CODE EXAMPLE FOR JAVA

android toast in adapter

// Toast in Adapter

// in onBindViewHolder()
Toast.makeText(holder.itemview.getContext, "Your Toast Msg Here! ",
               Toast.LENGTH_LONG).show();

// in view holder
Toast.makeText(itemview.getContext, "Your Toast Msg Here! ",
               Toast.LENGTH_LONG).show();

// if you are already taking context in adapter's constructor
// then you can do like this

Toast.makeText(context, "Your Toast Msg Here! ",
               Toast.LENGTH_LONG).show();