VibratorManager on Wear OS 3 and Android Chipmunk 2021.2.1 Beta

Question

    val context = ApplicationProvider.getApplicationContext<Application>()
    val vibratorManager = context?.getSystemService(Context.VIBRATOR_MANAGER_SERVICE) as VibratorManager
    val vibrator = vibratorManager.getDefaultVibrator()
    if ((drawCount == 240) or (drawCount == 60)){
        vibrator.vibrate(VibrationEffect.createOneShot(200, VibrationEffect.DEFAULT_AMPLITUDE))
    } else if ((drawCount <= 60) and (drawCount.mod(5) == 0)){
        vibrator.vibrate(VibrationEffect.createOneShot(100, VibrationEffect.DEFAULT_AMPLITUDE))
    }
    vibrator.cancel()
    vibratorManager.cancel()

The code above causes a blank screen on the Emulator and on Samsung Galaxy Watch 4 - Wear OS 3.2 - Android 11.

I copied the code from several answers here. When I comment out the above code, my app runs great on the Emulator and on the said watch.

1. Has anyone here written a code relating to the VibratorManager lately?
2. Is it my Gradle?
3. Should I use the latest Beta version of the Android Studio?
4. Is there another way to accomplish my task which is NOT to notify the user but to vibrate the watch without requiring a user input?

Thanks

Answer 1

Access application context in companion object in kotlin

The post above fixed my bug. Here is what I did.

1. In the MainActivity, I added his code:

init {
    instance = this
}

companion object {
    private var instance: MainActivity? = null

    fun applicationContext() : Context {
        return instance!!.applicationContext
    }
}

2. And on my function, I added this code from him:

val context: Context = MainActivity.applicationContext()

Answer 2

The following code snippet works for me

Declare variables

    private lateinit var mVibrator: Vibrator
    private lateinit var vibrationEffectSingle : VibrationEffect

Initialisation (in onCreate())

if (ContextCompat.checkSelfPermission(this, Manifest.permission.VIBRATE) == PackageManager.PERMISSION_GRANTED) {
    if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.S) {
        // VibratorManager was only added on API level 31 release.
        val vibratorManager = getSystemService(VIBRATOR_MANAGER_SERVICE) as VibratorManager
        mVibrator = vibratorManager.defaultVibrator
    } else {
        // backward compatibility for Android API < 31
        mVibrator = getSystemService(VIBRATOR_SERVICE) as Vibrator
    }
    vibrationEffectSingle = VibrationEffect.createOneShot(500, VibrationEffect.DEFAULT_AMPLITUDE)
}

Use

                mVibrator.vibrate(vibrationEffectSingle)

In the Manifest

    <uses-permission android:name="android.permission.VIBRATE" />