setTransitionListener

setTransitionListener(object : MotionLayout.TransitionListener {
    override fun onTransitionTrigger(
        p0: MotionLayout?,
        p1: Int,
        p2: Boolean,
        p3: Float
    ) {
        
    }

    override fun onTransitionStarted(p0: MotionLayout?, start: Int, end: Int) {
        if (start == startState) {
            img.alpha = 0.0f
            img_motion.alpha = 1.0f
        }
    }

    override fun onTransitionChange(p0: MotionLayout?, p1: Int, p2: Int, p3: Float) {
    }

    override fun onTransitionCompleted(p0: MotionLayout?, state: Int) {
        if (state == startState) {
            img.alpha = 1.0f
            img_motion.alpha = 0.0f
        }
    }
})