小贝子编程

如何获取文件 ID ?菲恢复分页



我正在使用Firebase Firestore Database，我正在尝试使用此堆栈溢出和链接对分页回收器数据的双重查询来加载数据

我的代码是供recycerview加载数据的

private void getNewFireData() {
final int limit = 3;
final int mmcurrentItem;
final int totalItem;
final int ScrolledItem;
mRecyclerView = rootView.findViewById(R.id.rv_post_list);
final LinearLayoutManager mManeger=new LinearLayoutManager(getActivity());
mRecyclerView.setLayoutManager(mManeger);
final List<Posts> list = new ArrayList<>();
final boolean[] isScrolling = {false};
final boolean[] isLastItemReached = {false};
final DocumentSnapshot lastVisible ;

FirebaseFirestore rootRef = FirebaseFirestore.getInstance();
final CollectionReference postRef = rootRef.collection("posts");
Query query = postRef.orderBy("datetime",
Query.Direction.DESCENDING).limit(limit);
query.get().addOnCompleteListener(new OnCompleteListener<QuerySnapshot>() {
@Override
public void onComplete(@NonNull Task<QuerySnapshot> task) {
if(task.isSuccessful()){
final DocumentSnapshot[] lastVisible = {task.getResult().getDocuments().get(task.getResult().size() - 1)};
for (DocumentSnapshot document : task.getResult()) {
Posts postModel = document.toObject(Posts.class);
list.add(postModel);
}
final Task<QuerySnapshot>[] mSnapy = new Task[]{task};
final NewPostAdapter mNewPostAdapter = new NewPostAdapter(list,getActivity()
, mSnapy[0]);
mRecyclerView.setAdapter(mNewPostAdapter);

mRecyclerView.addOnScrollListener(new RecyclerView.OnScrollListener() {
@Override
public void onScrollStateChanged(@NonNull RecyclerView recyclerView, int newState) {
super.onScrollStateChanged(recyclerView, newState);
if(newState==AbsListView.OnScrollListener.SCROLL_STATE_TOUCH_SCROLL){
isScrolling[0] =true;
}
}
@Override
public void onScrolled(@NonNull RecyclerView recyclerView, int dx, int dy) {
super.onScrolled(recyclerView, dx, dy);
LinearLayoutManager linearLayoutManager = ((LinearLayoutManager) recyclerView.getLayoutManager());
int firstVisibleItemPosition = linearLayoutManager.findFirstVisibleItemPosition();
int visibleItemCount = linearLayoutManager.getChildCount();
int totalItemCount = linearLayoutManager.getItemCount();


if (isScrolling[0] && (firstVisibleItemPosition + visibleItemCount == totalItemCount) && !isLastItemReached[0]) {
isScrolling[0] = false;
Query nextQuery = postRef.orderBy("datetime", Query.Direction.DESCENDING).startAfter(lastVisible[0]).limit(limit);
nextQuery.get().addOnCompleteListener(new OnCompleteListener<QuerySnapshot>() {
@Override
public void onComplete(@NonNull Task<QuerySnapshot> t) {
if (t.isSuccessful()) {
for (DocumentSnapshot d : t.getResult()) {
Posts productModel = d.toObject(Posts.class);
list.add(productModel);
mSnapy[0] =t;
}
mNewPostAdapter.notifyDataSetChanged();
lastVisible[0] = t.getResult().getDocuments().get(t.getResult().size() - 1);
if (t.getResult().size() < limit) {
isLastItemReached[0] = true;
}
}
}
});
}
}
});

}
}
});

}

视图持有人和适配器类为

public class NewPostAdapter extends RecyclerView.Adapter<NewPostAdapter.NewPostHolder> {
private List<Posts> list;
Context context;
Task<QuerySnapshot> task;
public NewPostAdapter(List<Posts> list, Context context, Task<QuerySnapshot> task) {
this.list = list;
this.context=context;
this.task=task;
}
@NonNull
@Override
public NewPostHolder onCreateViewHolder(@NonNull ViewGroup parent, int viewType) {
View view = LayoutInflater.from(parent.getContext()).inflate(R.layout.custum_home_post, parent, false);
return new NewPostHolder(view);
}
@Override
public void onBindViewHolder(@NonNull final NewPostHolder mHolder, final int position) {

mHolder.tvSendername.setText(list.get(position).getSendername());
mHolder.tvPostText.setText(list.get(position).getPosttext());
mHolder.tvServiceType.setText(list.get(position).getServicetype());
String datetime = list.get(position).getDatetime();
MyDateTime myDateTime = new MyDateTime();
String converteddatetime = myDateTime.getSaveTime(datetime);
mHolder.tvDatetime.setText(converteddatetime);

