CrossPlatformLiveData

Android LiveData inspired .NET implementation - lifecycle aware rx streams

Medium article about CrossPlatformLiveData

CrossPlatformLiveData is a C# library inspired by Android Jetpack LiveData, intended for platform independent use with Xamarin and other cross platform frameworks.

CrossPlatformLiveData is a light weight solution to effective implementation of MVVM architecture pattern.

Features:

• Rx stream with UI lifecycle awareness,
• Last value cache - state preservation,
• Everything that you need to implement MVVM pattern

Installation

• Core/Logic project - add CrossPlatformLiveData nuget,
• Android project - add CrossPlatformLiveData, CrossPlatformLiveData.Android nuggets,
• iOS project - add CrossPlatformLiveData, CrossPlatformLiveData.iOS nuggets

CrossPlatformLiveData.Android provides base UI classes with LifecycleManger linked to lifecycle events:
LiveDataActivity, LiveDataAppCompatActivity, LiveDataAppCompatDialogFragment, LiveDataFragment, LiveDataFragmentActivity, LiveDataSupportDialogFragment, LiveDataSupportFragment

CrossPlatformLiveData.iOS provides base UI classes with LifecycleManger linked to lifecycle events:
LiveDataViewController

For other platforms all you need to do is provide LifecycleManger with lifecyle events when they occur, implementation should be self explanatory.

Usage

Logic/Core:

Add LiveData fields in ViewModel/Presenter class:

public ILiveData<string> SampleLiveData { get; } = new LiveData<string>();

Post new value to LiveData:

SampleLiveData.PostValue("Hello World!");

UI:

Observe LiveData streams with LifecycleManager

viewModel.SampleLiveData.Observe(LifecycleManager, OnNextSample, e => {//handle error here}));

private void OnNextSample(string newText)
{
	someTextView.Text = newText;
}

RxWrapper (Optional)

Optionally you can use RxWrapper template class that reduces boilerplate code by bundling value, request status, and exception in single model:

public ILiveData<RxWrapper<SampleResponse>> NetworkingLiveData { get; } = new LiveData<RxWrapper<SampleResponse>>();

//Notify UI that request is pending
NetworkingLiveData.PostValue(RxWrapper<SampleResponse>.Pending());
//Data fetch has succeded
NetworkingLiveData.PostValue(RxWrapper<SampleResponse>.Ok(model1));
//Error has occured during network call
NetworkingLiveData.PostValue(RxWrapper<SampleResponse>.Error(new Exception("No network")));

private void OnNextNetworkingData(RxWrapper<SampleResponse> response)
{
	switch (response.Status)
	{
		case RxStatus.Ok:
			//Update UI on succes
			break;
		case RxStatus.Pending:
			//Show loading spinner
			break;
		case RxStatus.Error:
			//Display error alert
			break;
	}
}

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