Kotlin Listview CheckBox Tutorial with Example is the matter here.
It is not easy to implement the listview with checkbox in it’s every row item especially in the kotlin language.
This tutorial will provide easy to learn and time saving source code.
This example includes the features like select all, deselect all, make multiple selection etc.
We will learn how to get click position on checkbox, get the names of checked items and send it to the next activity.
If you are not familiar with kotlin then visit java version here.
Read Other Kotlin Listview Tutorials
Refer the output of kotlin listview checkbox example in below video.
Step 1. Model Class
Create a new project in the android studio with kotlin support.
Select the default activity as empty activity in your last step.
Now, make a new kotlin class. Give this class a sweet name like Model.kt
Source code for the model class is
class Model {
var isSelected: Boolean = false
var animal: String? = null
fun getAnimals(): String {
return this!!.animal.toString()
}
fun setAnimals(animal: String) {
this.animal = animal
}
fun getSelecteds(): Boolean {
return isSelected
}
fun setSelecteds(selected: Boolean) {
isSelected = selected
}
}
Step 3. Listview Layout File
We need to create a layout resource file which will represent the every row’s layout.
Create new layout resource file named lv_item.xml and add below code
<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:orientation="horizontal" android:layout_width="match_parent"
android:layout_height="match_parent">
<CheckBox
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:id="@+id/cb"
android:text="Checkbox"/>
<TextView
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:id="@+id/animal"
android:layout_marginLeft="20dp"
android:textSize="20sp"
android:text="animal"/>
</LinearLayout>
Step 4. Adding Custom Adapter
Before making adapter, create a new xml file named integer.xml in res/values directory(same directory in which string.xml is there)
Now add following code into integer.xml
<?xml version="1.0" encoding="utf-8"?> <resources> <integer name="btnplusview">1</integer> <integer name="btnpluspos">2</integer> </resources>
Prepare a new class CustomAdapter.kt
Copy and paste below source code into it
import android.content.Context
import android.view.LayoutInflater
import android.view.View
import android.view.ViewGroup
import android.widget.BaseAdapter
import android.widget.CheckBox
import android.widget.TextView
import android.widget.Toast
import java.util.ArrayList
/**
* Created by hardik on 9/1/17.
*/
class CustomAdapter(private val context: Context, modelArrayList: ArrayList<Model>) : BaseAdapter() {
private var modelArrayList: ArrayList<Model>
init {
this.modelArrayList = modelArrayList
}
override fun getViewTypeCount(): Int {
return count
}
override fun getItemViewType(position: Int): Int {
return position
}
override fun getCount(): Int {
return modelArrayList.size
}
override fun getItem(position: Int): Any {
return modelArrayList[position]
}
override fun getItemId(position: Int): Long {
return 0
}
override fun getView(position: Int, convertView: View?, parent: ViewGroup): View {
var convertView = convertView
val holder: ViewHolder
if (convertView == null) {
holder = ViewHolder()
val inflater = context
.getSystemService(Context.LAYOUT_INFLATER_SERVICE) as LayoutInflater
convertView = inflater.inflate(R.layout.lv_item, null, true)
holder.checkBox = convertView!!.findViewById(R.id.cb) as CheckBox
holder.tvAnimal = convertView.findViewById(R.id.animal) as TextView
convertView.tag = holder
} else {
// the getTag returns the viewHolder object set as a tag to the view
holder = convertView.tag as ViewHolder
}
holder.checkBox!!.text = "Checkbox $position"
holder.tvAnimal!!.setText(modelArrayList[position].getAnimals())
holder.checkBox!!.isChecked = modelArrayList[position].getSelecteds()
holder.checkBox!!.setTag(R.integer.btnplusview, convertView)
holder.checkBox!!.tag = position
holder.checkBox!!.setOnClickListener {
val tempview = holder.checkBox!!.getTag(R.integer.btnplusview) as View
val tv = tempview.findViewById(R.id.animal) as TextView
val pos = holder.checkBox!!.tag as Int
Toast.makeText(context, "Checkbox $pos clicked!", Toast.LENGTH_SHORT).show()
if (modelArrayList[pos].getSelecteds()) {
modelArrayList[pos].setSelecteds(false)
public_modelArrayList = modelArrayList
} else {
modelArrayList[pos].setSelecteds(true)
public_modelArrayList = modelArrayList
}
}
return convertView
}
private inner class ViewHolder {
var checkBox: CheckBox? = null
var tvAnimal: TextView? = null
}
companion object {
lateinit var public_modelArrayList: ArrayList<Model>
}
}
setTag() and getTag() methods are used to take care of each checkboxes in listview.
Description of setTag() method
this method is used to set a key and value pair to each view of the listview.
Look at the below lines from the Adapter class
holder.checkBox!!.setTag(R.integer.btnplusview, convertView) holder.checkBox!!.tag = position
In the first line, converView is set as a value and R.integer.btnplusview is set as a key.
