How do I open an URL from a RecyclerView in a Fragment in Kotlin?

Question

I have a list of items in a RecyclerView that is in a Fragment, and I am trying to make it open an URL by clicking on a certain item. For example, if I click on the first item, it should redirect me to url1, but if I click on the second, it should redirect to url2.

I have seen solutions for recyclerviews in main activity, but those don't seem work in Fragments.

This is DietAdapter.kt

class DietAdapter(val dietList: List<Diet>): RecyclerView.Adapter<DietAdapter.DietViewHolder>(){

inner class DietViewHolder(val itemBinding: ListitemBinding)
    :RecyclerView.ViewHolder(itemBinding.root) {
    fun bindItem(diet:Diet){
        itemBinding.titleImage.setImageResource(diet.titleImage)
        itemBinding.tvHeading.text = diet.heading
    }
}

override fun onCreateViewHolder(parent: ViewGroup, viewType: Int): DietViewHolder {
    return DietViewHolder(ListitemBinding.inflate(LayoutInflater.from(parent.context), parent, false))
}

override fun onBindViewHolder(holder: DietViewHolder, position: Int) {
    val diet = dietList[position]
    holder.bindItem(diet)

    holder.itemBinding.rowList.setOnClickListener(View.OnClickListener {
        val browserIntent = Intent(Intent.ACTION_VIEW, Uri.parse("<add url here>"))
        requireContext().startActivity(browserIntent) //<--here the requireContext throws "no value passed for parameter 'provider' "
    })

}
override fun getItemCount(): Int {
    return dietList.size
}

}

Answer 1

The quick and dirty solution:

Add a Context property to your constructor:

class DietAdapter(val context: Context, val dietList: List<Diet>) //...

and when you create the adapter in your fragment, pass requireContext() as the parameter for context. Now you can use context.startActivity() inside your adapter's click listener(s).

---

The solution with proper separation of concerns:

Your adapter should not be internally responsible for navigation. That is a job for the higher level object, the Fragment. Trying to have the adapter reach into the Fragment to do things that a Fragment should do makes your code more convoluted. Instead, the adapter should expose a listener property (changes from your code are commented):

class DietAdapter(
    val dietList: List<Diet>,
    var onItemClick: (Diet)->Unit = {}  // Added this
): RecyclerView.Adapter<DietAdapter.DietViewHolder>(){
    
    inner class DietViewHolder(val itemBinding: ListitemBinding)
        :RecyclerView.ViewHolder(itemBinding.root) {
        fun bindItem(diet:Diet){
            itemBinding.titleImage.setImageResource(diet.titleImage)
            itemBinding.tvHeading.text = diet.heading
        }
    }
    
    override fun onCreateViewHolder(parent: ViewGroup, viewType: Int): DietViewHolder {
        return DietViewHolder(ListitemBinding.inflate(LayoutInflater.from(parent.context), parent, false))
    }
    
    override fun onBindViewHolder(holder: DietViewHolder, position: Int) {
        val diet = dietList[position]
        holder.bindItem(diet)
    
        // Changed this:
        holder.itemBinding.rowList.setOnClickListener { onItemClick(diet) }
    
    }
    override fun getItemCount(): Int {
        return dietList.size
    }

}

Then, the fragment is where you decide what to do with clicked items:

val dietAdapter = DietAdapter(theDataList) { diet ->
    val browserIntent = Intent(Intent.ACTION_VIEW, Uri.parse("<add url here>"))
    requireContext().startActivity(browserIntent) 
}
binding.myRecyclerView.adapter = dietAdapter