Question

我试图使用RecyclerView在游戏中拥有可变数量的玩家。玩家的数量是通过加载此活动的额外传递来设置的。目标是让玩家#X： EditText ＆＃34;为每个玩家插入他的名字，抓住这些名字并将其发送到新的活动中。

我面临的问题是RecyclerView似乎不起作用。加载活动时，没有文本视图或编辑区域，请选择白色屏幕。底部按钮工作正常。我可以看到＆＃34;区＆＃34;通过向上和向下拉动为RecyclerView创建，它显示蓝色＆＃34;页面末尾＆＃34;标记。

这是代码，如果你可以帮我弄清楚发生了什么：

活动（java）

package com.olirwin.spartacus.deutsch;

import android.content.Intent;
import android.support.v7.app.AppCompatActivity;  
import android.os.Bundle;
import android.support.v7.widget.LinearLayoutManager;
import android.support.v7.widget.RecyclerView;
import android.text.Editable;
import android.text.TextWatcher;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;
import android.widget.Button;
import android.widget.EditText;
import android.widget.LinearLayout;
import android.widget.TextView;

import java.util.ArrayList;

public class players extends AppCompatActivity {

ArrayList<String> playerNames;
Button send;
PlayerAdapter Adapter;
RecyclerView playerList;
String[] names;

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

    playerNames = new ArrayList<String>();

    final ArrayList<Player> players = new ArrayList<Player>();
    send = findViewById(R.id.b_send);



    Bundle extra = new Bundle();
    final int numPlayers = extra.getInt("num");

    for (int i = 0; i < numPlayers; i++)
    {
        playerNames.add("Joueur " + (i+1) + " : ");
    }
    playerList = findViewById(R.id.player_list);
    playerList.setLayoutManager(new LinearLayoutManager(this));
    Adapter = new PlayerAdapter();
    playerList.setAdapter(Adapter);
    names = new String[numPlayers];



    Adapter.notifyDataSetChanged();

    send.setOnClickListener(new View.OnClickListener() {
        @Override
        public void onClick(View view) {
            for (int i = 0; i < numPlayers; i++) {
                players.add(new Player(names[i]));
            }

            Intent intent = new Intent(view.getContext(), Score.class);
            intent.putExtra("players", players);
            view.getContext().startActivity(intent);
        }
    });

}



private class PlayerAdapter extends             
RecyclerView.Adapter<PlayerAdapter.PlayerHolder> {


    @Override
    public PlayerHolder onCreateViewHolder(ViewGroup parent, int viewType) {
        View v = 
LayoutInflater.from(players.this).inflate(R.layout.list_cell, parent, 
false);
        return new PlayerHolder(v);
    }


    @Override
    public void onBindViewHolder(PlayerHolder holder, final int position) {
        holder.bind(playerNames.get(position));

        holder.mPlayerName.addTextChangedListener(new TextWatcher() {
            @Override
            public void beforeTextChanged(CharSequence charSequence, int 
start, int before,
                                          int count) {
                names[position] = charSequence.toString();
            }

            @Override
            public void onTextChanged(CharSequence charSequence, int start, 
int before,
                                      int count){

            }

            @Override
            public void afterTextChanged(Editable editable) {

            }
        });



    }

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



    public class PlayerHolder extends RecyclerView.ViewHolder {

        TextView mPlayerLabel;
        EditText mPlayerName;


        public PlayerHolder(View itemView) {
            super(itemView);
            mPlayerLabel = itemView.findViewById(R.id.player_label);
            mPlayerName = itemView.findViewById(R.id.player_name);
        }

        public void bind(String playerName) {
            mPlayerLabel.setText(playerName);
            mPlayerName.setHint("Nom de " + playerName);
        }

        public String getData(){
            return mPlayerName.getText().toString();
        }

    }
}
}

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="match_parent"
tools:context="com.olirwin.spartacus.deutsch.players">

<android.support.v7.widget.RecyclerView
    android:id="@+id/player_list"
    android:layout_width="0dp"
    android:layout_height="476dp"
    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_constraintHorizontal_bias="0.0"
    app:layout_constraintStart_toStartOf="parent"
    app:layout_constraintTop_toTopOf="parent"
    app:layout_constraintVertical_bias="0.0" />

