[Bottom Sheet] Add ability to disable dragging/expanding/collapsing t…

…he sheet when touching/scrolling the nested scrolling child view

PiperOrigin-RevId: 624204480

docs/components/BottomSheet.md

@@ -439,6 +439,7 @@ Behavior | Related method(s)
 `app:behavior_skipCollapsed` | `setSkipCollapsed`<br/>`getSkipCollapsed` | `false`
 `app:behavior_fitToContents` | `setFitToContents`<br/>`isFitToContents` | `true`
 `app:behavior_draggable` | `setDraggable`<br/>`isDraggable` | `true`
+`app:behavior_draggableOnNestedScroll` | `setDraggableOnNestedScroll`<br/>`isDraggableOnNestedScroll` | `true`
 `app:behavior_halfExpandedRatio` | `setHalfExpandedRatio`<br/>`getHalfExpandedRatio` | `0.5`
 `app:behavior_expandedOffset` | `setExpandedOffset`<br/>`getExpandedOffset` | `0dp`
 `app:behavior_significantVelocityThreshold` | `setSignificantVelocityThreshold` <br/> `getSignificantVelocityThreshold` | `500 pixels/s`

lib/java/com/google/android/material/bottomsheet/BottomSheetBehavior.java

@@ -306,6 +306,8 @@ void onLayout(@NonNull View bottomSheet) {}
 
  private boolean draggable = true;
 
+ private boolean draggableOnNestedScroll = true;
+
  @State int state = STATE_COLLAPSED;
 
  @State int lastStableState = STATE_COLLAPSED;
@@ -398,6 +400,9 @@ public BottomSheetBehavior(@NonNull Context context, @Nullable AttributeSet attr
  setSkipCollapsed(
  a.getBoolean(R.styleable.BottomSheetBehavior_Layout_behavior_skipCollapsed, false));
  setDraggable(a.getBoolean(R.styleable.BottomSheetBehavior_Layout_behavior_draggable, true));
+ setDraggableOnNestedScroll(
+ a.getBoolean(
+ R.styleable.BottomSheetBehavior_Layout_behavior_draggableOnNestedScroll, true));
  setSaveFlags(a.getInt(R.styleable.BottomSheetBehavior_Layout_behavior_saveFlags, SAVE_NONE));
  setHalfExpandedRatio(
  a.getFloat(R.styleable.BottomSheetBehavior_Layout_behavior_halfExpandedRatio, 0.5f));
@@ -739,6 +744,9 @@ public void onNestedPreScroll(
  if (isNestedScrollingCheckEnabled() && target != scrollingChild) {
  return;
  }
+ if (!draggableOnNestedScroll && target == scrollingChild) {
+ return;
+ }
  int currentTop = child.getTop();
  int newTop = currentTop - dy;
  if (dy > 0) { // Upward
@@ -877,7 +885,7 @@ public boolean onNestedPreFling(
 
  if (isNestedScrollingCheckEnabled() && nestedScrollingChildRef != null) {
  return target == nestedScrollingChildRef.get()
- && (state != STATE_EXPANDED
+ && ((state != STATE_EXPANDED && draggableOnNestedScroll)
  || super.onNestedPreFling(coordinatorLayout, child, target, velocityX, velocityY));
  } else {
  return false;
@@ -1170,7 +1178,7 @@ public boolean getSkipCollapsed() {
  }
 
  /**
- * Sets whether this bottom sheet is can be collapsed/expanded by dragging. Note: When disabling
+ * Sets whether this bottom sheet can be collapsed/expanded by dragging. Note: When disabling
  * dragging, an app will require to implement a custom way to expand/collapse the bottom sheet
  *
  * @param draggable {@code false} to prevent dragging the sheet to collapse and expand
@@ -1184,6 +1192,22 @@ public boolean isDraggable() {
  return draggable;
  }
 
+ /**
+ * Sets whether this bottom sheet can be collapsed/expanded by dragging on the nested scrolling
+ * child view. Default is true.
+ *
+ * @param draggableOnNestedScroll {@code false} to prevent dragging the nested scrolling child
+ * view to collapse and expand the sheet
+ * @attr ref com.google.android.material.R.styleable#BottomSheetBehavior_Layout_behavior_draggableOnNestedScroll
+ */
+ public void setDraggableOnNestedScroll(boolean draggableOnNestedScroll) {
+ this.draggableOnNestedScroll = draggableOnNestedScroll;
+ }
+
+ public boolean isDraggableOnNestedScroll() {
+ return draggableOnNestedScroll;
+ }
+
  /*
  * Sets the velocity threshold considered significant enough to trigger a slide
  * to the next stable state.

lib/java/com/google/android/material/bottomsheet/res/values/attrs.xml

@@ -41,6 +41,9 @@
  means to expand and collapse the sheet. Attribute declaration is in
  the resources package. -->
  <attr name="behavior_draggable"/>
+ <!-- Whether this bottom sheet is draggable when the nested scrolling child
+ view is scrolled. Default is true. -->
+ <attr name="behavior_draggableOnNestedScroll" format="boolean"/>
  <!-- The ratio to be used to set the height of half-expanded state in proportion to parent, when
  fitToContents is false. Defaults to true half, 0.5, if not explicitly set. Ratio must be a
  float value between 0 and 1 and produce a half-expanded state height larger than the