the boundaries. /// </summary> public class WrapLayoutOld : Layout<View> { /// <summary> /// Backing Storage for the Orientation property /// </summary> public static readonly BindableProperty OrientationProperty = BindableProperty.Create<WrapLayoutOld, StackOrientation> (w => w.Orientation, StackOrientation.Vertical, propertyChanged: (bindable, oldvalue, newvalue) => ((WrapLayoutOld)bindable).OnSizeChanged ()); /// <summary> /// Orientation (Horizontal or Vertical) /// </summary> public StackOrientation Orientation { get { return (StackOrientation)GetValue (OrientationProperty); } set { SetValue (OrientationProperty, value); } } /// <summary> /// Backing Storage for the Spacing property /// </summary> public static readonly BindableProperty SpacingProperty = BindableProperty.Create<WrapLayoutOld, double> (w => w.Spacing, 6, propertyChanged: (bindable, oldvalue, newvalue) => ((WrapLayoutOld)bindable).OnSizeChanged()); /// <summary> /// Spacing added between elements (both directions) /// </summary> /// <value>The spacing.</value> public double Spacing { get { return (double)GetValue (SpacingProperty); } set { SetValue (SpacingProperty, value); } } /// <summary> /// This is called when the spacing or orientation properties are changed - it forces /// the control to go back through a layout pass. /// </summary> private void OnSizeChanged() { this.ForceLayout(); } //http://forums.xamarin.com/discussion/17961/stacklayout-with-horizontal-orientation-how-to-wrap-vertically#latest // protected override void OnPropertyChanged // (string propertyName = null) // { // base.OnPropertyChanged(propertyName); // if ((propertyName == WrapLayout.OrientationProperty.PropertyName) || // (propertyName == WrapLayout.SpacingProperty.PropertyName)) { // this.OnSizeChanged(); // } // } /// <summary> /// This method is called during the measure pass of a layout cycle to get the desired size of an element. /// </summary> /// <param name="widthConstraint">The available width for the element to use.</param> /// <param name="heightConstraint">The available height for the element to use.</param> protected override SizeRequest OnSizeRequest (double widthConstraint, double heightConstraint) { if (WidthRequest > 0) widthConstraint = Math.Min (widthConstraint, WidthRequest); if (HeightRequest > 0) heightConstraint = Math.Min (heightConstraint, HeightRequest); double internalWidth = double.IsPositiveInfinity (widthConstraint) ? double.PositiveInfinity : Math.Max (0, widthConstraint); double internalHeight = double.IsPositiveInfinity (heightConstraint) ? double.PositiveInfinity : Math.Max (0, heightConstraint); return Orientation == StackOrientation.Vertical ? DoVerticalMeasure(internalWidth, internalHeight) : DoHorizontalMeasure(internalWidth, internalHeight); } /// <summary> /// Does the vertical measure. /// </summary> /// <returns>The vertical measure.</returns> /// <param name="widthConstraint">Width constraint.</param> /// <param name="heightConstraint">Height constraint.</param> private SizeRequest DoVerticalMeasure(double widthConstraint, double heightConstraint) { int columnCount = 1; double width = 0; double height = 0; double minWidth = 0; double minHeight = 0; double heightUsed = 0; foreach (var item in Children) { var size = item.GetSizeRequest(widthConstraint, heightConstraint); width = Math.Max (width, size.Request.Width); var newHeight = height + size.Request.Height + Spacing; if (newHeight > heightConstraint) { columnCount++; heightUsed = Math.Max(height, heightUsed); height = size.Request.Height; } else height = newHeight; minHeight = Math.Max(minHeight, size.Minimum.Height); minWidth = Math.Max (minWidth, size.Minimum.Width); } if (columnCount > 1) { height = Math.Max(height, heightUsed); width *= columnCount; // take max width } return new SizeRequest(new Size(width, height), new Size(minWidth,minHeight)); } /// <summary> /// Does the horizontal measure. /// </summary> /// <returns>The horizontal measure.</returns> /// <param name="widthConstraint">Width constraint.</param> /// <param name="heightConstraint">Height constraint.</param> private SizeRequest DoHorizontalMeasure(double widthConstraint, double heightConstraint) { int rowCount = 1; double width = 0; double height = 0; double minWidth = 0; double minHeight = 0; double widthUsed = 0; foreach (var item in Children) { var size = item.GetSizeRequest(widthConstraint, heightConstraint); height = Math.Max (height, size.Request.Height); var newWidth = width + size.Request.Width + Spacing; if (newWidth > widthConstraint) { rowCount++; widthUsed = Math.Max(width, widthUsed); width = size.Request.Width; } else width = newWidth; minHeight = Math.Max(minHeight, size.Minimum.Height); minWidth = Math.Max (minWidth, size.Minimum.Width); } if (rowCount > 1) { width = Math.Max(width, widthUsed); height = (height + Spacing) * rowCount - Spacing; // via MitchMilam } return new SizeRequest(new Size(width, height), new Size(minWidth,minHeight)); } /// <summary> /// Positions and sizes the children of a Layout. /// </summary> /// <param name="x">A value representing the x coordinate of the child region bounding box.</param> /// <param name="y">A value representing the y coordinate of the child region bounding box.</param> /// <param name="width">A value representing the width of the child region bounding box.</param> /// <param name="height">A value representing the height of the child region bounding box.</param> protected override void LayoutChildren (double x, double y, double width, double height) { if (Orientation == StackOrientation.Vertical) { double colWidth = 0; double yPos = y, xPos = x; foreach (var child in Children.Where(c => c.IsVisible)) { var request = child.GetSizeRequest (width, height); double childWidth = request.Request.Width; double childHeight = request.Request.Height; colWidth = Math.Max(colWidth, childWidth); if (yPos + childHeight > height) { yPos = y; xPos += colWidth + Spacing; colWidth = 0; } var region = new Rectangle (xPos, yPos, childWidth, childHeight); LayoutChildIntoBoundingRegion (child, region); yPos += region.Height + Spacing; } } else { double rowHeight = 0; double yPos = y, xPos = x; foreach (var child in Children.Where(c => c.IsVisible)) { var request = child.GetSizeRequest (width, height); double childWidth = request.Request.Width; double childHeight = request.Request.Height; rowHeight = Math.Max(rowHeight, childHeight); if (xPos + childWidth > width) { xPos = x; yPos += rowHeight + Spacing; rowHeight = 0; } var region = new Rectangle (xPos, yPos, childWidth, childHeight); LayoutChildIntoBoundingRegion (child, region); xPos += region.Width + Spacing; } } } } }
1 回答
你想要的是
WrapLayout你可以使用自定义控件here我也将在这里发布链接断点：