[Divider] Change shouldDrawDivider from private to protected to allow for more user flexibility.

PiperOrigin-RevId: 490032010

Author: leticiarossi

lib/java/com/google/android/material/divider/MaterialDividerItemDecoration.java

@@ -374,7 +374,8 @@ public void getItemOffsets(
       @NonNull RecyclerView parent,
       @NonNull RecyclerView.State state) {
     outRect.set(0, 0, 0, 0);
-    if (shouldAddOffset(parent, view, state)) {
+    // Only add offset if there's a divider displayed.
+    if (shouldDrawDivider(parent, view)) {
       if (orientation == VERTICAL) {
         outRect.bottom = thickness;
       } else {
@@ -384,22 +385,25 @@ public void getItemOffsets(
   }
 
   private boolean shouldDrawDivider(@NonNull RecyclerView parent, @NonNull View child) {
-    if (lastItemDecorated) {
-      return true;
-    }
     int position = parent.getChildAdapterPosition(child);
     RecyclerView.Adapter<?> adapter = parent.getAdapter();
+    boolean isLastItem = adapter != null && position == adapter.getItemCount() - 1;
+
     return position != RecyclerView.NO_POSITION
-        && adapter != null
-        && position != adapter.getItemCount() - 1;
+        && (!isLastItem || lastItemDecorated)
+        && shouldDrawDivider(position, adapter);
   }
 
-  private boolean shouldAddOffset(
-      @NonNull RecyclerView parent, @NonNull View child, @NonNull RecyclerView.State state) {
-    if (lastItemDecorated) {
-      return true;
-    }
-    int position = parent.getChildAdapterPosition(child);
-    return position != RecyclerView.NO_POSITION && position != state.getItemCount() - 1;
+  /**
+   * Whether a divider should be drawn below the current item that is being drawn.
+   *
+   * <p>Note: if lasItemDecorated is false, the divider below the last item will never be drawn even
+   * if this method returns true.
+   *
+   * @param position the position of the current item being drawn.
+   * @param adapter the {@link RecyclerView.Adapter} associated with the item being drawn.
+   */
+  protected boolean shouldDrawDivider(int position, @Nullable RecyclerView.Adapter<?> adapter) {
+    return true;
   }
 }

lib/javatests/com/google/android/material/divider/MaterialDividerItemDecorationTest.java

@@ -22,17 +22,13 @@
 
 import android.content.Context;
 import android.graphics.Color;
-import android.graphics.Rect;
-import androidx.recyclerview.widget.RecyclerView;
-import android.view.View;
 import android.widget.LinearLayout;
 import androidx.test.core.app.ApplicationProvider;
 import org.junit.Before;
 import org.junit.Rule;
 import org.junit.Test;
 import org.junit.rules.ExpectedException;
 import org.junit.runner.RunWith;
-import org.mockito.Mock;
 import org.robolectric.RobolectricTestRunner;
 
 /** Tests for {@link MaterialDividerItemDecoration}. */
@@ -46,16 +42,11 @@ public final class MaterialDividerItemDecorationTest {
 
   private final Context context = ApplicationProvider.getApplicationContext();
 
-  @Mock private RecyclerView.State state;
-  @Mock private View view;
-  @Mock private RecyclerView recyclerView;
-  private Rect rect;
   private MaterialDividerItemDecoration divider;
 
   @Before
   public void themeApplicationContext() {
     context.setTheme(R.style.Theme_MaterialComponents_Light_NoActionBar_Bridge);
-    rect = new Rect();
     divider = new MaterialDividerItemDecoration(context, LinearLayout.VERTICAL);
     divider.setDividerThickness(DIVIDER_THICKNESS);
   }
@@ -140,20 +131,4 @@ public void setLastItemNotDecorated_succeeds() {
 
     assertThat(divider.isLastItemDecorated()).isFalse();
   }
-
-  @Test
-  public void getItemOffsets_verticalOrientation_returnsCorrectRect() {
-    divider.getItemOffsets(rect, view, recyclerView, state);
-
-    assertThat(rect).isEqualTo(new Rect(0, 0, 0, DIVIDER_THICKNESS));
-  }
-
-  @Test
-  public void getItemOffsets_horizontalOrientation_returnsCorrectRect() {
-    divider.setOrientation(LinearLayout.HORIZONTAL);
-
-    divider.getItemOffsets(rect, view, recyclerView, state);
-
-    assertThat(rect).isEqualTo(new Rect(0, 0, DIVIDER_THICKNESS, 0));
-  }
 }