伙计们请不要将此问题视为重复，因为我在我的应用中找不到任何简单或简单的域实现。我正在创建一个聊天应用程序，我想要做的是让用户能够访问和阅读他收到的早期消息，即使没有互联网连接。
简而言之，我希望我的应用程序在没有互联网连接的情况下仍可访问，但我发现很难做到这一点，因为我是本地数据存储的新手。
以下是我的细读代码：
片段
public class ChatFragment extends Fragment {
public RecyclerView mChatsList;
public View mView;
public List<ChatsModel> mChatsModel;
public ChatsAdapter mChatsAdapter;
private Realm realm;
public ChatFragment() {
// Required empty public constructor
}
@Override
public View onCreateView(LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState) {
// Inflate the layout for this fragment
mView = inflater.inflate(R.layout.fragment_chat, container, false);
((AppCompatActivity) getActivity()).getSupportActionBar().setShowHideAnimationEnabled(true);
initUI();
realm = Realm.getDefaultInstance();
return mView;
}
//Method and views initializer
public void initUI() {
mChatsList = (RecyclerView) mView.findViewById(R.id.chatsList);
LinearLayoutManager layoutManager = new LinearLayoutManager(getActivity());
mChatsModel = new ArrayList<ChatsModel>();
mChatsAdapter = new ChatsAdapter(getActivity(), mChatsModel);
mChatsList.setLayoutManager(layoutManager);
mChatsList.setHasFixedSize(true);
mChatsAdapter.notifyDataSetChanged();
mChatsList.setAdapter(mChatsAdapter);
RecyclerView.ItemAnimator itemAnimator = new DefaultItemAnimator();
itemAnimator.setAddDuration(1000);
itemAnimator.setRemoveDuration(1000);
mChatsList.setItemAnimator(itemAnimator);
prepareItems();
Realm realm = Realm.getInstance(getActivity());
realm.executeTransaction(new Realm.Transaction() {
@Override
public void execute(Realm realm) {
ChatsModel chat = realm.createObject(ChatsModel.class);
chat.setUsername("username");
chat.setDate("date");
chat.setPicture("Picture");
}
}, new Realm.Transaction.Callback() {
@Override
public void onSuccess() {
Main.Mess(getString(R.string.real_sucess));
}
@Override
public void onError(Exception e) {
Main.Mess(getString(R.string.real_error));
}
});
}
// This is a simple method to add items to our recyclerview
private void prepareItems() {
Rests mRests = RestService.createService(Rests.class, Session.getToken(getActivity()));
mRests.suggest(new Callback<List<ChatsModel>>() {
@Override
public void success(List<ChatsModel> mChatsModel, Response response) {
RealmList<ChatsModel> mChatsModel2 = new RealmList<ChatsModel>();
mChatsAdapter.setUsers(mChatsModel);
}
@Override
public void failure(RetrofitError error) {
Main.Mess(getString(R.string.server_error));
}
});
}
}
我的适配器
public class ChatsAdapter extends RecyclerView.Adapter<RecyclerView.ViewHolder> {
private static final int TYPE_HEADER = 0;
private static final int TYPE_ITEM = 1;
private RealmList<ChatsModel> mChatsModel;
private Realm realm;
public Activity mActivity;
public ChatsAdapter(@NonNull Activity mActivity) {
super();
this.mChatsModel = new RealmList<>();
this.realm = Realm.getDefaultInstance();
this.mActivity = mActivity;
}
@Override
public RecyclerView.ViewHolder onCreateViewHolder (ViewGroup parent, int viewType) {
if(viewType == TYPE_HEADER) {
View v = LayoutInflater.from (parent.getContext ()).inflate (R.layout.ad_view, parent, false);
return new HeaderViewHolder (v);
} else if(viewType == TYPE_ITEM) {
View v = LayoutInflater.from (parent.getContext ()).inflate (R.layout.chats_item, parent, false);
return new ContentViewHolder (v);
}
return null;
}
private ChatsModel getItem (int position) {
return mChatsModel.get (position);
}
@Override
public void onBindViewHolder (RecyclerView.ViewHolder holder, final int position) {
if (holder instanceof HeaderViewHolder) {
HeaderViewHolder headerHolder = (HeaderViewHolder) holder;
if (Constant.SHOW_ADS) {
headerHolder.mAdView.setVisibility(View.VISIBLE);
AdRequest adRequest = new AdRequest.Builder().build();
headerHolder.mAdView.loadAd(adRequest);
} else {
headerHolder.mAdView.setVisibility(View.GONE);
}
}else if (holder instanceof ContentViewHolder) {
ContentViewHolder contentHolder = (ContentViewHolder) holder;
ChatsModel item = getItem (position - 1);
contentHolder.username.setText(item.getUsername());
contentHolder.date.setText(item.getDate());
contentHolder.message.setText(item.getMessage());
Picasso.with(mActivity.getApplicationContext())
.load(Constant.IMAGE_SMALL + item.getPicture())
.error(R.drawable.user)
.into(contentHolder.picture);
}
}
@Override
public int getItemViewType (int position) {
if(isPositionHeader (position)) {
return TYPE_HEADER;
}
return TYPE_ITEM;
}
public void setUsers(RealmList<ChatsModel> friendsItems) {
this.mChatsModel = friendsItems;
notifyDataSetChanged();
}
public List<ChatsModel> getSuggestionsModel() {
return this.mChatsModel;
}
private boolean isPositionHeader (int position) {
return position == 0;
}
@Override
public int getItemCount () {
return mChatsModel.size ();
}
public class HeaderViewHolder extends RecyclerView.ViewHolder {
public AdView mAdView;
public HeaderViewHolder(View itemView) {
super(itemView);
mAdView = (AdView) itemView.findViewById(R.id.ad_view);
}
}
public class ContentViewHolder extends RecyclerView.ViewHolder {
public ImageView picture;
public TextView username, date, message;
public LinearLayout chat;
public ContentViewHolder(View v) {
super(v);
picture = (ImageView) v.findViewById(R.id.picture);
username = (TextView) v.findViewById(R.id.username);
date = (TextView) v.findViewById(R.id.date);
message = (TextView) v.findViewById(R.id.message);
}
}
}
好的，那就是我的代码。
答案 0 :(得分：1)
您可以使用 SQLite数据库离线存储聊天记录，观看this YouTube tutorial，这种情况很广泛，但您可以跳过某些部分。
下载/发送聊天消息时，将它们镜像到数据库中并使用数据库和仅限数据库作为RecyclerView的数据源（永远不要让任何在线数据直接进入列表，始终首先将它存储在数据库中，并在将其放入布局时从数据库中读取它。）
为了提高性能，您可以在内存中存储相关的聊天消息（例如，在单独的ArrayList中）而不是始终从您刚写入的数据库中读取数据
答案 1 :(得分：0)
正如@geisshirt在评论中所说，使用RealmRecyclerViewAdapter代替RecyclerView.Adapter。关于你可以在official doc找到的android领域适配器的几个词。
另外，您可以查看RealmRecyclerViewAdapter example