Support for .NET 6

[markuspalme]

🚀 Feature Requests

The library currently targets Xamarin.iOS but not net6-ios/net6-android. The new TFMs are the future and using this library in new projects is currently not possible.

To address my own very short-term needs I have created a port of the iOS part of this library to .NET 6:
https://github.com/markuspalme/LottieNet6/

Platforms affected (mark all that apply)

• 📱 iOS
• 🤖 Android
• 🏁 WPF
• 🌎 UWP
• 🍎 MacOS
• 📺 tvOS
• 🐒 MAUI

[FreakyAli]

+1

[evgenyvalavin]

It is not currently possible to use Lottie on net6-ios due to breaking changes in net6-ios: "All code must be recompiled to support .NET 6. Existing assemblies (such as NuGets built for the old TargetFrameworkIdentifier xamarinios10) won’t work and won’t be supported. Non-xamarin specific assets for net4.x, netstandard, netcoreapp, net5.0+, etc. will work fine however." - Link
Any plans on rebuilding on .NET 6?

[markuspalme]

@evgenyvalavin I have forked the library and ported it to net6-ios:
https://www.nuget.org/packages/Lottie.iOS

But of course an update of this excellent library would be better than a fork long-term.

[evgenyvalavin]

@markuspalme thanks! I already use the NuGet package.

Let's hope together this library will be updated 😄

[FreakyAli]

@markuspalme @evgenyvalavin My understanding of this is that this library will be obsolete and won't be updated to .net 6 at all. Instead, there is a Skia Sharp control that is going to be the Future of Lottie Animations in most .Net environments https://mono.github.io/SkiaSharp.Extended/api/ui-maui/sklottieview.html, I mean obviously, that's not on par with BaseFlow's version but that's the best we have ATM.

[Pluxury]

@FreakyAli How can I use sklottieview in xamarin.native apps ?
I think this is not possible and we should wait for the update of this package anyway.

[FreakyAli]

@Pluxury You are right for now this seems to be the case

[AdamDiament]

Does anyone have an android .net6 port for this?

[petro2050]

@martijn00 what is the current plan for this?

[martijn00]

I'm more than happy to accept a PR to fix this and release a new version. I've already done some work but can't get iOS to work.

[IeuanWalker]

@martijn00 where is the work you already started and do you remember what problems you were having on iOS?

[AdamDiament]

@martijn00 where is the work you already started and do you remember what problems you were having on iOS?

@IeuanWalker this is the in progress PR. I'm not aware of the specific iOS issues #379

[ivmirx]

One more attempt with .NET 9, using the newest Swift version of Lottie (but the binding is done via Objective-C of course):

• https://github.com/QotoQot/Bindings.Lottie.iOS
• https://www.nuget.org/packages/QotoQot.Bindings.Lottie.iOS

And I also wrote a step-by-step guide for creating bindings based on Lottie for iOS.

[Grzegorz1223]

@ivmirx thank you for the bindings! they work great and allowed me to switch from the patchy Skia Lottie implementation.

The only doubt I have is if you ever achieved to run smooth Animations on Android under heavy MainThread loads? I tried to use Lottie animation as my custom "ActivityIndicator" but it freezes a lot on Android, while being completely smooth on iOS. I implemented my handler in the following way:

`public class LottieViewHandler : ViewHandler<SpinnerView, LottieAnimationView>
{
string? _currentAnimationKey;

    private const string ANIMATION_NAME = "animation.json";

    public static readonly IPropertyMapper<SpinnerView, LottieViewHandler> Mapper =
        new PropertyMapper<SpinnerView, LottieViewHandler>(ViewMapper)
        {
            [nameof(SpinnerView.Loop)] = MapLoop,
            [nameof(SpinnerView.Speed)] = MapSpeed,
            [nameof(SpinnerView.IsPlaying)] = MapIsPlaying,
            [nameof(SpinnerView.AutoPlay)] = MapAutoPlay,
        };

    public LottieViewHandler() : base(Mapper)
    {
    }

    protected override LottieAnimationView CreatePlatformView()
    {
        var v = new LottieAnimationView(Context)
        {
            RepeatCount = -1, //loop
            RenderMode = RenderMode.Hardware
        };

        v.EnableMergePathsForKitKatAndAbove(true);
         
        try
        {
            v.SetUseCompositionFrameRate(true);
        }
        catch
        {

