Add removeAllModels() to EpoxyAdapter

epoxy-adapter/src/main/java/com/airbnb/epoxy/EpoxyAdapter.java

@@ -348,6 +348,19 @@ protected void removeModel(EpoxyModel<?> model) {
     }
   }
 
+  /**
+   * Removes all models
+   */
+  protected void removeAllModels() {
+    int numModelsRemoved = models.size();
+
+    pauseModelListNotifications();
+    models.clear();
+    resumeModelListNotifications();
+
+    notifyItemRangeRemoved(0, numModelsRemoved);
+  }
+
   /**
    * Removes all models after the given model, which must have already been added. An example use
    * case is you want to keep a header but clear everything else, like in the case of refreshing

epoxy-adapter/src/main/java/com/airbnb/epoxy/SimpleEpoxyAdapter.java

@@ -59,6 +59,11 @@ public void removeModel(EpoxyModel<?> model) {
     super.removeModel(model);
   }
 
+  @Override
+  public void removeAllModels() {
+    super.removeAllModels();
+  }
+
   @Override
   public void removeAllAfterModel(EpoxyModel<?> model) {
     super.removeAllAfterModel(model);

epoxy-adapter/src/test/java/com/airbnb/epoxy/EpoxyAdapterTest.java

@@ -151,6 +151,20 @@ public void testRemoveModels() {
     checkDifferState();
   }
 
+  @Test
+  public void testRemoveAllModels() {
+    for (int i = 0; i < 10; i++) {
+      TestModel model = new TestModel();
+      testAdapter.addModels(model);
+    }
+
+    testAdapter.removeAllModels();
+    verify(observer).onItemRangeRemoved(0, 10);
+    assertEquals(0, testAdapter.models.size());
+
+    checkDifferState();
+  }
+
   @Test
   public void testRemoveAllAfterModels() {
     List<TestModel> models = new ArrayList<>();