I’ve created a list using the androidx.recyclerview.widget.RecyclerView. It gets its items from a SQLite database table.
When a item is clicked I belive this code is runned: clickLambda(currentItem.id)
My question is how can I get the ID or name of the item clicked?
Example I want when a item is clicked to have a function runned:
fun listOnClick(itemID: Int){
// TODO: How can I get the program to go here?
}
My code is located at GitHub.com/europa9/KotlinAndroidXRecycleViewSimpleSQLite. I’ll post it here as well:
MainActivity
package net.frindex.kotlinandroidxrecycleviewsimplesqlite
/**
*
* File: MainActivity.kt
* Version 1.0
* Date 24.10.2020
* Copyright (c) 2020 S Ditlefsen
* License: http://opensource.org/licenses/gpl-license.php GNU Public License
*
*/
import android.database.Cursor
import androidx.appcompat.app.AppCompatActivity
import android.os.Bundle
import android.util.Log
import androidx.recyclerview.widget.LinearLayoutManager
import com.facebook.stetho.Stetho
import kotlinx.android.synthetic.main.activity_main.*
import net.frindex.kotlinandroidxrecycleviewsimplesqlite.db.DatabaseHelper
import net.frindex.kotlinandroidxrecycleviewsimplesqlite.recyclerViewAdapters.IdTitleAdapter
import net.frindex.kotlinandroidxrecycleviewsimplesqlite.recyclerViewAdapters.IdTitleDataClass
import java.util.ArrayList
class MainActivity : AppCompatActivity() {
// Class variables
var db: DatabaseHelper? = null
private lateinit var categoriesList: ArrayList<IdTitleDataClass>
override fun onCreate(savedInstanceState: Bundle?) {
super.onCreate(savedInstanceState)
setContentView(R.layout.activity_main)
// DB :: Open Chrome and go to URL chrome://inspect/#devices
Stetho.initializeWithDefaults(this)
// List categories
listCategories()
} // onCreate
/*- List categories -------------------------------------------------------------------------- */
fun listCategories(){
// DB
db = DatabaseHelper(this)
// Fetch categories
var categoriesCursor: Cursor? = db!!.rawQuery("SELECT category_id, category_name FROM categories")
var categoriesSize: Int = categoriesCursor!!.count
Log.d("listCategories()", "categoriesSize=" + categoriesSize)
// Add a list of categories
categoriesList = ArrayList<IdTitleDataClass>()
while (categoriesCursor.moveToNext()) {
val categoryId = categoriesCursor.getInt(0)
val categoryName = categoriesCursor.getString(1)
Log.d("listCategories()", "categoryId=" + categoryId + " categoryName=" + categoryName)
categoriesList.add(IdTitleDataClass(categoryId, categoryName))
}
// Add to list
recycler_view.adapter = IdTitleAdapter(categoriesList) {
categoriesList[it]
}
recycler_view.layoutManager = LinearLayoutManager(this)
recycler_view.setHasFixedSize(true)
} // listCategories
/*- List on click ---------------------------------------------------------------------------- */
fun listOnClick(itemID: Int){
// TODO: How can I get the program to go here?
