具有重复值的回收站更新
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【中文标题】具有重复值的回收站更新【英文标题】：Recycler updates with duplicate values 【发布时间】：2019-12-10 10:27:16 【问题描述】：我使用擦除删除方法来删除一行，当我从回收器列表视图中删除一行时，它会复制我已删除的值下方的值。 如果我从列表中删除“测试 3”
它在第 3 和第 4 位显示重复的“测试 4”
我用于创建和删除列表的整个代码，任何人都可以帮我解决这个问题
public class fragmnetPendingAct extends Fragment
private SwipeRefreshLayout refreshLayout;
private RecyclerView recyclerView;
ArrayList<String> activitynames;
FirebaseAuth mAuth;
View view;
List<modelclasspendingact> modelclasspendingactList = new ArrayList<>();
public fragmnetPendingAct()
@Nullable
@Override
public View onCreateView(@NonNull LayoutInflater inflater, @Nullable ViewGroup container, @Nullable Bundle savedInstanceState)
View v = inflater.inflate(R.layout.fragment_pendingactivity,container,false);
refreshLayout = (SwipeRefreshLayout) v.findViewById(R.id.swipe_activitypend);
recyclerView = v.findViewById(R.id.recyclerviewpendingact);
LinearLayoutManager layoutManager = new LinearLayoutManager(getActivity());
layoutManager.setOrientation(LinearLayoutManager.VERTICAL);
recyclerView.setLayoutManager(layoutManager);
new ItemTouchHelper(itemtouchHelpercalback).attachToRecyclerView(recyclerView);
//listen to swipe horizontal
refreshLayout.setOnRefreshListener(new SwipeRefreshLayout.OnRefreshListener()
@Override
public void onRefresh()
// Get new Instance ID token
FirebaseUser mUser = mAuth.getInstance().getCurrentUser();
mUser.getIdToken(true)
.addOnCompleteListener(new OnCompleteListener<GetTokenResult>()
public void onComplete(@NonNull Task<GetTokenResult> task)
if (task.isSuccessful())
String token = task.getResult().getToken();
// Send token to your backend via HTTPS
getdatafromserver(token);
else
// Handle error -> task.getException();
Log.w(TAG, "getInstanceId failed second", task.getException());
);
refreshitems();
);
// Get new Instance ID token
FirebaseUser mUser = mAuth.getInstance().getCurrentUser();
mUser.getIdToken(true)
.addOnCompleteListener(new OnCompleteListener<GetTokenResult>()
public void onComplete(@NonNull Task<GetTokenResult> task)
if (task.isSuccessful())
String token = task.getResult().getToken();
Log.d(TAG, "onComplete lead: "+token);
// Send token to your backend via HTTPS
getdatafromserver(token);
else
// Handle error -> task.getException();
Log.w(TAG, "getInstanceId failed second", task.getException());
);
return v;
public void getdatafromserver(String token)
//new code using curl
String serverurl="xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx";
JsonObjectRequest jsonObjectRequest = new JsonObjectRequest(Request.Method.GET, serverurl,null,
new Response.Listener<JSONObject>()
@Override
public void onResponse(JSONObject response)
try
Log.d(TAG, "activity list: "+response);
JSONObject alldata=response.getJSONObject("payload");
JSONArray assetaarray=alldata.getJSONArray("activities");
modelclasspendingactList.removeAll(modelclasspendingactList);
for(int i=0;i<assetaarray.length();i++)
JSONObject getactivity=assetaarray.getJSONObject(i);
String activityid = String.valueOf(getactivity.getInt("id"));
String activityname = getactivity.getString("title");
String activitydesc = getactivity.getString("description");
Log.d(TAG, "activity name: "+activityname);
//list crreation
modelclasspendingactList.add(new modelclasspendingact(activityname,activitydesc,activityid));
pendingactAdapter adapter = new pendingactAdapter(modelclasspendingactList);
recyclerView.setAdapter(adapter);
adapter.notifyDataSetChanged();
catch (JSONException e)
e.printStackTrace();
, new Response.ErrorListener()
@Override
public void onErrorResponse(VolleyError error)
error.printStackTrace();
)
@Override
public Map<String, String> getHeaders() throws AuthFailureError
Map<String,String> headers=new HashMap<String,String>();
headers.put("Accept","*/*");
headers.put("Cache-Control","no-cache");
headers.put("cache-control","no-cache");
headers.put("token",token);
return headers;
;
singletonclasshttp.getInstance(getActivity()).addtorequestque(jsonObjectRequest);
private void refreshitems()
refreshLayout.setRefreshing(false);
//swipe function
ItemTouchHelper.SimpleCallback itemtouchHelpercalback = new ItemTouchHelper.SimpleCallback(0,ItemTouchHelper.LEFT | ItemTouchHelper.RIGHT)
@Override
public boolean onMove(@NonNull RecyclerView recyclerView, @NonNull RecyclerView.ViewHolder viewHolder, @NonNull RecyclerView.ViewHolder viewHolder1)
return false;
@Override
public void onSwiped(@NonNull RecyclerView.ViewHolder viewHolder, int i)
Log.d(TAG, "onSwiped: "+modelclasspendingactList.get(viewHolder.getAdapterPosition()).getPendid());
