Hello, I have updated my activity class as fragment, but I am not sure how to update the parts in the photo

Question

I have updated my activity class as fragment, but I am not sure how to update the parts in the photo.

My Code :

package com.nisaefendioglu.recentearthquakes.fragment

import android.os.Bundle
import android.util.Log
import androidx.fragment.app.Fragment
import androidx.recyclerview.widget.LinearLayoutManager
import com.nisaefendioglu.recentearthquakes.R
import com.nisaefendioglu.recentearthquakes.RecyclerAdapter
import com.nisaefendioglu.recentearthquakes.model.EarthquakeModelItem
import com.nisaefendioglu.recentearthquakes.service.ApiClient
import kotlinx.android.synthetic.main.earthquake.*
import retrofit2.Call
import retrofit2.Callback
import retrofit2.Response

class Earthquake : Fragment((R.layout.earthquake)) {

    private var listUsers: MutableList<EarthquakeModelItem> = mutableListOf<EarthquakeModelItem>()
    private var adapter: RecyclerAdapter? = null

    override fun onCreate(savedInstanceState: Bundle?) {
        super.onCreate(savedInstanceState)

        listUsers = mutableListOf()

        recyclerview.layoutManager = LinearLayoutManager(this@Earthquake)

        adapter = RecyclerAdapter(
            this,
            listUsers
        )
        recyclerview.adapter = adapter
        getUsersData()

    }

    private fun getUsersData() {

        ApiClient.apiService.getEarthquakes().enqueue(object :
            Callback<MutableList<EarthquakeModelItem>> {
            override fun onFailure(call: Call<MutableList<EarthquakeModelItem>>, t: Throwable) {
                Log.e("error", t.localizedMessage)
            }

            override fun onResponse(
                call: Call<MutableList<EarthquakeModelItem>>,
                response: Response<MutableList<EarthquakeModelItem>>
            ) {
                val usersResponse = response.body()
                listUsers.clear()
                usersResponse?.let { listUsers.addAll(it) }
                adapter?.notifyDataSetChanged()
            }

        })

    }

}

MainActivity.kt

package com.nisaefendioglu.recentearthquakes.view

import androidx.appcompat.app.AppCompatActivity
import android.os.Bundle
import androidx.fragment.app.Fragment
import com.nisaefendioglu.recentearthquakes.R
import com.nisaefendioglu.recentearthquakes.fragment.Earthquake
import com.nisaefendioglu.recentearthquakes.fragment.InfoFragment
import kotlinx.android.synthetic.main.activity_main.*


class MainActivity : AppCompatActivity() {
    override fun onCreate(savedInstanceState: Bundle?) {
        super.onCreate(savedInstanceState)
        setContentView(R.layout.activity_main)

        val info= InfoFragment()
        val earthquake = Earthquake()
        //val maps = MapFragment()

        setCurrentFragment(info)

        bottomNavigationView.setOnNavigationItemSelectedListener {
            when(it.itemId){
                R.id.infoFragment ->setCurrentFragment(info)
                R.id.earthquakeFragment ->setCurrentFragment(earthquake)
             //   R.id.mapsFragment->setCurrentFragment(maps)

            }
            true
        }

    }

    private fun setCurrentFragment(fragment: Fragment)=
        supportFragmentManager.beginTransaction().apply {
            replace(R.id.flFragment,fragment)
            commit()
        }

}

Error : e: /Users/nisa/AndroidStudioProjects/RecentEarthquakes/app/src/main/java/com/nisaefendioglu/recentearthquakes/fragment/Earthquake.kt: (26, 58): Type mismatch: inferred type is Earthquake but Context! was expected

e: /Users/nisa/AndroidStudioProjects/RecentEarthquakes/app/src/main/java/com/nisaefendioglu/recentearthquakes/fragment/Earthquake.kt: (29, 13): Type mismatch: inferred type is Earthquake but Context was expected

I have updated my activity class as fragment, but I am not sure how to update the parts in the photo. Can you help me?

