In MaterialDatePicker after rotation, open to the same page if it was changed via swipe

PiperOrigin-RevId: 266462896

Author: ldjcmu

lib/java/com/google/android/material/picker/MaterialCalendar.java

@@ -398,6 +398,7 @@ public void onScrolled(@NonNull RecyclerView recyclerView, int dx, int dy) {
             } else {
               currentItem = getLayoutManager().findLastVisibleItemPosition();
             }
+            current = monthsPagerAdapter.getPageMonth(currentItem);
             monthDropSelect.setText(monthsPagerAdapter.getPageTitle(currentItem));
           }
 

tests/javatests/com/google/android/material/picker/MaterialDatePickerPagesTest.java

@@ -15,14 +15,13 @@
  */
 package com.google.android.material.picker;
 
+import static com.google.android.material.picker.MaterialDatePickerTestUtils.findFirstVisibleItem;
 import static org.hamcrest.Matchers.lessThan;
 import static org.junit.Assert.assertEquals;
 import static org.junit.Assert.assertThat;
 
 import androidx.fragment.app.FragmentManager;
 import androidx.appcompat.app.AppCompatActivity;
-import androidx.recyclerview.widget.LinearLayoutManager;
-import androidx.recyclerview.widget.RecyclerView;
 import androidx.test.espresso.IdlingRegistry;
 import androidx.test.platform.app.InstrumentationRegistry;
 import androidx.test.rule.ActivityTestRule;
@@ -73,7 +72,7 @@ public void calendarSwipeCappedAtStart() {
     MaterialDatePickerTestUtils.swipeEarlier(dialogFragment);
     MaterialDatePickerTestUtils.swipeEarlier(dialogFragment);
 
-    assertEquals(start, findFirstVisibleItem());
+    assertEquals(start, findFirstVisibleItem(dialogFragment));
   }
 
   @Test
@@ -82,12 +81,12 @@ public void calendarSwipeCappedAtEnd() {
     MaterialDatePickerTestUtils.swipeLater(dialogFragment);
     MaterialDatePickerTestUtils.swipeLater(dialogFragment);
     MaterialDatePickerTestUtils.swipeLater(dialogFragment);
-    assertEquals(end, findFirstVisibleItem());
+    assertEquals(end, findFirstVisibleItem(dialogFragment));
   }
 
   @Test
   public void calendarOpensOnCurrent() {
-    assertEquals(opening, findFirstVisibleItem());
+    assertEquals(opening, findFirstVisibleItem(dialogFragment));
   }
 
   @Test
@@ -119,14 +118,6 @@ public void changingSelectorToDayMaintainsCurrentMonth() {
     MaterialDatePickerTestUtils.clickNext();
     MaterialDatePickerTestUtils.clickSelectorToggle();
     MaterialDatePickerTestUtils.clickSelectorToggle();
-    assertEquals(findFirstVisibleItem(), opening.monthsLater(1));
-  }
-
-  private Month findFirstVisibleItem() {
-    RecyclerView recyclerView =
-        dialogFragment.getView().findViewWithTag(MaterialCalendar.MONTHS_VIEW_GROUP_TAG);
-    MonthsPagerAdapter monthsPagerAdapter = (MonthsPagerAdapter) recyclerView.getAdapter();
-    return monthsPagerAdapter.getPageMonth(
-        ((LinearLayoutManager) recyclerView.getLayoutManager()).findFirstVisibleItemPosition());
+    assertEquals(findFirstVisibleItem(dialogFragment), opening.monthsLater(1));
   }
 }

tests/javatests/com/google/android/material/picker/MaterialDatePickerTestUtils.java

@@ -29,6 +29,7 @@
 import static org.hamcrest.core.IsEqual.equalTo;
 
 import android.app.Activity;
+import androidx.annotation.VisibleForTesting;
 import androidx.fragment.app.DialogFragment;
 import androidx.fragment.app.Fragment;
 import androidx.fragment.app.FragmentManager;
@@ -47,6 +48,8 @@
 
 public final class MaterialDatePickerTestUtils {
 
+  @VisibleForTesting public static final Month OPENING = Month.create(2018, Calendar.APRIL);
+
   private MaterialDatePickerTestUtils() {}
 
   private static final ViewInteraction onMonthsGroup =
@@ -68,9 +71,8 @@ public static MaterialDatePicker<Long> showDatePicker(
 
     Month start = Month.create(1900, Calendar.JANUARY);
     Month end = Month.create(2100, Calendar.DECEMBER);
-    Month current = Month.create(2018, Calendar.APRIL);
     CalendarConstraints calendarConstraints =
-        new CalendarConstraints.Builder().setStart(start).setEnd(end).setOpening(current).build();
+        new CalendarConstraints.Builder().setStart(start).setEnd(end).setOpening(OPENING).build();
 
     return showDatePicker(activityTestRule, themeResId, calendarConstraints);
   }
@@ -107,9 +109,8 @@ public static MaterialDatePicker<Pair<Long, Long>> showRangePicker(
       ActivityTestRule<? extends AppCompatActivity> activityTestRule, int themeResId) {
     Month start = Month.create(1900, Calendar.JANUARY);
     Month end = Month.create(2100, Calendar.DECEMBER);
-    Month current = Month.create(2018, Calendar.APRIL);
     CalendarConstraints calendarConstraints =
-        new CalendarConstraints.Builder().setStart(start).setEnd(end).setOpening(current).build();
+        new CalendarConstraints.Builder().setStart(start).setEnd(end).setOpening(OPENING).build();
     return showRangePicker(activityTestRule, themeResId, calendarConstraints);
   }
 
@@ -187,7 +188,8 @@ static void clickSelectorToggle() {
     InstrumentationRegistry.getInstrumentation().waitForIdleSync();
   }
 
-  static void swipeEarlier(DialogFragment dialogFragment) {
+  @VisibleForTesting
+  public static void swipeEarlier(DialogFragment dialogFragment) {
     int orientation = getOrientation(dialogFragment);
     if (orientation == LinearLayoutManager.HORIZONTAL) {
       onMonthsGroup.perform(swipeRight());
@@ -235,6 +237,15 @@ static void hideAllEditTextCursors(View view) {
     }
   }
 
+  @VisibleForTesting
+  public static Month findFirstVisibleItem(DialogFragment dialogFragment) {
+    RecyclerView recyclerView =
+        dialogFragment.getView().findViewWithTag(MaterialCalendar.MONTHS_VIEW_GROUP_TAG);
+    MonthsPagerAdapter monthsPagerAdapter = (MonthsPagerAdapter) recyclerView.getAdapter();
+    return monthsPagerAdapter.getPageMonth(
+        ((LinearLayoutManager) recyclerView.getLayoutManager()).findFirstVisibleItemPosition());
+  }
+
   private static int getOrientation(DialogFragment dialogFragment) {
     return ((LinearLayoutManager) getMonthsViewGroup(dialogFragment).getLayoutManager())
         .getOrientation();