package com.example.roomdemo
import androidx.appcompat.app.AppCompatActivity
import android.os.Bundle
import android.widget.Toast
import androidx.databinding.DataBindingUtil
import androidx.lifecycle.Observer
import androidx.lifecycle.ViewModelProvider
import androidx.recyclerview.widget.LinearLayoutManager
import com.example.roomdemo.databinding.ActivityMainBinding
import com.example.roomdemo.db.Subscriber
import com.example.roomdemo.db.SubscriberDatabase
import com.example.roomdemo.db.SubscriberRepository
class MainActivity : AppCompatActivity() {
private lateinit var binding: ActivityMainBinding
private lateinit var subscriberViewModel: SubscriberViewModel
override fun onCreate(savedInstanceState: Bundle?) {
super.onCreate(savedInstanceState)
binding = DataBindingUtil.setContentView(this,R.layout.activity_main)
val dao = SubscriberDatabase.getInstance(application).subscriberDAO
val repository = SubscriberRepository(dao)
val factory = SubscriberViewModelFactory(repository)
subscriberViewModel = ViewModelProvider(this,factory).get(SubscriberViewModel::class.java)
binding.myViewModel = subscriberViewModel
binding.lifecycleOwner = this
initRecyclerView()
subscriberViewModel.message.observe(this, Observer {
it.getContentIfNotHandled()?.let {
Toast.makeText(this, it, Toast.LENGTH_LONG).show()
}
})
}
private fun initRecyclerView() {
binding.subscriberRecyclerView.layoutManager = LinearLayoutManager(this)
displaySubscribersList()
}
private fun displaySubscribersList() {
subscriberViewModel.subscribers.observe(this, Observer {
binding.subscriberRecyclerView.adapter = MyRecyclerViewAdapter(it, {selecteditem:Subscriber->listItemClicked(selecteditem)})
})
}
private fun listItemClicked(subscriber: Subscriber) {
subscriberViewModel.initUpdateAndDelete(subscriber)
}
}
package com.example.roomdemo
import androidx.databinding.Bindable
import androidx.databinding.Observable
import androidx.lifecycle.LiveData
import androidx.lifecycle.MutableLiveData
import androidx.lifecycle.ViewModel
import androidx.lifecycle.viewModelScope
import com.example.roomdemo.db.Subscriber
import com.example.roomdemo.db.SubscriberRepository
import kotlinx.coroutines.launch
class SubscriberViewModel(private val repository: SubscriberRepository) : ViewModel(),Observable {
val subscribers = repository.subscribers
private var isUpdateOrDelete = false
private lateinit var subscriberToUpdateOrDelete : Subscriber
@Bindable
val inputName = MutableLiveData<String>()
@Bindable
val inputEmail = MutableLiveData<String>()
@Bindable
val saveOrUpdateButtonText = MutableLiveData<String>()
@Bindable
val clearAllOrDeleteButtonText = MutableLiveData<String>()
private val statusMessage = MutableLiveData<Event<String>>()
val message : LiveData<Event<String>>
get() = statusMessage
init {
saveOrUpdateButtonText.value = "Save"
clearAllOrDeleteButtonText.value = "Clear All"
}
fun saveOrUpdate() {
if(isUpdateOrDelete) {
subscriberToUpdateOrDelete.name = inputName.value!!
subscriberToUpdateOrDelete.email = inputEmail.value!!
update(subscriberToUpdateOrDelete)
}else {
val name = inputName.value!!
val email = inputEmail.value!!