SharedPreferences prefs = context.getSharedPreferences("DholkaAppPref", Context.MODE_PRIVATE);
String mUserid = prefs.getString("userid", "Couldn't load userid");
final String postid=task.getResult().getDocuments().get(position).getId();

if (mUserid.equalsIgnoreCase("LNvc0acRiaPioaKVnXasjkjEeYE2")) {
if (list.get(position).getVerified().equalsIgnoreCase("no")) {
mHolder.llPostAproval.setVisibility(View.VISIBLE);
mHolder.btPostApprove.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View v) {
if (list.get(position).getVerified().equalsIgnoreCase("no")) {
PostApproval approval = new PostApproval(context, postid);
}
}
});
mHolder.btPostDelete.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View v) {
String imagename = list.get(position).getPhotourl();
if (imagename.equalsIgnoreCase("nourl")) {
DocumentReference mPostref = FirebaseFirestore.getInstance().collection("posts").
document(postid);
mPostref.delete();
} else {
StorageReference mStorageref = FirebaseStorage.getInstance().getReferenceFromUrl(imagename);
mStorageref.delete();
DocumentReference mPostref = FirebaseFirestore.getInstance().collection("posts").
document(postid);
mPostref.delete();
}
}
});
} else {
mHolder.llPostAproval.setVisibility(View.GONE);
mHolder.cardHome.setVisibility(View.VISIBLE);
}
} else {
mHolder.llPostAproval.setVisibility(View.GONE);
}
if (mUserid.equalsIgnoreCase("LNvc0acRiaPioaKVnXasjkjEeYE2")) {

mHolder.cardHome.setVisibility(View.VISIBLE);
mHolder.cardHome.setOnLongClickListener(new View.OnLongClickListener() {
@Override
public boolean onLongClick(View v) {
final AlertDialog.Builder builder = new AlertDialog.Builder(context);
AlertDialog dialog;
builder.setMessage(R.string.dialog_delete_post)
.setPositiveButton(R.string.yes, new DialogInterface.OnClickListener() {
public void onClick(DialogInterface dialog, int id) {
// FIRE ZE MISSILES!
String imagename = list.get(position).getPhotourl();
if (imagename.equalsIgnoreCase("nourl")) {
DocumentReference mPostref = FirebaseFirestore.getInstance().collection("posts").
document(postid);
mPostref.delete();
} else {
StorageReference mStorageref = FirebaseStorage.getInstance().getReferenceFromUrl(imagename);
mStorageref.delete();
DocumentReference mPostref = FirebaseFirestore.getInstance().collection("posts").
document(postid);
mPostref.delete();
}
}
})
.setNegativeButton(R.string.no, new DialogInterface.OnClickListener() {
public void onClick(DialogInterface dialog, int id) {
dialog.dismiss();
}
});
dialog = builder.create();
dialog.show();

