maui-linux/Views/SkiaPicker.cs

662 lines
19 KiB
C#

// Licensed to the .NET Foundation under one or more agreements.
// The .NET Foundation licenses this file to you under the MIT license.
using SkiaSharp;
namespace Microsoft.Maui.Platform;
/// <summary>
/// Skia-rendered picker/dropdown control with full XAML styling support.
/// </summary>
public class SkiaPicker : SkiaView
{
#region BindableProperties
/// <summary>
/// Bindable property for SelectedIndex.
/// </summary>
public static readonly BindableProperty SelectedIndexProperty =
BindableProperty.Create(
nameof(SelectedIndex),
typeof(int),
typeof(SkiaPicker),
-1,
BindingMode.TwoWay,
propertyChanged: (b, o, n) => ((SkiaPicker)b).OnSelectedIndexChanged());
/// <summary>
/// Bindable property for Title.
/// </summary>
public static readonly BindableProperty TitleProperty =
BindableProperty.Create(
nameof(Title),
typeof(string),
typeof(SkiaPicker),
"",
propertyChanged: (b, o, n) => ((SkiaPicker)b).Invalidate());
/// <summary>
/// Bindable property for TextColor.
/// </summary>
public static readonly BindableProperty TextColorProperty =
BindableProperty.Create(
nameof(TextColor),
typeof(SKColor),
typeof(SkiaPicker),
SKColors.Black,
propertyChanged: (b, o, n) => ((SkiaPicker)b).Invalidate());
/// <summary>
/// Bindable property for TitleColor.
/// </summary>
public static readonly BindableProperty TitleColorProperty =
BindableProperty.Create(
nameof(TitleColor),
typeof(SKColor),
typeof(SkiaPicker),
new SKColor(0x80, 0x80, 0x80),
propertyChanged: (b, o, n) => ((SkiaPicker)b).Invalidate());
/// <summary>
/// Bindable property for BorderColor.
/// </summary>
public static readonly BindableProperty BorderColorProperty =
BindableProperty.Create(
nameof(BorderColor),
typeof(SKColor),
typeof(SkiaPicker),
new SKColor(0xBD, 0xBD, 0xBD),
propertyChanged: (b, o, n) => ((SkiaPicker)b).Invalidate());
/// <summary>
/// Bindable property for DropdownBackgroundColor.
/// </summary>
public static readonly BindableProperty DropdownBackgroundColorProperty =
BindableProperty.Create(
nameof(DropdownBackgroundColor),
typeof(SKColor),
typeof(SkiaPicker),
SKColors.White,
propertyChanged: (b, o, n) => ((SkiaPicker)b).Invalidate());
/// <summary>
/// Bindable property for SelectedItemBackgroundColor.
/// </summary>
public static readonly BindableProperty SelectedItemBackgroundColorProperty =
BindableProperty.Create(
nameof(SelectedItemBackgroundColor),
typeof(SKColor),
typeof(SkiaPicker),
new SKColor(0x21, 0x96, 0xF3, 0x30),
propertyChanged: (b, o, n) => ((SkiaPicker)b).Invalidate());
/// <summary>
/// Bindable property for HoverItemBackgroundColor.
/// </summary>
public static readonly BindableProperty HoverItemBackgroundColorProperty =
BindableProperty.Create(
nameof(HoverItemBackgroundColor),
typeof(SKColor),
typeof(SkiaPicker),
new SKColor(0xE0, 0xE0, 0xE0),
propertyChanged: (b, o, n) => ((SkiaPicker)b).Invalidate());
/// <summary>
/// Bindable property for FontFamily.
/// </summary>
public static readonly BindableProperty FontFamilyProperty =
BindableProperty.Create(
nameof(FontFamily),
typeof(string),
typeof(SkiaPicker),
"Sans",
propertyChanged: (b, o, n) => ((SkiaPicker)b).InvalidateMeasure());
/// <summary>
/// Bindable property for FontSize.
/// </summary>
public static readonly BindableProperty FontSizeProperty =
BindableProperty.Create(
nameof(FontSize),
typeof(float),
typeof(SkiaPicker),
14f,
propertyChanged: (b, o, n) => ((SkiaPicker)b).InvalidateMeasure());
/// <summary>
/// Bindable property for ItemHeight.
/// </summary>
public static readonly BindableProperty ItemHeightProperty =
BindableProperty.Create(
nameof(ItemHeight),
typeof(float),
typeof(SkiaPicker),
40f,
propertyChanged: (b, o, n) => ((SkiaPicker)b).Invalidate());
/// <summary>
/// Bindable property for CornerRadius.
