Member visibility issues with DragItemAdapter, and other issues

1. mDragItemId is private, i had to use reflection to get its value
2. setDragStartCallback in ViewHolder is public, but its argument is package private, so i can not override that method anyway

I bumped in this issue because i needed to implement a custom drawing for an empty space, it was achieved by alternating item appearance during binding of view holder and it was troublesome. Also I had to directly manipulate a view tree to achieve the same behavior for columns.

Also i had to use the trick below to achieve visually appealing jump for column when it’s ready to be dragged

override fun onStartDragAnimation(dragView: View) {

        // ATTENTION: dirty hacky games with reflection
        try {
            val method = this.javaClass.superclass.getDeclaredMethod(
                "setAnimationDY",
                Float::class.java
            )
            method.isAccessible = true
            method.invoke(this, targetElevation)
        } catch (ex: Throwable) {
            // Just ignore if no success
            Timber.e(ex)
        }

        val container = dragView as ConstraintLayout
        ObjectAnimator.ofFloat(container, ELEVATION, targetElevation).apply {
            interpolator = DecelerateInterpolator()
            duration = ANIMATION_DURATION
            start()
        }
    }

In conclusion, the library is great, but lacks flexibility

[woxblom]

Ah now I understand. I will put it on the todo list 😃

[Saad-e-Sayed]

Thank you sir. It finally worked! I can’t wait until I do it in my main project. And I will watch out for that small mistake in the next times for sure.