RecyclerView在刷新时多次上传项目。

huangapple
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英文:

recyclerview uploads items multiple time on refresh

问题

我已经实现了一个RecyclerView，在其中我想展示应用程序中创建的群组。目前我正在使用swipeRefreshLayout刷新RecyclerView，但每次刷新RecyclerView时，它会根据刷新的次数多次打印出相同的群组。

有谁可以帮助我解决这个问题？

以下是代码部分。

onCreateView 方法：

  1. @Nullable
  2. @Override
  3. public View onCreateView(@NonNull LayoutInflater inflater, @Nullable ViewGroup container, @Nullable Bundle savedInstanceState) {
  4.     // ... （你的其他代码）
  6.     swipeRefreshLayout.setOnRefreshListener(new SwipeRefreshLayout.OnRefreshListener() {
  7.         @Override
  8.         public void onRefresh() {
  9.             recyclerUpdater();
  10.             swipeRefreshLayout.setRefreshing(false);
  11.         }
  12.     });
  13.     return view;
  14. }

recyclerUpdate 函数，用于向 RecyclerView 适配器中添加字符串：

  1. private void recyclerUpdate() {
  2.     if(user != null) {
  3.         firebaseFirestore.collection("users").document(user.getUid()).collection("Groups").get()
  4.                 .addOnCompleteListener(new OnCompleteListener<QuerySnapshot>() {
  5.                     @Override
  6.                     public void onComplete(@NonNull Task<QuerySnapshot> task) {
  7.                         if (task.isSuccessful()) {
  8.                             mProjects.clear(); // 清空数据列表
  9.                             mProjectsId.clear(); // 清空 ID 列表
  10.                             for (QueryDocumentSnapshot document : task.getResult()) {
  11.                                 String title = document.getString(TITLE);
  12.                                 String groupId = document.getString(GROUP_ID);
  13.                                 mProjects.add(title);
  14.                                 mProjectsId.add(groupId);
  15.                             }
  16.                             projectAdapter.setItems(mProjects, mProjectsId, getActivity());
  17.                             projectAdapter.notifyDataSetChanged();
  18.                             Log.d(TAG, "onComplete: list: " + mProjects.toString());
  19.                         } else {
  20.                             Log.d(TAG, "onComplete: error getting documents", task.getException());
  21.                         }
  22.                     }
  23.                 });
  24.     }
  25. }

这是 RecyclerView 适配器部分：

  1. public class groupView extends RecyclerView.Adapter<groupView.ViewHolder> {
  2.     // ... （你的其他代码）
  4.     public void setItems(List<String> items, List<String> ids, Context context) {
  5.         mItems = items;
  6.         mIds = ids;
  7.         mContext = context;
  8.         notifyDataSetChanged(); // 更新数据后通知适配器更新UI
  9.     }
  11.     // ... （你的其他代码）
  12. }

提前感谢你的帮助！

英文:

I have implemented a recyclerview, where I want to show the groups that have been created in the app. Right now I am refreshing the recyclerview using the swipeRefreshLayout, but everytime I refresh the recyclerview, it prints out the same group multiple times according to how many times I refresh it.

Can anyone help me solve this problem?

Below is the code.

onCreateView method:

  1. @Nullable
  2. @Override
  3. public View onCreateView(@NonNull LayoutInflater inflater, @Nullable ViewGroup container, @Nullable Bundle savedInstanceState) {
  4.     Log.d(TAG, &quot;onCreateView: started&quot;);
  5.     View view = inflater.inflate(R.layout.fragment_projects, container, false); //This inflates the project_fragment layout to this java class.
  7.     swipeRefreshLayout = view.findViewById(R.id.swipeRefresh);
  9.     add_btn = view.findViewById(R.id.add_project_btn);
  10.     add_btn.setOnClickListener(new View.OnClickListener() {
  11.         @Override
  12.         public void onClick(View view) {
  13.             requestNewGroup();
  14.         }
  15.     });
  17.     initRecyclerView(view);
  18.     recyclerUpdater();
  20.     swipeRefreshLayout.setOnRefreshListener(new SwipeRefreshLayout.OnRefreshListener() {
  21.         @Override
  22.         public void onRefresh() {
  23.             recyclerUpdater();
  24.             swipeRefreshLayout.setRefreshing(false);
  25.         }
  26.     });
  27.     return view;
  28. }

recyclerUpdate function, where Strings are added to the recyclerView adapter:

