Скачать или смотреть Leveraging OnCurrentPageChanged in Xamarin Forms' Tabbed Pages for Dynamic Data Loading

Discover how to efficiently load data in Xamarin Forms Tabbed Pages only when a tab is selected using the `OnCurrentPageChanged` method.
---
This video is based on the question https://stackoverflow.com/q/64725182/ asked by the user 'mm sh' ( https://stackoverflow.com/u/1786401/ ) and on the answer https://stackoverflow.com/a/64729190/ provided by the user 'Jai Gupta' ( https://stackoverflow.com/u/5141991/ ) at 'Stack Overflow' website. Thanks to these great users and Stackexchange community for their contributions.

Visit these links for original content and any more details, such as alternate solutions, latest updates/developments on topic, comments, revision history etc. For example, the original title of the Question was: Xamarin Forms Tabbed Page Load Data when tab is Select

Also, Content (except music) licensed under CC BY-SA https://meta.stackexchange.com/help/l...
The original Question post is licensed under the 'CC BY-SA 4.0' ( https://creativecommons.org/licenses/... ) license, and the original Answer post is licensed under the 'CC BY-SA 4.0' ( https://creativecommons.org/licenses/... ) license.

If anything seems off to you, please feel free to write me at vlogize [AT] gmail [DOT] com.
---
Efficiently Load Data on Tab Selection in Xamarin Forms Tabbed Pages

Creating a dynamic and responsive user interface in your mobile applications can be a challenge, especially when dealing with data-heavy scenarios. One common scenario in Xamarin Forms applications is the need to load data when a user selects a specific tab in a TabbedPage. This approach not only enhances performance but also improves the user experience by minimizing wait times during the initial app load.

The Challenge: Preloading Data in Tabbed Pages

In Xamarin Forms, when you create a TabbedPage, each tab typically contains its own page and ViewModel. In a often-used pattern, all ViewModels would fetch their respective data immediately on application startup after the SplashScreen. However, this can lead to slow loading times and unnecessary data processing if the user does not switch to certain tabs.

So the question arises: How can we modify this behavior so that each ViewModel fetches data only when its corresponding tab is selected?

The Solution: Utilizing OnCurrentPageChanged

To achieve the desired functionality, we will leverage the OnCurrentPageChanged method. This method is called whenever the current page of a TabbedPage changes. By overriding this method, we can trigger the data fetching logic for the ViewModel each time a tab is selected.

Step 1: Modify Your XAML

First, you need to give your tab pages an x:Name identifier. This enables you to access each tab's elements from code behind later.

[[See Video to Reveal this Text or Code Snippet]]

Step 2: Override the OnCurrentPageChanged Method

Next, in the code behind of your TabbedPage, you will override the OnCurrentPageChanged method to include logic for loading data based on the selected tab.

[[See Video to Reveal this Text or Code Snippet]]

Step 3: Implement Data Loading Logic in Your ViewModels

In your individual ViewModels (e.g., HomeViewModel, ExploreViewModel, etc.), implement the CallMethodToLoadData method that fetches data from your REST API. Here you will handle the network calls and parse the data as required.

[[See Video to Reveal this Text or Code Snippet]]

Conclusion

By implementing the OnCurrentPageChanged method in your TabbedPage, you can ensure that the data for each tab is loaded only when that specific tab is selected. This not only optimizes app performance but also makes for a smoother user experience.

Using this approach, you will save resources and reduce lagging in your application - achieving a more responsive and efficient design.

With these steps, your Xamarin Forms app will become not only more effective but also more user-friendly. Happy coding!