我正在尝试从populateViewHolder方法中的firebaseRecyelerAdapter中删除项目。我正在使用 item.setVisibility（view.GONE），但是当再次返回该片段时，它再次显示了价值。 这是我的代码：
public class ChatsFragment extends Fragment {
private RecyclerView mConvList;
private DatabaseReference mConvDatabase;
private DatabaseReference mMessageDatabase;
private DatabaseReference mUsersDatabase;
private FirebaseAuth mAuth;
private String mCurrent_user_id;
private View mMainView;
private ProgressDialog pd;
public ChatsFragment() {
// Required empty public constructor
}
@Override
public View onCreateView(LayoutInflater inflater, ViewGroup container,
Bundle savedInstanceState) {
mMainView = inflater.inflate(R.layout.fragment_chats, container, false);
mConvList = (RecyclerView) mMainView.findViewById(R.id.conv_list);
mAuth = FirebaseAuth.getInstance();
mCurrent_user_id = mAuth.getCurrentUser().getUid();
mConvDatabase = FirebaseDatabase.getInstance().getReference().child("Chat").child(mCurrent_user_id);
mConvDatabase.keepSynced(true);
mUsersDatabase = FirebaseDatabase.getInstance().getReference().child("Users");
mMessageDatabase = FirebaseDatabase.getInstance().getReference().child("messages").child(mCurrent_user_id);
mUsersDatabase.keepSynced(true);
LinearLayoutManager linearLayoutManager = new LinearLayoutManager(getContext());
linearLayoutManager.setReverseLayout(true);
linearLayoutManager.setStackFromEnd(true);
mConvList.setHasFixedSize(true);
mConvList.setLayoutManager(linearLayoutManager);
// Inflate the layout for this fragment
return mMainView;
}
@Override
public void onStart() {
super.onStart();
Query conversationQuery = mConvDatabase.orderByChild("timestamp");
final FirebaseRecyclerAdapter<Conv, ConvViewHolder> firebaseConvAdapter = new FirebaseRecyclerAdapter<Conv, ConvViewHolder>(
Conv.class,
R.layout.users_single_layout,
ConvViewHolder.class,
conversationQuery
) {
@Override
protected void populateViewHolder(final ConvViewHolder convViewHolder, final Conv conv, final int i) {
final String list_user_id = getRef(i).getKey();
Query lastMessageQuery = mMessageDatabase.child(list_user_id).limitToLast(1);
lastMessageQuery.addChildEventListener(new ChildEventListener() {
@Override
public void onChildAdded(DataSnapshot dataSnapshot, String s) {
String data = dataSnapshot.child("message").getValue().toString();
convViewHolder.setMessage(data, conv.isSeen());
}
@Override
public void onChildChanged(DataSnapshot dataSnapshot, String s) {
}
@Override
public void onChildRemoved(DataSnapshot dataSnapshot) {
}
@Override
public void onChildMoved(DataSnapshot dataSnapshot, String s) {
}
@Override
public void onCancelled(DatabaseError databaseError) {
}
});
mUsersDatabase.child(list_user_id).addValueEventListener(new ValueEventListener() {
@Override
public void onDataChange(DataSnapshot dataSnapshot) {
final String userName = dataSnapshot.child("name").getValue().toString();
String userThumb = dataSnapshot.child("thumb_image").getValue().toString();
if(dataSnapshot.hasChild("online")) {
String userOnline = dataSnapshot.child("online").getValue().toString();
convViewHolder.setUserOnline(userOnline);
}
convViewHolder.setName(userName);
convViewHolder.setUserImage(userThumb, getContext());
convViewHolder.mView.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View view) {
Intent chatIntent = new Intent(getContext(), ChatActivity.class);
chatIntent.putExtra("user_id", list_user_id);
chatIntent.putExtra("user_name", userName);
startActivity(chatIntent);
}
});
convViewHolder.mView.setOnLongClickListener(new View.OnLongClickListener() {
@Override
public boolean onLongClick(View view) {
Toast.makeText(getContext(), "long clicked", Toast.LENGTH_SHORT).show();
firebaseConvAdapter.getRef(i).removeValue()
.addOnCompleteListener(new OnCompleteListener<Void>() {