/// </summary>
public static readonly BindableProperty CornerRadiusProperty =
BindableProperty.Create(
nameof(CornerRadius),
typeof(float),
typeof(SkiaPicker),
4f,
propertyChanged: (b, o, n) => ((SkiaPicker)b).Invalidate());
#endregion
#region Properties
/// <summary>
/// Gets or sets the selected index.
/// </summary>
public int SelectedIndex
{
get => (int)GetValue(SelectedIndexProperty);
set => SetValue(SelectedIndexProperty, value);
}
/// <summary>
/// Gets or sets the title/placeholder.
/// </summary>
public string Title
{
get => (string)GetValue(TitleProperty);
set => SetValue(TitleProperty, value);
}
/// <summary>
/// Gets or sets the text color.
/// </summary>
public SKColor TextColor
{
get => (SKColor)GetValue(TextColorProperty);
set => SetValue(TextColorProperty, value);
}
/// <summary>
/// Gets or sets the title color.
/// </summary>
public SKColor TitleColor
{
get => (SKColor)GetValue(TitleColorProperty);
set => SetValue(TitleColorProperty, value);
}
/// <summary>
/// Gets or sets the border color.
/// </summary>
public SKColor BorderColor
{
get => (SKColor)GetValue(BorderColorProperty);
set => SetValue(BorderColorProperty, value);
}
/// <summary>
/// Gets or sets the dropdown background color.
/// </summary>
public SKColor DropdownBackgroundColor
{
get => (SKColor)GetValue(DropdownBackgroundColorProperty);
set => SetValue(DropdownBackgroundColorProperty, value);
}
/// <summary>
/// Gets or sets the selected item background color.
/// </summary>
public SKColor SelectedItemBackgroundColor
{
get => (SKColor)GetValue(SelectedItemBackgroundColorProperty);
set => SetValue(SelectedItemBackgroundColorProperty, value);
}
/// <summary>
/// Gets or sets the hover item background color.
/// </summary>
public SKColor HoverItemBackgroundColor
{
get => (SKColor)GetValue(HoverItemBackgroundColorProperty);
set => SetValue(HoverItemBackgroundColorProperty, value);
}
/// <summary>
/// Gets or sets the font family.
/// </summary>
public string FontFamily
{
get => (string)GetValue(FontFamilyProperty);
set => SetValue(FontFamilyProperty, value);
}
/// <summary>
/// Gets or sets the font size.
/// </summary>
public float FontSize
{
get => (float)GetValue(FontSizeProperty);
set => SetValue(FontSizeProperty, value);
}
/// <summary>
/// Gets or sets the item height.
/// </summary>
public float ItemHeight
{
get => (float)GetValue(ItemHeightProperty);
set => SetValue(ItemHeightProperty, value);
}
/// <summary>
/// Gets or sets the corner radius.
/// </summary>
public float CornerRadius
{
get => (float)GetValue(CornerRadiusProperty);
set => SetValue(CornerRadiusProperty, value);
}
/// <summary>
/// Gets the items list.
/// </summary>
public IList<string> Items => _items;
/// <summary>
/// Gets the selected item.
/// </summary>
public string? SelectedItem => SelectedIndex >= 0 && SelectedIndex < _items.Count ? _items[SelectedIndex] : null;
/// <summary>
/// Gets or sets whether the dropdown is open.
/// </summary>
public bool IsOpen
{
get => _isOpen;
set
{
if (_isOpen != value)
{
_isOpen = value;
if (_isOpen)
{
RegisterPopupOverlay(this, DrawDropdownOverlay);
}
else
{
UnregisterPopupOverlay(this);
}
Invalidate();
}
}
}
#endregion
private readonly List<string> _items = new();
private bool _isOpen;
private float _dropdownMaxHeight = 200;
private int _hoveredItemIndex = -1;
/// <summary>
/// Event raised when selected index changes.
/// </summary>
public event EventHandler? SelectedIndexChanged;
public SkiaPicker()
{
IsFocusable = true;
}
private void OnSelectedIndexChanged()
{
SelectedIndexChanged?.Invoke(this, EventArgs.Empty);
Invalidate();
}
/// <summary>
/// Sets the items in the picker.
