Decoupled Kotlin class which allows start or stop TalkBack service.

TalkBackFacade.kt

class TalkBackFacade @Inject constructor(private val contextWeakReference: WeakReference<Context>) {

    fun isTalkBackEnabled() = Settings.Secure.getString(
        contextWeakReference.get()?.contentResolver,
        Settings.Secure.ACCESSIBILITY_ENABLED
    )?.toInt()?.toBoolean()
        ?: false

    fun enableTalkBack() = changeAccessibilityServicesState(
        true,
        TALK_BACK_SERVICE_NAME
    )

    fun disableTalkBack() = changeAccessibilityServicesState(
        false,
        TALK_BACK_SERVICE_NAME_DISABLED
    )

    private fun changeAccessibilityServicesState(
        enable: Boolean,
        accessibilityServiceName: String
    ): Boolean {
        return try {
            Settings.Secure.putString(
                contextWeakReference.get()?.contentResolver,
                Settings.Secure.ENABLED_ACCESSIBILITY_SERVICES,
                accessibilityServiceName
            )
            Settings.Secure.putString(
                contextWeakReference.get()?.contentResolver,
                Settings.Secure.ACCESSIBILITY_ENABLED,
                enable.intValue().toString()
            )
            true
        } catch (e: SecurityException) {
            Log.e("AccessibilityHelper", e.message.toString())
            false
        }
    }
}
// Consants and ext functions moved here for easily access
private const val TALK_BACK_SERVICE_NAME = "com.google.android.marvin.talkback/.TalkBackService"
private const val TALK_BACK_SERVICE_NAME_DISABLED = ""

fun Int.toBoolean() = this == 1
fun Boolean.intValue() = if (this) 1 else 0