[Lists] Added onSwipeStateChanged callback, drawable swiped state for ListCardView, and alpha changes to swiped view as it reaches the swipe-to-action state

PiperOrigin-RevId: 833409689

Author: imhappi

lib/java/com/google/android/material/listitem/ListItemCardView.java

@@ -35,6 +35,10 @@
  */
 public class ListItemCardView extends MaterialCardView implements SwipeableListItem {
 
+  private static final int[] SWIPED_STATE_SET = {R.attr.state_swiped};
+
+  private boolean isSwiped = false;
+
   private final int swipeMaxOvershoot;
   private boolean swipeToPrimaryActionEnabled;
 
@@ -84,4 +88,19 @@ public void setSwipeToPrimaryActionEnabled(boolean swipeToPrimaryActionEnabled)
   public boolean isSwipeToPrimaryActionEnabled() {
     return swipeToPrimaryActionEnabled;
   }
+
+  @Override
+  protected int[] onCreateDrawableState(int extraSpace) {
+    final int[] drawableState = super.onCreateDrawableState(extraSpace + 1);
+    if (isSwiped) {
+      mergeDrawableStates(drawableState, SWIPED_STATE_SET);
+    }
+    return drawableState;
+  }
+
+  @Override
+  public void onSwipeStateChanged(int swipeState) {
+    isSwiped = swipeState != STATE_CLOSED;
+    refreshDrawableState();
+  }
 }

lib/java/com/google/android/material/listitem/ListItemLayout.java

@@ -327,6 +327,16 @@ public void onViewPositionChanged(
                               - revealViewLp.rightMargin);
                   ((RevealableListItem) swipeToRevealLayout)
                       .setRevealedWidth(revealViewDesiredWidth);
+
+                  int fullSwipedOffset = getSwipeToActionOffset();
+                  int disappearingOffset =
+                      (fullSwipedOffset + getSwipeRevealViewRevealedOffset()) / 2;
+                  // If we're past the reveal view offset, we should start disappearing.
+                  if (revealViewOffset <= disappearingOffset) {
+                    contentView.setAlpha(
+                        (float) (revealViewOffset - fullSwipedOffset)
+                            / (disappearingOffset - fullSwipedOffset));
+                  }
                 }
 
                 @Override
@@ -475,11 +485,14 @@ private void startSettling(View contentView, @StableSwipeState int targetSwipeSt
   }
 
   private void setSwipeStateInternal(@SwipeState int swipeState) {
+    if (swipeState == this.swipeState) {
+      return;
+    }
     // If swipe to action is not supported but the swipe state to be set in
     // STATE_SWIPE_PRIMARY_ACTION, we do nothing.
-    if (swipeState == STATE_SWIPE_PRIMARY_ACTION
-        && !(contentView instanceof SwipeableListItem
-            && ((SwipeableListItem) contentView).isSwipeToPrimaryActionEnabled())) {
+    if (!(contentView instanceof SwipeableListItem)
+        || (swipeState == STATE_SWIPE_PRIMARY_ACTION
+            && !((SwipeableListItem) contentView).isSwipeToPrimaryActionEnabled())) {
       return;
     }
     this.swipeState = swipeState;
@@ -488,6 +501,8 @@ private void setSwipeStateInternal(@SwipeState int swipeState) {
         || swipeState == STATE_SWIPE_PRIMARY_ACTION) {
       this.lastStableSwipeState = swipeState;
     }
+
+    ((SwipeableListItem) contentView).onSwipeStateChanged(swipeState);
   }
 
   @Override

lib/java/com/google/android/material/listitem/SwipeableListItem.java

@@ -80,6 +80,9 @@ public interface SwipeableListItem {
   @Retention(RetentionPolicy.SOURCE)
   @interface StableSwipeState {}
 
+  /** Called whenever the swipe state of the SwipeableListItem changes. */
+  void onSwipeStateChanged(@SwipeState int swipeState);
+
   /**
    * Returns the overshoot, in pixels, that the SwipeableListItem is able to be swiped past the
    * {@link #STATE_OPEN} or {@link #STATE_SWIPE_PRIMARY_ACTION} states by, before settling.

lib/java/com/google/android/material/listitem/res-public/values/public.xml

@@ -19,6 +19,8 @@
   <public name="listItemCardViewStyle" type="attr"/>
   <public name="listItemCardViewSegmentedStyle" type="attr"/>
 
+  <public name="state_swiped" type="attr" />
+
   <public name="Widget.Material3.ListItemLayout" type="style"/>
   <public name="ThemeOverlay.Material3.ListItemLayout.Segmented" type="style"/>
   <public name="Widget.Material3.ListItemCardView" type="style"/>

lib/java/com/google/android/material/listitem/res/color/m3_list_item_background_color_selector.xml

@@ -14,8 +14,9 @@
   See the License for the specific language governing permissions and
   limitations under the License.
   -->
-<selector xmlns:android="http://schemas.android.com/apk/res/android">
+<selector xmlns:android="http://schemas.android.com/apk/res/android" xmlns:app="http://schemas.android.com/apk/res-auto">
   <item android:state_checkable="true" android:state_checked="true"
     android:color="?attr/colorSecondaryContainer"/>
+  <item app:state_swiped="true" android:color="?attr/colorSurface"/>
   <item android:color="@android:color/transparent"/>
 </selector>

lib/java/com/google/android/material/listitem/res/color/m3_segmented_list_item_background_color_selector.xml

@@ -14,8 +14,9 @@
   See the License for the specific language governing permissions and
   limitations under the License.
   -->
-<selector xmlns:android="http://schemas.android.com/apk/res/android">
+<selector xmlns:android="http://schemas.android.com/apk/res/android" xmlns:app="http://schemas.android.com/apk/res-auto">
   <item android:state_checkable="true" android:state_checked="true"
     android:color="?attr/colorSecondaryContainer"/>
-  <item android:color="?attr/colorSurfaceBright"/>
+  <item app:state_swiped="true" android:color="?attr/colorSurface"/>
+  <item android:color="?attr/colorSurface"/>
 </selector>

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

@@ -27,6 +27,11 @@
     <attr name="swipeToPrimaryActionEnabled" format="boolean"/>
   </declare-styleable>
 
+  <declare-styleable name="ListItemCardViewStates">
+    <!-- State when a ListItemCardView is being swiped. -->
+    <attr name="state_swiped" format="boolean" />
+  </declare-styleable>
+
   <!-- Shape appearance of a single item in the list. -->
   <attr name="listItemShapeAppearanceSingle" format="reference"/>
   <!-- Shape appearance of the first item in the list. -->