How to fix 'Cannot Resolve Symbol 'v7' error in Android Studio

EnigmaticBacon :

I'm trying to use the android support recyclerView widget, and though I've added all the dependencies to my build.gradle file (I think), the line "import android.support.v7.widget.RecyclerView;" in my activity isn't resolving. I'm new to Android Studio, so I might be missing something very basic.

So far I've tried adding the google repository in allprojects of the project build gradle, as well as that of my module build gradle. I've also shifted around my dependencies and tried changing version numbers. And I tried invalidating caches and restarting. I do seem to be able to import "import androidx.recyclerview.widget.RecyclerView;", but that isn't the same from what I've heard.

This is my build gradle file:

//noinspection GradleCompatible
apply plugin: 'com.android.application'
android {
    compileSdkVersion 28
    buildToolsVersion '28.0.3'
    defaultConfig {
        applicationId "com.example.chaos"
        minSdkVersion 20
        targetSdkVersion 28
        versionCode 1
        versionName "1.0"
        testInstrumentationRunner "androidx.test.runner.AndroidJUnitRunner"
    }
    buildTypes {
        customDebugType {
            debuggable true
        }
        release {
            minifyEnabled false
            proguardFiles getDefaultProguardFile('proguard-android-optimize.txt'), 'proguard-rules.pro'
        }
    }
}

dependencies {
    implementation fileTree(dir: 'libs', include: ['*.jar'])
    implementation 'com.android.support:appcompat-v7:28.0.0'
    implementation 'androidx.constraintlayout:constraintlayout:1.1.3'
    implementation 'com.android.support:design:28.0.0'
    //implementation 'com.android.support:recyclerview-v7:28.0.0'

    implementation 'android.arch.persistence.room:runtime:1.1.1'
    annotationProcessor 'android.arch.persistence.room:compiler:1.1.1'
    androidTestImplementation 'android.arch.persistence.room:testing:1.1.1'

   // implementation 'com.android.support:support-v7'

    testImplementation 'junit:junit:4.12'
    androidTestImplementation 'androidx.test:runner:1.1.2-alpha02'
    androidTestImplementation ('androidx.test.espresso:espresso-core:3.2.0-alpha02', {
        exclude group: 'com.android.support', module: 'support-annotations'
    })
}

And then this is the import I'm attempting in my main activity. It seems I can import android.support.v4 libraries, but v7 isn't even an auto-complete option. I'd appreciate the help!

import android.support.v7.app.AppCompatActivity;
import android.support.v7.widget.RecyclerView;

I expect the import line to resolve, as it currently doesn't.

bensadiku :

If you are using Android X, try this dependency instead

implementation 'androidx.recyclerview:recyclerview:1.0.0'