return false;
}
});
} else {
if (list.get(position).getVerified().equalsIgnoreCase("yes")) {
mHolder.cardHome.setVisibility(View.VISIBLE);
} else {
mHolder.cardHome.setVisibility(View.GONE);
}
}
String text = list.get(position).getPosttext();
if (text.length() > 150) {
text = text.substring(0, 150) + "...";
mHolder.tvPostText.setText(Html.fromHtml(text + "<font color='green'> <u>Read More</u></font>"));
mHolder.tvPostText.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View view) {
mHolder.tvPostText.setText(list.get(position).getPosttext());
}
});
} else {
mHolder.tvPostText.setText(list.get(position).getPosttext());
}
mHolder.tvTotalLike.setText("Likes : " + list.get(position).getTotal_like());
mHolder.tvTotalComments.setText("Comments : " + list.get(position).getTotal_comment());
final String photourl = list.get(position).getPhotourl();
if (photourl.equalsIgnoreCase("nourl")) {
mHolder.ivPostphoto.setVisibility(View.GONE);
} else {
mHolder.ivPostphoto.setVisibility(View.VISIBLE);
FirebaseStorage fs = FirebaseStorage.getInstance();
fs.getReferenceFromUrl(photourl);
StorageReference mImageRef = fs.getReference();
String ssss = fs.getReferenceFromUrl(photourl).getName();
mImageRef.child("post_photos/" + ssss).getDownloadUrl()
.addOnSuccessListener(new OnSuccessListener<Uri>() {
@Override
public void onSuccess(Uri uri) {
mHolder.postImageUri = uri;
/* Picasso.with(holder.ivPostphoto.getContext()).
load(uri).
placeholder(R.drawable.ic_image_black_24dp).
into(holder.ivPostphoto);*/
/* float thumb=0;
Glide.with(context).asBitmap()
.load(uri)
.thumbnail(thumb)
.into(mHolder.ivPostphoto);*/
Picasso.with(context).load(uri).fit().centerCrop()
.placeholder(R.drawable.ic_image_black_24dp)
.error(R.drawable.ic_image_black_24dp)
.into(mHolder.ivPostphoto);
//ivPostphoto.setImageURI(uri);

}
}).addOnFailureListener(new OnFailureListener() {
@Override
public void onFailure(@NonNull Exception e) {
}
});
}
final String senderId = list.get(position).getSenderid();
StorageReference mProfileRef =
FirebaseStorage.getInstance().getReference();
mProfileRef.child("profile_pic/" + senderId + ".jpg").getDownloadUrl()
.addOnSuccessListener(new OnSuccessListener<Uri>() {
@Override
public void onSuccess(Uri uri) {
//   Picasso.with(context).load(uri).into(holder.ivSenderphoto);
Picasso.with(context).load(uri).fit().centerCrop()
.placeholder(R.drawable.ic_account_circle_black_24dp)
.error(R.drawable.ic_account_circle_black_24dp)
.into(mHolder.ivSenderphoto);

}
}).addOnFailureListener(new OnFailureListener() {
@Override
public void onFailure(@NonNull Exception e) {
Picasso.with(context).load(R.drawable.ic_account_circle_black_24dp).fit().centerCrop()
.placeholder(R.drawable.ic_account_circle_black_24dp)
.error(R.drawable.ic_account_circle_black_24dp)
.into(mHolder.ivSenderphoto);
}
});
}
@Override
public int getItemCount() {
return list.size();
}

public class NewPostHolder extends RecyclerView.ViewHolder {
TextView tvSendername,tvDatetime,tvServiceType,tvPostText,tvTotalLike,tvTotalComments;
ImageView ivSenderphoto;
PhotoView ivPostphoto;
ImageButton ibLike,ibComments,ibShare, ibCall, ibMap;
LinearLayout llPostAproval;
Button btPostApprove,btPostDelete;
CardView cardHome;
Uri postImageUri;
View rootView;
RelativeLayout rlPosts;
View view;
NewPostHolder(View itemView) {
super(itemView);
view = itemView;
tvSendername=(TextView)itemView.findViewById(R.id.tv_poster_username);
tvDatetime=(TextView)itemView.findViewById(R.id.tv_poster_datetime);
tvServiceType=(TextView)itemView.findViewById(R.id.tv_poster_servicetype);
tvPostText=(TextView)itemView.findViewById(R.id.tv_poster_text);
tvTotalLike=(TextView)itemView.findViewById(R.id.tv_poster_total_likes);
tvTotalComments=(TextView)itemView.findViewById(R.id.tv_poster_total_comments);
ivSenderphoto=(ImageView)itemView.findViewById(R.id.iv_poster_photo);
ivPostphoto=(PhotoView) itemView.findViewById(R.id.iv_poster_images);
ibLike=(ImageButton)itemView.findViewById(R.id.ib_poster_like);
ibComments=(ImageButton)itemView.findViewById(R.id.ib_poster_comments);
ibShare=(ImageButton)itemView.findViewById(R.id.ib_poster_share);
ibCall=(ImageButton)itemView.findViewById(R.id.ib_poster_call);
ibMap=(ImageButton)itemView.findViewById(R.id.ib_poster_map);
llPostAproval=(LinearLayout)itemView.findViewById(R.id.linearPosterApproval);
btPostApprove=(Button)itemView.findViewById(R.id.bt_poster_approve);
btPostDelete=(Button)itemView.findViewById(R.id.bt_poster_delete);
cardHome=(CardView)itemView.findViewById(R.id.card_home_post);
rlPosts=(RelativeLayout)itemView.findViewById(R.id.rl_home_posts);
tvPostText.setTextIsSelectable(true);
}

