JetpackCompose And Counter! ! Easy Sample!

CounterActivity.kt

class CounterActivity : AppCompatActivity() {
    override fun onCreate(savedInstanceState: Bundle?) {
        super.onCreate(savedInstanceState)
        setContent {
            MaterialTheme {
                val countStatus = +state { 0 }
                
                val liveCount = MutableLiveData<Int>().apply {
                    value = 0
                    this.observe(this@MainActivity, Observer{ inc ->
                        countStatus.value = inc
                    })
                }
                
                val isRunCountup = MutableLiveData<Boolean>().apply {
                    value = false
                }
                
                var countInt = 0

                val countupLoop = {
                    Thread {
                        while (true) {
                            if (isRunCountup.value!!) liveCount.postValue(countInt++)
                            else return@Thread
                            Thread.sleep(1)
                        }
                    }.start()
                }
                
                run.observe(this@MainActivity, Observer {
                    if (it) countupLoop()
                })

                Column {
                    Padding(40.dp) {
                        Text("Count:${countStatus.value}", style = TextStyle(fontSize = 20.sp))
                    }
                    Padding(40.dp) {
                        Ripple(bounded = true) {
                            Button(onClick = { isRunCountup.toggle() }, text = "toggle")
                        }
                    }
                }
            }
        }
    }
}

fun MutableLiveData<Boolean>.toggle() = apply { value = !value!! }