} // listOnClick
} // MainActivity
DatabaseHelper
package net.frindex.kotlinandroidxrecycleviewsimplesqlite.db
import android.content.Context
import android.database.Cursor
import android.database.DatabaseUtils
import android.database.sqlite.SQLiteDatabase
import android.database.sqlite.SQLiteOpenHelper
class DatabaseHelper(context: Context):
SQLiteOpenHelper(context, DB_NAME, null, DB_VERSIOM) {
companion object {
private val DB_NAME = "kotlinandroidxrecycleviewsimplesqlite"
private val DB_VERSIOM = 1;
}
override fun onCreate(db: SQLiteDatabase?) {
val q1 = "CREATE TABLE categories" +
"(category_id Integer PRIMARY KEY, " +
"category_name TEXT)"
db?.execSQL(q1)
val q2 = "INSERT INTO categories(category_id, category_name) " +
"VALUES " +
"(NULL, 'Bread and cereal')," +
"(NULL, 'Bread')," +
"(NULL, 'Cereals')," +
"(NULL, 'Frozen bread and rolls')," +
"(NULL, 'Crispbread')," +
"(NULL, 'Sausage bread and lumps')," +
"(NULL, 'Dessert and baking')," +
"(NULL, 'Baking')," +
"(NULL, 'Biscuit')," +
"(NULL, 'Cakes')," +
"(NULL, 'Buns')"
db?.execSQL(q2)
}
override fun onUpgrade(db: SQLiteDatabase?, oldVersion: Int, newVersion: Int) {
db!!.execSQL("DROP TABLE IF EXISTS categories")
onCreate(db)
}
// Query database - insert or update
fun query(query: String): Boolean {
val db = this.writableDatabase
db.execSQL(query)
db.close()
return true;
} // query
// Count
fun count(query: String): Int {
val db = this.writableDatabase
val numRows =
DatabaseUtils.longForQuery(db, query, null).toInt()
db.close()
return numRows;
}
// Get
fun rawQuery(query: String?): Cursor? {
val db = this.writableDatabase
val mCursor: Cursor = db.rawQuery(query, null)
mCursor?.moveToFirst()
return mCursor
}
}
IdTitleAdapter
package net.frindex.kotlinandroidxrecycleviewsimplesqlite.recyclerViewAdapters
import androidx.recyclerview.widget.RecyclerView
import android.view.LayoutInflater
import android.view.View
import android.view.ViewGroup
import android.widget.TextView
import net.frindex.kotlinandroidxrecycleviewsimplesqlite.R
import kotlinx.android.synthetic.main.adapter_id_title_item_layout.view.*
class IdTitleAdapter(val list: ArrayList<IdTitleDataClass>,val clickLambda: (Int)->Unit) : RecyclerView.Adapter<IdTitleViewHolder>() {
override fun onCreateViewHolder(parent: ViewGroup, viewType: Int): IdTitleViewHolder {
val itemView = LayoutInflater.from(parent.context).inflate(R.layout.adapter_id_title_item_layout,parent,false)
return IdTitleViewHolder(itemView)
}
override fun getItemCount(): Int {
return list.size
}
override fun onBindViewHolder(holder: IdTitleViewHolder, position: Int) {
val currentItem = list[position]
holder.textViewTitle.text = currentItem.title
holder.itemView.setOnClickListener {
clickLambda(currentItem.id)
}
}
} // IdTitleAdapter
class IdTitleViewHolder(itemView: View) : RecyclerView.ViewHolder(itemView){
val textViewTitle: TextView = itemView.textViewTitle
} // IdTitleViewHolder
IdTitleDataClass
package net.frindex.kotlinandroidxrecycleviewsimplesqlite.recyclerViewAdapters
data class IdTitleDataClass (val id:Int, val title:String)
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"
android:id="@+id/constraintLayout">
<!-- Categories -->
<androidx.recyclerview.widget.RecyclerView
android:id="@+id/recycler_view"
android:layout_width="match_parent"
android:layout_height="match_parent"
app:layout_constraintBottom_toBottomOf="parent"
app:layout_constraintEnd_toEndOf="parent"
app:layout_constraintStart_toStartOf="parent"
tools:listitem="@layout/adapter_id_title_item_layout"
app:layout_constraintTop_toTopOf="parent" />
<!-- //Categories -->
</androidx.constraintlayout.widget.ConstraintLayout>
adapter_id_title_item_layout.xml
<?xml version="1.0" encoding="utf-8"?>
<androidx.cardview.widget.CardView xmlns:android="http://schemas.android.com/apk/res/android"
android:layout_width="match_parent"
android:layout_height="wrap_content">
<LinearLayout
android:layout_width="match_parent"
android:layout_height="match_parent"
android:orientation="horizontal"
android:layout_marginTop="15dp"
android:layout_marginBottom="15dp">
<TextView
android:id="@+id/textViewTitle"
android:layout_width="0dp"
android:layout_height="wrap_content"
android:layout_gravity="center"
android:layout_weight="1"
android:text="Title"
android:textAlignment="center"
android:textAppearance="@style/TextAppearance.AppCompat.Large"
android:textStyle="bold" />
</LinearLayout>
</androidx.cardview.widget.CardView>
