java - Android Studio RecyclerView

问题描述

我收到错误 E/RecyclerView：未连接适配器；运行程序时跳过布局。每当我运行代码时，我都无法在搜索片段中看到用户名和全名。我刚刚收到错误 E/RecyclerView: No adapter attach; 在 Logcat 中跳过布局。仅显示图像。我该如何解决这个问题？

我的片段是：

package com.example.getalong.Fragments;

import android.os.Bundle;

import androidx.annotation.NonNull;
import androidx.fragment.app.Fragment;
import androidx.recyclerview.widget.LinearLayoutManager;
import androidx.recyclerview.widget.RecyclerView;

import android.text.TextUtils;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;

import com.example.getalong.Adapter.UserAdapter;
import com.example.getalong.Model.User;
import com.example.getalong.R;
import com.google.firebase.database.DataSnapshot;
import com.google.firebase.database.DatabaseError;
import com.google.firebase.database.DatabaseReference;
import com.google.firebase.database.FirebaseDatabase;
import com.google.firebase.database.ValueEventListener;
import com.hendraanggrian.appcompat.widget.SocialAutoCompleteTextView;

import java.util.ArrayList;
import java.util.List;

public class SearchFragment extends Fragment {

    private RecyclerView recyclerView;
    private SocialAutoCompleteTextView search_bar;
    private List<User> mUsers;
    private UserAdapter userAdapter;

    @Override
    public View onCreateView(LayoutInflater inflater, ViewGroup container,
                             Bundle savedInstanceState) {
        View view = inflater.inflate(R.layout.fragment_search, container, false);

        recyclerView = view.findViewById(R.id.recycler_view_users);
        recyclerView.setHasFixedSize(true);
        recyclerView.setLayoutManager(new LinearLayoutManager(getContext()));

        mUsers = new ArrayList<>();
        userAdapter = new UserAdapter(getContext(), mUsers, true);
        recyclerView.setAdapter(userAdapter);

        search_bar = view.findViewById(R.id.search_bar);

        readUsers();

        return view;
    }

    private void readUsers() {

        DatabaseReference reference = FirebaseDatabase.getInstance().getReference().child("Users");
        reference.addValueEventListener(new ValueEventListener() {
            @Override
            public void onDataChange(@NonNull DataSnapshot dataSnapshot) {
                if(TextUtils.isEmpty(search_bar.getText().toString())){
                    mUsers.clear();

                    for(DataSnapshot snapshot : dataSnapshot.getChildren()){
                        User user = snapshot.getValue(User.class);
                        mUsers.add(user);
                    }

                    userAdapter.notifyDataSetChanged();
                }
            }

            @Override
            public void onCancelled(@NonNull DatabaseError error) {

            }
        });
    }
}

我的适配器类是：

package com.example.getalong.Adapter;

import android.content.Context;
import android.util.Log;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;
import android.widget.Button;
import android.widget.TextView;

import androidx.annotation.NonNull;
import androidx.recyclerview.widget.RecyclerView;

import com.example.getalong.Model.User;
import com.example.getalong.R;
import com.google.firebase.auth.FirebaseAuth;
import com.google.firebase.auth.FirebaseUser;
import com.google.firebase.database.DataSnapshot;
import com.google.firebase.database.DatabaseError;
import com.google.firebase.database.DatabaseReference;
import com.google.firebase.database.FirebaseDatabase;
import com.google.firebase.database.ValueEventListener;
import com.squareup.picasso.Picasso;

import java.util.List;

import de.hdodenhof.circleimageview.CircleImageView;

public class UserAdapter extends RecyclerView.Adapter<UserAdapter.ViewHolder> {

    private Context mContext;
    private List<User> mUsers;
    private boolean isFragment;

    private FirebaseUser firebaseUser;

    public UserAdapter(Context mContext, List<User> mUsers, boolean isFragment){
        this.mContext = mContext;
        this.mUsers = mUsers;
        this.isFragment = isFragment;
    }

    @NonNull
    @Override
    public ViewHolder onCreateViewHolder(@NonNull ViewGroup parent, int viewType) {
        View view = LayoutInflater.from(mContext).inflate(R.layout.user_item, parent, false);
        return new UserAdapter.ViewHolder(view);
    }


    @Override
    public void onBindViewHolder(@NonNull ViewHolder holder, int position) {

        firebaseUser = FirebaseAuth.getInstance().getCurrentUser();

        User user = mUsers.get(position);
        holder.btnFollow.setVisibility(View.VISIBLE);
        holder.username.setText(user.getUsername());
        holder.fullname.setText(user.getName());

        Picasso.get().load(user.getImageurl()).placeholder(R.mipmap.ic_launcher).into(holder.imageProfile);

        isFollowed(user.getId(), holder.btnFollow);

        if(user.getId().equals(firebaseUser.getUid())){
            holder.btnFollow.setVisibility(View.GONE);
        }
    }

    private void isFollowed(final String id, final Button btnFollow) {

        DatabaseReference reference = FirebaseDatabase.getInstance().getReference().child("follow").child(firebaseUser.getUid()).child("following");

        reference.addValueEventListener(new ValueEventListener() {
            @Override
            public void onDataChange(@NonNull DataSnapshot dataSnapshot) {
                if(dataSnapshot.child(id).exists()) {
                    btnFollow.setText("Following");
                }
                else {
                    btnFollow.setText("Follow");
                }
            }

