No resource identifier found for attribute 'layout_behavior' in package

For those who use AndroidX and don't want to add the old library:

com.android.support:design:28.0.0

you can add instead:

implementation 'com.google.android.material:material:1.0.0'

and use it like this:

app:layout_behavior="com.google.android.material.appbar.AppBarLayout$ScrollingViewBehavior"

Just in case someone else comes from Google and makes the same mistake I did, it's layout_behaviOr, not layout_behavioUr.

Note: The versions have changed by now, so replace below versions with the most recent ones.

The accepted answer gets rid of the error in case layout_behavior is not needed, however if you actually want to use:

app:layout_behavior="@string/appbar_scrolling_view_behavior"

Make sure to add the proper dependency to the build.gradle file of your module:

apply plugin: 'com.android.library'

android {
    compileSdkVersion 23
    buildToolsVersion "21.1.2"

   //Other stuff....
}

dependencies {

    //Importing the design library fixes the build
    compile 'com.android.support:design:23.1.0'

    //Other libraries....
}

I.e. add this line to your dependencies:

compile 'com.android.support:design:23.1.0'

That string resource is defined within the Material Design support library.

Since you're not using the CoordinatorLayout from the Material Design support library, you should be able to safely remove the app:layout_behavior attribute. It was probably cut & paste from other code.

NOTE: If you are actually using CoordinatorLayout and want the cooperative scrolling behaviors to work, you need to add the dependency for the latest version of the Material Design Support library to your Gradle build file:

compile 'com.android.support:design:23.0.1'

---

UPDATE: Note that with the latest versions of Gradle the compile configuration has been deprecated in favor of implementation and api configurations so your dependency could look like this:

implementation 'com.android.support:design:27.0.2'

This is only an example; the version numbers may be out of date when you read this, so make sure your version matches the version of the support library that you want to use.

For more info: What's the difference between implementation and compile in gradle