Merge "Fix exception from DateTimeView unregisters receiver again" into pi-dev

core/java/android/widget/DateTimeView.java

@@ -450,8 +450,10 @@ public class DateTimeView extends TextView {
 
         public void removeView(DateTimeView v) {
             synchronized (mAttachedViews) {
-                mAttachedViews.remove(v);
-                if (mAttachedViews.isEmpty()) {
+                final boolean removed = mAttachedViews.remove(v);
+                // Only unregister once when we remove the last view in the list otherwise we risk
+                // trying to unregister a receiver that is no longer registered.
+                if (removed && mAttachedViews.isEmpty()) {
                     unregister(getApplicationContextIfAvailable(v.getContext()));
                 }
             }

core/tests/coretests/src/android/widget/DateTimeViewTest.java

@@ -0,0 +1,41 @@
+/*
+ * Copyright (C) 2018 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package android.widget;
+
+import android.support.test.InstrumentationRegistry;
+import android.support.test.annotation.UiThreadTest;
+import android.support.test.filters.SmallTest;
+import android.support.test.runner.AndroidJUnit4;
+
+import org.junit.Test;
+import org.junit.runner.RunWith;
+
+@RunWith(AndroidJUnit4.class)
+@SmallTest
+public class DateTimeViewTest {
+
+    @UiThreadTest
+    @Test
+    public void additionalOnDetachedFromWindow_noException() {
+        final DateTimeView dateTimeView = new DateTimeView(InstrumentationRegistry.getContext());
+        dateTimeView.onAttachedToWindow();
+        dateTimeView.onAttachedToWindow();
+        // Even there is an additional detach (abnormal), DateTimeView should not unregister
+        // receiver again that raises "java.lang.IllegalArgumentException: Receiver not registered".
+        dateTimeView.onDetachedFromWindow();
+    }
+}