您好，我试图在我的 recylerview 中包含分页，但不知道为什么它不适用于 staggeredgrid 布局 这是我正在寻找的问题，因为答案是针对线性布局管理器的，我得到了如何在 staggerdgrid 布局管理器中实现分页的答案， 这是我实施后在我的代码中尝试了图像未加载
ScreenShot // 我现在得到什么的 ss
短代码
int pastVisiblesItems, visibleItemCount, totalItemCount;
int visibleThreshold = 1;
ContentLoadingProgressBar contentLoadingProgressBar;
private boolean isLoading = false;
contentLoadingProgressBar = view.findViewById(R.id.contentLoadingProgressBar);
final StaggeredGridLayoutManager linearLayoutManager = (StaggeredGridLayoutManager) postRecyclerView.getLayoutManager();
postRecyclerView.addOnScrollListener(new RecyclerView.OnScrollListener() {
@Override
public void onScrolled(@NonNull RecyclerView recyclerView, int dx, int dy) {
super.onScrolled(recyclerView, dx, dy);
int[] lastVisibleItemPositions = Objects.requireNonNull(linearLayoutManager).findLastVisibleItemPositions(null);
int lastVisibleItem = getLastVisibleItem(lastVisibleItemPositions);
int totalItemCount = linearLayoutManager.getItemCount();
if (!isLoading && totalItemCount <= (lastVisibleItem + visibleThreshold)) {
getData();
shimmerFrameLayout.startShimmer();
isLoading = true;
}
}
});
public int getLastVisibleItem(int[] lastVisibleItemPositions) {
int maxSize = 0;
for (int i = 0; i < lastVisibleItemPositions.length; i++) {
if (i == 0) {
maxSize = lastVisibleItemPositions[i];
} else if (lastVisibleItemPositions[i] > maxSize) {
maxSize = lastVisibleItemPositions[i];
}
}
return maxSize;
}
完整代码
public class Profile_Fragment extends Fragment implements PostAdapter.OnItemClickListener {
public static List<Upload> mUploads;
private final DatabaseReference databaseReference = FirebaseDatabase.getInstance().getReference("uploads");
PostAdapter postsAdapter;
ShimmerFrameLayout shimmerFrameLayout;
RecyclerView postRecyclerView;
Button editProfileButton;
CircleImageView profilePhoto;
ContentLoadingProgressBar contentLoadingProgressBar;
int visibleThreshold = 1;
private FirebaseStorage mStorage;
private ValueEventListener databaseEventListener;
private boolean isLoading = false;
@SuppressLint("SourceLockedOrientationActivity")
@Nullable
@Override
public View onCreateView(@NonNull LayoutInflater inflater, @Nullable ViewGroup container, @Nullable Bundle savedInstanceState) {
View view = inflater.inflate(R.layout.fragment_profile, container, false);
requireActivity().setRequestedOrientation(ActivityInfo.SCREEN_ORIENTATION_PORTRAIT);
ImageView accountSettings = view.findViewById(R.id.account_Settings);
RelativeLayout relativeLayout = view.findViewById(R.id.snipet_profile);
profilePhoto = relativeLayout.findViewById(R.id.circleImageView);
editProfileButton = relativeLayout.findViewById(R.id.edit_profile_button);
contentLoadingProgressBar = view.findViewById(R.id.contentLoadingProgressBar);
editProfileButton.setOnClickListener(v -> {
Fragment edit_profile = new Edit_Profile();
assert getFragmentManager() != null;
FragmentTransaction transaction = getFragmentManager().beginTransaction();
transaction.replace(R.id.fragment_container, edit_profile);
transaction.addToBackStack(null);
transaction.commit();
});
accountSettings.setOnClickListener(
v -> {
BottomSheet bottomSheet = new BottomSheet();
bottomSheet.show(requireActivity().getSupportFragmentManager(), bottomSheet.getTag());
}
);
postRecyclerView = view.findViewById(R.id.postRecyclerViewProfile);
shimmerFrameLayout = view.findViewById(R.id.shimmerEffect);
postRecyclerView.setLayoutManager(
new StaggeredGridLayoutManager(3, StaggeredGridLayoutManager.VERTICAL)
);
final StaggeredGridLayoutManager linearLayoutManager = (StaggeredGridLayoutManager) postRecyclerView.getLayoutManager();
postRecyclerView.addOnScrollListener(new RecyclerView.OnScrollListener() {
@Override
public void onScrolled(@NonNull RecyclerView recyclerView, int dx, int dy) {
super.onScrolled(recyclerView, dx, dy);
assert linearLayoutManager != null;
int[] lastVisibleItemPositions = linearLayoutManager.findLastVisibleItemPositions(null);
int lastVisibleItem = getLastVisibleItem(lastVisibleItemPositions);
int totalItemCount = linearLayoutManager.getItemCount();
if (!isLoading && totalItemCount <= (lastVisibleItem + visibleThreshold)) {
isLoading = true;
getData();
}
}
});
mUploads = new ArrayList<>();
postsAdapter = new PostAdapter(getContext(), mUploads);
postRecyclerView.setAdapter(postsAdapter);
postsAdapter.setOnItemClickListener(Profile_Fragment.this);
return view;
}
public int getLastVisibleItem(int[] lastVisibleItemPositions) {
int maxSize = 0;