}

}

现在，我的问题和我在前三个id(三个id是我的极限(后很难获得Document Id，在获得前三个文档后，下面显示错误。 因此，请帮助我获取next query文档ID。 希望你能理解。 谢谢大家的帮助 错误：

2020-02-15 16:56:56.138 22675-22675/app.burhani.dholkaapp E/AndroidRuntime: FATAL EXCEPTION: main
Process: app.burhani.dholkaapp, PID: 22675
java.lang.IndexOutOfBoundsException: Index: 3, Size: 3
at java.util.ArrayList.get(ArrayList.java:437)
at app.burhani.dholkaapp.newadapter.NewPostAdapter.onBindViewHolder(NewPostAdapter.java:81)
at app.burhani.dholkaapp.newadapter.NewPostAdapter.onBindViewHolder(NewPostAdapter.java:47)
at androidx.recyclerview.widget.RecyclerView$Adapter.onBindViewHolder(RecyclerView.java:7056)
at androidx.recyclerview.widget.RecyclerView$Adapter.bindViewHolder(RecyclerView.java:7098)
at androidx.recyclerview.widget.RecyclerView$Recycler.tryBindViewHolderByDeadline(RecyclerView.java:6010)
at androidx.recyclerview.widget.RecyclerView$Recycler.tryGetViewHolderForPositionByDeadline(RecyclerView.java:6277)
at androidx.recyclerview.widget.RecyclerView$Recycler.getViewForPosition(RecyclerView.java:6116)
at androidx.recyclerview.widget.RecyclerView$Recycler.getViewForPosition(RecyclerView.java:6112)
at androidx.recyclerview.widget.LinearLayoutManager$LayoutState.next(LinearLayoutManager.java:2303)
at androidx.recyclerview.widget.LinearLayoutManager.layoutChunk(LinearLayoutManager.java:1627)
at androidx.recyclerview.widget.LinearLayoutManager.fill(LinearLayoutManager.java:1587)
at androidx.recyclerview.widget.LinearLayoutManager.scrollBy(LinearLayoutManager.java:1391)
at androidx.recyclerview.widget.LinearLayoutManager.scrollVerticallyBy(LinearLayoutManager.java:1128)
at androidx.recyclerview.widget.RecyclerView.scrollStep(RecyclerView.java:1841)
at androidx.recyclerview.widget.RecyclerView$ViewFlinger.run(RecyclerView.java:5300)
at android.view.Choreographer$CallbackRecord.run(Choreographer.java:1163)
at android.view.Choreographer.doCallbacks(Choreographer.java:986)
at android.view.Choreographer.doFrame(Choreographer.java:894)
at android.view.Choreographer$FrameDisplayEventReceiver.run(Choreographer.java:1148)
at android.os.Handler.handleCallback(Handler.java:883)
at android.os.Handler.dispatchMessage(Handler.java:100)
at android.os.Looper.loop(Looper.java:214)
at android.app.ActivityThread.main(ActivityThread.java:7682)
at java.lang.reflect.Method.invoke(Native Method)
at com.android.internal.os.RuntimeInit$MethodAndArgsCaller.run(RuntimeInit.java:516)
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:950)

可能是因为您正在发送位置并且您给了错误，请尝试发送final String postid=task.getResult().getDocuments().get(position-1).getId();并查看您是否得到了您想要的对象。让我知道它对你有用

