“Нарисуйте значок между прокрученной зоной Android” Ответ

Нарисуйте значок между прокрученной зоной Android

public static final float ALPHA_FULL = 1.0f;

public void onChildDraw(Canvas c, RecyclerView recyclerView, RecyclerView.ViewHolder viewHolder, float dX, float dY, int actionState, boolean isCurrentlyActive) {
    if (actionState == ItemTouchHelper.ACTION_STATE_SWIPE) {
        // Get RecyclerView item from the ViewHolder
        View itemView = viewHolder.itemView;

        Paint p = new Paint();
        Bitmap icon;

        if (dX > 0) {
            /* Note, ApplicationManager is a helper class I created 
               myself to get a context outside an Activity class - 
               feel free to use your own method */

            icon = BitmapFactory.decodeResource(
                    ApplicationManager.getContext().getResources(), R.drawable.myleftdrawable);

            /* Set your color for positive displacement */
            p.setARGB(255, 255, 0, 0);

            // Draw Rect with varying right side, equal to displacement dX
            c.drawRect((float) itemView.getLeft(), (float) itemView.getTop(), dX,
                    (float) itemView.getBottom(), p);

            // Set the image icon for Right swipe
            c.drawBitmap(icon,
                    (float) itemView.getLeft() + convertDpToPx(16),
                    (float) itemView.getTop() + ((float) itemView.getBottom() - (float) itemView.getTop() - icon.getHeight())/2,
                    p);
        } else {
            icon = BitmapFactory.decodeResource(
                    ApplicationManager.getContext().getResources(), R.drawable.myrightdrawable);

            /* Set your color for negative displacement */
            p.setARGB(255, 0, 255, 0);

            // Draw Rect with varying left side, equal to the item's right side
            // plus negative displacement dX
            c.drawRect((float) itemView.getRight() + dX, (float) itemView.getTop(),
                    (float) itemView.getRight(), (float) itemView.getBottom(), p);

            //Set the image icon for Left swipe
            c.drawBitmap(icon,
                    (float) itemView.getRight() - convertDpToPx(16) - icon.getWidth(),
                    (float) itemView.getTop() + ((float) itemView.getBottom() - (float) itemView.getTop() - icon.getHeight())/2,
                    p);
        }

        // Fade out the view as it is swiped out of the parent's bounds
        final float alpha = ALPHA_FULL - Math.abs(dX) / (float) viewHolder.itemView.getWidth();
        viewHolder.itemView.setAlpha(alpha);
        viewHolder.itemView.setTranslationX(dX);

    } else {
        super.onChildDraw(c, recyclerView, viewHolder, dX, dY, actionState, isCurrentlyActive);
    }
}

private int convertDpToPx(int dp){
    return Math.round(dp * (getResources().getDisplayMetrics().xdpi / DisplayMetrics.DENSITY_DEFAULT));
}