  1.  private void recyclerUpdate() {
  2.     if(user != null) {
  3.         firebaseFirestore.collection(&quot;users&quot;).document(user.getUid()).collection(&quot;Groups&quot;).get()
  4.                 .addOnCompleteListener(new OnCompleteListener&lt;QuerySnapshot&gt;() {
  5.                     @Override
  6.                     public void onComplete(@NonNull Task&lt;QuerySnapshot&gt; task) {
  7.                         if (task.isSuccessful()) {
  8.                             for (QueryDocumentSnapshot document : task.getResult()) {
  9.                                 String title = document.getString(TITLE);
  10.                                 String groupId = document.getString(GROUP_ID);
  11.                                 mProjects.add(title);
  12.                                 mProjectsId.add(groupId);
  13.                             }
  14.                             projectAdapter.setItems(mProjects, mProjectsId, getActivity());
  15.                             projectAdapter.notifyDataSetChanged();
  16.                             Log.d(TAG, &quot;onComplete: list: &quot; + mProjects.toString());
  17.                         } else {
  18.                             Log.d(TAG, &quot;onComplete: error getting documents&quot;, task.getException());
  19.                         }
  20.                     }
  21.                 });
  22.     }
  23. }

recyclerViewAdapter:

  1. public class groupView extends RecyclerView.Adapter&lt;groupView.ViewHolder&gt;{
  3. private static final String TAG = groupView.class.getSimpleName();
  4. private List&lt;String&gt; mItems = new ArrayList&lt;&gt;();
  5. private List&lt;String&gt; mIds = new ArrayList&lt;&gt;();
  6. private Context mContext;
  8. public void setItems(List&lt;String&gt; items, List&lt;String&gt; ids, Context context) {
  9.     mItems = items;
  10.     mIds = ids;
  11.     mContext = context;
  12. }
  14. @NonNull
  15. @Override
  16. public ViewHolder onCreateViewHolder(@NonNull ViewGroup parent, int viewType) {
  17.     if(viewType == 0){
  18.         return ViewHolder.inflate(parent);
  19.     }else{
  20.         return null;
  21.     }
  23. }
  25. @Override
  26. public void onBindViewHolder(@NonNull ViewHolder holder, final int position) {
  27.     Log.d(TAG, &quot;onBindViewHolder: called&quot;);
  28.     if (holder instanceof ViewHolder) {
  29.         ((ViewHolder) holder).bind(mItems.get(position));
  30.         ((ViewHolder) holder).mLinearLayout.setOnClickListener(new View.OnClickListener() {
  31.             @Override
  32.             public void onClick(View view) {
  33.                 Log.d(TAG, &quot;onClick: clicked on: &quot; + mItems.get(position));
  34.                 //Sending ID as an intent, to be used in the process
  35.                 Intent intent = new Intent(mContext, projectClicked.class);
  36.                 intent.putExtra(&quot;itemPos&quot;, mItems.get(position));
  37.                 intent.putExtra(&quot;itemID&quot;, mIds.get(position));
  38.                 //intent.setFlags(Intent.FLAG_ACTIVITY_CLEAR_TOP); //close activitys before calling a new
  39.                 mContext.startActivity(intent);
  40.             }
  41.         });
  42.     }
  45. }
  47. @Override
  48. public int getItemCount() {
  49.     return mItems.size();
  50. }
  52. @Override
  53. public int getItemViewType(int position) {
  54.     return 0;
  55. }
  57. static class ViewHolder extends RecyclerView.ViewHolder{
  59.     private TextView mTextView;
  60.     private LinearLayout mLinearLayout;
  62.     public static ViewHolder inflate(ViewGroup parent) {
  63.         View view = LayoutInflater.from(parent.getContext()).inflate(R.layout.layout_listitem_group, parent,false);
  64.         return new ViewHolder(view);
  65.     }
  67.     public ViewHolder(@NonNull View itemView) {
  68.         super(itemView);
  70.         mTextView = itemView.findViewById(R.id.list_groups_title);
  71.         mLinearLayout = itemView.findViewById(R.id.listitem_groups);
  72.     }
  74.     public void bind(String text){
  75.         mTextView.setText(text);
  76.     }
  77. }

}

Thank you in advance!

答案1

得分: 0

你正在向 mProjects 和 mProjectsId 添加新项，而没有清空这些列表。
在 for 循环之前添加 clear()：

  1. if (task.isSuccessful()) {
  2.     mProjects.clear();
  3.     mProjectsId.clear();
  4.     for (QueryDocumentSnapshot document : task.getResult()) {
  5.         ...
英文:

You are adding new items to mProjects and mProjectsId not clearing these lists.
Add clear() before for loop:

  1. if (task.isSuccessful()) {
  2.    mProjects.clear();
  3.    mProjectsId.clear();
  4.    for (QueryDocumentSnapshot document : task.getResult()) {
  5.    ...

huangapple
  • 本文由 发表于 2020年10月17日 00:12:06
  • 转载请务必保留本文链接：https://go.coder-hub.com/64392776.html
  • android
  • android-recyclerview
  • java
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