MyAvaloniaDemo/AuroraDesk.Presentation/ViewModels/Pages/BreathePageViewModel.cs

using AuroraDesk.Presentation.ViewModels.Base;
using ReactiveUI;
using System.Collections.Generic;
using System.Linq;

namespace AuroraDesk.Presentation.ViewModels.Pages;

/// <summary>
/// 基于 Skottie 的呼吸动画页面 ViewModel
/// </summary>
public class BreathePageViewModel : RoutableViewModel
{
    private readonly IList<AnimationOption> _availableAnimations;
    private int _repeatCount = Avalonia.Skia.Lottie.Lottie.Infinity;
    private string _animationPath = "avares://AuroraDesk.Presentation/Resources/Animations/breathe.json";
    private string _pageTitle = "呼吸动画";
    private string _pageDescription = "演示如何在 Avalonia 中使用 Skottie 播放 Lottie 动画。";
    private AnimationOption? _selectedAnimation;
    private bool _isUpdatingSelection;

    /// <summary>
    /// 构造函数
    /// </summary>
    /// <param name="hostScreen">宿主 Screen</param>
    public BreathePageViewModel(IScreen hostScreen)
        : base(hostScreen, "BreatheAnimation")
    {
        _availableAnimations =
        [
            new AnimationOption("呼吸引导", "avares://AuroraDesk.Presentation/Resources/Animations/breathe.json"),
            new AnimationOption("呼吸引导 V2", "avares://AuroraDesk.Presentation/Resources/Animations/breatheV2.json"),
            new AnimationOption("科技律动 V3", "avares://AuroraDesk.Presentation/Resources/Animations/breathe_V3.json"),
        ];

        _selectedAnimation = _availableAnimations.FirstOrDefault(x => x.Path == _animationPath)
            ?? _availableAnimations.FirstOrDefault();

        if (_selectedAnimation is not null && _selectedAnimation.Path != _animationPath)
        {
            _animationPath = _selectedAnimation.Path;
        }
    }

    /// <summary>
    /// 动画文件的资源路径（avares URI）
    /// </summary>
    public string AnimationPath
    {
        get => _animationPath;
        set
        {
            if (value == _animationPath)
            {
                return;
            }

            this.RaiseAndSetIfChanged(ref _animationPath, value);

            if (_isUpdatingSelection)
            {
                return;
            }

            try
            {
                _isUpdatingSelection = true;
                var match = _availableAnimations.FirstOrDefault(x => x.Path == value);
                SelectedAnimation = match;
            }
            finally
            {
                _isUpdatingSelection = false;
            }
        }
    }

    /// <summary>
    /// 动画重复次数，默认无限循环
    /// </summary>
    public int RepeatCount
    {
        get => _repeatCount;
        set => this.RaiseAndSetIfChanged(ref _repeatCount, value);
    }

    /// <summary>
    /// 页面标题
    /// </summary>
    public string PageTitle
    {
        get => _pageTitle;
        set => this.RaiseAndSetIfChanged(ref _pageTitle, value);
    }

    /// <summary>
    /// 页面描述
    /// </summary>
    public string PageDescription
    {
        get => _pageDescription;
        set => this.RaiseAndSetIfChanged(ref _pageDescription, value);
    }

    /// <summary>
    /// 可供选择的动画资源列表
    /// </summary>
    public IReadOnlyList<AnimationOption> AvailableAnimations => (IReadOnlyList<AnimationOption>)_availableAnimations;

    /// <summary>
    /// 当前选中的动画资源
    /// </summary>
    public AnimationOption? SelectedAnimation
    {
        get => _selectedAnimation;
        set
        {
            if (ReferenceEquals(_selectedAnimation, value))
            {
                return;
            }

            this.RaiseAndSetIfChanged(ref _selectedAnimation, value);

            if (_isUpdatingSelection)
            {
                return;
            }

            if (value is null)
            {
                return;
            }

            try
            {
                _isUpdatingSelection = true;
                AnimationPath = value.Path;
            }
            finally
            {
                _isUpdatingSelection = false;
            }
        }
    }

    /// <summary>
    /// 表示可选动画的显示名称与路径
    /// </summary>
    public record AnimationOption(string DisplayName, string Path);
}