How to create bottomsheet with toolbar when expanded,

Question

I want to create bottom sheet layout, which when expanded to full screen should display toolbar. I have used following code but it is displaying toolbar even if its not expanded to full screen.

<?xml version="1.0" encoding="utf-8"?>
<android.support.design.widget.CoordinatorLayout
    xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:app="http://schemas.android.com/apk/res-auto"
    android:layout_width="match_parent"
    android:layout_height="wrap_content"
    android:layout_gravity="bottom"
    app:layout_behavior="@string/bottom_sheet_behavior">

    <include
        android:id="@+id/search_tab_toolbar"
        layout="@layout/search_tablayout"/>
    <TextView
        android:layout_width="match_parent"
        android:layout_height="50dp"
        android:id="@+id/search_tab_toolbar"
        android:background="@color/accent"/>

    <android.support.v7.widget.RecyclerView
        android:id="@+id/recyclerView"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        />


</android.support.design.widget.CoordinatorLayout>

Answer 1

You can use the setBottomSheetCallback from BottomSheetBehavior class.

Initially set the visibility of toobar as gone. Then in your code detect the state of the bottom sheet,

BottomSheetBehavior sheetBehavior = BottomSheetBehavior.from(layoutBottomSheet); //your bottom sheet layout 

sheetBehavior.setBottomSheetCallback(new BottomSheetBehavior.BottomSheetCallback() {
            @Override
            public void onStateChanged(@NonNull View bottomSheet, int newState) {
                switch (newState) {
                    case BottomSheetBehavior.STATE_HIDDEN:

                        break;
                    case BottomSheetBehavior.STATE_EXPANDED: 
                        //make toolbar visible
                        toolbar.setVisibility(View.VISIBLE);
                    break;
                    case BottomSheetBehavior.STATE_COLLAPSED:
                        //hide toolbar here
                        toolbar.setVisibility(View.GONE);
                    break;
                    case BottomSheetBehavior.STATE_DRAGGING:

                        break;
                    case BottomSheetBehavior.STATE_SETTLING:
                        break;
                }
            }

            @Override
            public void onSlide(@NonNull View bottomSheet, float slideOffset) {

            }
        });

Also, avoid doing stuff in STATE_DRAGGING and STATE_SETTLING. These will be called a lot of times and changing visibility in the these cases may decrease the performance of your app on lower end devices.