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Android kotlin update TextView every second

I want the text view to be updated every second or less in a dynamic random way and at the end of the loop the text view show the last random number.
I tried to add a sleep method but it did not work every time I click the button the text view show the last random number directly.
class MainActivity : AppCompatActivity() {
override fun onCreate(savedInstanceState: Bundle?) {
super.onCreate(savedInstanceState)
setContentView(R.layout.activity_main)
val rollButton: Button = findViewById(R.id.button1)
var result: TextView = findViewById(R.id.textView)
rollButton.setOnClickListener {
for (i in 1..10){
result.text = "${(1..6).random()}"
}
Toast.makeText(this, "Dice Rolled!", Toast.LENGTH_SHORT).show()
}
}
}

Coroutine delay is a way to do that, which is suggested in ltp's answer,
Another way is Runnable and Handler, an example function:
fun animateTextView(handler: Handler, textView: TextView, animate: Boolean = true) {
val runnable: Runnable = object : Runnable {
var randomNumber = 0
override fun run() {
randomNumber = (1..100).random()
textView.text = "$randomNumber"
handler.postDelayed(this, 500L)
}
}
// animate == false -> end text updates
if (animate) handler.postDelayed(runnable, 500L)
else handler.removeCallbacks(runnable)
}
Example use of the function:
private val textAnimaterHandler = Handler(Looper.getMainLooper())
animateTextView(textAnimaterHandler, binding.textView)
// Stop updates:
animateTextView(textAnimaterHandler, binding.textView, animate = false)

You can use Coroutine delay
rollButton.setOnClickListener {
CoroutineScope(Dispatchers.Main).launch {
//Disable button temporarily to prevent multiple clicks
it.isEnabled = false
for (i in 1..10) {
binding.textviewFirst.text = "${(1..6).random()}"
//One second delay before the next
delay(1000)
//If you want random delay - say 100ms to 1s
//delay((100L..1000L).random())
}
it.isEnabled = true
Toast.makeText(this#MainActivity, "Dice Rolled!", Toast.LENGTH_SHORT).show()
}
}

My timer keeps counting down, onFinish method didn't work. [Kotlin]

Im trying to stop Counter when time is over. But in my situation when time is over, timer restart and counting again. I don't know why my onFinish method doesn't work good. Thanks for all support.
countDownTimer = object : CountDownTimer(timeLeftInMillis, 1000) {
override fun onTick(millisUntilFinished: Long) {
timeLeftInMillis = millisUntilFinished
updateCountDownText()
}
override fun onFinish() {
isRunning = false
isStartingAlarm = true
startPauseButton.text = "Start"
startPauseButton.visibility = View.INVISIBLE
resetButton.visibility = View.VISIBLE
alarmSound.start()
}
}.start()

How can I set a CountDownTimer in Kotlin?

Using the CountDownTimer, is there a way I can let the user choose how much time the timer will count?
val timer = object : CountDownTimer(time * 1000, 1000) {
override fun onTick(millisUntilFinished: Long) {
bntTimer.text = (millisUntilFinished / 1000).toString()
if (!on)
turnOn()
}
override fun onFinish() {
bntTimer.text = "Timer"
if (on)
turnOff()
}
}
In this code the variable time is initialized with 5, but before starting the timer, the user can change it. However, it always count 5 seconds.
Here is where the variable time got modified
bntTimer.setOnClickListener(){
if(TextUtils.isEmpty(etTime.text)) {
Toast.makeText(this, "Por favor, informe o tempo.", Toast.LENGTH_SHORT).show();
}
else{
Toast.makeText(this#MainActivity, "Timer Contando", Toast.LENGTH_SHORT).show()
time = etTime.text.toString().toLong()
timer.start()
}
}

