关于java:如何从-firebase-RecyclerView-中删除项目

我目前正在 firebase RecyclerView 的帮忙下增加敌人，其中如果用户点击增加按钮，他将被增加到数据库 n 中，须要永恒删除点击的我的项目..那么，如何实现它通过 firebase 模型，因为咱们没有任何数据列表能够从中删除..

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<FriendsData,FriendsViewHolder> adapter=new FirebaseRecyclerAdapter<FriendsData, FriendsViewHolder>(                     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，它会在以下状况下从 Firebase 中删除一条正文单击正文.如果您理解 Firebase 查问，这仿佛很简略.一旦 RecyclerView 适配器设置正确，这也将更新 RecyclerView.您不须要数据列表，只须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/ .大多数状况下，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:您能够在 RecyclerView 适配器的 Viewholder 中暗藏视图.在 stackoverflow 中查看这些答案 在 RecyclerView 中暗藏视图

原文地址：https://www.itbaoku.cn/post/2...