Android - How to achieve setOnClickListener in Kotlin?
AndroidListenerKotlinAndroid Problem Overview
I wanted to know that how we set basic onClickListener in Kotlin for Android Development.
Android Solutions
Solution 1 - Android
There are five ways to use SetOnClickListener:
First:
button.setOnClickListener {
// Do some work here
}
Second:
button.setOnClickListener(object : View.OnClickListener {
override fun onClick(view: View?) {
// Do some work here
}
})
Third:
button.setOnClickListener(View.OnClickListener { view ->
// Do some work here
})
Fourth:
class MainActivity : AppCompatActivity(), View.OnClickListener{
lateinit var button : Button
override fun onCreate(savedInstanceState: Bundle?) {
super.onCreate(savedInstanceState)
setContentView(R.layout.activity_main)
button = findViewById(R.id.button1)
button.setOnClickListener(this)
}
override fun onClick(view: View?) {
when(view?.id){
R.id.button1->{
// do some work here
}
}
}
}
Fifth:
class MainActivity : AppCompatActivity(){
lateinit var button : Button
override fun onCreate(savedInstanceState: Bundle?) {
super.onCreate(savedInstanceState)
setContentView(R.layout.activity_main)
button = findViewById(R.id.button1)
button.setOnClickListener(listener)
}
val listener= View.OnClickListener { view ->
when (view.getId()) {
R.id.button1 -> {
// Do some work here
}
}
}
}
Cheers!
Solution 2 - Android
Suppose you have textView to click
text_view.text = "Hello Kotlin";
text_view.setOnClickListener {
val intent = Intent(this@MainActivity, SecondActivity::class.java)
intent.putExtra("key", "Kotlin")
startActivity(intent)
}
Solution 3 - Android
Use below code
val textview = findViewById<TextView>(R.id.textview)
textview.setOnClickListener(clickListener)
val button = findViewById<Button>(R.id.button)
button.setOnClickListener(clickListener)
clickListener code.
val clickListener = View.OnClickListener {view ->
when (view.getId()) {
R.id.textview -> firstFun()
R.id.button -> secondFun()
}
}
Solution 4 - Android
Here is an example on how to use the onClickListener in Kotlin
button1.setOnClickListener(object : View.OnClickListener{
override fun onClick(v: View?) {
//Your code here
}})
Solution 5 - Android
Method 1:
txtNext.setOnClickListener {
//Code statements
}
Method 2:
class FirstActivity : AppCompatActivity(), View.OnClickListener {
override fun onCreate(savedInstanceState: Bundle?) {
super.onCreate(savedInstanceState)
setContentView(R.layout.activity_first)
txtNext.setOnClickListener(this)
}
override fun onClick(v: View) {
when (v.id) {
R.id.txtNext -> {
//Code statements
}
else -> {
// else condition
}
}
}
}
Solution 6 - Android
For using multiple ids:
textview1.setOnClickListener(clickListener)
textview2.setOnClickListener(clickListener)
Create anonymous class:
private val clickListener: View.OnClickListener = View.OnClickListener { view ->
when (view.id) {
R.id.textview1-> {
Toast.makeText(this, "Clicked 1", Toast.LENGTH_SHORT).show()
}
R.id.textview2-> {
Toast.makeText(this, "Clicked 2", Toast.LENGTH_SHORT).show()
}
}
}
Solution 7 - Android
First you have to get the reference to the View (say Button, TextView, etc.) and set an OnClickListener to the reference using setOnClickListener() method
// get reference to button
val btn_click_me = findViewById(R.id.btn_click_me) as Button
// set on-click listener
btn_click_me.setOnClickListener {
Toast.makeText(this@MainActivity, "You clicked me.", Toast.LENGTH_SHORT).show()
}
Refer Kotlin SetOnClickListener Example for complete Kotlin Android Example where a button is present in an activity and OnclickListener is applied to the button. When you click on the button, the code inside SetOnClickListener block is executed.
Update
Now you can reference the button directly with its id by including the following import statement in Class file. Documentation.
import kotlinx.android.synthetic.main.activity_main.*
and then for the button
btn_click_me.setOnClickListener {
// statements to run when button is clicked
}
Refer Android Studio Tutorial.
Solution 8 - Android
Use this code to add onClickListener
in Kotlin
val button : Button = getView()?.findViewById<Button>(R.id.testButton) as Button
button.setOnClickListener {view ->
Toast.makeText(context, "Write your message here", Toast.LENGTH_LONG).show()
}
}
Solution 9 - Android
I see a lot of suggestions here, but this collection is missing the following.
button.setOnClickListener(::onButtonClicked)
and in the current class we have a method like this:
private fun onButtonClicked(view: View) {
// do stuff
}
Solution 10 - Android
Simply you can get OnClickListener in kotlin
view1.setOnClickListener{
//body
}
Solution 11 - Android
var tv = findViewById(R.id.tv)
as TextView
tv.setOnClickListener {
val i = Intent(this@MainActivity, SecondActivity::class.java)
startActivity(i)
finish()
}
Solution 12 - Android
A simple way would be to register a click listener and create a click listener with a lambda expression.
override fun onCreate(savedInstanceState: Bundle?) {
super.onCreate(savedInstanceState)
setContentView(R.layout.activity_main)
// click listener registered
myButton.setOnClickListener(clickListener)
}
And implement the clickListener
:
private val clickListener: View.OnClickListener = View.OnClickListener { _ ->
// do something here
}
You can replace _
with a name if you need the view to use it. For example, you need to check the id of click listener.
private val clickListener: View.OnClickListener = View.OnClickListener { view ->
if(view.id == login.id) {
// do something here
}
}
Solution 13 - Android
val button = findViewById<Button>(R.id.button)
button.setOnClickListener {
val intent =
Intent(this@MainActivity,ThirdActivity::class.java)
intent.putExtra("key", "Kotlin")
startActivity(intent)
}
Solution 14 - Android
**i have use kotlin-extension so i can access directly by button id:**
btnSignIN.setOnClickListener {
if (AppUtils.isNetworkAvailable(activity as BaseActivity)) {
if (checkValidation()) {
hitApiLogin()
}
}
}
Solution 15 - Android
There are several different ways to achieve this, as shown by the variety of answers on this question.
To actually assign the listener to the view, you use the same methods as you would in Java:
button.setOnClickListener()
However, Kotlin makes it easy to assign a lambda as a listener:
button.onSetClickListener {
// Listener code
}
Alternatively, if you want to use this listener for multiple views, consider a lambda expression (a lambda assigned to a variable/value for reference):
val buttonClickListener = View.OnClickListener { view ->
// Listener code
}
button.setOnClickListener(buttonClickListener)
another_button.setOnClickListener(buttonClickListener)
Solution 16 - Android
Simply do as below :
button.setOnClickListener{doSomething()}
Solution 17 - Android
findViewById<Button>(R.id.signUp)?.setOnClickListener(
Toast.makeText(mActivity, "Button Clicked", Toast.LENGTH_LONG).show()
)
Solution 18 - Android
button.setOnClickListener {
//write your code here
}
Solution 19 - Android
Button OnClickListener implementation from function in android using kotlin.
Very First Create Button View From .xml File
`<Button
android:id="@+id/btn2"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:text="Button2"
android:layout_weight="0.5"/>`
//and create button instance in Activity
private var btn1:Button?=null
or
//For Late Initialization can Follow like this,
private lateinit var btn1:Button
//in onCreate,
btn1=findViewById(R.id.btn1) as Button
btn1?.setOnClickListener { btn1Click() }
//implementing button OnClick event from Function,
private fun btn1Click() {
Toast.makeText(this, "button1", Toast.LENGTH_LONG).show()
}
Solution 20 - Android
You can use view.setOnClickListener{ // your task to execute }
Kotlin type inference and automatic lambda expression will handle the boilerplate. Note: Here view can be anything like TextView or button etc.
Solution 21 - Android
You use like that onclickListener in kotlin
val fab = findViewById(R.id.fab) as FloatingActionButton
fab.setOnClickListener {
...
}
Solution 22 - Android
First find the button, to prevent the cast from the View
you can use the <>
as follows :
val button = findViewById<Button>(R.id.button);
Once you have an instance of the Button
, you can now attach the click listener as follows :
button.setOnClickListener {
// You code here
}
Solution 23 - Android
Here's the solution. Your code will like this:
button.setOnClickListener {
//your code here
}
No need to add anything. like below:
val button = findViewById<Button>(R.id.Button)
button.setOnClickListener {
}
Solution 24 - Android
val saveButton:Button = findViewById(R.id.button_save)
saveButton.setOnClickListener{
// write code for click event
}
with view object
saveButton.setOnClickListener{
view -> // write code for click event
}
Solution 25 - Android
The easiest way that I know to achieve that is through Kotlin Android Extensions.
