BottomNavigationView itemReselections

rxbinding-material/src/androidTest/java/com/jakewharton/rxbinding3/material/RxBottomNavigationViewTest.java

@@ -47,4 +47,20 @@ public final class RxBottomNavigationViewTest {
     menu.performIdentifierAction(R.id.menu_item_two, 0);
     o.assertNoMoreEvents();
   }
+
+  @Test @UiThreadTest public void itemReselections() {
+    RecordingObserver<MenuItem> o = new RecordingObserver<>();
+    RxBottomNavigationView.itemReselections(view).subscribe(o);
+
+    menu.performIdentifierAction(R.id.menu_item_one, 0);
+    assertEquals(R.id.menu_item_one, o.takeNext().getItemId());
+
+    menu.performIdentifierAction(R.id.menu_item_one, 0);
+    assertEquals(R.id.menu_item_one, o.takeNext().getItemId());
+
+    o.dispose();
+
+    menu.performIdentifierAction(R.id.menu_item_one, 0);
+    o.assertNoMoreEvents();
+  }
 }

rxbinding-material/src/main/java/com/jakewharton/rxbinding3/material/BottomNavigationViewItemReselectionsObservable.kt

@@ -0,0 +1,54 @@
+@file:JvmName("RxBottomNavigationView")
+@file:JvmMultifileClass
+
+package com.jakewharton.rxbinding3.material
+
+import android.view.MenuItem
+import androidx.annotation.CheckResult
+import com.google.android.material.bottomnavigation.BottomNavigationView
+import com.jakewharton.rxbinding3.internal.checkMainThread
+import io.reactivex.Observable
+import io.reactivex.Observer
+import io.reactivex.android.MainThreadDisposable
+
+/**
+ * Create an observable which emits the reselected item in `view`.
+ *
+ * *Warning:* The created observable keeps a strong reference to `view`. Unsubscribe
+ * to free this reference.
+ *
+ */
+@CheckResult
+fun BottomNavigationView.itemReselections(): Observable<MenuItem> {
+    return BottomNavigationViewItemReselectionsObservable(this)
+}
+
+private class BottomNavigationViewItemReselectionsObservable(
+    private val view: BottomNavigationView
+) : Observable<MenuItem>() {
+
+    override fun subscribeActual(observer: Observer<in MenuItem>) {
+        if (!checkMainThread(observer)) {
+            return
+        }
+        val listener = Listener(view, observer)
+        observer.onSubscribe(listener)
+        view.setOnNavigationItemReselectedListener(listener)
+    }
+
+    private class Listener(
+        private val bottomNavigationView: BottomNavigationView,
+        private val observer: Observer<in MenuItem>
+    ) : MainThreadDisposable(), BottomNavigationView.OnNavigationItemReselectedListener {
+
+        override fun onNavigationItemReselected(item: MenuItem) {
+            if (!isDisposed) {
+                observer.onNext(item)
+            }
+        }
+
+        override fun onDispose() {
+            bottomNavigationView.setOnNavigationItemReselectedListener(null)
+        }
+    }
+}