<Button
    android:id="@+id/b_send"
    android:layout_width="wrap_content"
    android:layout_height="wrap_content"
    android:layout_gravity="center_horizontal"
    android:layout_marginBottom="8dp"
    android:layout_marginEnd="8dp"

    android:layout_marginStart="8dp"
    android:layout_marginTop="8dp"
    android:text="Valider"
    app:layout_constraintBottom_toBottomOf="parent"
    app:layout_constraintEnd_toEndOf="parent"
    app:layout_constraintStart_toStartOf="parent"
    app:layout_constraintTop_toBottomOf="@+id/player_list" />



</android.support.constraint.ConstraintLayout>

Answer 1

问题在于您的自定义适配器constructor，您甚至没有在列表中传递数据来填充！尝试学习调试它会让你的生活更轻松。！

 Adapter = new PlayerAdapter(playerNames,context);


private class PlayerAdapter extends             
RecyclerView.Adapter<PlayerAdapter.PlayerHolder> {

ArrayList<String> playerNames;

Context context;

   public PlayerAdapter (ArrayList<String> arrayList, Context context) {
            playerNames= arrayList;
            context = context;
        }


    @Override
    public PlayerHolder onCreateViewHolder(ViewGroup parent, int viewType) {
        View v = 
LayoutInflater.from(players.this).inflate(R.layout.list_cell, parent, 
false);
        return new PlayerHolder(v);
    }



}

Answer 2

未传递给适配器以进行填充的项目。

public class players extends AppCompatActivity {

ArrayList<String> playerNames;
Button send;
PlayerAdapter Adapter;
RecyclerView playerList;
String[] names;

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

    playerNames = new ArrayList<String>();

    final ArrayList<Player> players = new ArrayList<Player>();
    send = findViewById(R.id.b_send);



    Bundle extra = new Bundle();
    final int numPlayers = extra.getInt("num");

    for (int i = 0; i < numPlayers; i++)
    {
        playerNames.add("Joueur " + (i+1) + " : ");
    }
    playerList = findViewById(R.id.player_list);
    playerList.setLayoutManager(new LinearLayoutManager(this));
    Adapter = new PlayerAdapter(playerNames,this);
    playerList.setAdapter(Adapter);
    names = new String[numPlayers];



    Adapter.notifyDataSetChanged();

    send.setOnClickListener(new View.OnClickListener() {
        @Override
        public void onClick(View view) {
            for (int i = 0; i < numPlayers; i++) {
                players.add(new Player(names[i]));
            }

            Intent intent = new Intent(view.getContext(), Score.class);
            intent.putExtra("players", players);
            view.getContext().startActivity(intent);
        }
    });

}



private class PlayerAdapter extends             
RecyclerView.Adapter<PlayerAdapter.PlayerHolder> {
private ArrayList<String> playerNames;
private Context context;

  public PlayerAdapter (ArrayList<String> playerNames, Context context) {
    this.playerNames = playerNames;
    this.context = context;
}

    @Override
    public PlayerHolder onCreateViewHolder(ViewGroup parent, int viewType) {
        View v = 
LayoutInflater.from(players.this).inflate(R.layout.list_cell, parent, 
false);
        return new PlayerHolder(v);
    }


    @Override
    public void onBindViewHolder(PlayerHolder holder, final int position) {
        holder.bind(this.playerNames.get(position));

        holder.mPlayerName.addTextChangedListener(new TextWatcher() {
            @Override
            public void beforeTextChanged(CharSequence charSequence, int 
start, int before,
                                          int count) {
                names[position] = charSequence.toString();
            }

            @Override
            public void onTextChanged(CharSequence charSequence, int start, 
int before,
                                      int count){

            }

            @Override
            public void afterTextChanged(Editable editable) {

            }
        });



    }

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



    public class PlayerHolder extends RecyclerView.ViewHolder {

        TextView mPlayerLabel;
        EditText mPlayerName;


        public PlayerHolder(View itemView) {
            super(itemView);
            mPlayerLabel = itemView.findViewById(R.id.player_label);
            mPlayerName = itemView.findViewById(R.id.player_name);
        }

        public void bind(String playerName) {
            mPlayerLabel.setText(playerName);
            mPlayerName.setHint("Nom de " + playerName);
        }

        public String getData(){
            return mPlayerName.getText().toString();
        }

    }
}
}

希望这会有所帮助。

RecyclerView不显示项目 - Android

2 个答案: