MainActivity.kt
package com.example.roomexamples
import androidx.appcompat.app.AppCompatActivity
import android.os.Bundle
import android.text.method.ScrollingMovementMethod
import android.widget.TextView
import com.android.volley.Request
import com.android.volley.Response
import com.android.volley.toolbox.JsonArrayRequest
import com.android.volley.toolbox.Volley
import kotlinx.android.synthetic.main.activity_main.*
import org.jetbrains.anko.doAsync
import org.jetbrains.anko.toast
import org.jetbrains.anko.uiThread
import java.text.DateFormat
import java.util.*
class MainActivity : AppCompatActivity() {
override fun onCreate(savedInstanceState: Bundle?) {
super.onCreate(savedInstanceState)
setContentView(R.layout.activity_main)
val room = RoomSingleton.getInstance(this)
textView.movementMethod = ScrollingMovementMethod()
// Insert some products in database
btnInsert.setOnClickListener {
val url = "https://tradeogre.com/api/v1/history/BTC-KRB"
val request = JsonArrayRequest(
Request.Method.GET,
url,
null,
Response.Listener{
val list = arrayListOf<History>()
for (i in 0 until it.length()){
val obj = it.getJSONObject(i)
val timeMillis = obj.getLong("date")
val type = obj.getString("type")
val price = obj.getString("price").toBigDecimal()
val quantity = obj.getString("quantity").toBigDecimal()
var isSell = true
if (type.equals("buy")) isSell = false
val history = History(null,Date(timeMillis),isSell,price,quantity)
list.add(history)
}
doAsync {
room.historyDao().insertAll(list)
uiThread {
toast("done")
}
}
},Response.ErrorListener {
toast(it.toString())
}
)
// Add the request to the RequestQueue.
Volley.newRequestQueue(this).add(request)
}
btnSell.setOnClickListener {
doAsync {
val list = room.historyDao().allSale()
uiThread {
displayResult(list,textView)
}
}
}
btnBuy.setOnClickListener {
doAsync {
// Pass boolean parameter to room query
val list = room.historyDao().allByQuery(false)
uiThread {
displayResult(list,textView)
}
}
}
}
}
fun displayResult(list:List<History>,textView:TextView){
textView.text = ""
list.forEach {
textView.append(it.date.medium)
if (it.isSell){
textView.append("\nType: Sell")
}else{
textView.append("\nType: Buy")
}
textView.append("\nPrice: " + it.price)
textView.append("\nQuantity: " + it.quantity + "\n\n")
}
}
// Extension property to format date
val Date.medium:String
get() = DateFormat.getDateInstance(DateFormat.MEDIUM).format(this)
activity_main.xml
<?xml version="1.0" encoding="utf-8"?>
<androidx.constraintlayout.widget.ConstraintLayout
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="match_parent"
tools:context=".MainActivity">
<TextView
android:id="@+id/textView"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_marginStart="8dp"
android:layout_marginTop="32dp"
android:layout_marginEnd="8dp"
android:text=""
android:textAppearance="@style/TextAppearance.AppCompat.Medium"
app:layout_constraintEnd_toEndOf="parent"
app:layout_constraintStart_toStartOf="parent"
app:layout_constraintTop_toBottomOf="@+id/btnInsert"
/>
<Button
android:id="@+id/btnInsert"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_marginStart="8dp"
android:layout_marginTop="8dp"
android:text="Insert"
app:layout_constraintStart_toStartOf="parent"
app:layout_constraintTop_toTopOf="parent"
/>
<Button
android:id="@+id/btnSell"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_marginStart="8dp"
android:layout_marginTop="8dp"
android:text="Sell"
app:layout_constraintStart_toEndOf="@+id/btnInsert"
app:layout_constraintTop_toTopOf="parent"
/>
<Button
android:id="@+id/btnBuy"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_marginStart="8dp"
android:layout_marginTop="8dp"
android:text="Buy"
app:layout_constraintStart_toEndOf="@+id/btnSell"
app:layout_constraintTop_toTopOf="parent"
/>
</androidx.constraintlayout.widget.ConstraintLayout>
RoomSingleton.kt
package com.example.roomexamples
import android.content.Context
import androidx.room.*
@Database(entities = arrayOf(History::class), version = 1, exportSchema = false)
@TypeConverters(Converter::class)
abstract class RoomSingleton : RoomDatabase(){
abstract fun historyDao(): HistoryDao
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
}
}
}
RoomDao.kt
package com.example.roomexamples
import androidx.room.*
import java.math.BigDecimal
import java.util.*
@Entity(tableName = "historyTbl")
data class History(
@PrimaryKey(autoGenerate = true)
var id:Long?=null,
var date:Date,
var isSell:Boolean,
var price:BigDecimal,
var quantity:BigDecimal
)
@Dao
interface HistoryDao {
// SQLite have no boolean data type
// Room maps boolean data to an INTEGER column
// Room mapping true to 1 and false to 0
@Query("SELECT * FROM historyTbl WHERE isSell = 1 ORDER BY date DESC")
fun allSale():List<History>
@Query("SELECT * FROM historyTbl WHERE isSell =:isSell ORDER BY date DESC")
fun allByQuery(isSell: Boolean):List<History>
@Insert(onConflict = OnConflictStrategy.IGNORE)
fun insert(history:History)
@Insert(onConflict = OnConflictStrategy.IGNORE)
fun insertAll(histories:List<History>)
}
Converter.kt
package com.example.roomexamples
import androidx.room.TypeConverter
import java.math.BigDecimal
import java.util.*
class Converter{
companion object{
@TypeConverter
@JvmStatic
fun fromBigDecimal(value:BigDecimal):String{
return value.toString()
}
@TypeConverter
@JvmStatic
fun toBigDecimal(value:String):BigDecimal{
return value.toBigDecimal()
}
@TypeConverter
@JvmStatic
fun toDate(value:Long):Date{
//If your result always returns 1970, then comment this line
//val date = Date(value)
//If your result always returns 1970, then uncomment this line
val date = Date(value*1000L)
return date
}
@TypeConverter
@JvmStatic
fun fromDate(date:Date):Long{
return date.time
}
}
}
app build.gradle [required]
apply plugin: 'kotlin-kapt'
dependencies {
// Room
def room_version = "2.2.0-alpha01"
implementation "androidx.room:room-runtime:$room_version"
kapt 'androidx.room:room-compiler:2.2.0-alpha01'
// Anko Commons
implementation "org.jetbrains.anko:anko-commons:0.10.8"
// Volley network library
implementation 'com.android.volley:volley:1.1.1'
}