insert(Subscriber(0, name, email))
inputName.value = null
inputEmail.value = null
}
}
fun clearAllOrDelete() {
if(isUpdateOrDelete) {
delete(subscriberToUpdateOrDelete)
}else {
clearAll()
}
}
fun insert(subscriber: Subscriber)= viewModelScope.launch {
repository.insert(subscriber)
statusMessage.value = Event("Subscriber Inserted Successfully")
}
fun update(subscriber: Subscriber) = viewModelScope.launch {
repository.update(subscriber)
inputName.value = null
inputEmail.value = null
isUpdateOrDelete = false
saveOrUpdateButtonText.value = "Save"
clearAllOrDeleteButtonText.value = "Clear All"
statusMessage.value = Event("Subscriber Updated Successfully")
}
fun delete(subscriber: Subscriber) = viewModelScope.launch {
repository.delete(subscriber)
inputName.value = null
inputEmail.value = null
isUpdateOrDelete = false
saveOrUpdateButtonText.value = "Save"
clearAllOrDeleteButtonText.value = "Clear All"
statusMessage.value = Event("Subscriber Deleted Successfully")
}
fun clearAll()=viewModelScope.launch {
repository.deleteAll()
statusMessage.value = Event("All Subscribers Deleted Successfully")
}
fun initUpdateAndDelete(subscriber: Subscriber) {
inputName.value = subscriber.name
inputEmail.value = subscriber.email
isUpdateOrDelete = true
subscriberToUpdateOrDelete = subscriber
saveOrUpdateButtonText.value = "Update"
clearAllOrDeleteButtonText.value = "Delete"
}
override fun removeOnPropertyChangedCallback(callback: Observable.OnPropertyChangedCallback?) {
}
override fun addOnPropertyChangedCallback(callback: Observable.OnPropertyChangedCallback?) {
}
}
package com.example.roomdemo.db
import androidx.lifecycle.LiveData
import androidx.room.*
@Dao
interface SubscriberDAO {
@Insert
suspend fun insertSubscriber(subscriber: Subscriber): Long
@Update
suspend fun updateSubscriber(subscriber: Subscriber)
@Delete
suspend fun deleteSubscriber(subscriber: Subscriber)
@Query("DELETE FROM subscriber_data_table")
suspend fun deleteAll()
@Query("SELECT * FROM subscriber_data_table")
fun getAllSubscribers(): LiveData<List<Subscriber>>
}
package com.example.roomdemo
import androidx.lifecycle.ViewModel
import androidx.lifecycle.ViewModelProvider
import com.example.roomdemo.db.SubscriberRepository
class SubscriberViewModelFactory(private val repository: SubscriberRepository) : ViewModelProvider.Factory {
override fun <T : ViewModel?> create(modelClass: Class<T>): T {
if (modelClass.isAssignableFrom(SubscriberViewModel::class.java)) {
return SubscriberViewModel(repository) as T
}
throw IllegalArgumentException("Unknown View Model class")
}
}
package com.example.roomdemo.db
import android.content.Context
import androidx.room.Database
import androidx.room.Room
import androidx.room.RoomDatabase
@Database(entities = [Subscriber::class],version = 1)
abstract class SubscriberDatabase : RoomDatabase() {
abstract val subscriberDAO: SubscriberDAO
companion object {
@Volatile
private var INSTANCE: SubscriberDatabase? = null
fun getInstance(context: Context): SubscriberDatabase {
synchronized(this) {
var instance = INSTANCE
if (instance == null) {
instance = Room.databaseBuilder(
context.applicationContext,
SubscriberDatabase::class.java,
"subscriber_data_database"
).build()
}
return instance
}
}
}
}
<?xml version="1.0" encoding="utf-8"?>
<layout xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:app="http://schemas.android.com/apk/res-auto">
<LinearLayout
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:layout_marginBottom="20dp"
android:orientation="vertical">
<androidx.cardview.widget.CardView
android:id="@+id/card_view"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:layout_gravity="center"
android:clickable="true"
android:focusable="true"
app:cardBackgroundColor="@color/colorPrimary"
app:cardCornerRadius="10dp"
app:cardElevation="10dp">
<LinearLayout
android:id="@+id/list_item_layout"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:orientation="vertical">
<TextView
android:id="@+id/name_text_view"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_margin="10dp"
android:text="TextView"
android:textColor="@android:color/background_light"
android:textSize="30sp"
android:textStyle="bold" />
<TextView
android:id="@+id/email_text_view"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_margin="10dp"
android:text="TextView"
android:textColor="@android:color/background_light"
android:textSize="24sp"
android:textStyle="bold" />
</LinearLayout>
</androidx.cardview.widget.CardView>
</LinearLayout>
</layout>
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