Я использую Room Database
с LiveData
, но моя локальная база данных обновляется слишком быстро в соответствии с нашими требованиями, и в то же время мне приходится перезагружать мое представление о переработчике. Вместо вызова notifyDataSetChanged()
для адаптера, япопытка использовать DiffUtil
, но происходит сбой или перезагрузка неправильно, это неясно.Я следую этому уроку: Учебники Ссылка здесь
MyAdapter:
public class SwitchGridAdapter extends RecyclerView.Adapter<SwitchGridAdapter.ViewHolder> {
private List<Object> allItemsList;
private LayoutInflater mInflater;
private OnItemClickListener mClickListener;
private Context context;
private Queue<List<Object>> pendingUpdates =
new ArrayDeque<>();
// data is passed into the constructor
public SwitchGridAdapter(Context context,List<Appliance> applianceList,List<ZmoteRemote> zmoteRemoteList) {
this.mInflater = LayoutInflater.from(context);
this.context = context;
allItemsList = new ArrayList<>();
if (applianceList!=null) allItemsList.addAll(applianceList);
if (zmoteRemoteList!=null)allItemsList.addAll(zmoteRemoteList);
}
// inflates the cell layout from xml when needed
@Override
public ViewHolder onCreateViewHolder(ViewGroup parent, int viewType) {
View view = mInflater.inflate(R .layout.switch_grid_item, parent, false);
return new ViewHolder(view);
}
// binds the data to the textview in each cell
@Override
public void onBindViewHolder(ViewHolder holder, int position) {
// Doing some update with UI Elements
}
// total number of cells
@Override
public int getItemCount() {
return allItemsList.size();
}
// stores and recycles views as they are scrolled off screen
public class ViewHolder extends RecyclerView.ViewHolder implements View.OnClickListener,View.OnLongClickListener {
TextView myTextView;
ImageView imgSwitch;
ViewHolder(View itemView) {
super(itemView);
myTextView = (TextView) itemView.findViewById(R.id.txtSwitchName);
imgSwitch = (ImageView) itemView.findViewById(R.id.imgSwitchStatus);
itemView.setOnClickListener(this);
itemView.setOnLongClickListener(this);
}
@Override
public void onClick(View view) {
// handling click
}
@Override
public boolean onLongClick(View view) {
return true;
}
// convenience method for getting data at click position
Object getItem(int id) {
return allItemsList.get(id);
}
// allows clicks events to be caught
public void setClickListener(OnItemClickListener itemClickListener) {
this.mClickListener = itemClickListener;
}
// parent activity will implement this method to respond to click events
public interface OnItemClickListener {
void onItemClick(View view, int position);
void onItemLongPressListner(View view, int position);
}
// ✅✅✅✅✅✅✅✅✅✅✅✅✅✅✅✅✅✅✅✅✅
// From This Line Reloading with Diff Util is Done .
//✅✅✅✅✅✅✅✅✅✅✅✅✅✅✅✅✅✅✅✅✅
public void setApplianceList( List<Appliance> applianceList,List<ZmoteRemote> zmoteRemoteList)
{
if (allItemsList == null)
allItemsList = new ArrayList<>();
List<Object> newAppliances = new ArrayList<>();
if (applianceList!=null) newAppliances.addAll(applianceList);
updateItems(newAppliances);
}
// when new data becomes available
public void updateItems(final List<Object> newItems) {
pendingUpdates.add(newItems);
if (pendingUpdates.size() > 1) {
return;
}
updateItemsInternal(newItems);
}
// This method does the heavy lifting of
// pushing the work to the background thread
void updateItemsInternal(final List<Object> newItems) {
final List<Object> oldItems = new ArrayList<>(this.allItemsList);
final Handler handler = new Handler();
new Thread(new Runnable() {
@Override
public void run() {
final DiffUtil.DiffResult diffResult =
DiffUtil.calculateDiff(new DiffUtilHelper(oldItems, newItems));
handler.post(new Runnable() {
@Override
public void run() {
applyDiffResult(newItems, diffResult);
}
});
}
}).start();
}
// This method is called when the background work is done
protected void applyDiffResult(List<Object> newItems,
DiffUtil.DiffResult diffResult) {
dispatchUpdates(newItems, diffResult);
}
// This method does the work of actually updating
// the backing data and notifying the adapter
protected void dispatchUpdates(List<Object> newItems,
DiffUtil.DiffResult diffResult) {
// ❌❌❌❌❌❌ Next Line is Crashing the app ❌❌❌❌❌
pendingUpdates.remove();
dispatchUpdates(newItems, diffResult);
if (pendingUpdates.size() > 0) {
updateItemsInternal(pendingUpdates.peek());
}
}
}
Наблюдение LiveData
public void setUpAppliancesListLiveData()
{
if (applianceObserver!=null)
{
applianceObserver = null;
}
Log.e("Appliance Fetch","RoomName:"+this.roomName);
applianceObserver = new Observer<List<Appliance>>() {
@Override
public void onChanged(@Nullable List<Appliance> applianceEntities) {
// Log.e("Appliance Result","Appliance List \n\n:"+applianceEntities.toString());
new Thread(new Runnable() {
@Override
public void run() {
List<Appliance> applianceListTemp = applianceEntities;
zmoteRemoteList = new ArrayList<>(); //appDelegate.getDatabase().zmoteRemoteDao().getRemoteList(roomName);
// Sort according to name
Collections.sort(applianceListTemp, new Comparator<Appliance>() {
@Override
public int compare(Appliance item, Appliance t1) {
String s1 = item.getSwitchName();
String s2 = t1.getSwitchName();
return s1.compareToIgnoreCase(s2);
}
});
if(getActivity()!=null) {
getActivity().runOnUiThread(new Runnable() {
@Override
public void run() {
applianceList = applianceListTemp;
mRecyclerView.getRecycledViewPool().clear();
adapter.setApplianceList(applianceList,zmoteRemoteList);
}
});
}
}
}).start();
}
};
appDelegate.getDatabase().applianceDao().getApplinaceListByRoomName(this.roomName).observe(this, applianceObserver);
}