Recycleview displaying a grey area

Question

the RecyclerView is not shown as in the picture below and i cannot find any solution. What i tried:

• Rebuild
• Clean project
• Invalidate Cache

My build.gradle(Module:app)

apply plugin: 'com.android.application'

android {
    compileSdkVersion 28
    defaultConfig {
        applicationId "com.user.myapplication"
        minSdkVersion 15
        targetSdkVersion 28
        versionCode 1
        versionName "1.0"
        testInstrumentationRunner "android.support.test.runner.AndroidJUnitRunner"
    }
    buildTypes {
        release {
            minifyEnabled false
            proguardFiles getDefaultProguardFile('proguard-android.txt'), 'proguard-rules.pro'
        }
    }
}

dependencies {
    implementation fileTree(include: ['*.jar'], dir: 'libs')
    implementation 'com.android.support:appcompat-v7:28.0.0'
    implementation 'com.android.support.constraint:constraint-layout:1.1.3'
    testImplementation 'junit:junit:4.12'
    androidTestImplementation 'com.android.support.test:runner:1.0.2'
    androidTestImplementation 'com.android.support.test.espresso:espresso-core:3.0.2'
    implementation 'com.android.support:recyclerview-v7:28.0.0'
    implementation 'com.android.support:cardview-v7:28.0.0'
}

This is the activity_main.xml shown in the picutre

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout
    xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:app="http://schemas.android.com/apk/res-auto"
    xmlns:tools="http://schemas.android.com/tools"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    tools:context=".MainActivity"
    android:padding="8dp">

    <android.support.v7.widget.RecyclerView
        android:layout_width="match_parent"
        android:layout_height="match_parent">


    </android.support.v7.widget.RecyclerView>

</LinearLayout>

Answer 1

Well, 28.0.0 support library-APIs dependency actually works better with Android Studio 3.2.0 and up and this is because of AndroidX migrating.

So, upgrading Android Studio will help since you already added RecyclerView dependency and there were no issues with the preview nor, no errors shown.