The problem is you are making the timer object first then changing the time variable which has no longer effect on the existing timer object. So you must make the timer object again after changing the time variable.
You can make a function like below or a function with time as a parameter.
fun starTimer(){
time = etTime.text.toString().toLong()
val timer = object : CountDownTimer(time * 1000, 1000) {
override fun onTick(millisUntilFinished: Long) {
bntTimer.text = (millisUntilFinished / 1000).toString()
if (!on)
turnOn()
}
override fun onFinish() {
bntTimer.text = "Timer"
if (on)
turnOff()
}
}.start()
}
Then call the startTimer() function whenever you need it. Something like in your case
bntTimer.setOnClickListener(){
if(TextUtils.isEmpty(etTime.text)) {
Toast.makeText(this, "Por favor, informe o tempo.", Toast.LENGTH_SHORT).show();
}
else{
Toast.makeText(this#MainActivity, "Timer Contando", Toast.LENGTH_SHORT).show()
startTimer()
}
}

Kotlin: call a function every second

I want to create a simple countdown for my game, when the game starts I want this function to be called every second:
fun minusOneSecond(){
if secondsLeft > 0{
secondsLeft -= 1
seconds_thegame.text = secondsLeft.toString()
}
}
I tried this:
var secondsLeft = 15
timer.scheduleAtFixedRate(
object : TimerTask() {
override fun run() {
minusOneSecond()
}
},0, 1000
) // 1000 Millisecond = 1 second
But the app unfortunately stops, the 2nd time the run function is called
I just started with android development and Kotlin 3 weeks ago and so far I understand the most out of it.
With swift in Xcode I use this line and I thought something similar would work with Kotlin
setTimer = Timer.scheduledTimer(timeInterval: 1, target: self, selector: #selector(minusOneSecond), userInfo: nil, repeats: true)

Problem: Timer class uses a background thread with a queue to queue and execute all tasks sequentially. From your code, because you update UI (changing TextView content in minusOneSecond function). That why the app throws the following exception and make your app crash.
android.view.ViewRootImpl$CalledFromWrongThreadException: Only the
original thread that created a view hierarchy can touch its views.
Solution: There are many ways to achieve your task, but I prefer using post() and postDelayed() method from Handler class. Because it's simple and easy to understand.
val mainHandler = Handler(Looper.getMainLooper())
mainHandler.post(object : Runnable {
override fun run() {
minusOneSecond()
mainHandler.postDelayed(this, 1000)
}
})
Update: From author's comment about how to pause/resume the task from Handler. Here is an example.
class MainActivityKt : AppCompatActivity() {
lateinit var mainHandler: Handler
private val updateTextTask = object : Runnable {
override fun run() {
minusOneSecond()
mainHandler.postDelayed(this, 1000)
}
}
override fun onCreate(savedInstanceState: Bundle?) {
super.onCreate(savedInstanceState)
setContentView(R.layout.activity_main)
// Your logic code
...
mainHandler = Handler(Looper.getMainLooper())
}
override fun onPause() {
super.onPause()
mainHandler.removeCallbacks(updateTextTask)
}
override fun onResume() {
super.onResume()
mainHandler.post(updateTextTask)
}
fun minusOneSecond() {
if secondsLeft > 0 {
secondsLeft -= 1
seconds_thegame.text = secondsLeft.toString()
}
}
}

I am using this code to update a clock every minute
fixedRateTimer("timer", false, 0L, 60 * 1000) {
this#FullscreenActivity.runOnUiThread {
tvTime.text = SimpleDateFormat("dd MMM - HH:mm", Locale.US).format(Date())
}
}
so you have to run it with paratemer 1000 instead of 60*1000

val timer = object: CountDownTimer(10000, 1000) {
override fun onTick(millisUntilFinished: Long) {
// do something
}
override fun onFinish() {
// do something
}
}
timer.start()
You can also use CountDownTimer for this purpose. As this takes two parameters (the total time and the interval time)
Plus it also provides an on finish method to perform any task when the total time is finished.

please use
inline fun Timer.schedule(
time: Date,
period: Long,
crossinline action: TimerTask.() -> Unit
): TimerTask
reference: https://kotlinlang.org/api/latest/jvm/stdlib/kotlin.concurrent/java.util.-timer/schedule.html

I am calling my function every second like this
val handler = Handler()
handler.postDelayed(object : Runnable {
override fun run() {
//Call your function here
handler.postDelayed(this, 1000)//1 sec delay
}
}, 0)

