Exploring Advanced ViewDataBinding Techniques in Android

Imagine building an Android app with a Complex UI that is getting populated from the data model, whenever the data changes or we have to update the data then it will be a very tedious and error-prone task to manually update every view. What if there is a way to do this work in a single line of code, Thanks to the Android team they have provided methods in ViewDataBinding to do this.

Let’s understand two methods of ViewDataBinding which will help us in this scenario by taking an example of a Shopping App that displays a list of products that has product names, prices, and availability. Additionally, there is an “Add to Cart” button for each product.

1. invalidateAll() -

We can use the invalidateAll() method when there is a change in the product list such as showing only available products or showing only not available products. In that case, invalidateAll() on the root binding object for the list will ensure that all views in the list are updated accordingly.

binding.invalidateAll()

Instead of manually updating each view one by one, you can simply call invalidateAll() on the binding object.

Definition: This Function is used to do the re-evaluation of all the binding expressions and update the associated UI or basically, it is used to refresh the UI

2. executePendingBindings() -

executePendingBindings() can be used when you want to update the “Add to Cart” button immediately. In this case, after updating the availability status of the product in the data model, calling executePendingBindings() on the binding object associated with that specific product item’s layout will execute the pending binding updates, ensuring the button reflects the latest availability state.

binding.executePendingBindings()

Definition: The executePendingBindings() function is used to immediately update or execute the pending data binding updates. it ensures that all pending updates are applied to the associated UI components.

While both invalidateAll() and executePendingBindings() are used to update the UI when the underlying data model changes, they serve different purposes and are applied in different scenarios. Here's when you would typically use each method:

invalidateAll():

• This method is useful when you need to update multiple views in the layout simultaneously or when you want to ensure a complete refresh of the UI.

• For example, if you have a data-bound layout with numerous views, and you want to update all of them at once to reflect changes in the data model, you can invoke invalidateAll()

executePendingBindings():

• This method ensures that any pending binding updates for a particular view or views are executed immediately, without waiting for the next layout pass.

• For example, if you have a specific view that needs to be updated immediately after a change in the data model, you can call executePendingBindings() on that view's binding object to trigger the update.

In summary, use invalidateAll() when you need to update the entire layout or multiple views simultaneously, providing a comprehensive refresh of the UI. On the other hand, use executePendingBindings() when you want to immediately update specific views affected by changes in the data model, ensuring real-time updates.