Disabling User dragging on BottomSheet

implementation 'com.google.android.material:material:1.2.0-alpha05'

you can disable dragging the BottomSheet like this.

    override fun onCreateDialog(savedInstanceState: Bundle?): Dialog {
            val dialog = BottomSheetDialog(requireContext(), theme)
            dialog.setOnShowListener {
                setBottomSheetExpanded(dialog)
            }
            return dialog
        }
    
   open fun setBottomSheetExpanded(bottomSheetDialog: BottomSheetDialog) {
            val bottomSheet =
                bottomSheetDialog.findViewById<View>(R.id.design_bottom_sheet) as FrameLayout?
            bottomSheet?.let {
                val behavior: BottomSheetBehavior<*> = BottomSheetBehavior.from(bottomSheet)
                val layoutParams = bottomSheet.layoutParams
                bottomSheet.layoutParams = layoutParams
                behavior.state = BottomSheetBehavior.STATE_EXPANDED
                behavior.isDraggable = false / true
            }
        
    }

Edited) The library was updated! you can use new library version

implementation 'com.google.android.material:material:1.4.0'

The examples are the same, good luck and good code

Alright, so the accepted answer didn't work for me. However, Виталий Обидейко's answer inspired my final solution.

First, I created the following custom BottomSheetBehavior. It overrides all of the methods involving touch, and returns false (or did nothing) if it is locked. Otherwise, it acts like a normal BottomSheetBehavior. This disables the user's ability to drag down, and does not affect changing the state in code.

LockableBottomSheetBehavior.java

public class LockableBottomSheetBehavior<V extends View> extends BottomSheetBehavior<V> {

    private boolean mLocked = false;

    public LockableBottomSheetBehavior() {}

    public LockableBottomSheetBehavior(Context context, AttributeSet attrs) {
        super(context, attrs);
    }

    public void setLocked(boolean locked) {
        mLocked = locked;
    }

    @Override
    public boolean onInterceptTouchEvent(CoordinatorLayout parent, V child, MotionEvent event) {
        boolean handled = false;

        if (!mLocked) {
            handled = super.onInterceptTouchEvent(parent, child, event);
        }

        return handled;
    }

    @Override
    public boolean onTouchEvent(CoordinatorLayout parent, V child, MotionEvent event) {
        boolean handled = false;

        if (!mLocked) {
            handled = super.onTouchEvent(parent, child, event);
        }

        return handled;
    }

    @Override
    public boolean onStartNestedScroll(CoordinatorLayout coordinatorLayout, V child, View directTargetChild, View target, int nestedScrollAxes) {
        boolean handled = false;

        if (!mLocked) {
            handled = super.onStartNestedScroll(coordinatorLayout, child, directTargetChild, target, nestedScrollAxes);
        }

        return handled;
    }

    @Override
    public void onNestedPreScroll(CoordinatorLayout coordinatorLayout, V child, View target, int dx, int dy, int[] consumed) {
        if (!mLocked) {
            super.onNestedPreScroll(coordinatorLayout, child, target, dx, dy, consumed);
        }
    }

    @Override
    public void onStopNestedScroll(CoordinatorLayout coordinatorLayout, V child, View target) {
        if (!mLocked) {
            super.onStopNestedScroll(coordinatorLayout, child, target);
        }
    }

    @Override
    public boolean onNestedPreFling(CoordinatorLayout coordinatorLayout, V child, View target, float velocityX, float velocityY) {
        boolean handled = false;

        if (!mLocked) {
            handled = super.onNestedPreFling(coordinatorLayout, child, target, velocityX, velocityY);
        }

        return handled;

    }
}

Here's an example of how to use it. In my case, I needed it so the Bottom Sheet locked when expanded.

activity_home.xml

<?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="match_parent">

    <android.support.design.widget.AppBarLayout
        android:layout_width="match_parent"
        android:layout_height="wrap_content">
        <android.support.design.widget.CollapsingToolbarLayout
            android:layout_width="match_parent"
            android:layout_height="match_parent"
            app:layout_scrollFlags="scroll|snap"
            app:titleEnabled="false"/>
        <android.support.v7.widget.Toolbar
            android:id="@+id/toolbar"
            android:layout_width="match_parent"
            android:layout_height="?attr/actionBarSize"/>
    </android.support.design.widget.AppBarLayout>

    <!-- Use layout_behavior to set your Behavior-->
    <android.support.v7.widget.RecyclerView
        android:id="@+id/recyclerview"
        android:layout_width="match_parent"
        android:layout_height="match_parent"
        app:layoutManager="android.support.v7.widget.LinearLayoutManager"
        app:layout_behavior="com.myapppackage.LockableBottomSheetBehavior"/>