/// </summary>
public void SetItems(IEnumerable<string> items)
{
_items.Clear();
_items.AddRange(items);
if (SelectedIndex >= _items.Count)
{
SelectedIndex = _items.Count > 0 ? 0 : -1;
}
Invalidate();
}
private void DrawDropdownOverlay(SKCanvas canvas)
{
if (_items.Count == 0 || !_isOpen) return;
// Use ScreenBounds for overlay drawing to account for scroll offset
DrawDropdown(canvas, ScreenBounds);
}
protected override void OnDraw(SKCanvas canvas, SKRect bounds)
{
DrawPickerButton(canvas, bounds);
}
private void DrawPickerButton(SKCanvas canvas, SKRect bounds)
{
// Draw background
using var bgPaint = new SKPaint
{
Color = IsEnabled ? BackgroundColor : new SKColor(0xF5, 0xF5, 0xF5),
Style = SKPaintStyle.Fill,
IsAntialias = true
};
var buttonRect = new SKRoundRect(bounds, CornerRadius);
canvas.DrawRoundRect(buttonRect, bgPaint);
// Draw border
using var borderPaint = new SKPaint
{
Color = IsFocused ? new SKColor(0x21, 0x96, 0xF3) : BorderColor,
Style = SKPaintStyle.Stroke,
StrokeWidth = IsFocused ? 2 : 1,
IsAntialias = true
};
canvas.DrawRoundRect(buttonRect, borderPaint);
// Draw text or title
using var font = new SKFont(SKTypeface.Default, FontSize);
using var textPaint = new SKPaint(font)
{
IsAntialias = true
};
string displayText;
if (SelectedIndex >= 0 && SelectedIndex < _items.Count)
{
displayText = _items[SelectedIndex];
textPaint.Color = IsEnabled ? TextColor : TextColor.WithAlpha(128);
}
else
{
displayText = Title;
textPaint.Color = TitleColor;
}
var textBounds = new SKRect();
textPaint.MeasureText(displayText, ref textBounds);
var textX = bounds.Left + 12;
var textY = bounds.MidY - textBounds.MidY;
canvas.DrawText(displayText, textX, textY, textPaint);
// Draw dropdown arrow
DrawDropdownArrow(canvas, bounds);
}
private void DrawDropdownArrow(SKCanvas canvas, SKRect bounds)
{
using var paint = new SKPaint
{
Color = IsEnabled ? TextColor : TextColor.WithAlpha(128),
Style = SKPaintStyle.Stroke,
StrokeWidth = 2,
IsAntialias = true,
StrokeCap = SKStrokeCap.Round
};
var arrowSize = 6f;
var centerX = bounds.Right - 20;
var centerY = bounds.MidY;
using var path = new SKPath();
if (_isOpen)
{
path.MoveTo(centerX - arrowSize, centerY + arrowSize / 2);
path.LineTo(centerX, centerY - arrowSize / 2);
path.LineTo(centerX + arrowSize, centerY + arrowSize / 2);
}
else
{
path.MoveTo(centerX - arrowSize, centerY - arrowSize / 2);
path.LineTo(centerX, centerY + arrowSize / 2);
path.LineTo(centerX + arrowSize, centerY - arrowSize / 2);
}
canvas.DrawPath(path, paint);
}
private void DrawDropdown(SKCanvas canvas, SKRect bounds)
{
if (_items.Count == 0) return;
var dropdownHeight = Math.Min(_items.Count * ItemHeight, _dropdownMaxHeight);
var dropdownRect = new SKRect(
bounds.Left,
bounds.Bottom + 4,
bounds.Right,
bounds.Bottom + 4 + dropdownHeight);
// Draw shadow
using var shadowPaint = new SKPaint
{
Color = new SKColor(0, 0, 0, 40),
MaskFilter = SKMaskFilter.CreateBlur(SKBlurStyle.Normal, 4),
Style = SKPaintStyle.Fill
};
var shadowRect = new SKRect(dropdownRect.Left + 2, dropdownRect.Top + 2, dropdownRect.Right + 2, dropdownRect.Bottom + 2);
canvas.DrawRoundRect(new SKRoundRect(shadowRect, CornerRadius), shadowPaint);
// Draw dropdown background
using var bgPaint = new SKPaint
{
Color = DropdownBackgroundColor,
Style = SKPaintStyle.Fill,
IsAntialias = true
};
canvas.DrawRoundRect(new SKRoundRect(dropdownRect, CornerRadius), bgPaint);
// Draw border
using var borderPaint = new SKPaint
{
Color = BorderColor,
Style = SKPaintStyle.Stroke,
StrokeWidth = 1,
IsAntialias = true
};
canvas.DrawRoundRect(new SKRoundRect(dropdownRect, CornerRadius), borderPaint);
// Clip to dropdown bounds