@Override
public void onComplete(@NonNull Task<Void> task) {
Toast.makeText(getContext(), "deleted", Toast.LENGTH_SHORT).show();
}
});
return false;
}
});
}
@Override
public void onCancelled(DatabaseError databaseError) {
}
});
}
};
mConvList.setAdapter(firebaseConvAdapter);
}
public static class ConvViewHolder extends RecyclerView.ViewHolder {
Context context;
View mView;
public ConvViewHolder(View itemView) {
super(itemView);
mView = itemView;
}
public void setMessage(String message, boolean isSeen){
TextView userStatusView = (TextView) mView.findViewById(R.id.user_single_status);
userStatusView.setText(message);
if(!isSeen){
userStatusView.setTypeface(userStatusView.getTypeface(), Typeface.BOLD);
} else {
userStatusView.setTypeface(userStatusView.getTypeface(), Typeface.NORMAL);
}
}
public void setName(String name){
TextView userNameView = (TextView) mView.findViewById(R.id.user_single_name);
userNameView.setText(name);
}
public void setUserImage(String thumb_image, Context ctx){
CircleImageView userImageView = (CircleImageView) mView.findViewById(R.id.user_single_image);
Picasso.with(ctx).load(thumb_image).placeholder(R.mipmap.default_image).into(userImageView);
}
public void setUserOnline(String online_status) {
ImageView userOnlineView = (ImageView) mView.findViewById(R.id.user_single_online_icon);
if(online_status.equals("true")){
userOnlineView.setVisibility(View.VISIBLE);
} else {
userOnlineView.setVisibility(View.INVISIBLE);
}
} }}
我正在尝试删除 LongClicked 方法上的值。谢谢。 我也尝试使用item.remove（）方法，但不是 remove（）方法无法在此方法中识别。请帮助我
答案 0 :(得分：0)
您需要 firebaserecycleradapter ，然后通过获取Firebase数据库中数据的引用来找到数据的位置。然后将其删除。 去尝试一下。也许会对您有帮助：）
firebaseConvAdapter.getRef(i).removeValue().addOnCompleteListener(new OnCompleteListener<Void>() {
@Override
public void onComplete(@NonNull Task<Void> task) {
if (task.isSuccessful()){
//Your data is removed successfully!
}
}
});
答案 1 :(得分：0)
在您的build.gradle中
implementation 'com.firebaseui:firebase-ui-database:4.1.0'
在您的动作课中：
import android.support.annotation.NonNull;
import android.support.v7.app.AppCompatActivity;
import android.os.Bundle;
import android.support.v7.widget.LinearLayoutManager;
import android.support.v7.widget.RecyclerView;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;
import android.widget.Toast;
import com.firebase.ui.database.FirebaseRecyclerAdapter;
import com.firebase.ui.database.FirebaseRecyclerOptions;
import com.google.android.gms.tasks.OnCompleteListener;
import com.google.android.gms.tasks.Task;
import com.google.firebase.database.FirebaseDatabase;
import com.google.firebase.database.Query;
import com.gstech.merge.disasterapp.R;
import com.gstech.merge.disasterapp.holder.DisasterHolder;
import com.gstech.merge.disasterapp.model.DisasterModel;
import com.squareup.picasso.Picasso;
public class AdminPanel extends AppCompatActivity {
RecyclerView recyclerView;
FirebaseRecyclerAdapter adapter;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_admin_panel);
recyclerView = findViewById(R.id.recycler);
Query query = FirebaseDatabase.getInstance().getReference().child("disatsers");
FirebaseRecyclerOptions options = new FirebaseRecyclerOptions.Builder<DisasterModel>()
.setQuery(query, DisasterModel.class)
.build();
adapter = new FirebaseRecyclerAdapter<DisasterModel, DisasterHolder>(options) {
@Override
public DisasterHolder onCreateViewHolder(ViewGroup parent, int viewType) {
View view = LayoutInflater.from(parent.getContext())
.inflate(R.layout.recycler_disaster_view, parent, false);
return new DisasterHolder(view);
}
@Override
protected void onBindViewHolder(DisasterHolder holder, int position, final DisasterModel model) {
// Bind the Chat object to the ChatHolder
// ...