Second line says that the current position is set as a tag.
One important point is that we have make one public arraylist named public_modelArrayList
This arraylist is the list of the objects of the Model class.
Following line declares this public arraylist.
companion object {
lateinit var public_modelArrayList: ArrayList<Model>
}
This public arraylist is updated when the checkbox is clicked everytime.
Step 5. Making Next Activity
Let us create a next activity in which, we will send the selected checkbox’s values.
Create a new activity named NextActivity.
Add below code into NextActivity.kt class
import android.os.Bundle
import android.support.v7.app.AppCompatActivity
import android.widget.TextView
class NextActivity : AppCompatActivity() {
private var tv: TextView? = null
override fun onCreate(savedInstanceState: Bundle?) {
super.onCreate(savedInstanceState)
setContentView(R.layout.activity_next)
tv = findViewById(R.id.tv) as TextView
for (i in 0 until CustomAdapter.public_modelArrayList!!.size) {
if (CustomAdapter.public_modelArrayList!!.get(i).getSelecteds()) {
tv!!.text = tv!!.text.toString() + " " + CustomAdapter.public_modelArrayList!!.get(i).getAnimals()
}
}
}
}
We are printing the selected checkbox’s values in TextView.
Source code for activity_next.xml is as follows
<?xml version="1.0" encoding="utf-8"?>
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:tools="http://schemas.android.com/tools"
android:layout_width="match_parent"
android:layout_height="match_parent">
<TextView
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:textSize="20sp"
android:text=""
android:id="@+id/tv"/>
</RelativeLayout>
Step 6. Update Main Activity
Make your MainActivity.kt class looks like below
import android.content.Intent
import android.support.v7.app.AppCompatActivity
import android.os.Bundle
import android.view.View
import android.widget.Button
import android.widget.ListView
import java.util.ArrayList
class MainActivity : AppCompatActivity() {
private var lv: ListView? = null
private var modelArrayList: ArrayList<Model>? = null
private var customAdapter: CustomAdapter? = null
private var btnselect: Button? = null
private var btndeselect: Button? = null
private var btnnext: Button? = null
private val animallist = arrayOf("Lion", "Tiger", "Leopard", "Cat")
override fun onCreate(savedInstanceState: Bundle?) {
super.onCreate(savedInstanceState)
setContentView(R.layout.activity_main)
lv = findViewById(R.id.lv) as ListView
btnselect = findViewById(R.id.select) as Button
btndeselect = findViewById(R.id.deselect) as Button
btnnext = findViewById(R.id.next) as Button
modelArrayList = getModel(false)
customAdapter = CustomAdapter(this, modelArrayList!!)
lv!!.adapter = customAdapter
btnselect!!.setOnClickListener {
modelArrayList = getModel(true)
customAdapter = CustomAdapter(this@MainActivity, modelArrayList!!)
CustomAdapter.public_modelArrayList = modelArrayList as ArrayList<Model>
lv!!.adapter = customAdapter
}
btndeselect!!.setOnClickListener {
modelArrayList = getModel(false)
customAdapter = CustomAdapter(this@MainActivity, modelArrayList!!)
CustomAdapter.public_modelArrayList = modelArrayList as ArrayList<Model>
lv!!.adapter = customAdapter
}
btnnext!!.setOnClickListener {
val intent = Intent(this@MainActivity, NextActivity::class.java)
startActivity(intent)
}
}
private fun getModel(isSelect: Boolean): ArrayList<Model> {
val list = ArrayList<Model>()
for (i in 0..3) {
val model = Model()
model.setSelecteds(isSelect)
model.setAnimals(animallist[i])
list.add(model)
}
return list
}
}
Logic for select all and deselect all features are written in the above class.
Write below code into activity_main.xml
<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:tools="http://schemas.android.com/tools"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:orientation="vertical"
tools:context="com.example.parsaniahardik.kotlin_listview_checkbox.MainActivity">
<ListView
android:layout_width="match_parent"
android:layout_height="match_parent"
android:layout_weight="1"
android:id="@+id/lv">
</ListView>
<LinearLayout
android:layout_width="match_parent"
android:layout_height="50dp"
android:orientation="horizontal">
<Button
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:layout_gravity="center"
android:layout_weight="1"
android:id="@+id/select"
android:text="Select all"/>
<Button
android:layout_width="match_parent"
android:layout_height="50dp"
android:layout_weight="1"
android:id="@+id/deselect"
android:text="Deselct all"/>
<Button
android:layout_width="match_parent"
android:layout_height="50dp"
android:layout_weight="1"
android:id="@+id/next"
android:visibility="visible"
android:text="Next activity"/>
</LinearLayout>
</LinearLayout>
This was all the details about making a listview with checkbox in android with kotlin language.
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