Log.d(TAG, "onSwiped: position "+viewHolder.getAdapterPosition());
String activeid = modelclasspendingactList.get(viewHolder.getAdapterPosition()).getPendid();
// Get new Instance ID token
FirebaseUser mUser = mAuth.getInstance().getCurrentUser();
mUser.getIdToken(true)
.addOnCompleteListener(new OnCompleteListener<GetTokenResult>()
public void onComplete(@NonNull Task<GetTokenResult> task)
if (task.isSuccessful())
String token = task.getResult().getToken();
//send token and activity id to update function
markascompleted(activeid,token);
else
// Handle error -> task.getException();
Log.w(TAG, "getInstanceId failed second", task.getException());
);
Log.d(TAG, "onSwiped: position "+viewHolder.getAdapterPosition());
Log.d(TAG, "onSwiped: first list size "+modelclasspendingactList.size());
pendingactAdapter adapter = new pendingactAdapter(modelclasspendingactList);
modelclasspendingactList.remove(viewHolder.getAdapterPosition());
recyclerView.removeViewAt(viewHolder.getAdapterPosition());
adapter.notifyItemRemoved(viewHolder.getAdapterPosition());
// adapter.notifyItemRangeChanged(viewHolder.getAdapterPosition(), modelclasspendingactList.size());
// adapter.notifyDataSetChanged();
Log.d(TAG, "onSwiped: list size "+modelclasspendingactList.size());
// pendingactAdapter adapter = new pendingactAdapter(modelclasspendingactList);
// modelclasspendingactList.remove(viewHolder.getAdapterPosition());
// adapter.notifyItemRemoved(viewHolder.getAdapterPosition());
;
private void markascompleted(String activeid,String token)
//send data to server
//curl function
String serverurl="xxxxxxxxxxxxxxxxxxxxxxx";
Map<String, Object> jsonParams = new ArrayMap<>();
jsonParams.put("id", activeid);
jsonParams.put("activityStatus", "COMPLETED");
jsonParams.put("targetEmployeeId", "1001");
jsonParams.put("score", "1");
JsonObjectRequest jsonObjectRequest = new JsonObjectRequest(Request.Method.PUT, serverurl,new JSONObject(jsonParams),
new Response.Listener<JSONObject>()
@Override
public void onResponse(JSONObject response)
Log.d(TAG, "response: "+response);
try
if (response.optBoolean("success")==true)
Toast.makeText(getActivity(), response.getString("message"),Toast.LENGTH_LONG).show();
else
Toast.makeText(getActivity(),"Data Not Updated",Toast.LENGTH_LONG).show();
catch (JSONException e)
Toast.makeText(getActivity(),"Data Not Updated",Toast.LENGTH_LONG).show();
e.printStackTrace();
, new Response.ErrorListener()
@Override
public void onErrorResponse(VolleyError error)
Toast.makeText(getActivity(),"Data Not Saved",Toast.LENGTH_SHORT).show();
error.printStackTrace();
)
@Override
public Map<String, String> getHeaders() throws AuthFailureError
Map<String,String> headers=new HashMap<String,String>();
headers.put("Accept","*/*");
headers.put("Cache-Control","no-cache");
headers.put("Connection","keep-alive");
headers.put("Content-Type","application/json");
headers.put("cache-control","no-cache");
headers.put("token",token);
return headers;
;
singletonclasshttp.getInstance(getActivity()).addtorequestque(jsonObjectRequest);
【问题讨论】：
notifyItemRemoved 在此之后您不需要 notifyDataSetChanged @AnasMehar 问题仍然存在 可以在 notifyDataSetChanged 后使用调试检查你的适配器列表 list.size()。 @AlvinJohnNiravukalayil 不要打电话给notifyItemRangeChanged()
@AnasMehar 最初为 6，删除时为 5
【参考方案1】：
首先我会解释为什么会出现这种行为，然后我们会找到解决方案。 在这段代码中：
问题 1：
pendingactAdapter adapter = new pendingactAdapter(modelclasspendingactList);
您正在创建一个适配器并将您的 当前 数据传递给它。请注意，适配器将拥有您在构造函数中传递的列表的自己的副本。
modelclasspendingactList.remove(viewHolder.getAdapterPosition());
您要从中删除项目的列表与您刚刚在适配器中发送的列表不同，因此适配器仍有旧列表。 然后你调用removed，适配器尝试更新值，但你删除的项目仍在适配器的列表中。
解决方案： 在适配器中创建一个函数/方法，从适配器列表中删除项目。
问题 #2 的解决方案： 每次滑动视图时，您都在创建一个新的适配器实例/对象，这是不必要的。在类而不是函数中创建适配器，并在 onCreateView() 中实例化它。
【讨论】：
非常感谢兄弟。你救了我。【参考方案2】：几件事。
首先，removeViewAt 是RecyclerView.LayoutManager 的函数。我想你是想说recyclerView.LayoutManager.removeViewAt。
其次，调用removeViewAt 应该是不必要的，因为当notifyItemRemoved 被正确调用时，RecyclerView 会自动执行此操作。
第三，删除项目时不需要重新绑定整个列表。您可以删除notifyItemRangeChanged。
第四，您也不需要在删除项目时使整个适配器无效。您可以删除notifyDataSetChanged。事实上，这个功能只能作为最后的手段使用。
初始化你的RecyclerView:
pendingactAdapter adapter = new pendingactAdapter(modelclasspendingactList);
RecyclerView recyclerView = view.findViewById(R.id.my_recycler_view);
recyclerView.adapter = adapter;
recyclerView.layoutManager = LinearLayoutManager(getActivity());
所以你的删除顺序应该是
modelclasspendingactList.remove(viewHolder.getAdapterPosition());
adapter.notifyItemRemoved(viewHolder.getAdapterPosition());
【讨论】：
但是当我使用此代码时它会删除但它不对齐，删除的行中有一个间隙。 这似乎是布局管理器的问题。使用显示您如何初始化回收站视图的代码更新您的问题。我在答案中添加了一个示例。 我已经用整个代码更新了我的问题。我得到了解决方案，谢谢你的回答。以上是关于具有重复值的回收站更新的主要内容，如果未能解决你的问题，请参考以下文章