Kotlin showed type mismatch in fragment

Question

I have a fragment with RecyclerAdapter inside it. I want to initialize the adapter in the onCreateView method but it throws the error of "Type mismatch. Required : Context , Found : FragmentActivity" in this statement

I have no idea why the first one showed this error and the second one did not contains compile time error.

Error shown

recyclerView!!.adapter = RestaurantMenuAdapter(activity)

No Error shown

recyclerView!!.layoutManager = LinearLayoutManager(activity)

Fragment.kt

override fun onCreateView(inflater: LayoutInflater, container: ViewGroup?,
                          savedInstanceState: Bundle?): View? {
    // Inflate the layout for this fragment
    val view = inflater.inflate(R.layout.fragment_restaurant_menu, container, false)
    recyclerView = view.findViewById(R.id.restaurant_container)
    recyclerView!!.adapter = RestaurantMenuAdapter(activity)
    recyclerView!!.layoutManager = LinearLayoutManager(activity)

RecyclerAdapter.kt

class RestaurantMenuAdapter  (val context : Context) : RecyclerView.Adapter<RecyclerView.ViewHolder>() {
    override fun onCreateViewHolder(parent: ViewGroup, viewType: Int): RecyclerView.ViewHolder {
        val inflater = parent.context.getSystemService(Context.LAYOUT_INFLATER_SERVICE) as LayoutInflater
        return object : RecyclerView.ViewHolder(inflater.inflate(R.layout.item_menu1, parent, false)) {

        }
    }

    override fun onBindViewHolder(holder: RecyclerView.ViewHolder, position: Int) {

    }

    override fun getItemCount(): Int {
        return 10
    }
}

why you pass context to your adapter? i think you do not need to pass it. — savepopulation, Jan 10 '18 at 08:05
I may use context in the future. In fact, I used to pass Context as parameter in the adapter in java as the same way I did it in the above. In the past, I used to pass Fragment getActivity() as Context in the Adapter constructor as the parameter which accepted Context Type. I have no idea why this time did not work — Long Ranger, Jan 10 '18 at 08:12
Yes, at least I accepted to use activity.applicationContext to solve my problem. But I am still confusing with the activity in fragment — Long Ranger, Jan 10 '18 at 08:53

score 16 · Accepted Answer · edited Jan 10 '18 at 08:06

16

Change this to-:

recyclerView!!.adapter = RestaurantMenuAdapter(activity)

To-:

recyclerView!!.adapter = RestaurantMenuAdapter(activity.applicationContext)

edited Jan 10 '18 at 08:06

Yogesh Paliyal

604
7
21

answered Jan 10 '18 at 08:02

Shivam Oberoi

1,374
1
6
15

are you extending Fragment or FragmentActivity? – Shivam Oberoi Jan 10 '18 at 08:05
Yes, the Fragment extends to android.support.v4.app.Fragment – Long Ranger Jan 10 '18 at 08:07
do this then class RestaurantMenuAdapter (val context : Activity) – Shivam Oberoi Jan 10 '18 at 08:11
1

It seems this applicationContext works. But it showed I still need to add this activity!!.applicationContext before I passed to the adapter. – Long Ranger Jan 10 '18 at 08:19
Do one thing change this - (val context : Context) to-(val context : FragmentActivity) and do the same code below. – Shivam Oberoi Jan 10 '18 at 08:23

score 6 · Answer 2 · edited Jan 27 '20 at 00:09

6

recyclerView!!.adapter = RestaurantMenuAdapter(this)

To

recyclerView!!.adapter = RestaurantMenuAdapter(this.requireActivity())

edited Jan 27 '20 at 00:09

MartenCatcher

2,209
7
22
31

answered Jan 26 '20 at 11:37

Shivam Tripathi

441
5
6

score 2 · Answer 3 · answered Feb 23 '19 at 17:01

Keep the adapter as it and just use "activity!!" where you are initializing adapter.

recyclerView.adapter = RestaurantMenuAdapter(activity!!)

Your adapter will remain same.

class RestaurantMenuAdapter  (val context : Context) : RecyclerView.Adapter<RecyclerView.ViewHolder>() {
override fun onCreateViewHolder(parent: ViewGroup, viewType: Int): RecyclerView.ViewHolder {
    val inflater = parent.context.getSystemService(Context.LAYOUT_INFLATER_SERVICE) as LayoutInflater
    return object : RecyclerView.ViewHolder(inflater.inflate(R.layout.item_menu1, parent, false)) {

    }
}

override fun onBindViewHolder(holder: RecyclerView.ViewHolder, position: Int) {

}

override fun getItemCount(): Int {
    return 10
}
}

score 0 · Answer 4 · answered Jan 10 '18 at 08:03

Change in Recycler Adapter from Context to Activity.

class RestaurantMenuAdapter  (val context : Activity) : RecyclerView.Adapter<RecyclerView.ViewHolder>() {
    override fun onCreateViewHolder(parent: ViewGroup, viewType: Int): RecyclerView.ViewHolder {
        val inflater = parent.context.getSystemService(Context.LAYOUT_INFLATER_SERVICE) as LayoutInflater
        return object : RecyclerView.ViewHolder(inflater.inflate(R.layout.item_menu1, parent, false)) {

        }
    }

    override fun onBindViewHolder(holder: RecyclerView.ViewHolder, position: Int) {

    }

    override fun getItemCount(): Int {
        return 10
    }
}

Kotlin showed type mismatch in fragment

4 Answers4