Android: simple time counter

Question

I have a simple program with one TextView and two Buttons: Button1 and Button2.

Clicking on Button 1 will start a counter, increasing by 1 every 1 second and show res

Answer 1

As @hovanessyan suggested: You can use the Chronometer class. E.g., as follows (with Kotlin, Java analog):

class ChronometerToggler: Fragment() {
    private lateinit var chronometer: Chronometer
    private var isChronometerRunning = false
    private lateinit var toggleButton: FloatingActionButton

    override fun onCreateView(inflater: LayoutInflater, container: ViewGroup?, savedInstanceState: Bundle?): View? {
        val view = inflater.inflate(R.layout.my_layout, container, false)
        chronometer = view.findViewById(R.id.chronometer)
        toggleButton = view.findViewById(R.id.toggle_button)
        toggleButton.setOnClickListener {
            onToggleButtonPressed()
        }
        return view
    }

    private fun onToggleButtonPressed() {
        isChronometerRunning = !isChronometerRunning
        if (isChronometerRunning) {
            chronometer.base = SystemClock.elapsedRealtime()
            chronometer.start()
        }
        else {
            chronometer.stop()
        }
    }
}

In the my_layout.xml:

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