I believe you have been a member of Stack Overflow long enough to know that you should never post pictures of your code and/or error messages. Please edit and post your code and an explanation of the error you are getting. — hfontanez, Apr 10 '22 at 14:27
Does this answer your question? [Using context in a fragment](https://stackoverflow.com/questions/8215308/using-context-in-a-fragment) — a_local_nobody, Apr 10 '22 at 17:05

Manjeet deswal · Answer 1 · 2022-04-10T14:54:34.467

0

Just pass context as activity or context you can't use this as context because you are inside a fragment

edited Apr 10 '22 at 14:54

answered Apr 10 '22 at 14:50

Manjeet deswal

692
2
5
18

1

So what am I supposed to do? – Nisa Efendioglu Apr 10 '22 at 14:52
replace this@Earthquake with activity – Manjeet deswal Apr 10 '22 at 14:52
1

But in this case, my navigation button is getting an error, because it is set as fragment. bottomNavigationView.setOnNavigationItemSelectedListener { when(it.itemId){ R.id.infoFragment ->setCurrentFragment(info) R.id.earthquakeFragment ->setCurrentFragment(earthquake) // R.id.mapsFragment->setCurrentFragment(maps) } true } } – Nisa Efendioglu Apr 10 '22 at 14:56
what is the error – Manjeet deswal Apr 10 '22 at 15:18
e: /Users/nisa/AndroidStudioProjects/RecentEarthquakes/app/src/main/java/com/nisaefendioglu/recentearthquakes/view/MainActivity.kt: (26, 62): Type mismatch: inferred type is Earthquake but Fragment was expected – Nisa Efendioglu Apr 10 '22 at 15:21
share full code in post – Manjeet deswal Apr 10 '22 at 15:22
I added. MainActivity.kt – Nisa Efendioglu Apr 10 '22 at 15:23
try removing double parethness from fragment Fragment((R.layout.earthquake)) – Manjeet deswal Apr 10 '22 at 15:37
Fragment(R.layout.earthquake) – Manjeet deswal Apr 10 '22 at 15:37
Changing the onCreate part to onViewCreated worked for me. Thank you all. :) – Nisa Efendioglu Apr 10 '22 at 18:58

Muhammad Rio · Answer 2 · 2022-04-10T15:48:36.753

0

Use requireContext() to get the context from fragment.

If you get NullPointerException, that is because you call the recyclerView inside onCreate() method , as the document said,

you can not rely on things like the activity's content view hierarchy being initialized at this point.

If you are using a fragment , you should always call your View in the onCreateView() method.

edited Apr 10 '22 at 15:48

answered Apr 10 '22 at 14:57

Muhammad Rio

759
5
6

When I use it like that, it gives the following error: java.lang.NullPointerException: Attempt to invoke virtual method 'void androidx.recyclerview.widget.RecyclerView.setLayoutManager(androidx.recyclerview.widget.RecyclerView$LayoutManager)' on a null object reference – Nisa Efendioglu Apr 10 '22 at 14:59
@NisaEfendioglu you can fix it by defining your layout manager in the xml `app:layoutManager="androidx.recyclerview.widget.LinearLayoutManager"` – Muhammad Rio Apr 10 '22 at 15:03
it didn't work :( – Nisa Efendioglu Apr 10 '22 at 15:22
@NisaEfendioglu what error ?? still the same ?? – Muhammad Rio Apr 10 '22 at 15:23
java.lang.NullPointerException: Attempt to invoke virtual method 'void androidx.recyclerview.widget.RecyclerView.setLayoutManager(androidx.recyclerview.widget.RecyclerView$LayoutManager)' on a null object reference at com.nisaefendioglu.recentearthquakes.fragment.Earthquake.onCreate(Earthquake.kt:28) – Nisa Efendioglu Apr 10 '22 at 15:24
28 -> recyclerview.layoutManager = LinearLayoutManager(context) – Nisa Efendioglu Apr 10 '22 at 15:25
@NisaEfendioglu delete `recyclerview.layoutManager = LinearLayoutManager(context)` if you already define your layout manager in the xml. – Muhammad Rio Apr 10 '22 at 15:29
1

The `NullPointerException` is not saying you need to set a `LayoutManager`. It is saying you are attempting to set a `LayoutManager` on a null reference, meaning the `RecyclerView`; it is null. In your line of code for your fragment (`recyclerview.layoutManager = LinearLayoutManager(this@Earthquake)`), I do not see where you instantiate `recyclerview`. – Flash103 Apr 10 '22 at 15:29
@NisaEfendioglu and move your code inside `onCreate()` to `onCreateView()`. – Muhammad Rio Apr 10 '22 at 15:35
@Flash103 he is using `Kotlin`. He need not do `findViewById()` – Sambhav Khandelwal Apr 10 '22 at 16:22
Changing the onCreate part to onViewCreated worked for me. Thank you all. :) – Nisa Efendioglu Apr 10 '22 at 18:58

score 0 · Accepted Answer · answered Apr 10 '22 at 18:56

0

Changing the onCreate part to onViewCreated worked for me.

answered Apr 10 '22 at 18:56

Nisa Efendioglu

901
3
12
22

Hello, I have updated my activity class as fragment, but I am not sure how to update the parts in the photo

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