On your app/build.gradle
apply plugin: 'kotlin-android-extensions'
If your button is called 'btnAdd', then on your fragment or activity import the following:
import kotlinx.android.synthetic.main.fragment_transactions.btnAdd
override fun onViewCreated(view: View?, savedInstanceState: Bundle?) {
super.onViewCreated(view, savedInstanceState)
btnAdd.setOnClickListener {
Toast.makeText(context , "Done", 10).show()
}
}
Solution 26 - Android
If you want to simulate the old anonymous way in Kotlin I found this worked perfectly.
btnNewWay!!.setOnClickListener(object:View.OnClickListener {
override fun onClick(v: View?) {
//Your Code Here!
}})
Solution 27 - Android
Add clickListener on button like this
btUpdate.setOnClickListener(onclickListener)
add this code in your activity
val onclickListener: View.OnClickListener = View.OnClickListener { view ->
when (view.id) {
R.id.btUpdate -> updateData()
}
}
Solution 28 - Android
You can use setOnClickListener like this in Kotlin
button.setOnClickListener(View.OnClickListener {
//code
})
Solution 29 - Android
Add in build.gradle module file
android {
...
buildFeatures {
viewBinding true
}
}
For Activity add
private lateinit var binding: ResultProfileBinding
override fun onCreate(savedInstanceState: Bundle?) {
super.onCreate(savedInstanceState)
binding = ResultProfileBinding.inflate(layoutInflater)
val view = binding.root
setContentView(view)
}
Add on click
binding.button.setOnClickListener { Log.d("TAG", "Example") }
Solution 30 - Android
In case anyone else wants to achieve this while using binding. If the id of your view is button_save then this code can be written, taking advantage of the kotlin apply syntax
binding.apply {
button_save.setOnClickListener {
//dosomething
}
}
Take note binding is the name of the binding instance created for an xml file . Full code is below if you are writing the code in fragment. Activity works similarly
private lateinit var binding: FragmentProfileBinding
override fun onCreateView(
inflater: LayoutInflater, container: ViewGroup?,
savedInstanceState: Bundle?
): View? {
// Inflate the layout for this fragment
binding = FragmentProfileBinding.inflate(inflater, container, false)
return binding.root
}
// onActivityCreated is deprecated in fragment
override fun onViewCreated(view: View, savedInstanceState: Bundle?) {
super.onViewCreated(view, savedInstanceState)
binding.apply {
button_save.setOnClickListener {
//dosomething
}
}
}
Solution 31 - Android
Best for achieve click listener in Kotlin(Mean Without findview by id you can click or intalize the textview, button, spinner etc)
Step: -
- Go to your Build/gradle
- Add this line : - id 'kotlin-android-extensions'
- Then Sync the project.
This is Gradle File plugins { id 'com.android.application' id 'kotlin-android' id 'kotlin-android-extensions' }
android { compileSdkVersion 30 buildToolsVersion "30.0.3"
defaultConfig {
applicationId "com.safal.myapp"
minSdkVersion 21
targetSdkVersion 30
versionCode 1
versionName "1.0"
testInstrumentationRunner "androidx.test.runner.AndroidJUnitRunner"
}
buildTypes {
release {
minifyEnabled false
proguardFiles getDefaultProguardFile('proguard-android-optimize.txt'), 'proguard-rules.pro'
}
}
compileOptions {
sourceCompatibility JavaVersion.VERSION_1_8
targetCompatibility JavaVersion.VERSION_1_8
}
kotlinOptions {
jvmTarget = '1.8'
}
}
Solution 32 - Android
There are multiple ways to do it, I would prefer kotlin way of doing it and minimise the boilerplate code.
Say you have a Button defined in your layout file like this,
<Button
android:id="@+id/clickMe"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="Ok"
app:layout_constraintBottom_toBottomOf="parent"
app:layout_constraintEnd_toEndOf="parent"
app:layout_constraintStart_toStartOf="parent"
app:layout_constraintTop_toTopOf="parent" />
and you want to add onClickListener to this button clickMe
You would need below to do this,
-
Add kotlin extension to your existing plugins in build.gradle file like below and sync
plugins { id 'kotlin-android-extensions' }
-
Add the listener like this,
clickMe.setOnClickListener { Toast.makeText(this@MainActivity, "You clicked me!", Toast.LENGTH_SHORT).show() }