How to disable BottomSheetDialogFragment dragging

There is simpler way of achieving the same after material design 1.2.0 was released.

https://developer.android.com/reference/com/google/android/material/bottomsheet/BottomSheetBehavior#setdraggable

When calling from BottomSheetDialogFragment:

    override fun onCreateDialog(savedInstanceState: Bundle?): Dialog {
        val bottomSheetDialog = super.onCreateDialog(savedInstanceState) as BottomSheetDialog
        bottomSheetDialog.setOnShowListener {
            val bottomSheet = bottomSheetDialog
                .findViewById<FrameLayout>(com.google.android.material.R.id.design_bottom_sheet)

            if (bottomSheet != null) {
                val behavior: BottomSheetBehavior<*> = BottomSheetBehavior.from(bottomSheet)
                behavior.isDraggable = false
            }
        }
        return bottomSheetDialog
    }

Or with styling:

    <style name="SomeStyle" parent="Theme.MaterialComponents.Light.BottomSheetDialog">
        <item name="behavior_draggable">false</item>
    </style>

And then in onCreate of your dialog fragment:

    override fun onCreate(savedInstanceState: Bundle?) {
        super.onCreate(savedInstanceState)
        setStyle(DialogFragment.STYLE_NORMAL, R.style.SomeStyle)
    }

Having created MyActivity as follows:

public class MyActivity extends AppCompatActivity {

    @Override
    protected void onCreate(@Nullable Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_my);

        new MyBottomSheetFragment().show(getSupportFragmentManager(), "tag");
    }

    public static class MyBottomSheetFragment extends BottomSheetDialogFragment {

        @Override
        public void setupDialog(Dialog dialog, int style) {
            BottomSheetDialog bottomSheetDialog = (BottomSheetDialog) dialog;
            bottomSheetDialog.setContentView(R.layout.sample);

            try {
                Field behaviorField = bottomSheetDialog.getClass().getDeclaredField("behavior");
                behaviorField.setAccessible(true);
                final BottomSheetBehavior behavior = (BottomSheetBehavior) behaviorField.get(bottomSheetDialog);
                behavior.setBottomSheetCallback(new BottomSheetBehavior.BottomSheetCallback() {

                    @Override
                    public void onStateChanged(@NonNull View bottomSheet, int newState) {
                        if (newState == BottomSheetBehavior.STATE_DRAGGING{ 
                            behavior.setState(BottomSheetBehavior.STATE_EXPANDED);
                        }
                    }

                    @Override
                    public void onSlide(@NonNull View bottomSheet, float slideOffset) {
                    }
                });
            } catch (NoSuchFieldException e) {
                e.printStackTrace();
            } catch (IllegalAccessException e) {
                e.printStackTrace();
            }
        }
    }
}

Where R.layout.sample is a simple layout:

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:layout_width="match_parent"
    android:layout_height="wrap_content"
    android:orientation="vertical">

    <View
        android:layout_width="match_parent"
        android:layout_height="100dp"
        android:background="#e479da" />

    <View
        android:layout_width="match_parent"
        android:layout_height="100dp"
        android:background="#798de4" />

    <View
        android:layout_width="match_parent"
        android:layout_height="100dp"
        android:background="#e4db79" />

</LinearLayout>

You'll get following output:

^{A part of solution is borrowed from this answer.}