java.lang.NoClassDefFoundError: Failed resolution of: Landroidx/core/app/ActivityManagerCompat

Question

Description

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I want to build todolist app.I want to store information using RoomDatabse. I build Database with room and get infomation than save to database. But

Answer 1

Try migrating the project to AndroidX according to steps given in the link "https://developer.android.com/jetpack/androidx/migrate"

Change existing package and class names to those given in the sub-section "https://developer.android.com/jetpack/androidx/migrate#artifact_mappings"

Answer 2

In your gradle dependencies, do you use this?

implementation "androidx.room:room-runtime:$room_version"
annotationProcessor "androidx.room:room-compiler:$room_version"

If so, replace it with:

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

Answer 3

you might be missing the dependency ...

 androidx.core:core:1.0.0

which provides androidx.core.app.ActivityManagerCompat.