recyclerView中没有显示数据，需要返回显示

Question

我想创建一个 activity 来按全名搜索用户。我创建了我需要的一切并且它工作正常，除了一件事。当我按下搜索按钮时，结果不会显示在 recyclerview 中。我需要返回并显示结果。我需要执行这两个步骤才能看到结果。

是的，搜索栏和视图持有者重叠，我稍后会尝试修复。您知道如何做到搜索后立即显示结果而无需返回吗

这是我的视图持有者布局

<?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"
    xmlns:tools="http://schemas.android.com/tools"
    android:layout_width="match_parent"
    android:layout_height="75dp"
    android:layout_marginLeft="5dp"
    android:layout_marginRight="5dp"
    android:layout_marginTop="5dp"
    android:id="@+id/parent_layout"
    android:background="@drawable/recycler_view_border">

    <com.mikhaellopez.circularimageview.CircularImageView
        android:id="@+id/imageProfile"
        android:layout_width="60dp"
        android:layout_height="60dp"
        android:tint="#808080"
        android:layout_marginStart="10dp"
        android:layout_marginTop="7dp"
        app:civ_border_color="@color/dark_blue"
        app:civ_border_width="2dp"
        app:srcCompat="@drawable/defaultimage"/>

    <TextView
        android:id="@+id/userFullName"
        android:layout_toEndOf="@+id/imageProfile"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_marginTop="25dp"
        android:layout_marginEnd="20dp"
        android:layout_marginStart="10dp"
        android:gravity="center"
        android:text="@string/fullname"
        android:textSize="16sp"
        android:textColor="@color/black"/>

    <com.google.android.material.button.MaterialButton
        android:id="@+id/buttonAdd"
        android:layout_width="50dp"
        android:layout_height="50dp"
        android:layout_marginTop="13dp"
        android:layout_marginEnd="10dp"
        android:layout_marginStart="340dp"
        android:background="@drawable/btn_background"
        app:cornerRadius="8dp"
        android:drawableTop="@drawable/ic_action_add" />

</RelativeLayout>

这是我为 activity

设计的布局

<?xml version="1.0" encoding="utf-8"?>
<androidx.constraintlayout.widget.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="match_parent"
    tools:context=".SendFriendRequests">

    <LinearLayout
        android:id="@+id/linearlayout"
        android:layout_width="match_parent"
        android:layout_height="100dp"
        android:layout_marginLeft="13dp"
        android:orientation="vertical"
        app:layout_constraintEnd_toEndOf="parent"
        app:layout_constraintStart_toStartOf="parent"
        app:layout_constraintTop_toTopOf="parent">


        <EditText
            android:id="@+id/searchUsername"
            android:layout_width="318dp"
            android:layout_height="45dp"
            android:layout_marginTop="20dp"
            android:background="@drawable/edt_background"
            android:hint="@string/searchFriends"
            android:imeOptions="actionNext"
            android:importantForAutofill="no"
            android:inputType="text"
            android:paddingStart="16dp"
            android:paddingEnd="16dp" />


        <com.google.android.material.button.MaterialButton
            android:id="@+id/buttonSearch"
            android:layout_width="50dp"
            android:layout_height="50dp"
            android:layout_marginStart="333dp"
            android:layout_marginTop="-47dp"
            android:layout_marginEnd="10dp"
            android:background="@drawable/btn_background"
            android:drawableTop="@drawable/ic_action_search"
            app:cornerRadius="8dp" />


    </LinearLayout>

    <androidx.recyclerview.widget.RecyclerView
        android:id="@+id/recyclerView"
        android:layout_width="match_parent"
        android:layout_height="580dp"
        app:layout_constraintBottom_toBottomOf="parent"
        app:layout_constraintTop_toBottomOf="@+id/linearlayout"
        app:layout_constraintVertical_bias="0.99"
        tools:layout_editor_absoluteX="-16dp" />

</androidx.constraintlayout.widget.ConstraintLayout>

这是我的适配器

package com.example.chatappjava;

import android.annotation.SuppressLint;
import android.content.Context;
import android.content.Intent;
import android.util.Log;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;
import android.widget.Button;
import android.widget.RelativeLayout;
import android.widget.TextView;
import android.widget.Toast;

import androidx.recyclerview.widget.RecyclerView;

import com.bumptech.glide.Glide;
import com.mikhaellopez.circularimageview.CircularImageView;

import java.sql.Connection;
import java.sql.PreparedStatement;
import java.sql.SQLException;
import java.util.ArrayList;

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

    private static final String TAG = "ContactsAdapter";

    private ArrayList<UserData> arrayListUserData = new ArrayList<>();
    private Context context;

    public SendFriendRequestAdapter(ArrayList<UserData> arrayListUserData, Context context) {
        this.arrayListUserData = arrayListUserData;
        this.context = context;
    }

    @Override
    public ViewHolder onCreateViewHolder(ViewGroup parent, int viewType) {
        View view = LayoutInflater.from(parent.getContext()).inflate(R.layout.activity_send_friend_request_item, parent, false);
        ViewHolder holder = new ViewHolder(view);
        return holder;
    }

