Bottom Sheet Android- Scrolling issue

Question

I need the bottom sheet to stop at two positions. I have the following code for Bottom Sheet.

<android.support.design.widget.CoordinatorLayout xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:app="http://schemas.android.com/apk/res-auto"
xmlns:tools="http://schemas.android.com/tools"
android:id="@+id/main_content"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:fitsSystemWindows="true">

<RelativeLayout
    android:layout_width="match_parent"
    android:layout_height="match_parent">
    ....
</RelativeLayout>

<FrameLayout
    android:id="@+id/bottom_sheet"
    android:layout_width="match_parent"
    android:layout_height="wrap_content"
    app:layout_behavior="android.support.design.widget.BottomSheetBehavior">
       <ScrollView
        android:layout_width="match_parent"
        android:layout_height="match_parent">

            <LinearLayout
                android:layout_width="match_parent"
                android:layout_height="wrap_content"
                android:background="@color/white"
                android:minHeight="1000dp"
                android:orientation="vertical">
                ....
            </LinearLayout>
      </ScrollView>
 </FrameLayout>

and

View bottomSheet = coordinatorLayout.findViewById(R.id.bottom_sheet);
    final BottomSheetBehavior behavior = BottomSheetBehavior.from(bottomSheet);
    behavior.setBottomSheetCallback(new BottomSheetBehavior.BottomSheetCallback() {
        @Override
        public void onStateChanged(@NonNull View bottomSheet, int newState) {
            // React to state change
            Log.e("onStateChanged", "onStateChanged:" + newState);
            if (newState == BottomSheetBehavior.STATE_EXPANDED) {
                behavior.setPeekHeight(600);
                showAgain.setVisibility(View.GONE);
                mMap.getUiSettings().setScrollGesturesEnabled(false);
            } else if (newState == BottomSheetBehavior.STATE_COLLAPSED) {

                if (behavior.getPeekHeight() == 600) {
                    behavior.setState(BottomSheetBehavior.STATE_COLLAPSED);
                    behavior.setPeekHeight(80);
                    mMap.getUiSettings().setScrollGesturesEnabled(false);
                } else if (behavior.getPeekHeight() == 80) {
                    showAgain.setVisibility(View.VISIBLE);
                    mMap.getUiSettings().setScrollGesturesEnabled(true);
                }

            }
        }

        @Override
        public void onSlide(@NonNull View bottomSheet, float slideOffset) {
            // React to dragging events
            Log.e("onSlide", "onSlide " + slideOffset);
        }
    });

    behavior.setPeekHeight(600);

This code works fine except one thing. The very first time I have to scroll up the bottom sheet and then I can down scroll it. I cannot directly down scroll the sheet.

Any help will be appreciated.

Answer 1

Instead of using scrollview you can use NestedScrollView that works better with CoordinatorLayout make sure to use app:layout_behavior="@string/appbar_scrolling_view_behavior" for smooth scrolling of content inside NestedScrollView

mBottomSheetBehavior.setBottomSheetCallback(new BottomSheetBehavior.BottomSheetCallback() {
        @Override
        public void onStateChanged(@NonNull View bottomSheet, int newState) {
            if (newState == BottomSheetBehavior.STATE_COLLAPSED) {
                mBottomSheetBehavior.setPeekHeight(0);
            }
        }

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

@Override
public void onClick(View v) {
    switch (v.getId()) {
        case R.id.btn_negetive: {
            mBottomSheetBehavior.setState(BottomSheetBehavior.STATE_EXPANDED);
            mBottomSheetBehavior.setPeekHeight(Constants.PEEK_HEIGHT);
            mBottomSheetBehavior.setState(BottomSheetBehavior.STATE_COLLAPSED);
            break;
        }
        case R.id.btn_positive: {
            //some code
        }
    }
}

the above solution worked for me using this link: https://code.tutsplus.com/articles/how-to-use-bottom-sheets-with-the-design-support-library--cms-26031