IssueTracker

I am getting the same problem after the latest update...

I think this might be the same as issue 36949180. As mentioned in the comments there, try:
As a temporary workaround, try turning off Preferences > Compiler > Use External Build.

Deleting the out folder before rebuilding solves the problem

turning off Preferences > Compiler > Use External Build doesn't work if you have other modules as dependencies.

I'm having the same problem.

Same issue here

Also having this problem, but turning off Preferences > Compiler > Use External Build worked for me, even though I have other modules as dependencies, despite what jai.chan mentioned.

[Comment deleted]

Problem exists. Turning off "Use external build" helps.

Also having the same problem.But I don't know How can I fix ?

The problem is still there... :s

having the same issue here too

Still happens

A shame that google is not able to solve this issue since several years but is able to pop out yet another android version.

Android Studio 1.4 and this or similar bug is still here! My project is completely blocked due to inability to add a new activity class without getting "cannot find symbol" for it. The other classes are getting compiled except that activty. I've checked in the build/intermediates/classes - the activity .class is missing, not even compiled though it is hollow class, no syntax error.

Already tried:
Invalidate Cache and Restart - nope
Deleted /build directory and rebuild - nope
./gradlew clean of entire project - nope
Restarting after everything above - nope
Recreating a new blank activity - nope
Checked manifest entries for the activity - nope
Combination of the above - nope

Desperation mode: on

I've just managed to workaround it! Simple Refactor > Move to another package did remove the error, but after I moved it back to the original package the error appeared again. Have NO idea what's going on!

Damn, I've found that class in the long forgotten exclude list in my build.gradle! What a stupid mistake of mine. Mystery revealed! (chuckle)

The target release was 25.0.1 and we're now at 26.0.0-beta2. Could you guys at least put an actual, realistic target on this issue?

Scrolling behavior with CoordinatorLayout has been implemented, and should be available in the next release.

Passing bug to Avigail to comment about bottom nav elevation behavior.

I could not find any info about this, is this released ?

Any news on when this will be released?

I'm revisiting a project with this issue and this is still not fixed on v27.1.1. If I have a BottomNavigationView inside a parent CoordinatorLayout, it doesn't scroll. It works though perfectly when manually setting translationY:

appBarLayout.addOnOffsetChangedListener(new AppBarLayout.OnOffsetChangedListener() {
    @Override
    public void onOffsetChanged(AppBarLayout appBarLayout, int verticalOffset) {
        bottomNavigationView.setTranslationY(verticalOffset*-1);
    }
});

However, when trying the same technique, while having the BottomNavigationView inside a FrameLayout, which itself is the child of the parent CoordinatorLayout, the BottomNavigationView doesn't even show up in the UI.
Trying the same AppBarLayout OffsetChangedListener on a different UI component (such as a FAB), while inside the FrameLayout, works just as if the FAB was a direct child of the CoordinatorLayout.

So what's the difference between the 2 setups? Why does the FAB work, but not the BottomNavigationView?
Also, where's the scrolling behavior that was about to be released?

Scrolling behavior has been added. You can use it by setting a HideBottomViewOnScrollBehavior on the BottomNavigationView: app:layout_behavior="@string/hide_bottom_view_on_scroll_behavior".

See class documentation for BottomNavigationView: https://developer.android.com/reference/com/google/android/material/bottomnavigation/BottomNavigationView.

And for HideBottomViewOnScrollBehavior: https://developer.android.com/reference/com/google/android/material/behavior/HideBottomViewOnScrollBehavior.

This is available in our 28.0.0-alpha1 release or the 1.0.0-alpha1 release or later.

When the bottom bar is partly visible (eg user scrolled just a bit and stopped scrolling), does the bottom bar snaps automatically to either be fully visible or hidden like
a CollapsingToolbarLayout would do with  app:layout_scrollFlags="scroll|snap"  ?

Im on 28.0.0 and the bottom shadow still doesnt show up at the top when i set the app:elevation in BNV.

is it yet to be fixed ? Here is my layout

    <android.support.design.widget.BottomNavigationView
        android:id="@+id/landing_bottom_nav"
        android:layout_width="0dp"
        android:layout_height="wrap_content"
        android:background="@color/white"
        app:elevation="4dp"
        android:elevation="4dp"
        app:layout_constraintBottom_toBottomOf="parent"
        app:menu="@menu/landing_menu"/>

With this HideBottomViewOnScrollBehavior , Scrolling behavior working fine but, Showing white space occupying the size of that bottom view.