DelegatesAndExtensions

DelegatesAndExtensions.kt

fun alphaWithBounceAnimator(): ReadWriteProperty<ImageView, Int> =
        object : ReadWriteProperty<ImageView, Int> {

            override fun getValue(thisRef: ImageView, property: KProperty<*>): Int {
                return thisRef.imageAlpha
            }

            override fun setValue(thisRef: ImageView, property: KProperty<*>, value: Int) {

                val animX = ObjectAnimator.ofFloat(thisRef, "scaleX", 1f, 2.5f, 1f)
                val animY = ObjectAnimator.ofFloat(thisRef, "scaleY", 1f, 2.5f, 1f)
                val alpha = ObjectAnimator.ofInt(thisRef.imageAlpha, value).apply {
                    addUpdateListener { thisRef.imageAlpha = it.animatedValue as Int }
                }

                if(thisRef.imageAlpha != value) {
                    AnimatorSet().apply {
                        playTogether(animX, animY, alpha)
                        duration = 250L
                        interpolator = AccelerateDecelerateInterpolator()

                    }.start()
                }
            }

        }

var ImageView.imageAlfa: Int by alphaWithBounceAnimator()

usage.kt

imageView.imageAlfa = 1