OnSwipeTouchListener.kt

import android.annotation.SuppressLint
import android.view.MotionEvent
import android.view.View
import android.view.View.OnTouchListener
import java.util.*

/**
 * Detects left and right swipes across a view.
 */

class OnSwipeTouchListener : OnTouchListener {

    var dX: Float = 0.toFloat()
    var dY: Float = 0.toFloat()
    var startPointX: Float = 0.toFloat()
    var startPointY: Float = 0.toFloat()
    private var startClickTime: Long = 0
    private var view: View? = null


    @SuppressLint("ClickableViewAccessibility")
    override fun onTouch(view: View, event: MotionEvent): Boolean {
        this.view = view
        when (event.action) {

            MotionEvent.ACTION_DOWN -> {
                startClickTime = Calendar.getInstance().timeInMillis
                dX = view.x - event.rawX
                dY = view.y - event.rawY
                startPointX = event.rawX
                startPointY = event.rawY
            }

            MotionEvent.ACTION_UP -> {

                when {
                    (view.x >= view.width / 1.5) -> {
                        setPosition(view, (+view.width).toFloat())
                        resetPosition(view)
                    }
                    (-view.x >= view.width / 1.5) -> {
                        setPosition(view, (-view.width).toFloat())
                        resetPosition(view)
                    }
                    else -> {
                        resetPosition(view)
                    }
                }
            }

            MotionEvent.ACTION_MOVE -> {
                when {
                    Math.abs(event.rawY - startPointY) * 1.5 > Math.abs(event.rawX - startPointX) -> resetPosition(
                        view
                    )
                    else -> resetPosition(view)
                }
            }
            else -> return false
        }
        return true
    }

    private fun resetPosition(view: View?) {
        view?.animate()?.x(0F)?.setDuration(200)?.start()
    }

    private fun setPosition(view: View?, position: Float) {
        view?.animate()
            ?.x(position)
            ?.setDuration(200)
            ?.start()
    }
}