material-components/material-components-android · error · IllegalArgumentException

The view is not a child of CoordinatorLayout

Error message

The view is not a child of CoordinatorLayout

What it means

BottomSheetBehavior.from(View) retrieves the behavior attached to a view by casting its ViewGroup.LayoutParams to CoordinatorLayout.LayoutParams. If the view's layout params are not that type, the view is not a direct child of a CoordinatorLayout and from() throws IllegalArgumentException.

Source

Thrown at lib/java/com/google/android/material/bottomsheet/BottomSheetBehavior.java:2467

          @Override
          public SavedState[] newArray(int size) {
            return new SavedState[size];
          }
        };
  }

  /**
   * A utility function to get the {@link BottomSheetBehavior} associated with the {@code view}.
   *
   * @param view The {@link View} with {@link BottomSheetBehavior}.
   * @return The {@link BottomSheetBehavior} associated with the {@code view}.
   */
  @NonNull
  @SuppressWarnings("unchecked")
  public static <V extends View> BottomSheetBehavior<V> from(@NonNull V view) {
    ViewGroup.LayoutParams params = view.getLayoutParams();
    if (!(params instanceof CoordinatorLayout.LayoutParams)) {
      throw new IllegalArgumentException("The view is not a child of CoordinatorLayout");
    }
    CoordinatorLayout.Behavior<?> behavior =
        ((CoordinatorLayout.LayoutParams) params).getBehavior();
    if (!(behavior instanceof BottomSheetBehavior)) {
      throw new IllegalArgumentException("The view is not associated with BottomSheetBehavior");
    }
    return (BottomSheetBehavior<V>) behavior;
  }

  /**
   * Sets whether the BottomSheet should update the accessibility status of its {@link
   * CoordinatorLayout} siblings when expanded.
   *
   * <p>Set this to true if the expanded state of the sheet blocks access to siblings (e.g., when
   * the sheet expands over the full screen).
   */
  public void setUpdateImportantForAccessibilityOnSiblings(
      boolean updateImportantForAccessibilityOnSiblings) {

View on GitHub (pinned to ac7e18efee)

Solutions

1. Make the sheet a direct child of the CoordinatorLayout with app:layout_behavior="...BottomSheetBehavior".
2. Call from() only after the view is inflated and attached (onCreateOptionsMenu of the fragment / after setContentView).
3. If wrapping is unavoidable, apply the behavior to the outermost direct child instead and query that view.

Example fix

<!-- before -->
<androidx.coordinatorlayout.widget.CoordinatorLayout ...>
  <FrameLayout ...>
    <LinearLayout android:id="+id/bottom_sheet" ... /> <!-- not a direct child -->
  </FrameLayout>
</androidx.coordinatorlayout.widget.CoordinatorLayout>

<!-- after -->
<androidx.coordinatorlayout.widget.CoordinatorLayout ...>
  <LinearLayout
      android:id="+id/bottom_sheet"
      app:layout_behavior="com.google.android.material.bottomsheet.BottomSheetBehavior"
      ... />
</androidx.coordinatorlayout.widget.CoordinatorLayout>

private static boolean isCoordinatorChild(View v) {
  return v.getLayoutParams() instanceof CoordinatorLayout.LayoutParams;
}
// usage: if (isCoordinatorChild(sheet)) BottomSheetBehavior.from(sheet);

When it happens

Trigger: Calling BottomSheetBehavior.from(bottomSheet) where bottomSheet is inside a NestedScrollView/FrameLayout wrapper, a different parent container, or not yet attached to the hierarchy (generic LayoutParams).

Common situations: The sheet view is wrapped in another container for layout reasons; calling from() before the view is laid out (e.g. in Activity.onCreate before setContentView completes, or on a programmatically created view not yet added to the CoordinatorLayout); accessing a sheet from the wrong fragment's view.

Related errors

• The view is not a child of CoordinatorLayout
• The view is not associated with BottomSheetBehavior
• The view is not associated with HideViewOnScrollBehavior
• ratio must be a float value between 0 and 1
• offset must be greater than or equal to 0

AI-assisted analysis of material-components/material-components-android@ac7e18efee (2026-08-14). Data as JSON: /api/errors/564798bb5f9131d7. Report an issue: GitHub.