Failed to instantiate one or more classes: java.lang.ClassNotFoundException: androidx.databinding.DataBinderMapperImpl

Issue

I’ve created a multi-module project. I’ve created a custom view using data binding in one of its library modules.

Problem: The custom view is not showing in the layout editor but it’s OK on the device. This is the error shown in the layout editor issues:

java.lang.ClassNotFoundException: androidx.databinding.DataBinderMapperImpl
    at com.android.tools.idea.rendering.classloading.RenderClassLoader.getNonProjectClassData(RenderClassLoader.java:244)
    at com.android.tools.idea.rendering.classloading.RenderClassLoader.loadClassFromNonProjectDependency(RenderClassLoader.java:207)
    at org.jetbrains.android.uipreview.ModuleClassLoader.load(ModuleClassLoader.java:379)
    at com.android.tools.idea.rendering.classloading.RenderClassLoader.findClass(RenderClassLoader.java:169)
    at org.jetbrains.android.uipreview.ModuleClassLoader.findClass(ModuleClassLoader.java:332)
    at java.base/java.lang.ClassLoader.loadClass(ClassLoader.java:589)
    at java.base/java.lang.ClassLoader.loadClass(ClassLoader.java:522)
    at org.jetbrains.android.uipreview.ModuleClassLoader.loadClass(ModuleClassLoader.java:287)
    at ir.kharidarim.core.ui.custom.TitledEditText.init(TitledEditText.java:72)
    at ir.kharidarim.core.ui.custom.TitledEditText.<init>(TitledEditText.java:63)
    at jdk.internal.reflect.GeneratedConstructorAccessor3564.newInstance(Unknown Source)
    at java.base/jdk.internal.reflect.DelegatingConstructorAccessorImpl.newInstance(DelegatingConstructorAccessorImpl.java:45)
    at java.base/java.lang.reflect.Constructor.newInstance(Constructor.java:490)
    at org.jetbrains.android.uipreview.ViewLoader.createNewInstance(ViewLoader.java:399)
    at org.jetbrains.android.uipreview.ViewLoader.loadClass(ViewLoader.java:189)
    at org.jetbrains.android.uipreview.ViewLoader.loadView(ViewLoader.java:147)
    at com.android.tools.idea.rendering.LayoutlibCallbackImpl.loadView(LayoutlibCallbackImpl.java:303)
    at android.view.BridgeInflater.loadCustomView(BridgeInflater.java:417)
    at android.view.BridgeInflater.loadCustomView(BridgeInflater.java:428)
    at android.view.BridgeInflater.createViewFromTag(BridgeInflater.java:332)
    at android.view.LayoutInflater.createViewFromTag(LayoutInflater.java:959)
    at android.view.LayoutInflater.rInflate_Original(LayoutInflater.java:1121)
    at android.view.LayoutInflater_Delegate.rInflate(LayoutInflater_Delegate.java:72)
    at android.view.LayoutInflater.rInflate(LayoutInflater.java:1095)
    at android.view.LayoutInflater.rInflateChildren(LayoutInflater.java:1082)
    at android.view.LayoutInflater.rInflate_Original(LayoutInflater.java:1124)
    at android.view.LayoutInflater_Delegate.rInflate(LayoutInflater_Delegate.java:72)
    at android.view.LayoutInflater.rInflate(LayoutInflater.java:1095)
    at android.view.LayoutInflater.rInflateChildren(LayoutInflater.java:1082)
    at android.view.LayoutInflater.rInflate_Original(LayoutInflater.java:1124)
    at android.view.LayoutInflater_Delegate.rInflate(LayoutInflater_Delegate.java:72)
    at android.view.LayoutInflater.rInflate(LayoutInflater.java:1095)
    at android.view.LayoutInflater.rInflateChildren(LayoutInflater.java:1082)
    at android.view.LayoutInflater.inflate(LayoutInflater.java:680)
    at android.view.LayoutInflater.inflate(LayoutInflater.java:499)
    at com.android.layoutlib.bridge.impl.RenderSessionImpl.inflate(RenderSessionImpl.java:353)
    at com.android.layoutlib.bridge.Bridge.createSession(Bridge.java:431)
    at com.android.tools.idea.layoutlib.LayoutLibrary.createSession(LayoutLibrary.java:141)
    at com.android.tools.idea.rendering.RenderTask.createRenderSession(RenderTask.java:714)
    at com.android.tools.idea.rendering.RenderTask.lambda$inflate$7(RenderTask.java:870)
    at com.android.tools.idea.rendering.RenderExecutor$runAsyncActionWithTimeout$2.run(RenderExecutor.kt:187)
    at java.base/java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1128)
    at java.base/java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:628)
    at java.base/java.lang.Thread.run(Thread.java:834)

I’ve already added dataBinding = true to build.gradle. I’m using Android Studio Arctic Fox.

Neither Clean and rebuild nor Invalidate cache worked.

Solution

Solved by setting viewBinding = true in build.gradle

Answered By – Aref Bahreini

This Answer collected from stackoverflow, is licensed under cc by-sa 2.5 , cc by-sa 3.0 and cc by-sa 4.0

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