您好，我已经将我的 activity class 更新为片段，但我不确定如何更新照片中的部分

Question

我已经将我的 activity class 更新为片段，但我不确定如何更新照片中的部分。

我的代码：

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()
        }

}

错误： e: /Users/nisa/AndroidStudioProjects/RecentEarthquakes/app/src/main/java/com/nisaefendioglu/recentearthquakes/fragment/Earthquake.kt: (26, 58): 类型不匹配：推断类型是 Earthquake 但 Context!预计

e: /Users/nisa/AndroidStudioProjects/RecentEarthquakes/app/src/main/java/com/nisaefendioglu/recentearthquakes/fragment/Earthquake.kt: (29, 13): 类型不匹配：推断类型是地震，但上下文是预期的

我已经将我的 activity class 更新为片段，但我不确定如何更新照片中的部分。你能帮帮我吗？

Answer 1

只需将上下文作为 activity 或上下文传递，您不能将其用作上下文，因为您在片段中

Answer 2

使用 requireContext() 从片段中获取上下文。

如果你得到NullPointerException，那是因为你在onCreate()方法里面调用了recyclerView，正如文档所说，

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

如果您使用片段，您应该始终在 onCreateView() 方法中调用您的 View。

Answer 3

将 onCreate 部分更改为 onViewCreated 对我有用。

您好，我已经将我的 activity class 更新为片段，但我不确定如何更新照片中的部分

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

java

android

kotlin

android-recyclerview