    @Override
    public void onBindViewHolder(ViewHolder holder, @SuppressLint("RecyclerView") int position) {
        Log.d(TAG, "onBindViewHolder: called.");

        Glide.with(context)
                .asBitmap()
                .load(arrayListUserData.get(position).image)
                .into(holder.userProfileImage);

        holder.userFullName.setText(arrayListUserData.get(position).name);

        holder.buttonAdd.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View view) {
                try {
                    Connection conn = DatabaseConnection.createDatabaseConnection();

                    PreparedStatement st1 = conn.prepareStatement(
                            " insert into FRIEND_REQUESTS values (?,?,?)");
                    st1.setString(1, arrayListUserData.get(position).friendId);
                    st1.setString(2, arrayListUserData.get(position).userId);
                    st1.setInt(3, 0);
                    st1.execute();

                    showToast("Friend request is sended");

                    Intent intent = new Intent(context, MainActivity.class);
                    intent.putExtra("IdAccount", arrayListUserData.get(position).userId);
                    context.startActivity(intent);

                } catch (SQLException e) {
                    e.printStackTrace();
                } catch (Exception e) {
                    e.printStackTrace();
                }
            }
        });

        holder.parentLayout.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View view) {
                Intent intent = new Intent(context.getApplicationContext(), specificchat.class);
                intent.putExtra("userId", arrayListUserData.get(position).userId);
                intent.putExtra("friendId", arrayListUserData.get(position).friendId);
                intent.putExtra("friendName", arrayListUserData.get(position).name);
                intent.putExtra("friendImage", arrayListUserData.get(position).image);
                context.startActivity(intent);
            }
        });
    }

    private void showToast(String message) {
        Toast.makeText(context.getApplicationContext(), message, Toast.LENGTH_SHORT).show();
    }

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

    public class ViewHolder extends RecyclerView.ViewHolder {

        CircularImageView userProfileImage;
        TextView userFullName;
        RelativeLayout parentLayout;
        Button buttonAdd;

        public ViewHolder(View itemView) {
            super(itemView);
            userProfileImage = itemView.findViewById(R.id.imageProfile);
            userFullName = itemView.findViewById(R.id.userFullName);
            parentLayout = itemView.findViewById(R.id.parent_layout);
            buttonAdd = itemView.findViewById(R.id.buttonAdd);
        }
    }
}

这是我的javaclass，它使用了适配器

package com.example.chatappjava;

import android.content.Intent;
import android.os.Bundle;
import android.view.View;
import android.widget.Button;
import android.widget.EditText;

import androidx.appcompat.app.AppCompatActivity;
import androidx.recyclerview.widget.LinearLayoutManager;
import androidx.recyclerview.widget.RecyclerView;

import java.sql.Connection;
import java.sql.ResultSet;
import java.sql.SQLException;
import java.sql.Statement;
import java.util.ArrayList;

public class SendFriendRequests extends AppCompatActivity {

    private ArrayList<UserData> arrayListUserData = new ArrayList<>();
    private Button searchButton;
    private EditText searchUsername;
    private String userId;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);

        Intent intent = getIntent();
        userId = intent.getStringExtra("IdAccount");
        setContentView(R.layout.activity_send_friend_request);
        searchButton = findViewById(R.id.buttonSearch);
        searchUsername = findViewById(R.id.searchUsername);

        searchButton.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View view) {
                try {
                    Connection conn = DatabaseConnection.createDatabaseConnection();
                    Statement statement = conn.createStatement();

                    ResultSet resultat = statement.executeQuery("select ID, FULLNAME, IMAGE from USERS where ID not in (select FRIEND_ID from FRIENDSLIST where USER_ID = " + userId  + ") and FULLNAME like '%" + searchUsername.getText().toString() + "%' and ID not in (select RECEIVER_ID from FRIEND_REQUESTS where SENDER_ID = " + userId  + ")");
                    while (resultat.next()) {
                        arrayListUserData.add(new UserData(resultat.getString("FULLNAME"), resultat.getString("IMAGE"), resultat.getString("ID"), userId));
                    }
                } catch (SQLException e) {
                    e.printStackTrace();
                } catch (Exception e) {
                    e.printStackTrace();
                }
                initRecycleView();

            }
        });


    }

    private void initRecycleView() {
        RecyclerView recyclerView = findViewById(R.id.recyclerView);
        SendFriendRequestAdapter adapter = new SendFriendRequestAdapter(arrayListUserData, this);
        recyclerView.setAdapter(adapter);
        recyclerView.setLayoutManager(new LinearLayoutManager(this));

    }
}

Answer 1

我认为你的 XML 中的 RecyclerView 需要调整为 android:layout_height = "0dp"

<androidx.recyclerview.widget.RecyclerView
        android:id="@+id/recyclerView"
        android:layout_width="match_parent"
        android:layout_height="0dp"
        app:layout_constraintBottom_toBottomOf="parent"
        app:layout_constraintTop_toBottomOf="@+id/linearlayout"/>

recyclerView中没有显示数据，需要返回显示

Data doesn't show in recyclerView, need to go back to show it

android

android-recyclerview