MainActivity.kt
package com.cfsuman.jetpack
import androidx.appcompat.app.AppCompatActivity
import android.os.Bundle
import androidx.lifecycle.Observer
import androidx.lifecycle.ViewModelProviders
import androidx.recyclerview.widget.LinearLayoutManager
import androidx.recyclerview.widget.RecyclerView
import kotlinx.android.synthetic.main.activity_main.*
import org.jetbrains.anko.doAsync
import java.util.*
class MainActivity : AppCompatActivity() {
private lateinit var model: StudentViewModel
override fun onCreate(savedInstanceState: Bundle?) {
super.onCreate(savedInstanceState)
setContentView(R.layout.activity_main)
// Get the view model
model = ViewModelProviders.of(this).get(StudentViewModel::class.java)
// Specify layout for recycler view
val linearLayoutManager = LinearLayoutManager(
this, RecyclerView.VERTICAL,false)
recyclerView.layoutManager = linearLayoutManager
// Observe the model
model.allStudents.observe(this, Observer{ students->
// Data bind the recycler view
recyclerView.adapter = RecyclerViewAdapter(students)
})
// Insert data into table
btn.setOnClickListener {
doAsync {
model.insert(Student(null, UUID.randomUUID().toString()))
}
}
}
}
RoomSingleton.kt
package com.cfsuman.jetpack
import androidx.room.Database
import androidx.room.Room
import androidx.room.RoomDatabase
import android.content.Context
@Database(entities = arrayOf(Student::class), version = 1, exportSchema = false)
abstract class RoomSingleton : RoomDatabase(){
abstract fun studentDao():StudentDao
companion object{
private var INSTANCE: RoomSingleton? = null
fun getInstance(context:Context): RoomSingleton{
if (INSTANCE == null){
INSTANCE = Room.databaseBuilder(
context,
RoomSingleton::class.java,
"roomdb")
.build()
}
return INSTANCE as RoomSingleton
}
}
}
RoomEntity.kt
package com.cfsuman.jetpack
import androidx.room.ColumnInfo
import androidx.room.Entity
import androidx.room.PrimaryKey
@Entity(tableName = "studentTbl")
data class Student(
@PrimaryKey
var id:Long?,
@ColumnInfo(name = "uuid")
var name: String
)
RoomDao.kt
package com.cfsuman.jetpack
import androidx.lifecycle.LiveData
import androidx.room.Dao
import androidx.room.Insert
import androidx.room.OnConflictStrategy
import androidx.room.Query
@Dao
interface StudentDao{
@Query("SELECT * FROM studentTbl ORDER BY id DESC")
fun allStudents(): LiveData<List<Student>>
@Insert(onConflict = OnConflictStrategy.REPLACE)
fun insert(student: Student)
}
StudentViewModel.kt
package com.cfsuman.jetpack
import androidx.lifecycle.AndroidViewModel
import androidx.lifecycle.LiveData
import android.app.Application
class StudentViewModel(application:Application): AndroidViewModel(application){
private val db:RoomSingleton = RoomSingleton.getInstance(application)
internal val allStudents : LiveData<List<Student>> = db.studentDao().allStudents()
fun insert(student:Student){
db.studentDao().insert(student)
}
}
RecyclerViewAdapter.kt
package com.cfsuman.jetpack
import android.view.LayoutInflater
import android.view.View
import android.view.ViewGroup
import androidx.recyclerview.widget.RecyclerView
import kotlinx.android.synthetic.main.custom_view.view.*
class RecyclerViewAdapter(val students: List<Student>)
: RecyclerView.Adapter<RecyclerViewAdapter.ViewHolder>(){
override fun onCreateViewHolder(parent: ViewGroup, viewType: Int)
: RecyclerViewAdapter.ViewHolder {
val v: View = LayoutInflater.from(parent.context)
.inflate(R.layout.custom_view,parent,false)
return ViewHolder(v)
}
override fun onBindViewHolder(holder: RecyclerViewAdapter.ViewHolder, position: Int) {
holder.id.text = students[position].id.toString()
holder.name.text = students[position].name
}
override fun getItemCount(): Int {
return students.size
}
override fun getItemId(position: Int): Long {
return super.getItemId(position)
}
override fun getItemViewType(position: Int): Int {
