ExpandableStackView

ExpandableStackView.kt

class ExpandableStackView @JvmOverloads constructor(
    context: Context, attrs: AttributeSet? = null, defStyleAttr: Int = 0
) : MotionLayout(context, attrs, defStyleAttr) {

    fun setAdapter(adapter: BaseAdapter) {

        val scene = MotionScene(this)

        val startSetId = View.generateViewId()
        val startSet = ConstraintSet()
        startSet.clone(this)

        val endSetId = View.generateViewId()
        val endSet = ConstraintSet()
        endSet.clone(this)

        val transitionId = View.generateViewId()
        val transaction = TransitionBuilder.buildTransition(
            scene,
            transitionId,
            startSetId, startSet,
            endSetId, endSet
        )

        transaction.duration = 1000

        scene.addTransition(transaction)
        scene.setTransition(transaction)
        setScene(scene)

        setTransition(transitionId)
    }

    private fun boundTwoViewEnd(
        constraintSet: ConstraintSet,
        firstView: View,
        secondView: View
    ) {
        constraintSet.connect(
            secondView.id,
            ConstraintSet.TOP,
            firstView.id,
            ConstraintSet.BOTTOM,
            fromDpToPx(16).toInt()
        )
    }

    private fun boundTwoViewStart(
        constraintSet: ConstraintSet,
        firstView: View,
        secondView: View,
        marginBottom: Int
    ) {
        constraintSet.connect(
            secondView.id,
            ConstraintSet.TOP,
            firstView.id,
            ConstraintSet.TOP,
            marginBottom
        )
    }

    private fun connectViewToParent(
        constraintSet: ConstraintSet,
        firstView: View
    ) {
        constraintSet.connect(
            firstView.id,
            ConstraintSet.START,
            ConstraintSet.PARENT_ID,
            ConstraintSet.START
        )

        constraintSet.connect(
            firstView.id,
            ConstraintSet.END,
            ConstraintSet.PARENT_ID,
            ConstraintSet.END
        )
    }

}