avatarRey | AndroidGeek.co

Summary

This article provides a guide on how to use Flow with Room Database in Android development, specifically focusing on adding delete and edit functionality to a Contacts List App.

Abstract

The article is a continuation of a series of guides on using Flow with Room Database in Android development. In this part, the author demonstrates how to add delete and edit functionality to a Contacts List App. The delete functionality is implemented using a swipe to the left gesture, while the edit functionality is implemented using a swipe to the right gesture. The author provides code snippets and explanations for each step of the process, including adding dependencies, creating callbacks, and handling the swipe gestures. The article also covers how to handle undo actions for deleted items and how to pass data between fragments for editing.

Bullet points

  • The article is a guide on how to use Flow with Room Database in Android development.
  • The focus of this article is on adding delete and edit functionality to a Contacts List App.
  • The delete functionality is implemented using a swipe to the left gesture.
  • The edit functionality is implemented using a swipe to the right gesture.
  • The author provides code snippets and explanations for each step of the process.
  • The article covers how to handle undo actions for deleted items.
  • The article also covers how to pass data between fragments for editing.
  • The author provides a link to the GitHub source code for the project.
  • The author encourages readers to join Medium to read more valuable stories.
  • The author thanks readers for their time and encourages them to clap and comment if they enjoyed the article.

How to use Flow with Room Database (Complete Guide — Part 4)

in the previous article we were working on Contacts List App , and we could add new contact and see the list of our contacts .

you can read the previous article here (Part1-Part2 👇) :

and also we added search , sort and delete All functionality :

let me show you , what I want to doin this article :

Delete: swipe to left for deleting

Edit: swipe to right for editing

Add this dependency into your gradle for decorating RecyclerView Swipe :

//RecyclerView Decorator
implementation 'com.github.xabaras:RecyclerViewSwipeDecorator:1.3'

Sync your project and then , inside your binding.app{…} in the main activity, insert this block :

val swipeCallback = object : ItemTouchHelper.SimpleCallback(0, ItemTouchHelper.LEFT or ItemTouchHelper.RIGHT) {
    override fun onMove(recyclerView: RecyclerView, viewHolder: RecyclerView.ViewHolder, target: RecyclerView.ViewHolder): Boolean {
        return false
    }
    override fun onSwiped(viewHolder: RecyclerView.ViewHolder, direction: Int) {
        val position = viewHolder.adapterPosition
        val contact = contactsAdapter.differ.currentList[position]
        when (direction) {
            ItemTouchHelper.LEFT -> {
                viewModel.deleteContact(contact)
                Snackbar.make(binding.root, "Item Deleted!", Snackbar.LENGTH_LONG).apply {
                    setAction("UNDO") {
                        viewModel.saveContact(false, contact)
                    }
                }.show()
            }
            ItemTouchHelper.RIGHT -> {
                val addContactFragment = AddContactFragment()
                val bundle = Bundle()
                bundle.putInt(BUNDLE_ID, contact.id)
                addContactFragment.arguments = bundle
                addContactFragment.show(supportFragmentManager, AddContactFragment().tag)
            }
        }
    }
    override fun onChildDraw(
        c: Canvas,
        recyclerView: RecyclerView,
        viewHolder: RecyclerView.ViewHolder,
        dX: Float,
        dY: Float,
        actionState: Int,
        isCurrentlyActive: Boolean
    ) {
        RecyclerViewSwipeDecorator.Builder(c, recyclerView, viewHolder, dX, dY, actionState, isCurrentlyActive)
            .addSwipeLeftLabel("Delete")
            .addSwipeLeftBackgroundColor(Color.RED)
            .addSwipeLeftActionIcon(R.drawable.ic_baseline_delete_24)
            .setSwipeLeftLabelColor(Color.WHITE)
            .setSwipeLeftActionIconTint(Color.WHITE)
            .addSwipeRightLabel("Edit")
            .addSwipeRightBackgroundColor(Color.GREEN)
            .setSwipeRightLabelColor(Color.WHITE)
            .setSwipeRightActionIconTint(Color.WHITE)
            .addSwipeRightActionIcon(R.drawable.ic_baseline_edit_24)
            .create()
            .decorate()
        super.onChildDraw(c, recyclerView, viewHolder, dX, dY, actionState, isCurrentlyActive)
    }
}
val itemTouchHelper = ItemTouchHelper(swipeCallback)
itemTouchHelper.attachToRecyclerView(rvContacts)

let me explain what happen inside this block :

the blowing block is for deleting and here I’m using an action of Snackbar, it called → UNDO ( setAction(“UNDO”) )

so i can re-insert my deleted item into database :

ItemTouchHelper.LEFT -> {
                viewModel.deleteContact(contact)
                Snackbar.make(binding.root, "Item Deleted!", Snackbar.LENGTH_LONG).apply {
                    setAction("UNDO") {
                        viewModel.saveContact(false, contact)
                    }
                }.show()
            }

and for Editing ,

ItemTouchHelper.RIGHT -> {
                val addContactFragment = AddContactFragment()
                val bundle = Bundle()
                bundle.putInt(BUNDLE_ID, contact.id)
                addContactFragment.arguments = bundle
                addContactFragment.show(supportFragmentManager, AddContactFragment().tag)
            }

I sent my data as bundle into my add fragment . for that i added this variable into my Constants.kt

const val NEW = "new"
const val EDIT = "edit"
const val BUNDLE_ID = "bundle_id"

and then in my AddContactFragment :

first add :

private var type = ""
private var isEdit = false

and then get the bundle data :

contactId = arguments?.getInt(BUNDLE_ID) ?: 0

and I should check the id for future action:

if (contactId > 0) {
    type = EDIT
    isEdit = true
} else {
    isEdit = false
    type = NEW
}

and then , inside binding .apply {…} , for getting data and showing into EditText :

if (type == EDIT) {
    viewModel.getDetailsContact(contactId)
    viewModel.contactsDetail.observe(viewLifecycleOwner) { itData ->
        itData.data?.let {
            edtName.setText(it.name)
            edtPhone.setText(it.phone)
        }
    }
}

and the last step to save new data or update , i have to do some changes into my ViewModel :

fun saveContact(isEdite: Boolean, entity: ContactsEntity) = viewModelScope.launch {
    if (isEdite) {
        repository.updateTask(entity)
    } else {
        repository.saveContact(entity)
    }
}

I added new parameter as boolean to understand the data that i wanted to save is a new record or is used for update.

so my button’s code should change like this:

btnSave.setOnClickListener {
    name = edtName.text.toString()
    phone = edtPhone.text.toString()
    if (name.isEmpty() || phone.isEmpty()) {
        Snackbar.make(it, "Name and Phone cannot be Empty!", Snackbar.LENGTH_SHORT).show()
    } else {
        entity.id = contactId
        entity.name = name
        entity.phone = phone
        viewModel.saveContact(isEdit, entity)
        edtName.setText("")
        edtPhone.setText("")
        dismiss()
    }
}

It’s Done 😊 Good work ✨

GitHub Source :

If you would rather watch a video of this tutorial, I have embedded the one I made and put on YouTube below:

Join Medium to read thousands of valuable stories ✨

Thank you for reading, and Happy Coding! 😊

Don’t forget to clap and comment if you enjoyed 👏😊

Flow
Android
Kotlin
Android App Development
Room Database
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