BottomSheetDialogFragment - How to set expanded height (or min top offset)

Question

I create a BottomSheetDialogFragment and I want to adjust it\'s maximum expanded height. How can I do that? I can retrieve the BottomSheetBehaviour

Answer 1

BIG UPDATE Avoiding duplicated code I'm giving a link to the full answer in where you can find all the explanation about how to get full behavior like Google Maps.

---

I want to adjust it's maximum expanded height. How can I do that?

Both BottomSheet and BottomSheetDialogFragment use a BottomSheetBehavior that you can found in Support Library 23.x

That Java class has 2 different uses for mMinOffset, one of them is used to define the area of the parent it will use to draw his content (maybe a NestedScrollView). And the other use if for define the expanded anchor point, I mean, if you slide it up form STATE_COLLAPSEDit will animate your BottomSheetuntil he reached this anchor point BUT if you can still keep sliding up to cover all parent height (CoordiantorLayout Height).

If you took a look at BottomSheetDialog you will see this method:

private View wrapInBottomSheet(int layoutResId, View view, ViewGroup.LayoutParams params) {
    final CoordinatorLayout coordinator = (CoordinatorLayout) View.inflate(getContext(),
            android.support.design.R.layout.design_bottom_sheet_dialog, null);
    if (layoutResId != 0 && view == null) {
        view = getLayoutInflater().inflate(layoutResId, coordinator, false);
    }
    FrameLayout bottomSheet = (FrameLayout) coordinator.findViewById(android.support.design.R.id.design_bottom_sheet);
    BottomSheetBehavior.from(bottomSheet).setBottomSheetCallback(mBottomSheetCallback);
    if (params == null) {
        bottomSheet.addView(view);
    } else {
        bottomSheet.addView(view, params);
    }
    // We treat the CoordinatorLayout as outside the dialog though it is technically inside
    if (shouldWindowCloseOnTouchOutside()) {
        final View finalView = view;
        coordinator.setOnTouchListener(new View.OnTouchListener() {
            @Override
            public boolean onTouch(View v, MotionEvent event) {
                if (isShowing() &&
                        MotionEventCompat.getActionMasked(event) == MotionEvent.ACTION_UP &&
                        !coordinator.isPointInChildBounds(finalView,
                                (int) event.getX(), (int) event.getY())) {
                    cancel();
                    return true;
                }
                return false;
            }
        });
    }
    return coordinator;
}

No idea which one of those 2 behaviors you want but if you need the second one follow those steps:

1. Create a Java class and extend it from CoordinatorLayout.Behavior
2. Copy paste code from default BottomSheetBehavior file to your new one.

3. Modify the method clampViewPositionVertical with the following code:
   

   @Override
   public int clampViewPositionVertical(View child, int top, int dy) {
       return constrain(top, mMinOffset, mHideable ? mParentHeight : mMaxOffset);
   }
   int constrain(int amount, int low, int high) {
       return amount < low ? low : (amount > high ? high : amount);
   }
   

4. Add a new state

   public static final int STATE_ANCHOR_POINT = X;
   

5. Modify the next methods: onLayoutChild, onStopNestedScroll, BottomSheetBehavior from(V view) and setState (optional)

And here is how its looks like:
[]