Eliminar ToDos

In this case, we will focus on how to remove a "to do" using a trash can icon in the user interface and manage it in the ViewModel. This process not only improves the user experience but also optimizes the local database.

What is the process to remove a "to do"?

To implement the removal functionality, we must follow a series of steps within our ViewModel. Here we explain how to do it:

1. Identification of the "to do" to remove:

• • Each "to do" has an index in our collection. The first thing to do is to verify that this index exists.
  • If the index is not found, the function should terminate immediately.

1. Location of the "to do" within the collection:

• • Create a variable to_do_to_remove to temporarily store the "to do" we want to remove.
  • Assign the to do located at the index found to this variable.

1. Delete the "to do":

• • Use the delete function of the context that handles local storage (Core Data, in this case).
  • Pass to_do_to_remove to that function to delete it.

1. Save the changes:

• • Call the save_data function to ensure that the changes are reflected in storage.

// Assumes the language used is Swift func deleteAll() { guard let index = all.index(of: all) else { return } let toDoToRemove = all[index] storeContainer.viewContext.delete(toDoToRemove) saveData() }

How do we bind the delete action to the interface?

Once we have configured the delete functionality in the ViewModel, it is important to associate this function to the frontend interactive element, in this case, the trash can icon.

1. Associate the action button with the ViewModel:

• • Identify the button associated with the delete action in the component in the XAML or SwiftUI file.
  • Bind this button to the deleteAll() method within the ViewModel.

1. Update the state of the interface:

• • After calling the delete function, the application should update the list of visible "to dos" to confirm that the item is no longer displayed in any file category.

What additional considerations should you have in the process?

• • Error handling: It is essential to handle possible errors properly. For example, what happens if the "to do" is not present when attempting to delete.
  • Testing and validation: Run tests to confirm that the deletion works under different circumstances and that it does not generate inconsistent states in the database.
  • Resource optimization: Ensure that storage and retrieval operations are efficient, avoiding unnecessary memory or CPU usage.

Careful development of this functionality will not only improve the efficiency of our application but will also offer a much more pleasant and controlled user experience. Keep practicing and running new features to perfect your development skills!