最后我解决了错误。 错误是下一个查询的大小querysnapshot大小。 我在第一次查询和下一次查询中使用此方法使用此方法使用新List保存文档 ID

for (QueryDocumentSnapshot document : t.getResult()) {
listId.add(document.getId());
}

并在Adapter使用带有位置listId获取 ID。 最终查询代码为

Task<QuerySnapshot> mSnapy;
boolean isScrolling = false;
boolean isLastItemReached = false;
DocumentSnapshot lastVisible;
NewPostAdapter mNewPostAdapter;
private void getNewFireData() {
final int limit = 3;
mRecyclerView = rootView.findViewById(R.id.rv_post_list);
final LinearLayoutManager mManeger=new LinearLayoutManager(getActivity());
mRecyclerView.setLayoutManager(mManeger);
mRecyclerView.setHasFixedSize(true);
mRecyclerView.invalidate();
final List<Posts> list = new ArrayList<>();
final List<String> listId=new ArrayList<>();
FirebaseFirestore rootRef = FirebaseFirestore.getInstance();
final CollectionReference postRef = rootRef.collection("posts");
Query query = postRef.orderBy("datetime",
Query.Direction.DESCENDING).limit(limit);
query.get().addOnCompleteListener(new OnCompleteListener<QuerySnapshot>() {
@Override
public void onComplete(@NonNull Task<QuerySnapshot> task) {

if(task.isSuccessful()){
lastVisible = task.getResult().getDocuments().get(task.getResult().size() - 1);
for (DocumentSnapshot document : task.getResult()) {
Posts postModel = document.toObject(Posts.class);
list.add(postModel);
}
for (QueryDocumentSnapshot document : task.getResult()) {
listId.add(document.getId());
}
mSnapy=task;
mNewPostAdapter = new NewPostAdapter(list,getActivity()
, mSnapy,listId,myContext);

mRecyclerView.addOnScrollListener(new RecyclerView.OnScrollListener() {
@Override
public void onScrollStateChanged(@NonNull RecyclerView recyclerView, int newState) {
super.onScrollStateChanged(recyclerView, newState);
if(newState==AbsListView.OnScrollListener.SCROLL_STATE_TOUCH_SCROLL){
isScrolling =true;
}
}
@Override
public void onScrolled(@NonNull RecyclerView recyclerView, int dx, int dy) {
super.onScrolled(recyclerView, dx, dy);
LinearLayoutManager linearLayoutManager = ((LinearLayoutManager) recyclerView.getLayoutManager());
int firstVisibleItemPosition = linearLayoutManager.findFirstVisibleItemPosition();
int visibleItemCount = linearLayoutManager.getChildCount();
int totalItemCount = linearLayoutManager.getItemCount();
if (isScrolling && (firstVisibleItemPosition + visibleItemCount ==
totalItemCount) && !isLastItemReached) {
isScrolling = false;
Query nextQuery = postRef.orderBy("datetime",
Query.Direction.DESCENDING).startAfter(lastVisible).limit(limit);
nextQuery.get().addOnCompleteListener(new OnCompleteListener<QuerySnapshot>() {
@Override
public void onComplete(@NonNull Task<QuerySnapshot> t) {
if (t.isSuccessful()) {
for (DocumentSnapshot d : t.getResult()) {
Posts productModel = d.toObject(Posts.class);
list.add(productModel);
}
for (QueryDocumentSnapshot document : t.getResult()) {
listId.add(document.getId());
}
mSnapy = t;
System.out.println("Task Data "+mSnapy.getResult().getDocuments());
mNewPostAdapter.notifyDataSetChanged();
lastVisible = t.getResult().getDocuments().get(t.getResult().size() - 1);
if (t.getResult().size() < limit) {
isLastItemReached = true;
}
}
}
});
}
}
});
//          mNewPostAdapter.setHasStableIds(true);
mRecyclerView.setAdapter(mNewPostAdapter);

}
}
});
}

我找到了代码下面的另一个答案 只需在模态Post.classdodId上创建一个新的 obejct 并像下面这样使用它

for (QueryDocumentSnapshot document : task.getResult()) {
Posts modal=document.toObject(Posts.class);
modal.setDoc_id(document.getId());
list.add(modal);
}

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