for (int i = 0; i < lastVisibleItemPositions.length; i++) {
if (i == 0) {
maxSize = lastVisibleItemPositions[i];
} else if (lastVisibleItemPositions[i] > maxSize) {
maxSize = lastVisibleItemPositions[i];
}
}
return maxSize;
}
private void getData() {
contentLoadingProgressBar.setVisibility(View.VISIBLE);
mStorage = FirebaseStorage.getInstance();
databaseEventListener = databaseReference.addValueEventListener(new ValueEventListener() {
@Override
public void onDataChange(@NonNull DataSnapshot snapshot) {
if (snapshot.exists()) {
postRecyclerView.setVisibility(View.VISIBLE);
shimmerFrameLayout.stopShimmer();
shimmerFrameLayout.setVisibility(View.GONE);
contentLoadingProgressBar.setVisibility(View.GONE);
mUploads.clear();
for (DataSnapshot dataSnapshot : snapshot.getChildren()) {
Upload upload = dataSnapshot.getValue(Upload.class);
Objects.requireNonNull(upload).setmKey(dataSnapshot.getKey());
mUploads.add(upload);
}
}
//notify the adapter
postsAdapter.notifyDataSetChanged();
}
@Override
public void onCancelled(@NonNull DatabaseError error) {
}
});
}
@Override
public void onClick(View view) {
}
@Override
public void onItemClick(int position) {
}
@Override
public void onDeleteClick(int position) {
Upload selectedItem = mUploads.get(position);
String selectedKey = selectedItem.getmKey();
StorageReference imageRef = mStorage.getReferenceFromUrl(selectedItem.getmImageUrl());
imageRef.delete().addOnSuccessListener(aVoid -> {
databaseReference.child(selectedKey).removeValue();
Toast.makeText(getContext(), "Post Deleted", Toast.LENGTH_SHORT).show();
})
.addOnFailureListener(aVoid -> Toast.makeText(getContext(), "Failed", Toast.LENGTH_SHORT).show());
}
@Override
public void onDestroyView() {
super.onDestroyView();
databaseReference.removeEventListener(databaseEventListener);
}
}
更新 1
添加了 adapter.class
public class PostAdapter extends RecyclerView.Adapter<PostAdapter.PostViewHolder> {
public static List<Upload> mUploads;
public Context mcontext;
private OnItemClickListener mListener;
// ShimmerFrameLayout shimmerFrameLayout;
public PostAdapter(Context context, List<Upload> uploads) {
mUploads = uploads;
mcontext = context;
}
@NonNull
@Override
public PostViewHolder onCreateViewHolder(@NonNull ViewGroup parent, int viewType) {
View view;
LayoutInflater.from(mcontext).inflate(R.layout.post_item_container_profile, parent, false);
view = LayoutInflater.from(parent.getContext()).inflate(R.layout.post_item_container_profile, parent, false);
return new PostViewHolder(view);
}
@Override
public void onBindViewHolder(@NonNull PostViewHolder holder, int position) {
Upload uploadCurrent = mUploads.get(position);
Shimmer shimmer = new Shimmer.ColorHighlightBuilder()
.setBaseColor(Color.parseColor("#F3F3F3"))
.setBaseAlpha(1)
.setHighlightColor(Color.parseColor("#E7E7E7"))
.setHighlightAlpha(1)
.setDropoff(50)
.build();
ShimmerDrawable shimmerDrawable = new ShimmerDrawable();
shimmerDrawable.setShimmer(shimmer);
Glide.with(mcontext)
.load(uploadCurrent.getmImageUrl())
.diskCacheStrategy(DiskCacheStrategy.AUTOMATIC)
.placeholder(shimmerDrawable)
.centerCrop()
.fitCenter()
.into(holder.imageView);
}
@Override
public int getItemCount() {
return mUploads.size();
}
public void setOnItemClickListener(OnItemClickListener listener) {
mListener = listener;
}
public interface OnItemClickListener {
void onClick(View view);
void onItemClick(int position);
void onDeleteClick(int position);
}
public class PostViewHolder extends RecyclerView.ViewHolder implements View.OnClickListener,
View.OnCreateContextMenuListener, MenuItem.OnMenuItemClickListener {
ShapeableImageView imageView;
PostViewHolder(@NonNull View itemView) {
super(itemView);
imageView = itemView.findViewById(R.id.imagePost);
itemView.setOnClickListener(this);
itemView.setOnCreateContextMenuListener(this);
}
@Override
public void onClick(View v) {
if (mListener != null) {
int position = getAdapterPosition();
if (position != RecyclerView.NO_POSITION) {
mListener.onItemClick(position);
}
}
}
@Override
public void onCreateContextMenu(ContextMenu menu, View v, ContextMenu.ContextMenuInfo menuInfo) {
MenuItem delete = menu.add(Menu.NONE, 2, 2, "Delete");
delete.setOnMenuItemClickListener(this);
}
@Override
public boolean onMenuItemClick(MenuItem item) {
if (mListener != null) {
int position = getAdapterPosition();
if (position != RecyclerView.NO_POSITION) {
if (item.getItemId() == 2) {
mListener.onDeleteClick(position);
return true;
}
}
}
return false;
}
}
}