How to use

onChanged

method

in

android.support.v7.widget.RecyclerView$AdapterDataObserver

@Override
public void setAdapter(Adapter adapter) {
  super.setAdapter(adapter);
  if(adapter != null) {
    adapter.registerAdapterDataObserver(emptyObserver);
  }
  emptyObserver.onChanged();
}

@Override
public void setAdapter(Adapter adapter) {
  super.setAdapter(adapter);
  if (adapter != null) {
    adapter.registerAdapterDataObserver(observer);
    observer.onChanged();
  }
}

public void setAdapter(Adapter adapter) {
  Adapter oldAdapter = getAdapter();
  if (oldAdapter != null && emptyObserver != null) {
    oldAdapter.unregisterAdapterDataObserver(emptyObserver);
  }
  super.setAdapter(adapter);
  if (adapter != null) {
    adapter.registerAdapterDataObserver(emptyObserver);
  }
  emptyObserver.onChanged();
}

@Test
public void notifyParentDataSetWithExpansionPreservationChangedNoChanges() {
  assertEquals(25, mExpandableRecyclerAdapter.getItemCount());
  mExpandableRecyclerAdapter.notifyParentDataSetChanged(true);
  verify(mDataObserver).onChanged();
  assertEquals(25, mExpandableRecyclerAdapter.getItemCount());
  int flatIndex = 0;
  for (Parent<Object> baseParent : mBaseParents) {
    verifyParentItemsMatch(baseParent, baseParent.isInitiallyExpanded(), flatIndex);
    flatIndex++;
    if (baseParent.isInitiallyExpanded()) {
      flatIndex += baseParent.getChildList().size();
    }
  }
}

@Test
public void notifyParentDataSetChangedWithoutExpansionPreservationAllCollapsed() {
  mExpandableRecyclerAdapter.collapseAllParents();
  Parent<Object> movedParent = mBaseParents.remove(0);
  mBaseParents.add(movedParent);
  Parent<Object> newParent = generateParent(true, 1);
  mBaseParents.add(3, newParent);
  mExpandableRecyclerAdapter.notifyParentDataSetChanged(false);
  verify(mDataObserver).onChanged();
  assertEquals(27, mExpandableRecyclerAdapter.getItemCount());
  verifyParentItemsMatch(mBaseParents.get(0), false, 0);
  verifyParentItemsMatch(newParent, true, 6);
  verifyParentItemsMatch(mBaseParents.get(9), false, 22);
  verifyParentItemsMatch(mBaseParents.get(10), true, 23);
}

@Test
public void notifyParentDataSetWithoutExpansionPreservationChangedNoChanges() {
  assertEquals(25, mExpandableRecyclerAdapter.getItemCount());
  mExpandableRecyclerAdapter.notifyParentDataSetChanged(false);
  verify(mDataObserver).onChanged();
  assertEquals(25, mExpandableRecyclerAdapter.getItemCount());
  int flatIndex = 0;
  for (Parent<Object> baseParent : mBaseParents) {
    verifyParentItemsMatch(baseParent, baseParent.isInitiallyExpanded(), flatIndex);
    flatIndex++;
    if (baseParent.isInitiallyExpanded()) {
      flatIndex += baseParent.getChildList().size();
    }
  }
}

@Override public void onChanged()
{
 super.onChanged();
 initIndex(adapter);
}

@Override
public void onChanged() {
  super.onChanged();
  notifyDataSetChanged();
}

@Override
public void onChanged() {
  super.onChanged();
  reset();
}

@Override
public void onChanged() {
  super.onChanged();
  reset();
}

@Override
public void setAdapter(Adapter adapter) {
  if (mWrapAdapter != null && mDataObserver != null && isRegisterDataObserver) {
    mWrapAdapter.getInnerAdapter().unregisterAdapterDataObserver(mDataObserver);
  }
  mWrapAdapter = (LRecyclerViewAdapter) adapter;
  super.setAdapter(mWrapAdapter);
  mWrapAdapter.getInnerAdapter().registerAdapterDataObserver(mDataObserver);
  mDataObserver.onChanged();
  isRegisterDataObserver = true;
  mWrapAdapter.setRefreshHeader(mRefreshHeader);
  //fix bug: https://github.com/jdsjlzx/LRecyclerView/issues/115
  if (mLoadMoreEnabled && mWrapAdapter.getFooterViewsCount()==0) {
    mWrapAdapter.addFooterView(mFootView);
  }
}

@Override
public void setAdapter(Adapter adapter) {
  if (mWrapAdapter != null && mDataObserver != null) {
    mWrapAdapter.getInnerAdapter().unregisterAdapterDataObserver(mDataObserver);
  }
  mWrapAdapter = (LuRecyclerViewAdapter) adapter;
  super.setAdapter(mWrapAdapter);
  mWrapAdapter.getInnerAdapter().registerAdapterDataObserver(mDataObserver);
  mDataObserver.onChanged();
  if (mLoadMoreEnabled && mWrapAdapter.getFooterViewsCount()==0) {
    mWrapAdapter.addFooterView(mFootView);
  }
}

  @Override
  public void onChanged()
  {
    super.onChanged();
    findSections();
  }
};

/**
 * set view when no content item
 *
 * @param emptyView visiable view when items is empty
 */
public void setEmptyView(View emptyView) {
  this.mEmptyView = emptyView;
  mDataObserver.onChanged();
}

/**
 * set view when no content item
 *
 * @param emptyView visiable view when items is empty
 */
public void setEmptyView(View emptyView) {
  this.mEmptyView = emptyView;
  mDataObserver.onChanged();
}

  @Override
  public void onChanged()
  {
    super.onChanged();
    checkIfEmpty();
  }
};

@Override
public void onChanged() {
  super.onChanged();
  notifyDataSetChanged();
}

@Override
public void onChanged() {
  super.onChanged();
  update();
}

@Test
public void shouldNotifyChangeOnAdditionalObservablesUpdateWhenObservingAndObserved() {
 repositoryAdapter.startObserving();
 repositoryAdapter.registerAdapterDataObserver(observer);
 runUiThreadTasksIncludingDelayedTasks();
 verify(observer, never()).onChanged();
 repositoryAdapter.getItemCount(); // usage before event
 updateDispatcher.update();
 runUiThreadTasksIncludingDelayedTasks();
 repositoryAdapter.stopObserving();
 verify(observer).onChanged();
}

@Test
public void shouldNotifyChangeOnStartObservingAfterUsage() {
 repositoryAdapter.registerAdapterDataObserver(observer);
 repositoryAdapter.getItemCount(); // "usage".
 // Because the adapter is not observing any data change, after the usage, it doesn't know of any
 // change of data, so for extra guarantee, it'll notify change as soon as it starts observing.
 repositoryAdapter.startObserving();
 runUiThreadTasksIncludingDelayedTasks();
 repositoryAdapter.stopObserving();
 verify(observer).onChanged();
}