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

HomeActivity.java

public class HomeActivity extends AppCompatActivity {
    BottomSheetBehavior mBottomSheetBehavior;

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

        RecyclerView recyclerView = (RecyclerView) findViewById(R.id.recyclerview);
        recyclerView.setAdapter(new SomeAdapter());

        mBottomSheetBehavior = BottomSheetBehavior.from(recyclerView);
        mBottomSheetBehavior.setBottomSheetCallback(new MyBottomSheetCallback());
    }

    class MyBottomSheetCallback extends BottomSheetBehavior.BottomSheetCallback() {
        @Override
        public void onStateChanged(@NonNull View bottomSheet, int newState) {
            if (newState == BottomSheetBehavior.STATE_EXPANDED) {
                if (mBottomSheetBehavior instanceof LockableBottomSheetBehavior) {
                    ((LockableBottomSheetBehavior) mBottomSheetBehavior).setLocked(true);
                }
            }
        }

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

Hope this helps clear up a lot of the confusion!

It can be now no longer relevant, but I will leave it here:

import android.content.Context
import android.util.AttributeSet
import androidx.coordinatorlayout.widget.CoordinatorLayout
import android.view.MotionEvent
import android.view.View
import com.google.android.material.bottomsheet.BottomSheetBehavior

@Suppress("unused")
class LockableBottomSheetBehavior<V : View> : BottomSheetBehavior<V> {
    constructor() : super()
    constructor(context: Context, attrs: AttributeSet) : super(context, attrs)

    var swipeEnabled = true

    override fun onInterceptTouchEvent(
        parent: CoordinatorLayout,
        child: V,
        event: MotionEvent
    ): Boolean {
        return if (swipeEnabled) {
            super.onInterceptTouchEvent(parent, child, event)
        } else {
            false
        }
    }

    override fun onTouchEvent(parent: CoordinatorLayout, child: V, event: MotionEvent): Boolean {
        return if (swipeEnabled) {
            super.onTouchEvent(parent, child, event)
        } else {
            false
        }
    }

    override fun onStartNestedScroll(
        coordinatorLayout: CoordinatorLayout,
        child: V,
        directTargetChild: View,
        target: View,
        axes: Int,
        type: Int
    ): Boolean {
        return if (swipeEnabled) {
            super.onStartNestedScroll(
                coordinatorLayout,
                child,
                directTargetChild,
                target,
                axes,
                type
            )
        } else {
            false
        }
    }

    override fun onNestedPreScroll(
        coordinatorLayout: CoordinatorLayout,
        child: V,
        target: View,
        dx: Int,
        dy: Int,
        consumed: IntArray,
        type: Int
    ) {
        if (swipeEnabled) {
            super.onNestedPreScroll(coordinatorLayout, child, target, dx, dy, consumed, type)
        }
    }

    override fun onStopNestedScroll(
        coordinatorLayout: CoordinatorLayout,
        child: V,
        target: View,
        type: Int
    ) {
        if (swipeEnabled) {
            super.onStopNestedScroll(coordinatorLayout, child, target, type)
        }
    }

    override fun onNestedPreFling(
        coordinatorLayout: CoordinatorLayout,
        child: V,
        target: View,
        velocityX: Float,
        velocityY: Float
    ): Boolean {
        return if (swipeEnabled) {
            super.onNestedPreFling(coordinatorLayout, child, target, velocityX, velocityY)
        } else {
            false
        }
    }
}

And use it in your xml file:

app:layout_behavior="com.your.package.LockableBottomSheetBehavior"

It disables all users actions, it can be used when you want control BottomSheet only programmatically.

check state in onStateChanged method of setBottomSheetCallback if state is BottomSheetBehavior.STATE_DRAGGING then change it to BottomSheetBehavior.STATE_EXPANDED this way you can stop STATE_DRAGGING by user. like below

final BottomSheetBehavior behavior = BottomSheetBehavior.from(bottomSheet);
        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) {
            }
        });

---

use button to open close bottom sheet like below

fab.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View view) {
                if (behavior.getState() == BottomSheetBehavior.STATE_HIDDEN) {
                    behavior.setState(BottomSheetBehavior.STATE_EXPANDED);
                } else {
                    behavior.setState(BottomSheetBehavior.STATE_COLLAPSED);
                }
            }
        });

---

don't use setPeekHeight or app:behavior_peekHeight

by above way you can reach your goal