Customizing Your Xamarin.Forms App with a Dark Theme using DynamicResources

When it comes to creating a visually appealing mobile app, customizing your theme can be a crucial step in enhancing user experience. In this article, we'll explore how to implement a dark theme for our Xamarin.Forms app using DynamicResources.

Understanding DynamicResources

Unlike traditional StaticResources, DynamicResources allow us to assign values dynamically at runtime. This means that instead of hardcoding colors or styles in your XAML file, you can define them programmatically and apply them to various elements in your app.

Implementing a Dark Theme

To create a dark theme for our Xamarin.Forms app, we'll need to define the necessary DynamicResources and update our App.xaml file accordingly. Here's an example of how to do this:

```csharp

SetDynamicResource(DynamicNavigationBarColor, 'Accent')

SetDynamicResource(Elevation4dpColor, 'DarkElevation4dp')

SetDynamicResource(DynamicSecondaryTextColor, 'TextSecondaryDarkColor')

SetDynamicResource(DynamicPrimaryTextColor, 'TextPrimaryDarkColor')

SetDynamicResource(DynamicHasShadow, false)

SetDynamicResource(DynamicBottomShadow, ShadowType.None)

SetDynamicResource(DynamicTopShadow, ShadowType.None)

SetDynamicResource(DynamicBarTextColor, 'TextPrimaryDarkColor')

SetDynamicResource(DynamicNavigationBarColor, 'DarkElevation2dp')

public static void SetDynamicResource(string targetResourceName, T value)

{

throw new InvalidOperationException($'key not found in the resource dictionary');

}

public static void SetDynamicResource(string targetResourceName, string sourceResourceName)

const string Elevation4dpColor = nameof(Elevation4dpColor);

const string DynamicHasShadow = nameof(DynamicHasShadow);

const string DynamicBottomShadow = nameof(DynamicBottomShadow);

const string DynamicTopShadow = nameof(DynamicTopShadow);

const string DynamicBarTextColor = nameof(DynamicBarTextColor);

const string DynamicBackgroundColor = nameof(DynamicBackgroundColor);

const string DynamicNavigationBarColor = nameof(DynamicNavigationBarColor);

const string DynamicSecondaryTextColor = nameof(DynamicSecondaryTextColor);

const string DynamicPrimaryTextColor = nameof(DynamicPrimaryTextColor);

```

Swapping StaticResources for DynamicResources

To apply the dark theme to our app, we'll need to swap out any instances of StaticResource with DynamicResource in our XAML file. This will allow us to dynamically update the values of these resources at runtime.

For example, instead of using `StaticResource={StaticResource DarkSurface}`, we can use `DynamicResource={DynamicResource DynamicBackgroundColor}`.

Animated Transition between Themes

To provide a seamless user experience when switching between themes, it's essential to include an animated transition. This can be achieved by creating a custom animation or using Xamarin.Forms' built-in animations.

In this article, we've explored how to create a dark theme for our Xamarin.Forms app using DynamicResources. By swapping out StaticResources for DynamicResources and updating our App.xaml file accordingly, we can dynamically update the values of these resources at runtime. Additionally, including an animated transition between themes provides a seamless user experience.

References

* 'Xamarin.Forms Documentation: DynamicResources'(https://docs.microsoft.com/en-us/xamarin/xamarin-forms/app-fundamentals/styles-xaml/dynamic-resources)

* 'Xamarin.Forms Documentation: Animations'(https://docs.microsoft.com/en-us/xamarin/xamarin-forms/app-fundamentals/effects/animations)

Note that this article is a summary of the provided text and may not cover all aspects of theming in Xamarin.Forms. For a more comprehensive guide, please refer to the official documentation or additional resources.

Xamarin studio dark theme