Crash when using ConstraintLayout in Notification

Question

I get an InflationException when I use a ConstraintLayout in a custom Notification. I can use them elsewhere in my app, just not in a custom layout for a Notification. I'm assuming that any widget contained in a support library simply can't be used in a RemoteView, but I can't find any confirmation on that. Does anybody know?

E/StatusBar: couldn't inflate view for notification com.example.app/0x1
android.view.InflateException: Binary XML file line #2: Binary XML file line #2: Error inflating class android.support.constraint.ConstraintLayout
Caused by: android.view.InflateException: Binary XML file line #2: Error inflating class android.support.constraint.ConstraintLayout
Caused by: java.lang.ClassNotFoundException: Didn't find class "android.support.constraint.ConstraintLayout" on path: DexPathList[[],nativeLibraryDirectories=[/system/priv-app/TeleService/lib/arm64, /system/fake-libs64, /system/priv-app/TeleService/TeleService.apk!/lib/arm64-v8a, /system/lib64, /vendor/lib64, /system/lib64, /vendor/lib64]]
    at dalvik.system.BaseDexClassLoader.findClass(BaseDexClassLoader.java:93)
    at java.lang.ClassLoader.loadClass(ClassLoader.java:379)
    at java.lang.ClassLoader.loadClass(ClassLoader.java:312)
    at android.view.LayoutInflater.createView(LayoutInflater.java:606)
    at android.view.LayoutInflater.createViewFromTag(LayoutInflater.java:790)
    at android.view.LayoutInflater.createViewFromTag(LayoutInflater.java:730)
    at android.view.LayoutInflater.inflate(LayoutInflater.java:492)
    at android.view.LayoutInflater.inflate(LayoutInflater.java:423)
    at android.widget.RemoteViews.inflateView(RemoteViews.java:3278)
    at android.widget.RemoteViews.-wrap1(Unknown Source:0)
    at android.widget.RemoteViews$AsyncApplyTask.doInBackground(RemoteViews.java:3380)
    at android.widget.RemoteViews$AsyncApplyTask.doInBackground(RemoteViews.java:3376)
    at android.os.AsyncTask$2.call(AsyncTask.java:333)
    at java.util.concurrent.FutureTask.run(FutureTask.java:266)
    at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1162)
    at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:636)
    at java.lang.Thread.run(Thread.java:764)
E/AndroidRuntime: FATAL EXCEPTION: main
Process: com.example.app, PID: 9732
android.app.RemoteServiceException: Bad notification posted from package com.example.app: Couldn't inflate contentViewsandroid.view.InflateException: Binary XML file line #2: Binary XML file line #2: Error inflating class android.support.constraint.ConstraintLayout
    at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1775)
    at android.os.Handler.dispatchMessage(Handler.java:105)
    at android.os.Looper.loop(Looper.java:164)
    at android.app.ActivityThread.main(ActivityThread.java:6541)
    at java.lang.reflect.Method.invoke(Native Method)
    at com.android.internal.os.Zygote$MethodAndArgsCaller.run(Zygote.java:240)
    at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:767)

Answer 1

A RemoteViews object (and, consequently, an App Widget) can support the following layout classes:

• FrameLayout
• LinearLayout
• RelativeLayout
• GridLayout

And the following widget classes:

• AnalogClock
• Button
• Chronometer
• ImageButton
• ImageView
• ProgressBar
• TextView
• ViewFlipper
• ListView
• GridView
• StackView
• AdapterViewFlipper

Descendants of these classes are not supported.

Read more: https://developer.android.com/guide/topics/appwidgets/index.html#CreatingLayout

Answer 2

RemoteView can only support the following layout classes:

FrameLayout

LinearLayout

RelativeLayout

GridLayout

As mentioned here