HashMap实现单选（HansMap的遍历）-CFANZ编程社区

1. MainActivity 主要代码以及 activity_main 布局文件代码

MainActivity 代码：

import android.support.v7.app.AppCompatActivity;
import android.os.Bundle;
import android.support.v7.widget.GridLayoutManager;
import android.support.v7.widget.RecyclerView;
import android.widget.Toast;

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

/**
 * author: wu
 * date: on 2018/11/12.
 * describe:单选主 Activity
 */
public class MainActivity extends AppCompatActivity {
    private List<String> list;
    private RecyclerView rv_one;

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

        //列表中添加数据
        setList();
        //设置单选适配器
        setOne();
    }

    private void setList() {
        list = new ArrayList<>();
        list.add("英雄联盟");
        list.add("王者荣耀");
        list.add("刺激战场");
        list.add("绝地求生");
        list.add("第五人格");
        list.add("唱歌");
        list.add("聊天");
        list.add("全军出击");
    }

    private void setOne() {
        rv_one = findViewById(R.id.rv_one);
        OneAdapter adapter = new OneAdapter(this, list);
        rv_one.setAdapter(adapter);
        rv_one.setLayoutManager(new GridLayoutManager(this, 3));
        //adapter中item点击事件
        adapter.setOnItemClickListerer(new OneAdapter.OnItemClickListener() {
            @Override
            public void onItemClick(int position, String name) {
                Toast.makeText(MainActivity.this, name, Toast.LENGTH_SHORT).show();
            }
        });
    }
}

activity_main 代码：

<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:orientation="vertical">

    <TextView
        android:layout_width="match_parent"
        android:layout_height="40dp"
        android:background="@color/colorPrimary"
        android:gravity="center"
        android:text="HashMap实现单选" />

    <android.support.v7.widget.RecyclerView
        android:id="@+id/rv_one"
        android:layout_width="match_parent"
        android:layout_height="wrap_content" />

</LinearLayout>

2. OneAdapter 主要代码以及 adapter_one 布局文件代码

OneAdapter 代码：

import android.content.Context;
import android.graphics.Color;
import android.support.v7.widget.RecyclerView;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;
import android.widget.TextView;

import java.util.HashMap;
import java.util.List;

/**
 * author: wu
 * date: on 2018/11/12.
 * describe:单选适配器
 */

public class OneAdapter extends RecyclerView.Adapter<OneAdapter.GoodsListHolder> {
    private final LayoutInflater mInflater;
    private Context context;
    private List<String> list;
    //存储对号
    private HashMap<Integer, TextView> hashMapCheck = new HashMap<>();
    //存储名称
    private HashMap<Integer, TextView> hashMapName = new HashMap<>();

    public OneAdapter(Context mContext, List<String> list) {
        this.context = mContext;
        this.list = list;
        mInflater = LayoutInflater.from(context);
    }

    //接口回调
    public interface OnItemClickListener {
        void onItemClick(int position, String name);
    }

    public OneAdapter.OnItemClickListener mOnItemClickListerer;

    public void setOnItemClickListerer(OneAdapter.OnItemClickListener listerer) {
        this.mOnItemClickListerer = listerer;
    }

    @Override
    public int getItemCount() {
        return list != null ? list.size() : 0;
    }

    @Override
    public void onBindViewHolder(final GoodsListHolder holder, final int position) {
        holder.tv_name.setText(list.get(position));//设置显示名称
        hashMapCheck.put(position, holder.tv_check);//存储对号
        hashMapName.put(position, holder.tv_name);//存储名称
        //默认选中第一项
        if (position == 0) {
            holder.tv_check.setVisibility(View.VISIBLE);
            holder.tv_name.setTextColor(Color.parseColor("#FF3300"));
        } else {
            holder.tv_check.setVisibility(View.GONE);
            holder.tv_name.setTextColor(Color.parseColor("#FF666666"));
        }
        //item点击事件
        holder.itemView.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                //遍历对号全都隐藏
                for (HashMap.Entry<Integer, TextView> entry : hashMapCheck.entrySet()) {
                    entry.getValue().setVisibility(View.GONE);
                }
                //遍历名称设置为黑色
                for (HashMap.Entry<Integer, TextView> entry : hashMapName.entrySet()) {
                    entry.getValue().setTextColor(Color.parseColor("#FF666666"));
                }
                //设置选中的对号显示，和名称字体颜色
                holder.tv_check.setVisibility(View.VISIBLE);
                holder.tv_name.setTextColor(Color.parseColor("#FF3300"));
                //点击回调
                mOnItemClickListerer.onItemClick(position, list.get(position));
            }
        });
    }

    @Override
    public GoodsListHolder onCreateViewHolder(ViewGroup parent, int viewType) {
        View view = mInflater.inflate(R.layout.adapter_one, parent, false);
        GoodsListHolder viewHolder = new GoodsListHolder(view);
        return viewHolder;
    }

    class GoodsListHolder extends RecyclerView.ViewHolder {
        TextView tv_check, tv_name;

        public GoodsListHolder(View itemView) {
            super(itemView);
            tv_name = itemView.findViewById(R.id.tv_name);
            tv_check = itemView.findViewById(R.id.tv_check);
        }
    }
}

adapter_one 代码：

<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:layout_width="match_parent"
    android:layout_height="35dp"
    android:layout_margin="10dp"
    android:layout_weight="1"
    android:gravity="center"
    android:orientation="horizontal"
    android:background="#FFEEEEEE">

    <TextView
        android:id="@+id/tv_check"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_centerInParent="true"
        android:text="√"
        android:textColor="#FF3300"
        android:textSize="12sp"
        android:visibility="gone"/>

    <TextView
        android:id="@+id/tv_name"
        android:layout_width="wrap_content"
        android:layout_height="match_parent"
        android:layout_marginLeft="2dp"
        android:gravity="center"
        android:text="不限"
        android:textColor="#FF666666"
        android:textSize="12sp" />
</LinearLayout>

这样便可以用 HashMap 实现多选。