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How can I ensure that the LazyColumn and mutable list are updated when an item is deleted using the SwipeToDismiss feature in Android Studio?

asked 2022-09-07 11:00:00 +0000

pufferfish gravatar image

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answered 2021-04-12 13:00:00 +0000

devzero gravatar image

To ensure that the LazyColumn and mutable list are updated when an item is deleted using the SwipeToDismiss feature in Android Studio, follow these steps:

  1. Implement the SwipeToDismissCallback in your RecyclerView adapter that defines the behavior when an item is swiped to be dismissed.

  2. In the onSwiped method of the SwipeToDismissCallback, remove the corresponding item from the mutable list.

  3. Call the submitList method on the adapter with the updated list.

  4. In the activity that contains the RecyclerView, observe the mutable list in your ViewModel and update the LazyColumn accordingly.

Here's an example implementation of the SwipeToDismissCallback:

class MyAdapter(private var myDataList: MutableList<MyData>) : RecyclerView.Adapter<MyAdapter.ViewHolder>(), SwipeToDismissCallback {

    // ...

    override fun onSwiped(viewHolder: RecyclerView.ViewHolder, direction: Int) {
        val position = viewHolder.adapterPosition
        myDataList.removeAt(position)
        notifyItemRemoved(position)
    }

    // ...
}

And here's an example on how to observe the mutable list in your ViewModel:

class MyViewModel : ViewModel() {

    private val _myDataList = MutableLiveData<List<MyData>>()
    val myDataList: LiveData<List<MyData>> get() = _myDataList

    init {
        // initialize myDataList
    }

    fun removeItemAt(position: Int) {
        val currentList = _myDataList.value.orEmpty().toMutableList()
        currentList.removeAt(position)
        _myDataList.value = currentList
    }
}

Note that the removeItemAt method is called from the onSwiped method of the adapter.

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Asked: 2022-09-07 11:00:00 +0000

Seen: 12 times

Last updated: Apr 12 '21