return super.getItemViewType(position)
}
class ViewHolder(itemView:View): RecyclerView.ViewHolder(itemView){
val id = itemView.tvId
val name = itemView.tvName
}
}
activity_main.xml
<?xml version="1.0" encoding="utf-8"?>
<androidx.constraintlayout.widget.ConstraintLayout
xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:tools="http://schemas.android.com/tools"
xmlns:app="http://schemas.android.com/apk/res-auto"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:id="@+id/rootLayout"
tools:context=".MainActivity"
android:background="#fdfdfc">
<Button
android:text="Insert Data"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:id="@+id/btn"
android:layout_marginTop="8dp"
app:layout_constraintTop_toTopOf="parent"
android:layout_marginStart="8dp"
app:layout_constraintStart_toStartOf="parent"
app:layout_constraintEnd_toEndOf="parent"
android:layout_marginEnd="8dp"/>
<androidx.recyclerview.widget.RecyclerView
android:id="@+id/recyclerView"
android:layout_width="match_parent"
android:layout_height="0dp"
app:layout_constraintEnd_toEndOf="parent"
android:layout_marginEnd="8dp"
app:layout_constraintStart_toStartOf="parent"
android:layout_marginStart="8dp"
app:layout_constraintHorizontal_bias="0.0"
android:layout_marginBottom="8dp"
app:layout_constraintBottom_toBottomOf="parent"
android:layout_marginTop="8dp"
app:layout_constraintTop_toBottomOf="@+id/btn"/>
</androidx.constraintlayout.widget.ConstraintLayout>
custom_view.xml
<?xml version="1.0" encoding="utf-8"?>
<com.google.android.material.card.MaterialCardView
xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:app="http://schemas.android.com/apk/res-auto"
xmlns:tools="http://schemas.android.com/tools"
android:layout_width="match_parent"
android:layout_height="wrap_content"
app:contentPadding="10dp"
android:layout_margin="3dp"
app:cardElevation="2dp"
app:cardMaxElevation="3dp">
<androidx.constraintlayout.widget.ConstraintLayout
android:layout_width="match_parent"
android:layout_height="wrap_content">
<TextView
android:id="@+id/tvId"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
tools:text="100"
android:layout_margin="10dp"
app:layout_constraintBottom_toBottomOf="parent"
android:layout_marginBottom="8dp"
android:layout_marginTop="8dp"
app:layout_constraintTop_toTopOf="parent"
app:layout_constraintStart_toStartOf="parent"
android:layout_marginStart="8dp"/>
<TextView
android:id="@+id/tvName"
android:layout_width="0dp"
android:layout_height="wrap_content"
tools:text="dsfdfdsfdfdf"
android:layout_marginTop="4dp"
app:layout_constraintTop_toTopOf="parent"
app:layout_constraintEnd_toEndOf="parent"
android:layout_marginEnd="8dp"
app:layout_constraintStart_toEndOf="@+id/tvId"
android:layout_marginStart="8dp"
app:layout_constraintHorizontal_bias="0.0"
android:layout_margin="10dp"
/>
</androidx.constraintlayout.widget.ConstraintLayout>
</com.google.android.material.card.MaterialCardView>
gradle settings
apply plugin: 'kotlin-kapt'
dependencies {
// Material components theme
implementation 'com.google.android.material:material:1.0.0'
// ViewModel and LiveData
def lifecycle_version = "2.0.0"
implementation "androidx.lifecycle:lifecycle-extensions:$lifecycle_version"
// Room support
def room_version = "2.1.0-alpha04"
implementation "androidx.room:room-runtime:$room_version"
kapt 'androidx.room:room-compiler:2.1.0-alpha04'
// Anko Commons
implementation "org.jetbrains.anko:anko-commons:0.10.5"
// RecyclerView
implementation 'androidx.recyclerview:recyclerview:1.0.0'
}
- kotlin - Volley UTF-8 encoding
- kotlin - Room singleton
- kotlin - Room LiveData ViewModel
- kotlin - Room select where
- kotlin syntax - ArrayList
- kotlin syntax - List add item
- kotlin syntax - List filter
- kotlin syntax - takeIf and takeUnless
- kotlin syntax - take, takeLast, takeWhile, takeLastWhile
- kotlin syntax - Difference between takeWhile and filter