My solution
viewModelScope.launch(Dispatchers.IO) {
while(isActive) {
when(val response = repository.getApi()) {
is NetworkState.Success -> {
getAllData.postValue(response.data)
}
is NetworkState.Error -> this#MainViewModel.isActive = false
}
delay(API_CALL_DELAY)
}
}

if you use any background task or background service try this code
val timer = Executors.newSingleThreadScheduledExecutor().scheduleAtFixedRate({
Log.d("RUNNING ","Thread")
},0,10,TimeUnit.SECONDS)
if you work with UI thers like update UI layout try this code
val timer = Executors.newSingleThreadScheduledExecutor().scheduleAtFixedRate({
Log.d("RUNNING ","BACKGROUN Thread")
runOnUiThread {
Log.d("RUNNING ","Update UI Thread")
btnUpdate.setText(System.currentTimeMillis().toString())
}
},0,1,TimeUnit.SECONDS)

I'm using recursion with Coroutine its very simple
private fun loop() {
CoroutineScope(IO).launch {
delay(5000)
CoroutineScope(Main).launch {
ManagerToWorker()
loop()
}
}
}

var isActionAchieved = false
var secondsPassed = 0
fun cDTimer(){
if (!isActionAchieved && secondsPassed < 10){ // repeat check if Action NOT Achieved for max of 10 seconds
Handler(Looper.getMainLooper()).postDelayed({
repeatThisFunction()
repeater()
secondsPassed++
}, 1000) //one second till next execution
}
}
fun repeater(){
cDTimer()
}

Accessing CountDownTimer variable globally

I'm just starting with Kotlin to make Android Apps (it's my first programming language) and I'm using a CountDownTimer. I want to access the p0 parameter globally, but I don't know how to. Here's the code:
class MainActivity : AppCompatActivity() {
var score: Int = 0
override fun onCreate(savedInstanceState: Bundle?) {
super.onCreate(savedInstanceState)
setContentView(R.layout.activity_main)
var timeTimer = object : CountDownTimer(10000, 1000) {
override fun onFinish() {
timeView.text = "Time's up!"
}
override fun onTick(p0: Long) {
timeView.text = "Time's left: " + p0/1000
}
}.start()
}
fun point (view: View) {
score++
p0 = p0 + 1000
scoreView.text = "Score: $score"
}
}
Function point is called by clicking a button. The thing I'm trying to achieve is making CountDownTimer longer by 1 second every time a user clicks a button.
This line p0 = p0 + 1000 obviously won't work because p0 is inside another code block. Is there any way to make it globally accessible? I've thought about putting CountDownTimer outside onCreate and just starting it in the onCreate, but I think it still wouldn't work as p0 is still inside CountDownTimer code block.

var timeTimer = object : CountDownTimer(10000, 1000) {
override fun onFinish() {
timeView.text = "Time's up!"
}
override fun onTick(p0: Long) {
timeLeft = p0 //timeLeft is global --only way I think to keep track remaining time.
timeView.text = "Time's left: " + p0/1000
}
}.start()
This should be global (better at the bottom after all methods of the Activity)
fun resetTimer(time){
timeTimer.cancel()
timeTimer = object : CountDownTimer(time, 1000) {
override fun onFinish() {
timeView.text = "Time's up!"
}
override fun onTick(p0: Long) {
timeLeft = p0
timeView.text = "Time's left: " + p0/1000
}
}.start()
}
So finally
fun point (view: View) {
score++
resetTimer(timeLeft + 1000)
scoreView.text = "Score: $score"
}

I don't know what's the reach of your App, but you can do a couple of things:
Create a custom Application class for your App and check the variable there. You need to create a class that extends from Application and add that class into your manifest, in the <application/> tag under the android:name attribute. You can access your custom Application class from anywhere by using it like a Singleton, for example MyApp.getInstance().setPvalue(someIntValue).
Maybe you want to save that value in your SharedPreferences so It's kept saved if you close the App.
Maybe you want to have that value in a Service, so if you close the App the timer is still going to be counting down.
I answer a pretty similar question the other day:
How to keep the countDownTimer counts after i swap the activity?
Hope it helps.