如何从 firebase RecyclerView 中删除项目

我目前正在 firebase RecyclerView 的帮助下添加朋友，其中如果用户点击添加按钮，他将被添加到数据库 n 中，需要永久删除点击的项目..那么，如何实现它通过 firebase 模型，因为我们没有任何数据列表可以从中删除..

这是代码

@Override
public void onStart(){

super.onStart();
SharedPreferences prefs = PreferenceManager.getDefaultSharedPreferences(mContext);
EmailPref=prefs.getString("EmailPref", EmailPref);
if(EmailPref!=null){

    final Firebase ref = new Firebase(constants.FIREBASE_URL+"rootssahaj/authGplus");


    FirebaseRecyclerAdapter adapter=new FirebaseRecyclerAdapter(
                     FriendsData.class,
                     R.layout.chat_view_list,
                      FriendsViewHolder.class,
                     ref

                ) {
        @TargetApi(Build.VERSION_CODES.KITKAT)
        @Override
        protected void populateViewHolder(FriendsViewHolder friendsViewHolder, FriendsData s, int position) {
            String key = this.getRef(position).getKey();
            Log.e("SahajLOG", "String Keyyy " + key + " n EmailPref" + EmailPref);

            if (!Objects.equals(key, EmailPref)) {
                friendsViewHolder.mName.setText(s.getUserNAME());
                Picasso.with(context).load(s.getPicurl()).transform(new CircleTransform()).into(friendsViewHolder.mImageProfile);


                String keylocal = key;
                Log.e("pavan", "Populate AddF key" + keylocal+" " + position);
                SharedPreferences prefs = PreferenceManager.getDefaultSharedPreferences(mContext);
                prefs.getString("keylocal" + position, keylocal + position);
                if (keylocal != null) {
                    prefs.edit().putString("keylocal" + position, keylocal + position).commit();
                }
            } else {
                friendsViewHolder.mCardView.setVisibility(View.GONE);
                //friendsViewHolder.setVisibility(View.GONE);
            }

        }
    };

    recyclerView.setLayoutManager(new LinearLayoutManager(getActivity()));
    recyclerView.setItemAnimator(new SlideInLeftAnimator());
    recyclerView.getItemAnimator().setAddDuration(1000);
    recyclerView.getItemAnimator().setRemoveDuration(1000);
    recyclerView.getItemAnimator().setMoveDuration(1000);
    recyclerView.getItemAnimator().setChangeDuration(1000);


    SlideInLeftAnimator animator = new SlideInLeftAnimator();
    animator.setInterpolator(new OvershootInterpolator());
    recyclerView.setItemAnimator(animator);
    AlphaInAnimationAdapter alphaAdapter = new AlphaInAnimationAdapter(adapter);
    alphaAdapter.setDuration(500);
    alphaAdapter.setInterpolator(new OvershootInterpolator(.5f));
    alphaAdapter.setFirstOnly(false);
    recyclerView.setAdapter(new ScaleInAnimationAdapter(alphaAdapter));


}

}

public class FriendsViewHolder extends RecyclerView.ViewHolder{

ImageView mImageProfile;
android.widget.TextView mName;
private int mVisibility;
Boolean CallAdd=false;
Button mAdd;
String keylocal;
CardView mCardView;

public FriendsViewHolder(View itemView) {
    super(itemView);
    mCardView=(CardView)itemView.findViewById(R.id.cardView);
    mImageProfile=(ImageView)itemView.findViewById(R.id.profilePICC);
    mName=(android.widget.TextView)itemView.findViewById(R.id.NameUSER);
    context = itemView.getContext();
    mAdd=(Button)itemView.findViewById(R.id.addButton);
    SharedPreferences prefs = PreferenceManager.getDefaultSharedPreferences(context);
    if(prefs.getBoolean("CallAdd", CallAdd)){
        AddaddButton();

    }

    mAdd.setOnClickListener(new View.OnClickListener() {
        @Override
        public void onClick(View v) {
            SharedPreferences prefs = PreferenceManager.getDefaultSharedPreferences(mContext);
           EmailPref = prefs.getString("EmailPref", EmailPref);
           keylocal=prefs.getString("keylocal"+getAdapterPosition(),keylocal+getAdapterPosition());

           final Firebase mFirebaseRef = new Firebase(constants.FIREBASE_URL + "rootssahaj/authGplus/"+ EmailPref);
            mFirebaseRef.child("friends").child(keylocal).setValue("true");
            Log.e("pavan", "Chat Adapter " + EmailPref + keylocal + " final key: " + keylocal);
            //remove(getAdapterPosition());

        }
    });
}
public void AddaddButton(){
    if (mAdd.getVisibility() == View.INVISIBLE) {
        mAdd.setVisibility(View.VISIBLE);
    }
}

}
解决方案

如果您查看此代码，它会在以下情况下从 Firebase 中删除一条注释单击注释.如果您了解 Firebase 查询，这似乎很简单.一旦 RecyclerView 适配器设置正确，这也将更新 RecyclerView.您不需要数据列表，只需要您要删除的内容的值，例如 ID 或键.

@Override

    public void onLongClick(View v, int i) {
        mquery.orderByChild("text")
                .equalTo((String) notes.get(i).getName())
                .addListenerForSingleValueEvent(new ValueEventListener() {
                    public void onDataChange(DataSnapshot dataSnapshot) {
                        if (dataSnapshot.hasChildren()) {
                            DataSnapshot firstChild = dataSnapshot.getChildren().iterator().next();
                            firstChild.getRef().removeValue();
                        }
                    }

                    public void onCancelled(FirebaseError firebaseError) {
                    }
                });

来自https://www.itbaoku.cn/ .大多数情况下，我只是复制和粘贴.这是一个抽象类，可用于为 Firebase 数据库制作 RecyclerView 适配器.所有代码都在该 GitHub 存储库中.这是 FirebaseRecyclerAdapter.class 中的一个片段，它从 Firebase 中删除了该值并更新了 recyclerView:

@Override

public void onChildRemoved(DataSnapshot dataSnapshot) {
    String key = dataSnapshot.getKey();

    if (mKeys.contains(key)) {
        int index = mKeys.indexOf(key);
        T item = mItems.get(index);

        mKeys.remove(index);
        mItems.remove(index);

        notifyItemRemoved(index);
        itemRemoved(item, key, index);
    }
}

更新:您可以在 RecyclerView 适配器的 Viewholder 中隐藏视图.在 stackoverflow 中查看这些答案 在 RecyclerView 中隐藏视图

原文地址：https://www.itbaoku.cn/post/2...