내가 NetworkBoundResource & 페이징 해방은 서로 관련이없는 결론에 도달했다 :
여기
@Query("SELECT * FROM items ORDER BY id DESC")
LivePagedListProvider<Integer,MyItem> loadListPaginated();
내 NetworkBoundResource
구현 : 여기에
는 DAO이다 . 그들은 모두 당신이 내 다오
@Dao
public interface UserDao {
@Insert(onConflict = OnConflictStrategy.REPLACE)
void insert(User... user);
@Insert(onConflict = OnConflictStrategy.REPLACE)
void insert(List<User> users);
@Query("Select * from User ")
public abstract DataSource.Factory<Integer,User> getList();
}
2.then를 데이터 소스 를 사용할 필요가 DB를 호출 라이브러리에 대해 Google에 의해 지역에서 https://developer.android.com/topic/libraries/architecture/paging.html
1. 플로우 데이터를로드를 줄 기사에 따라 경찰이 자신의 기능
이 우리가 필요로하는 네트워크에서 데이터를 요청하는 것은 BoundaryCallback 클래스를 LivePagedListBuilder와 함께 구현한다.
public class UserBoundaryCallback extends PagedList.BoundaryCallback<User> {
public static final String TAG = "ItemKeyedUserDataSource";
GitHubService gitHubService;
AppExecutors executors;
private MutableLiveData networkState;
private MutableLiveData initialLoading;
public UserBoundaryCallback(AppExecutors executors) {
super();
gitHubService = GitHubApi.createGitHubService();
this.executors = executors;
networkState = new MutableLiveData();
initialLoading = new MutableLiveData();
}
public MutableLiveData getNetworkState() {
return networkState;
}
public MutableLiveData getInitialLoading() {
return initialLoading;
}
@Override
public void onZeroItemsLoaded() {
//super.onZeroItemsLoaded();
fetchFromNetwork(null);
}
@Override
public void onItemAtFrontLoaded(@NonNull User itemAtFront) {
//super.onItemAtFrontLoaded(itemAtFront);
}
@Override
public void onItemAtEndLoaded(@NonNull User itemAtEnd) {
// super.onItemAtEndLoaded(itemAtEnd);
fetchFromNetwork(itemAtEnd);
}
public void fetchFromNetwork(User user) {
if(user==null) {
user = new User();
user.userId = 1;
}
networkState.postValue(NetworkState.LOADING);
gitHubService.getUser(user.userId,20).enqueue(new Callback<List<User>>() {
@Override
public void onResponse(Call<List<User>> call, Response<List<User>> response) {
executors.diskIO().execute(()->{
if(response.body()!=null)
userDao.insert(response.body());
networkState.postValue(NetworkState.LOADED);
});
}
@Override
public void onFailure(Call<List<User>> call, Throwable t) {
String errorMessage;
errorMessage = t.getMessage();
if (t == null) {
errorMessage = "unknown error";
}
Log.d(TAG,errorMessage);
networkState.postValue(new NetworkState(Status.FAILED, errorMessage));
}
});
}
}
3.My VM 코드이 콜백의 각 항목이 인덱스/오프셋 포함되어 있다고 가정
public class UserViewModel extends ViewModel {
public LiveData<PagedList<User>> userList;
public LiveData<NetworkState> networkState;
AppExecutors executor;
UserBoundaryCallback userBoundaryCallback;
public UserViewModel() {
executor = new AppExecutors();
}
public void init(UserDao userDao)
{
PagedList.Config pagedListConfig =
(new PagedList.Config.Builder()).setEnablePlaceholders(true)
.setPrefetchDistance(10)
.setPageSize(20).build();
userBoundaryCallback = new UserBoundaryCallback(executor);
networkState = userBoundaryCallback.getNetworkState();
userList = (new LivePagedListBuilder(userDao.getList(), pagedListConfig).setBoundaryCallback(userBoundaryCallback))
.build();
}
}