Updated AndroidX

app/build.gradle

@@ -175,22 +175,22 @@ dependencies {
 
     def core_version = "1.2.0-beta01"
     def appcompat_version = "1.1.0"
-    def fragment_version = "1.2.0-beta02"
-    def recyclerview_version = "1.1.0-beta05"
-    def coordinatorlayout_version = "1.1.0-beta01"
+    def fragment_version = "1.2.0-rc01"
+    def recyclerview_version = "1.1.0-rc01"
+    def coordinatorlayout_version = "1.1.0-rc01"
     def constraintlayout_version = "2.0.0-beta2"
     def material_version = "1.1.0-beta01"
-    def browser_version = "1.2.0-alpha08"
+    def browser_version = "1.2.0-alpha09"
     def lbm_version = "1.0.0"
     def swiperefresh_version = "1.0.0"
     def documentfile_version = "1.0.1"
-    def lifecycle_version = "2.2.0-beta01"
-    def room_version = "2.2.0"
+    def lifecycle_version = "2.2.0-rc01"
+    def room_version = "2.2.1"
     def paging_version = "2.1.0"
     def preference_version = "1.1.0"
     def work_version = "2.2.0"
     def exif_version = "1.1.0-rc01"
-    def biometric_version = "1.0.0-rc01"
+    def biometric_version = "1.0.0-rc02"
     def billingclient_version = "2.0.3"
     def javamail_version = "1.6.5-SNAPSHOT"
     def jsoup_version = "1.12.1"

app/src/main/java/androidx/lifecycle/ComputableLiveData.java

@@ -37,7 +37,7 @@ import java.util.concurrent.atomic.AtomicBoolean;
  * @param <T> The type of the live data
  * @hide internal
  */
-@RestrictTo(RestrictTo.Scope.LIBRARY_GROUP)
+@RestrictTo(RestrictTo.Scope.LIBRARY_GROUP_PREFIX)
 public abstract class ComputableLiveData<T> {
     @SuppressWarnings("WeakerAccess") /* synthetic access */
     final Executor mExecutor;

app/src/main/java/androidx/lifecycle/Transformations.java

@@ -65,6 +65,7 @@ public class Transformations {
      * {@code mapFunction} to each value set.
      */
     @MainThread
+    @NonNull
     public static <X, Y> LiveData<Y> map(
             @NonNull LiveData<X> source,
             @NonNull final Function<X, Y> mapFunction) {
@@ -129,6 +130,7 @@ public class Transformations {
      * value set
      */
     @MainThread
+    @NonNull
     public static <X, Y> LiveData<Y> switchMap(
             @NonNull LiveData<X> source,
             @NonNull final Function<X, LiveData<Y>> switchMapFunction) {
@@ -158,4 +160,35 @@ public class Transformations {
         });
         return result;
     }
+
+    /**
+     * Creates a new {@link LiveData} object that does not emit a value until the source LiveData
+     * value has been changed.  The value is considered changed if {@code equals()} yields
+     * {@code false}.
+     *
+     * @param source the input {@link LiveData}
+     * @param <X>    the generic type parameter of {@code source}
+     * @return       a new {@link LiveData} of type {@code X}
+     */
+    @MainThread
+    @NonNull
+    public static <X> LiveData<X> distinctUntilChanged(@NonNull LiveData<X> source) {
+        final MediatorLiveData<X> outputLiveData = new MediatorLiveData<>();
+        outputLiveData.addSource(source, new Observer<X>() {
+
+            boolean mFirstTime = true;
+
+            @Override
+            public void onChanged(X currentValue) {
+                final X previousValue = outputLiveData.getValue();
+                if (mFirstTime
+                        || (previousValue == null && currentValue != null)
+                        || (previousValue != null && !previousValue.equals(currentValue))) {
+                    mFirstTime = false;
+                    outputLiveData.setValue(currentValue);
+                }
+            }
+        });
+        return outputLiveData;
+    }
 }