        }

        return v;
    }

    protected override void ConnectHandler(LottieAnimationView platformView)
    {
        base.ConnectHandler(platformView);
        ApplyAll(VirtualView, platformView);
    }

    protected override void DisconnectHandler(LottieAnimationView platformView)
    {
        try
        {
            platformView.CancelAnimation();
            platformView.ClearAnimation();
        }
        catch (ObjectDisposedException)
        {
            /* already disposed */
        }

        base.DisconnectHandler(platformView);
    }

    static void MapLoop(IElementHandler h, SpinnerView v)
    {
        var handler = (LottieViewHandler)h;
        var p = handler.PlatformView;
        if (p is null)
        {
            return;
        }

        p.RepeatCount = v.Loop ? -1 : 0;
    }

    static void MapSpeed(IElementHandler h, SpinnerView v)
    {
        var handler = (LottieViewHandler)h;
        var p = handler.PlatformView;
        if (p is null)
        {
            return;
        }

        p.Speed = (float)v.Speed;
    }

    static void MapIsPlaying(IElementHandler h, SpinnerView v)
    {
        var handler = (LottieViewHandler)h;
        var p = handler.PlatformView;
        if (p is null)
        {
            return;
        }

        if (v.IsPlaying)
        {
            if (!p.IsAnimating)
            {
                p.PlayAnimation();
            }
        }
        else
        {
            if (p.IsAnimating)
            {
                p.PauseAnimation();
            }
        }
    }

    static void MapAutoPlay(IElementHandler h, SpinnerView v)
    {
        var handler = (LottieViewHandler)h;
        var p = handler.PlatformView;
        if (p is null)
        {
            return;
        }

        if (v.AutoPlay && !p.IsAnimating)
        {
            p.PlayAnimation();
        }
    }

    void ApplyAll(SpinnerView v, LottieAnimationView p)
    {
        LoadCompositionAsync(v);
        MapLoop(this, v);
        MapSpeed(this, v);
        
        if (p.Composition is not null)
        {
            if (v.AutoPlay || v.IsPlaying)
            {
                p.PlayAnimation();
            }
            else
            {
                p.PauseAnimation();
            }
        }
    }
    
    void LoadCompositionAsync(SpinnerView v)
    {
        var p = PlatformView;
        if (p is null)
        {
            return;
        }

        var anim = ANIMATION_NAME;
        
        if (string.IsNullOrWhiteSpace(anim))
        {
            _currentAnimationKey = null;

            try
            {
                p.CancelAnimation();
                p.ClearAnimation();
                p.Progress = 0f;
            }
            catch
            {
                 /* ignore */
            }

            return;
        }
        
        var baseName = anim.EndsWith(".json", StringComparison.OrdinalIgnoreCase) ? anim[..^5] : anim;
        
        var requestKey = baseName;
        _currentAnimationKey = requestKey;
        
        int rawId = 0;
        try
        {
            rawId = Context.Resources?.GetIdentifier(baseName, "raw", Context.PackageName) ?? 0;
        }
        catch (Exception)
        {
            rawId = 0;
        }

        LottieTask task;

        if (rawId != 0)
        {
            task = LottieCompositionFactory.FromRawRes(Context, rawId);
        }
        else
        {
            var fileName = anim.EndsWith(".json", StringComparison.OrdinalIgnoreCase) ? anim : $"{baseName}.json";
            task = LottieCompositionFactory.FromAsset(Context, fileName);
        }
        
        task.AddListener(new LottieListener(comp =>
        {
            if (!string.Equals(_currentAnimationKey, requestKey, StringComparison.Ordinal))
            {
                return;
            }
            
            p.Composition = comp;
            
            p.RepeatCount = v.Loop ? -1 : 0;
            p.Speed = (float)v.Speed;

            if (v.AutoPlay || v.IsPlaying)
            {
                p.PlayAnimation();
            }
        }));
    }
    
    sealed class LottieListener : Java.Lang.Object, ILottieListener
    {
        private readonly Action<LottieComposition> _onResult;
        public LottieListener(Action<LottieComposition> onResult) => _onResult = onResult;
        public void OnResult(Java.Lang.Object result) => _onResult((LottieComposition)result);
    }
    
}`

Do you see something I'm missing, or it's just Android peculiarty of how it is using the Composers?

BTW a workaround for Android is to convert your Lottie json to gif, and show it instead, it is perfectly smooth under any conditions, while on iOS the gifs are freezeing under heavy loads.

CC: @martijn00 @AdamDiament