title: Error inflating class androidx.constraintlayout.ConstraintLayout after migration to androidx
body: <p>I just made a migration to androidx through Android Studio menu option <strong>Refactor</strong> -> <strong>Refactor to AndroidX</strong></p>
  
  <p>I'm getting the following error:  </p>
  
  <blockquote>
    <p>android.view.InflateException: Binary XML file line #2: Binary XML file line #2: Error inflating class androidx.constraintlayout.ConstraintLayout</p>
  </blockquote>
  
  <p>Any idea?</p>
  
  <p>Stacktrace:</p>
  
  <pre><code>2018-10-19 00:25:58.128 28131-28131/com.midounoo.midounoo E/AndroidRuntime: FATAL EXCEPTION: main
      Process: com.midounoo.midounoo, PID: 28131
      java.lang.RuntimeException: Unable to start activity ComponentInfo{com.midounoo.midounoo/com.midounoo.midounoo.Base.MainActivity}: android.view.InflateException: Binary XML file line #2: Binary XML file line #2: Error inflating class androidx.constraintlayout.ConstraintLayout
          at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2724)
          at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2789)
          at android.app.ActivityThread.-wrap12(ActivityThread.java)
          at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1527)
          at android.os.Handler.dispatchMessage(Handler.java:110)
          at android.os.Looper.loop(Looper.java:203)
          at android.app.ActivityThread.main(ActivityThread.java:6255)
          at java.lang.reflect.Method.invoke(Native Method)
          at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:1063)
          at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:924)
       Caused by: android.view.InflateException: Binary XML file line #2: Binary XML file line #2: Error inflating class androidx.constraintlayout.ConstraintLayout
       Caused by: android.view.InflateException: Binary XML file line #2: Error inflating class androidx.constraintlayout.ConstraintLayout
       Caused by: java.lang.ClassNotFoundException: Didn't find class "androidx.constraintlayout.ConstraintLayout" on path: DexPathList[[zip file "/data/app/com.midounoo.midounoo-2/base.apk", zip file "/data/app/com.midounoo.midounoo-2/split_lib_dependencies_apk.apk", zip file "/data/app/com.midounoo.midounoo-2/split_lib_slice_0_apk.apk", zip file "/data/app/com.midounoo.midounoo-2/split_lib_slice_1_apk.apk", zip file "/data/app/com.midounoo.midounoo-2/split_lib_slice_2_apk.apk", zip file "/data/app/com.midounoo.midounoo-2/split_lib_slice_3_apk.apk", zip file "/data/app/com.midounoo.midounoo-2/split_lib_slice_4_apk.apk", zip file "/data/app/com.midounoo.midounoo-2/split_lib_slice_5_apk.apk", zip file "/data/app/com.midounoo.midounoo-2/split_lib_slice_6_apk.apk", zip file "/data/app/com.midounoo.midounoo-2/split_lib_slice_7_apk.apk", zip file "/data/app/com.midounoo.midounoo-2/split_lib_slice_8_apk.apk", zip file "/data/app/com.midounoo.midounoo-2/split_lib_slice_9_apk.apk"],nativeLibraryDirectories=[/data/app/com.midounoo.midounoo-2/lib/arm64, /system/lib64, /vendor/lib64, /system/vendor/lib64]]
          at dalvik.system.BaseDexClassLoader.findClass(BaseDexClassLoader.java:56)
          at java.lang.ClassLoader.loadClass(ClassLoader.java:380)
          at java.lang.ClassLoader.loadClass(ClassLoader.java:312)
          at android.view.LayoutInflater.createView(LayoutInflater.java:609)
          at android.view.LayoutInflater.createViewFromTag(LayoutInflater.java:787)
          at android.view.LayoutInflater.createViewFromTag(LayoutInflater.java:727)
          at android.view.LayoutInflater.inflate(LayoutInflater.java:495)
          at android.view.LayoutInflater.inflate(LayoutInflater.java:426)
          at android.view.LayoutInflater.inflate(LayoutInflater.java:377)
          at androidx.appcompat.app.AppCompatDelegateImpl.setContentView(AppCompatDelegateImpl.java:469)
          at androidx.appcompat.app.AppCompatActivity.setContentView(AppCompatActivity.java:140)
          at com.midounoo.midounoo.Base.MainActivity.onCreate(MainActivity.java:43)
          at android.app.Activity.performCreate(Activity.java:6666)
          at android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1118)
          at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2677)
          at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2789)
          at android.app.ActivityThread.-wrap12(ActivityThread.java)
          at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1527)
          at android.os.Handler.dispatchMessage(Handler.java:110)
          at android.os.Looper.loop(Looper.java:203)
          at android.app.ActivityThread.main(ActivityThread.java:6255)
          at java.lang.reflect.Method.invoke(Native Method)
          at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:1063)
  </code></pre>