holder.type.setText("দুর্যোগের ধরণঃ " + model.getDisaster_type());
holder.address.setText("Division: " + model.getDivision()
+ ", District: " + model.getDistrtct()
+ ", Upazilla: " + model.getUpazilla()
+ ", Union: " + model.getUnion()
+ ", Ward: " + model.getWard()
);
holder.datetime.setText("Date: " + model.getDate() + ", Time: " + model.getTime());
holder.details.setText("আহতের সংখ্যাঃ " + model.getInjured() + ", মৃতের সংখ্যাঃ " + model.getDeath()
+ ", পরিবারের সংখ্যাঃ " + model.getTotalfamily() + ", পাকা বাড়ির সংখ্যাঃ " + model.getPakabar()
+ ", কাঁচা বাড়ির সংখ্যাঃ " + model.getKachabari() + ", গবাদি পশুর সংখ্যাঃ " + model.getAnimals());
holder.others.setText("অন্যান্যঃ " + model.getOthers());
Picasso.get().load(model.getPhotourl()).placeholder(R.drawable.loading).into(holder.image);
}
};
recyclerView.setAdapter(adapter);
recyclerView.setLayoutManager(new LinearLayoutManager(this));
}
@Override
protected void onStart() {
super.onStart();
adapter.startListening();
}
@Override
protected void onStop() {
super.onStop();
adapter.stopListening();
}
}
并为视图持有者创建另一个类：
public class NewsHolder extends RecyclerView.ViewHolder {
public ImageView cover;
public TextView title;
public CardView newscard;
public NewsHolder(@NonNull View itemView) {
super(itemView);
cover = itemView.findViewById(R.id.cover);
title = itemView.findViewById(R.id.title);
newscard = itemView.findViewById(R.id.newscard);
}
}
以及用于recyclerview的xml布局：
<?xml version="1.0" encoding="utf-8"?>
<android.support.constraint.ConstraintLayout xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:app="http://schemas.android.com/apk/res-auto"
xmlns:tools="http://schemas.android.com/tools"
android:layout_width="match_parent"
android:layout_height="wrap_content">
<android.support.v7.widget.CardView
android:layout_width="0dp"
android:layout_height="wrap_content"
android:layout_marginBottom="8dp"
android:layout_marginEnd="8dp"
android:layout_marginStart="8dp"
android:layout_marginTop="8dp"
app:layout_constraintBottom_toBottomOf="parent"
app:layout_constraintEnd_toEndOf="parent"
app:layout_constraintStart_toStartOf="parent"
app:layout_constraintTop_toTopOf="parent">
<android.support.constraint.ConstraintLayout
android:layout_width="match_parent"
android:layout_height="match_parent"
android:background="@android:color/darker_gray">
<TextView
android:id="@+id/datetime"
android:layout_width="0dp"
android:layout_height="wrap_content"
android:layout_margin="8dp"
android:text="TextView"
app:layout_constraintEnd_toEndOf="parent"
app:layout_constraintStart_toStartOf="parent"
app:layout_constraintTop_toBottomOf="@+id/address" />
<TextView
android:id="@+id/details"
android:layout_width="0dp"
android:layout_height="wrap_content"
android:layout_margin="8dp"
android:text="TextView"
app:layout_constraintEnd_toEndOf="parent"
app:layout_constraintStart_toStartOf="parent"
app:layout_constraintTop_toBottomOf="@+id/datetime" />
<TextView
android:id="@+id/others"
android:layout_width="0dp"
android:layout_height="wrap_content"
android:layout_margin="8dp"
android:text="TextView"
app:layout_constraintEnd_toEndOf="parent"
app:layout_constraintStart_toStartOf="parent"
app:layout_constraintTop_toBottomOf="@+id/details" />
<TextView
android:id="@+id/address"
android:layout_width="0dp"
android:layout_height="wrap_content"
android:layout_margin="8dp"
android:text="TextView"
app:layout_constraintEnd_toEndOf="parent"
app:layout_constraintStart_toStartOf="parent"
app:layout_constraintTop_toBottomOf="@+id/type" />
<ImageView
android:id="@+id/image"
android:layout_width="0dp"
android:layout_height="120dp"
android:layout_marginEnd="8dp"
android:layout_marginStart="8dp"
android:layout_marginTop="8dp"
android:scaleType="centerCrop"
app:layout_constraintEnd_toEndOf="parent"
app:layout_constraintStart_toStartOf="parent"
app:layout_constraintTop_toBottomOf="@+id/others"
app:srcCompat="@drawable/bd_gov_logo" />
<TextView
android:id="@+id/type"
android:layout_width="0dp"
android:layout_height="wrap_content"
android:layout_margin="8dp"
android:text="TextView"
app:layout_constraintEnd_toEndOf="parent"
app:layout_constraintStart_toStartOf="parent"
app:layout_constraintTop_toTopOf="parent" />
</android.support.constraint.ConstraintLayout>
</android.support.v7.widget.CardView>
</android.support.constraint.ConstraintLayout>
Thatz it !!!！根据需要编辑类。谢谢兄弟：）