未解决的参考：LinearLayoutManager/RecyclerView

Question

I started building a movie database app using Kotlin based on a tutorial I found online (see this link for details. While building the movie fragment file, I noticed an "unresolved reference: LinearLayoutManager" and an "unresolved reference: RecyclerView" error. I have included the code below to and everything matches up like the tutorial except for those errors:

import android.os.Bundle
import android.support.v4.app.Fragment
import android.support.v7.widget.LinearLayoutManager
import android.support.v7.widget.RecyclerView
import android.view.LayoutInflater
import android.view.View
import android.view.ViewGroup
import com.dburgnerjr.movietvshowdatabase.R
import com.dburgnerjr.movietvshowdatabase.commons.inflate
import kotlinx.android.synthetic.main.movie_fragment.*

class MovieFragment : Fragment() {

    private val movieList by lazy {
        movie_list
    }

    override fun onCreateView(inflater: LayoutInflater?, container: ViewGroup?, savedInstanceState: Bundle?): View? {
        return container?.inflate(R.layout.movie_fragment)
    }

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

        movieList.setHasFixedSize(true)
        movieList.layoutManager = LinearLayoutManager(context)
    }
}

Anything I overlooked?

Answer 1

Considering Jetpack, you can use AndroidX as:

implementation 'androidx.recyclerview:recyclerview:1.0.0'

Instead of:

compile 'com.android.support:recyclerview-v7:25.3.1'

And in the layout.xml , you need something like:

    <androidx.recyclerview.widget.RecyclerView
        xmlns:app="http://schemas.android.com/apk/res-auto"
        android:id="@+id/recyclerView"
        android:layout_width="match_parent"
        android:layout_height="match_parent"
        android:scrollbars="vertical"/>

Answer 2

I figured it out. I saw this post and noticed that I missed a

compile 'com.android.support:recyclerview-v7:25.3.1'

reference in my build.gradle file. Problem solved.

Answer 3

if you use androidx, please changed your gradle with the below.

from :

implementation 'com.android.support:recyclerview-v7:28.0.0'

to :

implementation 'androidx.recyclerview:recyclerview:1.0.0'