With API 28 and "androidx.appcompat" library project says "AppCompatActivity" symbol not found

Question

I updated my build and target version to 28 (Pie) and replaced the relevant dependencies. Now my project says Symbol not found on AppCompatActivity. I have tried to

• Clean project
• Rebuild project
• Invalidate Caches / Restart

But the result is the same. Moreover when I try Ctrl+Space after extends keyword in activity class there is no "AppCompatActivity suggestion. I tried to investigate if its present in libraries folder, it's present there.

Now, what should I do to make it work? If there is any variation/alternative with androidx libs please let me know. Here is my complete build.gradle file

apply plugin: 'com.android.application' apply plugin: 'com.google.gms.google-services'  android {     compileSdkVersion 28     defaultConfig {         applicationId "com.invogen.messagingapp"         minSdkVersion 16         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(dir: 'libs', include: ['*.jar']) //    implementation 'com.android.support:appcompat-v7:28.0.0' //    implementation 'com.android.support.constraint:constraint-layout:1.1.3' //    implementation 'com.android.support:design:28.0.0' //    implementation 'com.android.support:support-v4:28.0.0'      // Libs for newer API 28     implementation 'androidx.appcompat:appcompat:1.0.2'     implementation 'androidx.constraintlayout:constraintlayout:1.1.3'     implementation 'com.google.android.material:material:1.1.0-alpha01'     implementation 'androidx.cardview:cardview:1.0.0'       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'      // Libs for Firebase Functionality     implementation 'com.google.firebase:firebase-core:16.0.5' //    implementation 'com.google.firebase:firebase-database:16.0.4'     implementation 'com.google.firebase:firebase-messaging:17.3.4'     implementation 'com.google.firebase:firebase-auth:16.0.5'     implementation 'com.google.firebase:firebase-storage:16.0.4'      // Lib for Firebase UI Elements     implementation 'com.firebaseui:firebase-ui-database:4.2.1'      // Libs for QR Code     implementation 'com.google.zxing:core:3.2.1'     implementation 'com.journeyapps:zxing-android-embedded:3.2.0@aar'      // Lib for Circle Image View (Profile Image)     implementation 'de.hdodenhof:circleimageview:2.2.0'      // Lib for Loading Images     implementation 'com.squareup.picasso:picasso:2.71828'      //Lib for Cropping Images     api 'com.theartofdev.edmodo:android-image-cropper:2.8.+'   } apply plugin: 'com.google.gms.google-services' 

Some other posts suggest adding the below two parameters in Manifest file

android:appComponentFactory="anystrings be placeholder" tools:replace="android:appComponentFactory" 

But with these two lines project sync with multiple error and Android Studio says

Compilation failed; see the compiler error output for details.

If I have to add more detail to the question please let me know.

Answer 1

you should replace the target class.

eg.

import android.support.v7.app.AppCompatActivity; 

replace to :

import androidx.appcompat.app.AppCompatActivity;