Android GridView Example Using Kotlin

1. Creating New Project in Kotlin

• Open Android Studio.
• Go to File => New => New Project.Give Name To your application. Then, check Include Kotlin Support and click next button.
• Select minimum SDK you need. However, we have selected 21 as minimum SDK. Then, click next button.
• Then, select Empty Activity => click next => click finish.

2. Here we take GridView in our layout and set numColumns=3.It means 3 Columns in View. As in below xml layout.

main_activity.xml

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout 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"
    android:orientation="vertical"
    tools:context="com.dharmendra.gridview.MainActivity">


    <GridView
        android:id="@+id/gridView"
        android:numColumns="3"
        android:layout_width="match_parent"
        android:layout_height="match_parent" />
</LinearLayout>

3.MainActivity.kt

package com.dharmendra.gridview

import android.os.Bundle
import android.support.v7.app.AppCompatActivity
import android.widget.ArrayAdapter
import android.widget.GridView
import android.widget.Toast

class MainActivity : AppCompatActivity() {

    override fun onCreate(savedInstanceState: Bundle?) {
        super.onCreate(savedInstanceState)
        setContentView(R.layout.activity_main)

        //Find View By Id for GridView
        val gridView = findViewById<GridView>(R.id.gridView) as GridView

        //Define ArrayList
        var arrayList = ArrayList<Int>()

        //While Loop to Insert value in ArrayList
        var i = 0
        while (i <= 20) {
            arrayList.add(i)
            i++
        }

        //Create Adapter

        val myAdapter: ArrayAdapter<Int> = ArrayAdapter(this@MainActivity, android.R.layout.simple_list_item_1, arrayList)

        //Set Adapter
        gridView.adapter = myAdapter

        //GridView On Click

        gridView.setOnItemClickListener { adapterView, view, position, id ->

            Toast.makeText(this@MainActivity, "You have Click " + arrayList.get(position), Toast.LENGTH_LONG).show()
        }


    }
}

Output: