我在 Android 中遇到了Java class的问题，在此我想为某些Fragment创建一个 PaginationAdapter ，然后才尝试这样做
SickFragmentToAll.java
adapter = new PaginationAdapterAll(getActivity(), fragment);
SickFragmentToCanceled
adapter = new PaginationAdapterCanceled(getActivity(), fragment);
PaginationAdapterAll
public PaginationAdapter(Context context, SickFragmentToAll fragment) {
this.context = context;
this.mCallback = (PaginationAdapterCallback) fragment;
results = new ArrayList<>();
}
PaginationAdapterCanceled
public PaginationAdapter(Context context, SickFragmentToCanceled fragment) {
this.context = context;
this.mCallback = (PaginationAdapterCallback) fragment;
results = new ArrayList<>();
}
它起作用，但效率不高，因为每个Fragment都有1个不同的PaginationAdapter。如何让 PaginationAdapter 动态 ？
使它看起来像这样
SickFragmentToAll
adapter = new PaginationAdapter(getActivity(), fragment);
SickFragmentToCanceled
adapter = new PaginationAdapter(getActivity(), fragment);
PaginationAdapter **
public PaginationAdapter(Context context, Fragment fragment) {
this.context = context;
this.mCallback = (PaginationAdapterCallback) fragment; // The problem here, I want to make it dynamically
results = new ArrayList<>();
}
我尝试使用Fragment fragment，但它不起作用
[更新]完整代码
SickFragmentToAll.java
@SuppressWarnings("deprecation")
public class SickFragmentToAll extends Fragment implements PaginationAdapterCallback {
private static final String TAG = "FRAGMENT_ALL";
PaginationAdapter adapter;
LinearLayoutManager linearLayoutManager;
RecyclerView rv;
ProgressBar progressBar;
LinearLayout errorLayout;
Button btnRetry;
TextView txtError;
View RootView;
private static int PAGE_START = 1;
private boolean isLoading = false;
private boolean isLastPage = false;
private int TOTAL_PAGES = 2;
private int currentPage = PAGE_START;
private MovieService movieService;
private SickFragmentToAll fragment;
public SickFragmentToAll(){
};
@Override
public View onCreateView(LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState) {
RootView = inflater.inflate(R.layout.activity_main, container, false);
super.onCreate(savedInstanceState);
rv = (RecyclerView) RootView.findViewById(R.id.main_recycler);
progressBar = (ProgressBar) RootView.findViewById(R.id.main_progress);
errorLayout = (LinearLayout) RootView.findViewById(R.id.error_layout);
btnRetry = (Button) RootView.findViewById(R.id.error_btn_retry);
txtError = (TextView) RootView.findViewById(R.id.error_txt_cause);
adapter = new PaginationAdapter(getActivity(), fragment);
linearLayoutManager = new LinearLayoutManager(getActivity(), LinearLayoutManager.VERTICAL, false);
rv.setLayoutManager(linearLayoutManager);
rv.setItemAnimator(new DefaultItemAnimator());
rv.setAdapter(adapter);
rv.addOnScrollListener(new PaginationScrollListener(linearLayoutManager) {
@Override
protected void loadMoreItems() {
isLoading = true;
currentPage += 1;
loadNextPage();
}
@Override
public int getTotalPageCount() {
return TOTAL_PAGES;
}
@Override
public boolean isLastPage() {
return isLastPage;
}
@Override
public boolean isLoading() {
return isLoading;
}
});
movieService = MovieApi.getClient().create(MovieService.class);
loadFirstPage();
btnRetry.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View view) {
loadFirstPage();
}
});
return RootView;
}
private void loadFirstPage() {
Log.d(TAG, "loadFirstPage: ");
// To ensure list is visible when retry button in error view is clicked
hideErrorView();
callRootApi().enqueue(new Callback<Root>() {
@Override
public void onResponse(Call<Root> call, Response<Root> response) {
// Got data. Send it to adapter
hideErrorView();
List<Result> results = fetchResults(response);
progressBar.setVisibility(View.GONE);
adapter.addAll(results);
if (currentPage <= TOTAL_PAGES)
adapter.addLoadingFooter();
else
isLastPage = true;
}
@Override
public void onFailure(Call<Root> call, Throwable t) {
t.printStackTrace();
showErrorView(t);
}
});
}
private List<Result> fetchResults(Response<Root> response) {
Root root = response.body();
return root.getResult();
}
private void loadNextPage() {
Log.d(TAG, "loadNextPage: " + currentPage);
callRootApi().enqueue(new Callback<Root>() {
@Override
public void onResponse(Call<Root> call, Response<Root> response) {
adapter.removeLoadingFooter();
isLoading = false;
List<Result> results = fetchResults(response);
adapter.addAll(results);
if (currentPage != TOTAL_PAGES)
adapter.addLoadingFooter();
else
isLastPage = true;
}
@Override
public void onFailure(Call<Root> call, Throwable t) {
t.printStackTrace();
adapter.showRetry(true, fetchErrorMessage(t));
}
});
}
private Call<Root> callRootApi() {
return movieService.getRoot(
"00.15.09.001",
"S",
1,
1,
currentPage
);
}
@Override
public void retryPageLoad() {
loadNextPage();
}
private void showErrorView(Throwable throwable) {
if (errorLayout.getVisibility() == View.GONE) {
errorLayout.setVisibility(View.VISIBLE);
progressBar.setVisibility(View.GONE);
txtError.setText(fetchErrorMessage(throwable));
}
}
private String fetchErrorMessage(Throwable throwable) {
String errorMsg = getResources().getString(R.string.error_msg_unknown);
if (!isNetworkConnected()) {
errorMsg = getResources().getString(R.string.error_msg_no_internet);
} else if (throwable instanceof TimeoutException) {
errorMsg = getResources().getString(R.string.error_msg_timeout);
}
return errorMsg;
}
private void hideErrorView() {
if (errorLayout.getVisibility() == View.VISIBLE) {
errorLayout.setVisibility(View.GONE);
progressBar.setVisibility(View.VISIBLE);
}
}
private boolean isNetworkConnected() {
ConnectivityManager cm = (ConnectivityManager) getActivity().getSystemService(Context.CONNECTIVITY_SERVICE);
return cm.getActiveNetworkInfo() != null;
}
}
PaginationAdapter.java
public class PaginationAdapter extends RecyclerView.Adapter<RecyclerView.ViewHolder> {
/* -------------------------------- View Types -------------------------------- */
private static final int ITEM = 0;
private static final int LOADING = 1;
private static final String BASE_URL_IMG = "empty";
private PaginationAdapterCallback mCallback;
private boolean isLoadingAdded = false;
private boolean retryPageLoad = false;
private String errorMessage;
private List<Result> results;
private Context context;
public PaginationAdapter(Context context, SickFragmentToAll fragment) {
this.context = context;
this.mCallback = (PaginationAdapterCallback) fragment; // The problem here
results = new ArrayList<>();
}
public List<Result> getData() {
return results;
}
public void setData(List<Result> results) {
this.results = results;
}
@Override
public RecyclerView.ViewHolder onCreateViewHolder(ViewGroup parent, int viewType) {
RecyclerView.ViewHolder viewHolder = null;
LayoutInflater inflater = LayoutInflater.from(parent.getContext());
switch (viewType) {
case ITEM:
View viewItem = inflater.inflate(R.layout.item_list, parent, false);
viewHolder = new MainItem(viewItem);
break;
case LOADING:
View viewLoading = inflater.inflate(R.layout.item_progress, parent, false);
viewHolder = new LoadingStatus(viewLoading);
break;
}
return viewHolder;
}
@Override
public void onBindViewHolder(RecyclerView.ViewHolder holder, int position) {
Result result = results.get(position); // Movie
switch (getItemViewType(position)) {
case ITEM:
final MainItem Item = (MainItem) holder;
Item.ReqNo.setText(result.getReqNo());
/* -------------------------------- Load Photo -------------------------------- */
loadImage(result.getPhoto())
.listener(new RequestListener<String, GlideDrawable>() {
@Override
public boolean onException(Exception e, String model, Target<GlideDrawable> target, boolean isFirstResource) {
// TODO: 08/11/16 handle failure
Item.proggressBar.setVisibility(View.GONE);
return false;
}
@Override
public boolean onResourceReady(GlideDrawable resource, String model, Target<GlideDrawable> target, boolean isFromMemoryCache, boolean isFirstResource) {
/* -------------------------------- Image ready, Hide Proggress Now -------------------------------- */
Item.proggressBar.setVisibility(View.GONE);
return false; // return false if you want Glide to handle everything else.
}
})
.into(Item.Photo);
break;
case LOADING:
LoadingStatus LoadingStatus = (LoadingStatus) holder;
if (retryPageLoad) {
LoadingStatus.errorLayout.setVisibility(View.VISIBLE);
LoadingStatus.proggressBar.setVisibility(View.GONE);
LoadingStatus.errorText.setText(
errorMessage != null ?
errorMessage :
context.getString(R.string.error_msg_unknown));
} else {
LoadingStatus.errorLayout.setVisibility(View.GONE);
LoadingStatus.proggressBar.setVisibility(View.VISIBLE);
}
break;
}
}
@Override
public int getItemCount() {
return results == null ? 0 : results.size();
}
@Override
public int getItemViewType(int position) {
return (position == results.size() - 1 && isLoadingAdded) ? LOADING : ITEM;
}
/* -------------------------------- Helpers - bind Views -------------------------------- */
private DrawableRequestBuilder<String> loadImage(@NonNull String posterPath) {
return Glide
.with(context)
.load(BASE_URL_IMG + posterPath)
.diskCacheStrategy(DiskCacheStrategy.ALL) // cache both original & resized image
.centerCrop()
.crossFade();
}
/* -------------------------------- Helpers - Pagination -------------------------------- */
public void add(Result r) {
results.add(r);
notifyItemInserted(results.size() - 1);
}
public void addAll(List<Result> moveResults) {
for (Result result : moveResults) {
add(result);
}
}
public void remove(Result r) {
int position = results.indexOf(r);
if (position > -1) {
results.remove(position);
notifyItemRemoved(position);
}
}
public void clear() {
isLoadingAdded = false;
while (getItemCount() > 0) {
remove(getItem(0));
}
}
public boolean isEmpty() {
return getItemCount() == 0;
}
public void addLoadingFooter() {
isLoadingAdded = true;
add(new Result());
}
public void removeLoadingFooter() {
isLoadingAdded = false;
int position = results.size() - 1;
Result result = getItem(position);
if (result != null) {
results.remove(position);
notifyItemRemoved(position);
}
}
public Result getItem(int position) {
return results.get(position);
}
/**
* Displays Pagination retry footer view along with appropriate errorMsg
*
* @param show
* @param errorMsg to display if page load fails
*/
public void showRetry(boolean show, @Nullable String errorMsg) {
retryPageLoad = show;
notifyItemChanged(results.size() - 1);
if (errorMsg != null) this.errorMessage = errorMsg;
}
/* -------------------------------- View Holders -------------------------------- */
protected class MainItem extends RecyclerView.ViewHolder {
private TextView ReqNo;
private TextView Method;
private TextView Name;
private TextView Branch;
private TextView Departement_Position;
private TextView Type;
private TextView Description;
private TextView Status;
private TextView Date;
private TextView LeaveGroup;
private TextView Flag;
private TextView Code_Status;
private ImageView Photo;
private ProgressBar proggressBar;
public MainItem(View itemView) {
super(itemView);
ReqNo = (TextView) itemView.findViewById(R.id.ReqNo);
Method = (TextView) itemView.findViewById(R.id.Method);
Name = (TextView) itemView.findViewById(R.id.Name);
Branch = (TextView) itemView.findViewById(R.id.Departement_Position);
Type = (TextView) itemView.findViewById(R.id.Type);
Description = (TextView) itemView.findViewById(R.id.Description);
Status = (TextView) itemView.findViewById(R.id.Status);
Date = (TextView) itemView.findViewById(R.id.Date);
LeaveGroup = (TextView) itemView.findViewById(R.id.LeaveGroup);
Flag = (TextView) itemView.findViewById(R.id.Flag);
Code_Status = (TextView) itemView.findViewById(R.id.Code_Status);
Photo = (ImageView) itemView.findViewById(R.id.movie_poster);
proggressBar = (ProgressBar) itemView.findViewById(R.id.movie_progress);
}
}
protected class LoadingStatus extends RecyclerView.ViewHolder implements View.OnClickListener {
private ProgressBar proggressBar;
private ImageButton retryButton;
private TextView errorText;
private LinearLayout errorLayout;
public LoadingStatus(View itemView) {
super(itemView);
proggressBar = (ProgressBar) itemView.findViewById(R.id.loadmore_progress);
retryButton = (ImageButton) itemView.findViewById(R.id.loadmore_retry);
errorText = (TextView) itemView.findViewById(R.id.loadmore_errortxt);
errorLayout = (LinearLayout) itemView.findViewById(R.id.loadmore_errorlayout);
errorText.setOnClickListener(this);
errorLayout.setOnClickListener(this);
}
@Override
public void onClick(View view) {
switch (view.getId()) {
case R.id.loadmore_retry:
case R.id.loadmore_errorlayout:
showRetry(false, null);
mCallback.retryPageLoad();
break;
}
}
}
}
我想让PaginationAdapter充满活力，。知道怎么去达吗？
答案 0 :(得分：1)
希望这会对你有所帮助。
让我们说PaginationAdapterCallback就像这样
public interface PaginationAdapterCallback{
void loadNextPage();
void retryPageLoad();
void loadFirstPage();
}
创建一个父类SickFragment实现PaginationAdapterCallback
public abstract SickFragment implements PaginationAdapterCallback{
}
制作儿童课程。
SickFragmentToCanceled extends SickFragment
SickFragmentToAll extends SickFragment
现在使用以下构造函数
创建PaginationAdapter
PaginationAdapter(Context context, SickFragment fragment)
您将找到所需的所有方法。
答案 1 :(得分：0)
我已经体验过它并将其替换为thisContext
尝试替换
adapter = new PaginationAdapter(getActivity(), fragment);
到
thisContext = container.getContext();
adapter = new PaginationAdapter(thisContext);
首先在班级thisContext
Context thisContext
我希望它有效
答案 2 :(得分：0)
我尝试替换 adapter = new PaginationAdapter(getActivity(), fragment);到adapter = new PaginationAdapter(getActivity());这对我有用，你试过替换吗？