            @Override
            public void onCancelled(@NonNull DatabaseError error) {

            }
        });
    }

    @Override
    public int getItemCount() {
        return mUsers.size();
    }

    public class ViewHolder extends RecyclerView.ViewHolder{

        public CircleImageView imageProfile;
        public TextView username;
        public TextView fullname;
        public Button btnFollow;

        public ViewHolder(@NonNull View itemView) {
            super(itemView);

            imageProfile = itemView.findViewById(R.id.image_profile);
            username = itemView.findViewById(R.id.username);
            fullname = itemView.findViewById(R.id.fullname);
            btnFollow = itemView.findViewById(R.id.btn_follow);
        }
    }
}

我的模型用户类是：

package com.example.getalong.Model;

public class User {

    private String name;
    private String email;
    private String username;
    private String bio;
    private String imageurl;
    private String id;

    public User(){
    }

    public User(String name, String email, String username, String bio, String imageurl, String id){
        this.name = name;
        this.email = email;
        this.username = username;
        this.imageurl = imageurl;
        this.bio = bio;
        this.id = id;
    }

    public String getName() {
        return name;
    }

    public void setName(String name) {
        this.name = name;
    }

    public String getEmail() {
        return email;
    }

    public void setEmail(String email) {
        this.email = email;
    }

    public String getUsername() {
        return username;
    }

    public void setUsername(String username) {
        this.username = username;
    }

    public String getBio() {
        return bio;
    }

    public void setBio(String bio) {
        this.bio = bio;
    }

    public String getImageurl() {
        return imageurl;
    }

    public void setImageurl(String imageurl) {
        this.imageurl = imageurl;
    }

    public String getId() {
        return id;
    }

    public void setId(String id) {
        this.id = id;
    }
}

我的资源文件是：

片段搜索.xml

<?xml version="1.0" encoding="utf-8"?>
<RelativeLayout
    xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:tools="http://schemas.android.com/tools"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    tools:context=".Fragments.SearchFragment">

    <com.google.android.material.appbar.AppBarLayout
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:id="@+id/bar"
        android:background="?android:attr/windowBackground">

        <androidx.appcompat.widget.Toolbar
            android:layout_width="match_parent"
            android:layout_height="wrap_content"
            android:id="@+id/toolbar"
            android:background="?android:attr/windowBackground">

            <ImageView
                android:layout_width="wrap_content"
                android:layout_height="wrap_content"
                android:src="@drawable/ic_search"/>

            <com.hendraanggrian.appcompat.widget.SocialAutoCompleteTextView
                android:layout_width="match_parent"
                android:layout_height="wrap_content"
                android:id="@+id/search_bar"
                android:background="@android:color/transparent"
                android:hint="Search"
                android:layout_marginStart="10dp"
                android:layout_marginLeft="10dp" />
        </androidx.appcompat.widget.Toolbar>
    </com.google.android.material.appbar.AppBarLayout>

    <androidx.recyclerview.widget.RecyclerView
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:id="@+id/recycler_view_users"
        android:layout_below="@id/bar"/>

    <androidx.recyclerview.widget.RecyclerView
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:id="@+id/recycler_view_tags"
        android:layout_below="@id/recycler_view_users"
        android:layout_marginTop="5dp"/>

</RelativeLayout>

用户项目.xml

<?xml version="1.0" encoding="utf-8"?>
<RelativeLayout
    xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:app="http://schemas.android.com/apk/res-auto"
    android:layout_width="match_parent"
    android:layout_height="wrap_content"
    android:padding="10dp">

    <de.hdodenhof.circleimageview.CircleImageView
        android:layout_width="50dp"
        android:layout_height="50dp"
        android:id="@+id/image_profile"
        android:src="@mipmap/ic_launcher"/>

    <LinearLayout
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_toEndOf="@id/image_profile"
        android:layout_toRightOf="@id/image_profile"
        android:layout_marginStart="5dp"
        android:layout_marginLeft="5dp"
        android:orientation="vertical"
        android:layout_centerVertical="true">

        <TextView
            android:id="@+id/username"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:maxLines="1"
            android:text="Username"
            android:textColor="@color/design_default_color_primary_dark"
            android:textStyle="bold" />

        <TextView
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:id="@+id/fullname"
            android:text="Fullname"
            android:maxLines="1"/>
    </LinearLayout>

    <Button
        android:layout_width="wrap_content"
        android:layout_height="30dp"
        android:background="@drawable/button_background"
        android:backgroundTint="@color/background"
        app:backgroundTint="@color/background"
        android:id="@+id/btn_follow"
        android:textColor="@color/colorPrimary"
        android:layout_alignParentEnd="true"
        android:layout_alignParentRight="true"
        android:layout_centerVertical="true"
        android:visibility="gone"/>
</RelativeLayout>

标签： javaandroidfirebaseandroid-recyclerview

java - Android Studio RecyclerView

问题描述

解决方案

将您的适配器放在回调方法中。

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