<?xml version="1.0" encoding="utf-8"?>

 <LinearLayout 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"

     android:orientation="vertical">

     <TextView

         android:layout_width="wrap_content"

         android:layout_height="wrap_content"

         android:id="@+id/wordTextView"

         android:text="word"

         android:textSize="26dp"

         android:layout_gravity="center"/>

     <ListView

         android:layout_width="match_parent"

         android:layout_height="match_parent"

         android:id="@+id/definitions_ListView">

     </ListView>

 </LinearLayout>

 package com.chenye.dictionarychange;

 import android.support.v7.app.AppCompatActivity;

 import android.os.Bundle;

 import android.view.View;

 import android.widget.AdapterView;

 import android.widget.ArrayAdapter;

 import android.widget.ListView;

 import android.widget.TextView;

 import android.widget.Toast;

 import org.w3c.dom.Text;

 import java.util.ArrayList;

 import java.util.Collection;

 import java.util.Collections;

 import java.util.HashMap;

 import java.util.Scanner;

 public class MainActivity extends AppCompatActivity {

     private HashMap<String, String> dictionary;  // 存放单词-单词含义的字典

     private ArrayList<String> chosenWords; // 将所有单词存放到chosenwords

     private String word;   //单词

     private ArrayList<String> definations; // 含义列表

     private ArrayAdapter<String> adapter;

     @Override

     protected void onCreate(Bundle savedInstanceState) {

         super.onCreate(savedInstanceState);

         setContentView(R.layout.activity_main);

         readAllDefination();

         this.chosenWords = new ArrayList<>(this.dictionary.keySet());  // 获取到所有单词并存在在ArrayList中

         this.definations = new ArrayList<>();

         this.adapter = new ArrayAdapter<>(this, android.R.layout.simple_list_item_1, this.definations);  // 初始化ArrayAdapter

         // 随机选择5个单词含义

         pick4Definations();

         // 将列表添加到adapter中

         ListView defnListView = findViewById(R.id.definitions_ListView);

         defnListView.setAdapter(this.adapter);

         // 监听这个列表， 用到了匿名内部类

         defnListView.setOnItemClickListener(new AdapterView.OnItemClickListener() {

             @Override

             public void onItemClick(AdapterView<?> adapterView, View view, int i, long l) {

                 ListView defnListView = findViewById(R.id.definitions_ListView);

                 String chooseDefnText = defnListView.getItemAtPosition(i).toString();  // 获取点击位置的字符串， i是list的位置, 大部分情况下i和l（list的第几行）是一样的

                 String correctDefn = MainActivity.this.dictionary.get(word);   // 获取对应单词的解释

                 // 如果选择和正确结果一致，则：

                 if(correctDefn.equals(chooseDefnText)){

                     Toast.makeText(MainActivity.this, "Correct", Toast.LENGTH_SHORT).show();

                 }else{

                     Toast.makeText(MainActivity.this, "Wrong", Toast.LENGTH_SHORT).show();

                 }

                 // 选择之后在重新刷新一次列表,即再次挑选一个单词和5个单词的含义

                 pick4Definations();

             }

         });

     }

     public void pick4Definations(){

         Collections.shuffle(this.chosenWords);  // 打乱单词的存放位置

         this.word = this.chosenWords.get(0);  // 获取存放单词的list中的第一个单词

         TextView wordText = findViewById(R.id.wordTextView);

         wordText.setText(this.word);  // 显示单词

         this.definations.clear();  // 防止结果有脏数据，清空一下单词含义的list

         for(int i = 0; i < 4; i++){

             String defn = this.dictionary.get(this.chosenWords.get(i));  // 获取到单词对应的意思

             this.definations.add(defn);

         }

         Collections.shuffle(this.definations);  // 打乱结果

         this.adapter.notifyDataSetChanged();  // 通知adpter改变

     }

     // 将所有单词及其含义放在dictionary这个字典中

     private void readAllDefination(){

         Scanner scanner = new Scanner(getResources().openRawResource(R.raw.gre_words));

         if(this.dictionary == null){

             this.dictionary = new HashMap<>();

         }

         while (scanner.hasNext()){

             String line = scanner.nextLine();

             String[] spiece = line.split("\t");

             this.dictionary.put(spiece[0], spiece[1]);

         }

     }

 }