canvas.Save();
canvas.ClipRoundRect(new SKRoundRect(dropdownRect, CornerRadius));
// Draw items
using var font = new SKFont(SKTypeface.Default, FontSize);
using var textPaint = new SKPaint(font)
{
Color = TextColor,
IsAntialias = true
};
for (int i = 0; i < _items.Count; i++)
{
var itemTop = dropdownRect.Top + i * ItemHeight;
if (itemTop > dropdownRect.Bottom) break;
var itemRect = new SKRect(dropdownRect.Left, itemTop, dropdownRect.Right, itemTop + ItemHeight);
// Draw item background
if (i == SelectedIndex)
{
using var selectedPaint = new SKPaint
{
Color = SelectedItemBackgroundColor,
Style = SKPaintStyle.Fill
};
canvas.DrawRect(itemRect, selectedPaint);
}
else if (i == _hoveredItemIndex)
{
using var hoverPaint = new SKPaint
{
Color = HoverItemBackgroundColor,
Style = SKPaintStyle.Fill
};
canvas.DrawRect(itemRect, hoverPaint);
}
// Draw item text
var textBounds = new SKRect();
textPaint.MeasureText(_items[i], ref textBounds);
var textX = itemRect.Left + 12;
var textY = itemRect.MidY - textBounds.MidY;
canvas.DrawText(_items[i], textX, textY, textPaint);
}
canvas.Restore();
}
public override void OnPointerPressed(PointerEventArgs e)
{
if (!IsEnabled) return;
if (IsOpen)
{
// Use ScreenBounds for popup coordinate calculations (accounts for scroll offset)
var screenBounds = ScreenBounds;
var dropdownTop = screenBounds.Bottom + 4;
if (e.Y >= dropdownTop)
{
var itemIndex = (int)((e.Y - dropdownTop) / ItemHeight);
if (itemIndex >= 0 && itemIndex < _items.Count)
{
SelectedIndex = itemIndex;
}
}
IsOpen = false;
}
else
{
IsOpen = true;
}
Invalidate();
}
public override void OnPointerMoved(PointerEventArgs e)
{
if (!_isOpen) return;
// Use ScreenBounds for popup coordinate calculations (accounts for scroll offset)
var screenBounds = ScreenBounds;
var dropdownTop = screenBounds.Bottom + 4;
if (e.Y >= dropdownTop)
{
var newHovered = (int)((e.Y - dropdownTop) / ItemHeight);
if (newHovered != _hoveredItemIndex && newHovered >= 0 && newHovered < _items.Count)
{
_hoveredItemIndex = newHovered;
Invalidate();
}
}
else
{
if (_hoveredItemIndex != -1)
{
_hoveredItemIndex = -1;
Invalidate();
}
}
}
public override void OnPointerExited(PointerEventArgs e)
{
_hoveredItemIndex = -1;
Invalidate();
}
public override void OnKeyDown(KeyEventArgs e)
{
if (!IsEnabled) return;
switch (e.Key)
{
case Key.Enter:
case Key.Space:
IsOpen = !IsOpen;
e.Handled = true;
Invalidate();
break;
case Key.Escape:
if (IsOpen)
{
IsOpen = false;
e.Handled = true;
Invalidate();
}
break;
case Key.Up:
if (SelectedIndex > 0)
{
SelectedIndex--;
e.Handled = true;
}
break;
case Key.Down:
if (SelectedIndex < _items.Count - 1)
{
SelectedIndex++;
e.Handled = true;
}
break;
}
}
public override void OnFocusLost()
{
base.OnFocusLost();
if (IsOpen)
{
IsOpen = false;
}
}
protected override SKSize MeasureOverride(SKSize availableSize)
{
return new SKSize(
availableSize.Width < float.MaxValue ? Math.Min(availableSize.Width, 200) : 200,
40);
}
/// <summary>
/// Override to include dropdown area in hit testing.
/// </summary>
protected override bool HitTestPopupArea(float x, float y)
{
// Use ScreenBounds for hit testing (accounts for scroll offset)
var screenBounds = ScreenBounds;
// Always include the picker button itself
if (screenBounds.Contains(x, y))
return true;
// When open, also include the dropdown area
if (_isOpen && _items.Count > 0)
{
var dropdownHeight = Math.Min(_items.Count * ItemHeight, _dropdownMaxHeight);
var dropdownRect = new SKRect(
screenBounds.Left,
screenBounds.Bottom + 4,
screenBounds.Right,
screenBounds.Bottom + 4 + dropdownHeight);
return dropdownRect.Contains(x, y);
}
return false;
}
}