我想在全屏上的SKCanvasView上方放置一个按钮

Question

图像通过SKCanvasView显示（全屏）。我想在其中放置按钮之类的控件，但它在启动时显示，但是在显示图像时消失。！

Answer 1

您可以使用absolute-layout布置控件：

public TileAlignmentPage()
{
    Title = "Tile Alignment";
    var layout = new AbsoluteLayout();

    SKCanvasView canvasView = new SKCanvasView();
    canvasView.PaintSurface += OnCanvasViewPaintSurface;
    ...
    AbsoluteLayout.SetLayoutBounds(canvasView, new Rectangle(0, 0, 1, 1));
    AbsoluteLayout.SetLayoutFlags(canvasView, AbsoluteLayoutFlags.All);

    Button clear_button = new Button { Text = "-" };
    ...
    AbsoluteLayout.SetLayoutBounds(clear_button, new Rectangle(0.5, 0.45, 250, 50));
    AbsoluteLayout.SetLayoutFlags(clear_button, AbsoluteLayoutFlags.PositionProportional);

    Button update_button = new Button { Text = "+" };
    ...
    AbsoluteLayout.SetLayoutBounds(update_button, new Rectangle(0.5, 0.55, 250, 50));
    AbsoluteLayout.SetLayoutFlags(update_button, AbsoluteLayoutFlags.PositionProportional);

    layout.Children.Add(canvasView);
    layout.Children.Add(clear_button);
    layout.Children.Add(update_button);
    Content = layout;
}